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Transcript of 10121-4504-01-RT-Literature_Survey_Background_Studies-08-13-14
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RPSEA
LITERATURE SURVEY AND BACKGROUND STUDIES REPORT
(TASK V)
Document Number: 10121.4504.01.01
Intelligent Casing-Intelligent Formation Telemetry (ICIFT) System
Contract Number: 10121-4504-01
July 15, 2014
Harold L. Stalford Professor (PI) The University of Oklahoma
865 Asp Avenue Norman, OK 73019
Authored By
Harold L. Stalford Professor (PI) Ramadan M. Ahmed, Assistant Professor (Co-PI)
Jason Edwards, Research Assistant Victor H. Soriano, Research Assistant
Michael Nash, Research Assistant
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LEGAL NOTICE
This report was prepared by The University of Oklahoma as an account of work sponsored by the Research Partnership to Secure Energy for America, RPSEA. Neither RPSEA members of RPSEA, the National Energy Technology Laboratory, the U.S. Department of Energy, nor any person acting on behalf of any of the entities:
a. MAKES ANY WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED WITH RESPECT TO ACCURACY, COMPLETENESS, OR USEFULNESS OF THE INFORMATION CONTAINED IN THIS DOCUMENT, OR THAT THE USE OF ANY INFORMATION, APPARATUS, METHOD, OR PROCESS DISCLOSED IN THIS DOCUMENT MAY NOT INFRINGE PRIVATELY OWNED RIGHTS, OR
b. ASSUMES ANY LIABILITY WITH RESPECT TO THE USE OF, OR FOR ANY AND ALL
DAMAGES RESULTING FROM THE USE OF, ANY INFORMATION, APPARATUS, METHOD, OR PROCESS DISCLOSED IN THIS DOCUMENT.
THIS IS AN INTERIM REPORT. THEREFORE, ANY DATA, CALCULATIONS, OR CONCLUSIONS REPORTED HEREIN SHOULD BE TREATED AS PRELIMINARY. REFERENCE TO TRADE NAMES OR SPECIFIC COMMERCIAL PRODUCTS, COMMODITIES, OR SERVICES IN THIS REPORT DOES NOT REPRESENT OR CONSTIITUTE AND ENDORSEMENT, RECOMMENDATION, OR FAVORING BY RPSEA OR ITS CONTRACTORS OF THE SPECIFIC COMMERCIAL PRODUCT, COMMODITY, OR SERVICE.
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ABSTRACT
Downhole measurement and telemetry systems are reviewed with respect to their measurement
techniques and data transmission mechanisms under downhole conditions. The review covers, in
particular, the systems that relate to instrumented casing and borehole telemetry. The 1978 U.S. patent
issued to the Exxon Production Research Company on its cement monitoring method is part of the
review of the historical development of instrumented casing. The methods of borehole telemetry (e.g.,
wireline, electromagnetic, wired drill pipe, acoustic) are reviewed as well as their capabilities and
reliability. RF signal transmission in rock formations is reviewed.
A review of intelligent systems is presented from which eight fundamental principles and characteristics
are identified as drivers in the development of intelligent systems for downhole applications in oil and
gas fields. They are suitable for providing guidance in the development of intelligent casing‐intelligent
formation telemetry (ICIFT) systems that are deployed in the casing, on the external surface of the
casing, external to the casing and/or in the formation.
The review of sensor technologies includes those that are applicable to producing wells. The review
covers, in particular, sensor technologies that provide measurements of temperature, pressure and
flow. The review of real‐time distributive sensing capabilities of fiber optic sensors covers temperature
(DTS), pressure (DPS), strain (DSS), chemical (DCS) and acoustic (DAS)‐based measurements. Fiber optic‐
based distributive sensors are strong candidates in the development of ICIFT systems.
The technology of Radio Frequency Identification (RFID) is explored for its capability to make
measurements and transmit data. In particular, the sensing and telemetry technologies of Surface
Acoustic Wave (SAW) RFID are reviewed. The microelectromechanical systems (MEMS)‐based
technology of SAW RFID sensing is found to be very attractive for ICIFT systems in downhole applications
because of it has the ability to communicate and act as sensors with no onboard power source (i.e.
passive), drawing all operating power directly from an interrogating signal. The power supply options
for SAW RFID based ICIFT system are assessed. The SAW RFID technology offers the potential for
wireless permanent, downhole, behind‐the‐casing sensing and telemetry networks with its wireless
passive sensors embedded in cement, fluids, and rock formations outside the casing. SAW RFID
technology based on piezoelectric materials has the robust nature of withstanding high temperature
and high pressure environments. As discrete sensors, SAW RFID‐based sensors are candidates in the
development of ICIFT systems that are deployed in the casing, on the external surface of the casing,
external to the casing and/or in the formation.
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Signature
________
H
e and Date P
____________
arold L. Stalfo
Page
___________
ord (Signatur
___
e)
____
July 15, 2
___________
Date
2014
___
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THIS PAGE INTENTIONALLY LEFT BLANK
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Table of Contents
ABSTRACT .......................................................................................................................................................... 3
TABLE OF CONTENTS .......................................................................................................................................... 6
LIST OF FIGURES ................................................................................................................................................. 8
LIST OF TABLES ................................................................................................................................................... 9
1. INTRODUCTION AND EXECUTIVE SUMMARY ............................................................................................. 10
2. INTELLIGENT SYSTEMS .............................................................................................................................. 13
2.1 CONCEPT OF INTELLIGENT SYSTEM ...................................................................................................................... 13 2.2 RECENT APPLICATIONS OF INTELLIGENT SYSTEMS .................................................................................................. 17
2.2.1 Predicting Production Behavior ..................................................................................................... 17 2.2.2 Maximize Oil Production and Improved Operations ..................................................................... 18 2.2.3 Intelligent Chemical Tracers .......................................................................................................... 19 2.2.4 Intelligent Software and Remote Advisory Services ...................................................................... 20 2.2.5 Control and Diagnostics in Advanced Completions ....................................................................... 20 2.2.6 Optimize Waterflood ..................................................................................................................... 22
2.3 SUMMARY ‐ CHAPTER ON INTELLIGENT SYSTEMS ................................................................................................... 22 2.4 REFERENCES ‐ CHAPTER ON INTELLIGENT SYSTEMS ................................................................................................. 22
3. FIBER OPTIC SENSORS AND REAL‐TIME, DISTRIBUTED SENSING ................................................................. 27
3.1 EARLY HISTORY OF FIBER OPTIC SENSING ............................................................................................................. 27 3.2 FIBER OPTIC DISTRIBUTED TEMPERATURE SYSTEM (DTS) SENSING ........................................................................... 28 3.3 FIBER OPTIC DISTRIBUTED SENSING: DTS, DPS, DSS, DAS, AND DCS ..................................................................... 31 3.4 FIBER OPTIC DISTRIBUTED SENSING PRODUCTS ..................................................................................................... 32 3.5 U. S. PATENTS ON FIBER OPTIC SENSING TECHNOLOGY .......................................................................................... 34 3.6 REFERENCES ‐ CHAPTER ON FIBER OPTIC SENSING ................................................................................................. 34
4. INSTRUMENTED CASING ........................................................................................................................... 39
4.1 BRIEF HISTORY ‐ INSTRUMENTED CASING ............................................................................................................. 39 4.2 U. S. PATENTS ‐ INSTRUMENTED CASING ............................................................................................................. 40 4.3 REFERENCES ‐ CHAPTER ON INSTRUMENTED CASING .............................................................................................. 46
5. BOREHOLE TELEMETRY ............................................................................................................................. 48
5.1 WELL LOGGING METHODS ................................................................................................................................ 48 5.2 WIRELINE TELEMETRY ...................................................................................................................................... 48 5.3 RF SIGNAL TRANSMISSION IN ROCK FORMATIONS ................................................................................................. 48 5.4 ELECTROMAGNETIC TELEMETRY ......................................................................................................................... 49 5.5 WIRED DRILL PIPE TELEMETRY ........................................................................................................................... 50 5.6 ACOUSTIC METHODS ....................................................................................................................................... 51 5.7 MUD PRESSURE PULSES ................................................................................................................................... 52 5.8 REFERENCES – CHAPTER ON BOREHOLE TELEMETRY ............................................................................................... 52
6. BOREHOLE TELEMETRY – CAPABILITIES AND RELIABILITY .......................................................................... 54
6.1 HARDWIRED TELEMETRY .................................................................................................................................. 54 6.2 ELECTROMAGNETIC TELEMETRY ......................................................................................................................... 55 6.3 ACOUSTIC METHODS ....................................................................................................................................... 55
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6.4 MUD PULSE TELEMETRY ................................................................................................................................... 56 6.5 TELEMETRY DATA RATES .................................................................................................................................. 57 6.6 REFERENCES ‐ CHAPTER ON BOREHOLE TELEMETRY – CAPABILITIES AND RELIABILITY .................................................... 58
7. SENSOR TECHNOLOGIES APPLICABLE TO PRODUCING WELLS .................................................................... 59
7.1 SENSOR TECHNOLOGIES.................................................................................................................................... 59 7.2 SENSOR SELECTION .......................................................................................................................................... 59 7.3 BASIC SENSING TECHNOLOGIES .......................................................................................................................... 60
7.3.1 Temperature .................................................................................................................................. 60 7.3.1.1 Thermocouples .............................................................................................................................. 60 7.3.1.2 Resistance Temperature Detectors (RTDs), Thermistors ............................................................... 60 7.3.1.3 Distributed Temperature System (“DTS”, Fiber Optic) .................................................................. 61
7.3.2 Pressure ......................................................................................................................................... 62 7.3.2.1 Piezoelectric Strain Gauges ........................................................................................................... 62 7.3.2.2 Piezoresistive Strain Gauges .......................................................................................................... 62 7.3.2.3 Capacitive Measurement .............................................................................................................. 63 7.3.2.4 Electromagnetic ............................................................................................................................ 64 7.3.2.5 Potentiometric .............................................................................................................................. 64 7.3.2.6 Resonant ....................................................................................................................................... 64 7.3.2.7 Optical ........................................................................................................................................... 65
7.4 REAL‐TIME, DISTRIBUTED INSTRUMENTATION TECHNIQUES .................................................................................... 66 7.4.1 Instrumentation Techniques .......................................................................................................... 66
7.4.1.1 Distributed Temperature Sensing, DTS (Schlumberger) ................................................................ 66 7.4.1.2 WellWatcher Sapphire Gauge (Schlumberger) .............................................................................. 66
7.5 BRIEF SUMMARY OF SENSOR TECHNOLOGIES ........................................................................................................ 66
8. RFID SENSOR TECHNOLOGY, BOREHOLE TELEMETRY APPLICATIONS .......................................................... 68
8.1 INDUCTIVE COUPLING RFID .............................................................................................................................. 68 8.1.1 Signal Modulation ......................................................................................................................... 70 8.1.2 Active Tags .................................................................................................................................... 71
8.2 SAW RFID .................................................................................................................................................... 71 8.2.1 A Brief History of SAW Devices ...................................................................................................... 71 8.2.2 Principles of Operation .................................................................................................................. 71
8.2.2.1 Reflective Delay Lines .................................................................................................................... 72 8.2.2.2 Resonators ..................................................................................................................................... 73 8.2.2.3 Antenna and Power ....................................................................................................................... 73 8.2.2.4 SAW Sensors .................................................................................................................................. 74
8.3 REFERENCES – CHAPTER ON RFID SENSOR TECHNOLOGY, BOREHOLE TELEMETRY APPLICATIONS ................................... 78
APPENDIX A: SUMMARY OF COLLECTED U. S. PATENTS ON FIBER OPTIC SENSORS ............................................. 80
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List of Figures
Figure 6.1: Erratic ECD measurements are shown clearly when using wired‐pipe telemetry ................... 55
Figure 6.2: Comparison of the final synchronized data for the first pressure buildup of memory gauge
7763 and ATS140. A log‐log plot of the first pressure buildup for both gauges ........................................ 56
Figure 7.3.1: Resistance Temperature Detector scheme (Wikipedia, 2012b) ........................................... 61
Figure 7.3.2: Piezoelectric Strain Gauge scheme (Ashauer and Konrad 2002) ........................................... 62
Figure 7.3.3: Piezoresistive Pressure Sensor (Ashauer and Konrad 2002) ................................................ 63
Figure 7.3.4: Capacitive Pressure Sensor (USGS, 2012) ............................................................................. 63
Figure 7.3.5: Electromagnetic (Inductive) Pressure Sensor (USGS, 2012) ................................................. 64
Figure 7.3.6: Resonant Pressure Sensor (OG&E,1997) ............................................................................... 65
Figure 7.3.7: Optical Pressure Sensor (Wikipedia, 2012a) ......................................................................... 65
Figure 8.1: B‐Field Produced by Current Coil (Lee 1998) ............................................................................ 69
Figure 8.2: Operation of a SAW Tag System(Plessky and Reindl, 2010) ..................................................... 72
Figure 8.3: SAW RDL(Kalinin 2004) ............................................................................................................. 72
Figure 8.4: Schematic of SAW Resonator(Kalinin 2005) ............................................................................. 73
Figure 8.5: Variation of the continuous phase difference φ3 1 between the first and third response as
a function of temperature (Reindl et al. 2003) ........................................................................................... 74
Figure 8.6: SAW Substrate with Pressure‐Isolated Cavity .......................................................................... 74
Figure 8.7: Time‐delay response of SAW Pressure Sensor ......................................................................... 75
Figure 8.8: Frequency Response of SAW Pressure Sensor ......................................................................... 75
Figure 8.9: Schematic of SAW Measuring Pressure Driven Laminar Flow .................................................. 76
Figure 8.10: SAW Sensor Response to Changing Flow Rate ....................................................................... 76
Figure 8.11: SAW Communication Diagram from (Brocato et al. 2007) ..................................................... 77
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List of Tables
Table 3.1 Comparison of Different DTS Technologies ................................................................................ 28
Table 7.1: Pressure Sensor Summary ......................................................................................................... 66
Table 7.2: Temperature Sensor Summary .................................................................................................. 66
Table 7.3: Flow Sensor Summary ................................................................................................................ 67
Table 8.1: SAW Detection Range and Power .............................................................................................. 73
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1. Introduction and Executive Summary
This report is aimed to describe some key technologies that might be used in designing an intelligent
casing‐intelligent formation telemetry (ICIFT) system, and identify the state‐of‐the‐art in those
technologies. Traditional downhole telemetry methods are included such as Mud Pulse Telemetry,
Electromagnetic (EM) Telemetry, Acoustic Telemetry, and Wired Pipe Telemetry; traditional sensing
technologies reviewed include MWD sensing elements and Instrumented Casing. Real‐time distributed
sensing provided by fiber optic sensors are included in the review. Furthermore, we explore two
technologies that have seen limited use for downhole sensing and telemetry; these are Inductive
Coupling Radio Frequency Identification (RFID) and Surface Acoustic Wave (SAW) RFID. These
technologies are attractive because of their ability to communicate and act as sensors with no onboard
power source (i.e. passive), drawing all operating power directly from an interrogating signal. This offers
the potential for a permanent, downhole, behind‐the‐casing wireless distributed sensing network. In
addition, the SAW RFID, due to its robust nature, can withstand high temperatures and high pressures
(HTHP) that exceed the specifications usually required of downhole tools; this suggests its suitability for
HTHP and geothermal wells.
The principal objective of the literature survey and background studies (Task 5) is to provide the
necessary information to assess borehole telemetry system components (Task 6), which are needed to
develop the Intelligent Casing‐Intelligent Formation Telemetry (ICIFT) System. This task also provides
vital information to design and develop RFID sensor and transceiver prototypes (Task 7). During the
survey, focus was given to the measurement techniques and data transmission mechanisms under
downhole conditions. Borehole telemetry systems are addressed in Chapters 4‐9.
Intelligent systems and the concept of an intelligent system are addressed in Chapter 2. Eight
fundamental principles and characteristics P1‐P8 were identified as the drivers in the development of
intelligent systems for downhole applications in oil and gas fields:
(P1) Provide permanent downhole components that are operable over the life of a well
(P2) Permit wells and fields to be remotely monitored and controlled from surface
(P3) Reduce or eliminate physical interventions, mitigate risk, allow proactive and/or reactive
management
(P4) Provide real‐time data (e.g., temperature, pressure, fluid flow, phase composition)
(P5) Enable selective zonal isolation, independent modulation and multi‐zone/field‐wide
deployments
(P6) Optimize production and increase ultimate reservoir recovery
(P7) Accelerate cash flow, reduce overall costs and maximize net present value (NPV)
(P8) Provide well integrity monitoring; improve health, safety and environmental (HSE) issues
In the overall project, the fundamental principles and characteristics P1‐P8 provide guidance in the
development of intelligent casing‐intelligent formation telemetry (ICIFT) systems that are deployed in
the casing, on the external surface of the casing, external to the casing and/or in the formation.
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Real‐time distributed sensing provided by fiber optic sensors are reviewed in Chapter 3. Fiber optic
sensor technologies offer a wide range of subsurface measurements that includes distributed
temperature sensing (DTS), distributed strain sensing (DSS), distributed pressure sensing (DPS),
distributed acoustic sensing (DAS), and distributed chemical sensing (DCS). A number of these are found
to be in practice and/or under development for deployment outside the casing, particularly for on‐shore
applications.
Historical Development of Instrumented Casing and Borehole Telemetry: Instrumented casing was
introduced into the Industry in 1983 in order to explain events related to poor cementing jobs. Since
then, a number of efforts have been made to obtain real‐time information from downhole, which is
presented in different patents (Chapters 4 and 5). Currently, there is not a standard procedure in the oil
industry that could provide an integrated telemetry system using casing strings.
Investigations on Borehole Telemetric Measurements, Capabilities and Reliability: Wireline telemetry
provides high quality information from formations (Chapter 6), but not in real drilling time. The industry
is moving towards using different telemetry techniques (wire‐pipe, acoustic and repeater‐less EM
telemetry), which provide the same high quality data without going into the risks associated with
wireline. However, there is not recognized system that can provide the same technical/economical
advantage compared to wire line system.
The intelligent pipe (wired drill pipe telemetry) provides high quality, high‐speed data transmission,
even though; it is not applicable to the majority of the drilling operations because of extremely high
initial cost. On the other hand, several attempts have been made to develop a reliable acoustic
telemetry technology as an alternative to mud pulse telemetry in drilling application. However, most of
them were abandoned due to problems related acoustic transmission such as requirement of several
repeaters and the effect of drillstring noise. In 2006, a new Acoustic Telemetry system (ATS) was
developed and showed good match with downhole sensor measurements during drill stem testing (DST)
operations.
Repeater‐less EM telemetry is a reliable means of transmission only in depths shallower than 9,000 feet,
although, there have been some exceptions where it has been achieved to depths greater than 15,000
feet.
Mud pulse telemetry is the most widely used technology worldwide almost in any drilled hole. Today,
mud pulse tools in the industry are capable of transmitting close to 15 bits per second of data from
downhole to surface using high‐speed measurement while drilling tools.
Assessment of Instrumentation Techniques: Instrumentation techniques that have the potential to
provide distributed real‐time pressure, temperature, and flow measurements must require a low power‐
to‐measurement point ratio (Chapter 7). Passive sensors are ideal, but none are on the market today.
Based on the investigation of temperature and pressure transducers, a resonant technology, such as the
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synthetic sapphire pressure sensors in use by Schlumberger, with the low power to measurement point
ratio of the distributed temperature (DTS) sensors would be ideal.
Integrated RFID Sensor Technology and Its Application in Borehole Telemetry: SAW RFID sensing
technology has been investigated. SAW RFID has been shown to be capable of measuring temperature
and pressure reliably and transmitting that data wirelessly from the sensor to a receiver (Chapter 8).
Flow measurements using SAW RFID are possible given a priori knowledge of the environment. Finally,
impedance varying sensor provide a method of measuring a wide range of physical parameters, and
have been shown to work with SAW RFID even at high impedances.
RFID Power Supply: RFID technology is divided into two categories, IC and SAW based techniques. SAW
based RFID technology has been shown to operate at greater distances than IC based RFID with
significantly reduced power consumption (Chapter 8). Furthermore, the rugged nature of SAW based
RFID makes it well suited to surviving harsh borehole environments. In addition, the ability of a SAW
based RIFD to create a permanent wireless passive distributed sensing network makes it an ideal
candidate for an ICIFT system.
RF Signal Transmission: RF transmission through rock has been studied over the years only for very
specific purposes (Chapter 9). While it might be possible to adapt some of this analysis for us in an ICIFT
system, this would generally require major alterations. We can loosely define, however, the frequency
range of interest based on our knowledge of other downhole systems. To summarize, EM operates in
the 10Hz range at about 10,000 ft. while borehole radar in the 100 MHz range at about 100 ft. For
distances less than those of borehole radar, a wireless sensor system might be able to operate in the
MHz or even GHz range. These frequency ranges will need to be tested experimentally to determine the
optimum frequency.
The data rates of various wired/wireless telemetry systems have approximate ranges as follows:
Wireline System (100‐500 Kb/s)
Wired Drill Pipe Telemetry System (50‐500 Kb/s)
Fiber Optic System (10‐100 Mb/s)
Mud Pulse Telemetry (1.5‐40 b/s)
Acoustic Telemetry (10‐30 b/s)
Electromagnetic Telemetry (10‐100 b/s)
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2. Intelligent Systems
This is a report on the project “Intelligent Casing‐Intelligent Formation Telemetry (ICIFT) System.” The
project addresses the development of intelligent systems (particularly, sensor and telemetry based
systems) that are deployed outside the casing (e.g., on the external surface of the casing, in the cement,
in the formation, in fluids external to the casing). Intelligent systems deployed inside the casing have
been in practice for over a decade. To get an idea of what comprises an intelligent system this report
starts out in Section 2.1 by reviewing the notion of “intelligent” system and its usage as applied in the oil
and gas industry. The literature review identifies seven fundamental principles and characteristics of
such intelligent systems; these are highlighted at the end of Section 2.1. Some recent applications of
intelligent systems are given as examples in Section 2.2.
2.1 Concept of Intelligent System
The first intelligent completion was installed in August 1997 at Saga Snorre Tension Leg Platform in the
North Sea (Norway). The system installed was WellDynamics’ SCRAMS (Surface Controlled Reservoir
Analysis and Management System) used to control the Infinitely Variable Interval Control Valve
(IV‐ICV™) hydraulically with hydraulic force provided from the hydraulic control lines from surface,
Bærheim (2009). The literature 1998‐2013 is reviewed for its insight into the use of the concept
“intelligent” system within the oil and gas industry.
Jalali et al. (1998) reports on an Intelligent Completion Systems (ICS) that integrates reservoir sensors
and remotely controllable inflow/outflow devices deployed permanently in the wellbore and points out
that deployment of ICS architectures of minimal complexity has a pronounced effect on production
performance.
Robinson (2003) refers to Intelligent Completions as the implementation of remotely monitored and
controlled well completions having benefits that include increase recovery, production acceleration and
savings from reduced well intervention. Furthermore, Intelligent Completions are capable of collecting,
transmitting, and analyzing wellbore production, reservoir, and completion‐integrity data, enabling
remote action to enhance reservoir control and well production performance. A production‐
engineering association steering group developed a standard communications protocol for downhole
monitoring and control equipment and called it Intelligent Well Instrumentation Standard (IWIS).
Al‐Asimi (2003) documents the use of real‐time measurements from permanent‐monitoring sensors that
identify, diagnose and act to mitigate production problems, improve the accuracy of production
allocation and greatly reduce or eliminate intervention costs to acquire such data. Angel (2003)
emphasizes that advanced intelligent well (IW) system technology has the potential to enhance
reservoir characterization and real‐time production management due to reduction of workover and
intervention costs, elimination of deferred production, acceleration of cash flow and incremental
recoverables from producing assets. Vachon (2004) describes Baker Oil Tools success with all‐electric
intelligent well system in a subsea deepwater application and installation of hydraulic choking valves.
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Baker Hughes’ Intelligent Well Systems (IWS), Intelligent Production Systems (IPS) and successes in using
them are described on its website.
Glandt (2003 and 2005) remarks that a well equipped with intelligent components is considered “smart”
only when it maximizes the well’s value over the life of the project and that smart completions are
deigned to add significant value in doing the following.
Monitoring well operating conditions downhole, e.g., flow, pressure, temperature, phase composition, and water (pH).
Image the distribution of reservoir attributes away from the well (e.g., resistivity and acoustic impedance)
Control the inflow and outflow rates of segregated segments of the well.
Potters and Kapteijn (2005) introduced the “Smart Field” concept as an approach to address recovery
optimization in asset management that utilizes advanced system engineering and optimization concepts.
It is an approach that focuses on detecting and monitoring subsurface changes (e.g., reservoir
surveillance, reservoir monitoring). It is an approach that covers workflow process integration,
encapsulation of knowledge in a shared earth model, advanced 3D visualization, increasing detail in
reservoir models, and remotely controlled operation centers. It is emphasized that individual activities
do not necessarily add value unless they are effectively connected and integrated in closed loop. That is,
traditional data from reservoir surveillance (e.g., well testing, wireline logging, downhole sampling) must
be integrated with all new data sources (e.g., distributed temperature sensing, geo‐mechanical stress
sensing, surface or downhole tilt and displacement behavior, 4D seismic) in order to monitor the
dynamic state of the reservoir with increasing accuracy on a smaller scale and optimize asset recovery.
Glandt (2005) describes a Smart Well or an Intelligent Completion System well as a well equipped with
permanent downhole measurement equipment/control valves that is capable of collecting transmitting
and analyzing completion, production and reservoir data and allowing selective zonal control to
optimize the production process, without physical intervention, and optimize reservoir recovery.
Esmaiel (2005) emphasizes that Smart well technology has incorporated downhole measurement and
control of oil, water and gas flow rates. Going et al. (2006) defines intelligent well system as a
completion system that provides the ability to remotely monitor and control production or injection in a
multitude of zones in a single well. The system emphasizes that the subsystems, which contribute to the
intelligence must become more aware of each other to begin to implement closed loop control in order
that the greatest value is achieved from the intelligent well system.
Gao et al. (2007) notes that wells equipped with permanent downhole measurement equipment and/or
control values are known as smart wells or intelligent completions and points out that: (a) smart well
technology enables operators to actively monitor, remotely choke or shut selected zones with poor
performance without intervention; (b) intelligent well technology provides the means to manipulate
downhole valves and acquire data required for produced fluids estimation and allocation to individual
zones; (c) intelligent well completions assist in reservoir management and production accounting; and
(d) permanent monitoring systems must function for the life of a smart well. Lacy et al. (2007) describes
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the first occasion worldwide that a subsea well had been completed with expandable sand screens and
intelligent completion systems, a forward leap in subsea well technology. The work describes how three
control lines from surface can independently control up to four downhole remotely operated sliding
sleeves.
In an overview of smart well technology, Omair 2007, documented some definitions of intelligent well
technology in use by Schlumberger, WellDynamics (Halliburton), Baker Hughes and the Intelligent Well
Reliability Group (IWRG); greater details can be found on their websites.
Schlumberger: A well equipped with monitoring equipment and completion components that can be adjusted to optimize production, either automatically or with some operator intervention. WellDynamics (Halliburton): A well that combines a series of components that collect, transmit and analyze completion, production and reservoir data, and enable selective zonal control to optimize the production process without intervention. Baker Hughes: A well with implementation of fundamental process control downhole, enabling surveillance, interpretation and actuation in a continuous feedback loop, operating at or near real‐time. Intelligent Well Reliability Group (IWRG): A well equipped with means to monitor specific parameters (e.g., fluid flow, temperature, and pressure) and controls enabling flow from all zones to be independently modulated from a remote location.
Bærheim (2009) emphasizes that smart well technology yields reduced well intervention costs as well as
improved reservoir management utilizing such elements as flow control devices; feed‐through isolation
packers; control, communication and power cables; downhole sensors; and surface data acquisition and
control. Schiozer et al. (2009) compares smart and conventional wells, pointing out that (a) smart wells
add flexibility to the operation of petroleum fields by allowing operation of valves to control production
to improve field production via sensors and valves that can be controlled independently; (b) they are
employed in projects involving different objectives, such as production control of gas and water,
production by different zones in stratified reservoirs, and margin fields; (c) they can maximize NPV (net
present value), mitigate risk, improve oil production as well as control water production, or a
combination of these objectives; and (d) the operation of smart wells can be proactive, anticipating
problems, or reactive, in general. Sun et al. (2009) describes how intelligent well systems (IWS) added
value in accelerating hydrocarbon production, managing production allocations, delaying or minimizing
water production, increasing recovery and decreasing intervention costs. Uchendu et al. (2013) reviews
the deployment of the first onshore intelligent well technology in one of the largest fields in the
Western Swamp area in Nigeria; the Halliburton Well Dynamics direct hydraulic system was used as the
pilot intelligent completion system.
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Tye (2010) addresses Intelligent Integration and Operation and Intelligent Energy. Conventional
hydrocarbon deposits are hard to find and limited in volume. Unconventional reserves, on the other
hand, are relatively easy to locate and often plentiful. The word unconventional is derived from the
unusual production processes required to develop and produce commercial viable oil and gas.
Principles of intelligent energy such as integration, operation and technology can mitigate risk and
enable integrated operations for unconventional reservoirs. The drivers to come into unconventional
assets are financial, economic and structural with an alignment of long term strategic plans and short‐
term opportunistic risk taking. In fact, the principles and concepts of intelligent energy have a clear role
to play in identifying, evaluating, integrating and operating unconventional business and asset targets.
This business with a large unconventional fuels mix is clearly a challenge, particularly one built through
acquisition.
Shaw (2011) considers Intelligent Completion as one that has instruments to understand downhole
conditions and improves flow control based on those conditions, requiring not only flow control
components but also a system and methodology to control such components. Such methodologies
include the use of hydraulic power, electric power, or combination of the two. Even though the control
of ICVs has moved towards pure hydraulic systems to reduce cost and increase reliability, improved
downhole electronics has led to an increased acceptance of some electronic equipment downhole.
Van Den Berg et al. (2012) points out that the application of smart field elements has produced
significant field development with remote controlled platform and increase field management.
Furthermore, in production and operations, the smart field has provided the development of a standard
set of software tools and processes, covering data acquisition, real time well monitoring, production
allocation and integrated modelling and production optimization. Real time monitoring of wells and
facilities has created significant business impact through faster response to trips and shutdowns and
avoidance of mishaps.
Shevchenko et al. (2012) describes how an Intelligent Field provides additional value of oil and gas asset
by forming a cycle of gathering of qualitative data, treatment, modeling, decision making and prompt
performance. Different primary transducers are used for real‐time data receiving. Supervisory control
and data acquisition (SCADA) is upgraded. Remote control and different real‐time expert and simulating
systems are used. Downhole monitoring systems (DMS) serve as the main source of information for
operation of wells equipped with ESP (Electrical submersible pump) reporting pressure and temperature
at the ESP intake, motor temperature and loading, isolation resistance, horizontal and vertical vibration,
along with a number of additional parameters that are available depending on setting and transducer
specifications.
Silva et al. (2012) discusses intelligent well technology and how remote flow control and monitoring
capabilities can lead to fewer interventions (i.e., reduced well count) and improved reservoir
management. It is emphasized that an integrated intelligent well system provides the ability to manage
the field effectively while addressing project objectives even though complexity of the downhole
completion increases after IW installation. An increasing variety of real‐time, downhole, monitoring and
measurement systems are now available for deployment with other in development. It is emphasized
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that measurement uncertainty, noise, missing data, filtering, time synchronization, limited storage
capacity and different sample rates need to be properly managed to avoid error propagation during the
data analysis and assimilation phase. Applications include post‐processing and data interpretation, data
reconciliation and assimilation in regards to reservoir management, advanced completions, well
performance, flow assurance, well stimulation and condition monitoring.
Muradov and Davies (2012, 2013) point out that the ambition of the Digital Oilfield is to provide
continuous optimization of field production by real‐time, well control and monitoring. For that purpose,
high precision permanent downhole gauges (PDGs) are usually installed that measure tubing and
annulus pressure and temperature near the intelligent completion valves (ICV). The availability of
reliable, quantitative interpretation methods need to be developed to complement the recent
innovations in the downhole temperature sensing. Such temperature sensors include discrete or
distributed, both with and without accompanying pressure measurements. The applications of such
sensing technology immediately increase the added value derived from intelligent well technology.
Based on the usage of intelligent systems represented in the literature, the fundamental principles and
characteristics of such systems include the following:
Provide permanent downhole components that are operable over the life of a well
Permit wells and fields to be remotely monitored and controlled from surface
Reduce or eliminate physical interventions, mitigate risk, allow proactive and/or reactive
management
Provide real‐time data (e.g., temperature, pressure, fluid flow, phase composition)
Enable selective zonal isolation, independent modulation and multi‐zone/field‐wide
deployments
Optimize production and increase ultimate reservoir recovery
Accelerate cash flow, reduce overall costs and maximize net present value (NPV)
Provide well integrity monitoring; improve health, safety and environmental (HSE) issues
2.2 Recent Applications of Intelligent Systems
Some recent applications of intelligent systems are described in this section. The examples selected
deal with predicting production behavior, maximizing oil production, and improving overall operations.
Intelligent chemical tracers are used to monitor cleanup efficiency. Intelligent software with its data
mining capability is shown to have added value in the development of intelligent field’s with its accurate
predictive capability after training and validation. The roles that interval control valves (ICVs) and inflow
control devices (ICDs) play in the development of intelligent wells are highlighted. Optimized waterflood
is mentioned in the development of smart workflows.
2.2.1 Predicting Production Behavior Piovesan and Kozman (2009) show that artificial intelligent algorithms can deliver results that support
decisions and improve production performance in offshore as well as in remote onshore locations. Al‐
Jasmi et al. (2013) describe how smart surveillance is used to predict the short‐term, unexpected
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production behavior by coupling statistics and artificial intelligent analysis as well as monitoring
production in real time. Temizel et al. (2013) present two indices‐Well Present Performance Index
(WPPI) and Well Future Potential Index (WFPI)‐that are determined from an algorithm that processes
data available from intelligent fields and that can be used to assist engineering judgment.
2.2.2 Maximize Oil Production and Improved Operations Loermans and Kelder (2006) introduce Borehole Gravity Measurement (BHGM) tools for applications to
Intelligent Energy projects and describe how such tools are beneficial for reservoir and production
monitoring, including advancing flood fronts identification, saturation determination and simple
interpretation models. Since BHGM has the capability of measuring even beyond a thousand feet from
a well, it provides a method for logging industry to measure deeper into the formation. BHGM tools
combined with other smart technologies will enhance Intelligent Energy projects with more complete
understanding of the reservoirs being produced, leading to maximum hydrocarbon recovery and
business value.
Anoze and Cunha (2007) introduce a method for optimizing the production in intelligent wells that
varies the wells inflow control valves settings as determined by an optimization algorithm that is
coupled to commercial flow simulators. Results are presented that show that the intelligent wells
scenarios increased the recovery factor and reduced the production and injection of water when
compared with the base case (conventional completion). A significant increase of the expected
cumulative oil production is realized. In intelligent completions, the ability to control multiple
production zones is determined by downhole inflow control valves (ICVs) and inflow control devices
(ICDs). Such devices may be binary (on‐off behavior), or multi‐position, choking the production zone
with a discrete number of positions, or infinity variable positions. Intelligent completions technology
when combined with an optimization algorithm provides significant benefits for multiple‐zone producing
wells.
Van der Linden et al. (2010) presents computational power modeling that adds quantitative
“intelligence” to monitoring functions involving physical knowledge and that supplements an operator’s
insight into the performance of such processes. The modeling is used to compute key performance
indicators and to detect unexpected deviations from the expected. In an advanced production and
reservoir management level, such computational power modeling helps in the solutions of severe
production problems and early event detections as well as the optimization of production and the
support to operators and engineers in their daily work.
Cullick and Sukkestad (2010) investigate smart‐field strategies with intelligent completions using Interval
control valves (ICVs) and interval control devices (ICDs). They implement and validate a methodology to
optimize valve‐control strategies and maximize oil production. A numerical flow simulator is used to
evaluate inflow and upflow performance as affected by interval control values (ICV), to assess the long‐
term installation of ICV and manage the risk of using ICVs. Examples are presented evaluating the
provable long‐term value in terms of ultimate recovery, the impact on long‐term value and well
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performance from valve failure, and the impact of reservoir uncertainty on long‐term value in terms of
predicted ultimate recovery and more effective operations practices.
Obarwinker et al. (2013) investigate supervisory control and data acquisition (SCADA) system that
connects to the production facilities’ controllers and data sources and that collects measured data and
stores them in a data base for production well information. A method is presented that integrates high‐
frequency data for management and appropriate date visualization and tools so that operators on the
platform, engineers and management have exactly the same view of the data at the same time. Getting
the high‐frequency data in time and in the appropriate format allows engineers to make advance use of
such real‐time data in their daily work. It has the potential to change the way operators work together
with engineers and to substantially improve operations.
Mateeva et al. (2014) investigate permanently buried seismic sources and receivers, refraction seismic,
down‐hole seismic, and the newly developed distributed acoustic sensing (DAS) to enable low‐cost and
non‐intrusive seismic surveillance. Seismic monitoring is particularly attractive for its ability to sense a
large volume of the subsurface, illuminating it between and away from existing wells. DAS allows non‐
intrusive Vertical Seismic Profiling (VSP) measurements in almost any well outfitted with a fiber‐optic
cable (economical up‐scaling of downhole seismic). They show that the increased use of such well and
reservoir surveillance data in intelligent well systems provide technological advances in the area of data
acquisition and integration, leading to improved and optimized Enhanced Oil Recovery (EOR). Such data
are instrumental in monitoring reservoir changes induced by well treatments.
2.2.3 Intelligent Chemical Tracers Williams and Vilela (2012) addresses the high cost and risks of acquiring surveillance information using
conventional technology, such as production logging tools that are forcing operators to forgo acquisition
of fluid inflow distribution information and manage fields with a blurred understanding of the reservoir.
Without surveillance data, a reservoir engineer cannot be sure if completion equipment is performing as
intended, if both laterals are contributing as expected or which portions of the lateral are contributing at
what levels, and where water break‐through has occurred in the well. Intelligent chemical tracers
consist of smart plastic and unique chemical compounds that are combined into a matrix that resembles
strips of plastic which are sensitive to either oil or water. They emphasize that such tracers are
economical, easy to deploy and have none of the negative effects of radioactive isotope‐based
surveillance techniques. Williams and Nyhavn (2012) describes how intelligent chemical tracers provide
insight into inflow distribution without intervention operations or major alterations to completion
designs. The tracer system are referred to as “intelligent” because the tracer material is designed to
only release their unique chemical compound when it comes in contact with the target fluid. Unique
chemical tracers are deployed at strategic locations in the completion so that fluids entering the
completion contact the tracers and a unique chemical fingerprint is observed and identified. Intelligent
tracer technology can be deployed in a variety of forms and methods that have a very minor impact on
completion design and effectively no additional risk to the overall success of the well.
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Abay et al. (2013) reported on the successful use of intelligent chemical tracers to monitor cleanup
efficiency, downhole completion functionality and inflow surveillance from the deepest sections of long
horizontal multilateral wells. The chemical tracers supported the diagnosis of completion functionality
and provided another measurement for understanding well performance during the cleanup and restart
phases. The intelligent chemical tracers successfully gave clear indications of cleanup efficiency and
verified inflow from the deepest toe‐sections, a key to determining well productivity and optimal well
lengths for future wells.
2.2.4 Intelligent Software and Remote Advisory Services Davies et al. (2007) shows that data mining adds value to intelligent field’s development with its
accurate predictive capability after training and validation. A hybrid system based on genetic algorithms
is developed for optimizing valve control in intelligent well systems under technical and geological
uncertainties and is shown to provide decision making support, Almeida et al. (2010).
Saeverhagen et al. (2013) investigate operation key performance indicators (KPI) and introduce
intelligent software for calculating and benchmarking KPIs. The KPI analytical approach is shown to
promote a high focus level on continuous improvement. Operational improvements result from
increased operational focus and utilization of remote services, including remote advisory, KPI Service,
monitoring, benchmarking, reporting and advice to operations. POT or “flat time” on the drilling curve
can be significantly reduced by critically analyzing certain work tasks at the rig site, combined with
remote services. In combination with remote advisory services, the KPI analytical approach provides a
powerful solution to improve overall operational performance. Remote centers operating 24/7 provides
an excellent environment for immersive training of engineering and field personnel with low risk to
ongoing operations. The KPI analytical approach in combination with senior subject matter experts
placed in remote centers help provide critical advice for support of complex well construction
operations. Remote advisory services enhance the overall drilling progress, reducing human judgment as
a result.
2.2.5 Control and Diagnostics in Advanced Completions Patricio et al. (1997) developed two kinds of neutral nets specialized on control, diagnostics, and process
optimization in the development of an intelligent system for oil production.
Konopcznski et al. (2002) investigate improving ultimate hydrocarbon recovery through more efficient
operation of downhole electrical submersible pumps (ESPs) in conjunction with intelligent well
completions. They considered an intelligent well completion system as one capable of collecting,
transmitting and analyzing completion, production, and reservoir data, and taking action to better
control well and production processes. They looked at the value coming from intelligent well
completions that provides the capability to restrict or exclude production from specific zones
experiencing water or gas breakthrough permitting.
Hembling et al. (2006) developed a device for zonal isolation and compartmentalization of the reservoir
to be used in intelligent well systems with multi‐laterals. The new isolation device simplifies zonal
isolation compared with conventional methods such as cementing of the mother‐bore and/or the use of
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complex mechanical systems and packers. The new device uses a rubber elastomer bonded onto a base
pipe called swell packer. The rubber swells in hydrocarbon and provides an effective seal down hole
between a base pipe and an open hole. The system saves time and money in the completions and
allows for larger ICV’s to be run. Laboratory test verified swelling and sealing of swell packer for the
range of crude samples provided by this application. The technology was successfully demonstrated in
field applications.
Olowoleru et al. (2009) presented their work of advanced completions that employed interval control
valves (ICVs) and inflow control devices (ICDs) and reported on how they improved the well cleanup
process. For a long, horizontal well, such advanced completions are shown to have greater cleanup
efficiency over that achieved by conventional, open hole completion methods.
Peringod et al. (2011) developed a downhole pressure gauge system installed on top of the packer that
assists in fine‐tuning choke settings during auto gas lifting. The system uses high pressure gas from a gas
reservoir admitted into the tubing using an intelligent completion and special intelligent completion
valves (ICV) with gas trim and straddle packers. The system is shown to boost production significantly in
the field as well as improving operational performance. The system has applications in auto gas lift
scenarios where gas recycling is the strategy for reservoir pressure maintenance. This includes scenarios
where gas lift is determined to be the most viable artificial lift mode for wells that have the volatile
nature of crude and high gas oil ratio (GOR).
Chris et al. (2011) reported on the integration of conventional surface‐controllable downhole zonal flow
control valves with data surveillance gauges, intelligent sensors and isolation packers, all in one single
completion joint. The new system reduced installation time substantially in comparison to conventional
intelligent completion installations. The system was successfully implemented to complicated highly‐
dipping, multi‐layered sandstone reservoir with commingled production. The application included two
of the fourteen horizontal producer wells for which the modular integrated intelligent completion
system (IICS) was used to actively control and permanently monitor zonal inflow for optimal production.
Al‐Mohanna et al. (2013) addresses the use of Intelligent Completions to prevent cross flow between
laterals and choke back laterals with high water or gas inflow basically by balancing the drawdown and
rates from each lateral. They emphasize how intelligent completions provide isolation, selective flow
control or water shut off for each lateral, real time annulus and tubing P & T monitoring for each lateral,
pressure build‐up, interference testing between laterals, real time position sensor to confirm choke
position, production optimization for each lateral, faster operation time due to fewer position,
enhanced reserve recovery, extended well life, reduced future intervention, and minimal production
interruption. Inflow control devices (ICD) were installed along the horizontal laterals to equalize the
production along the wellbore and prevent water conning at the heel for the case that the well is close
to the aquifer. The system was run on 3‐1/2” tubing string along with 9‐5/8” x 3‐1/2” multiport packers.
Stolboushkin et al. (2013) designed and developed an intelligent electro‐hydraulic firing head and
showed that numerous benefits in safety and operational flexibility are realized by combining the
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intelligent pulse recognition of an electronic firing head with the firing system of a hydraulic firing head;
the tool works in an HPHT environment as well as in a broad range of environments.
2.2.6 Optimize Waterflood In the development of an intelligent waterflood system, Rahman et al. (2013) implement the use of fiber
optic distributive sensing for monitoring injection profiles in a large number of injection wells in the
Belridge Field in California.
Yunus and Chetri (2014) investigate the use of data collected from a variety of sources within different
wells and facilities in the field to automate real‐time monitoring for optimizing water‐flood and effective
water injection for pressure support. Real time monitoring and short‐term unexpected production
behavior are developed into smart workflows. Real time data are converted into information for swift
action to optimize water‐flood and effective water injection processes for pressure support.
2.3 Summary ‐ Chapter on Intelligent Systems
Eight fundamental principles and characteristics P1‐P8 are drivers in the development of intelligent
systems for downhole applications in oil and gas fields:
(P1) Provide permanent downhole components that are operable over the life of a well
(P2) Permit wells and fields to be remotely monitored and controlled from surface
(P3) Reduce or eliminate physical interventions, mitigate risk, allow proactive and/or reactive
management
(P4) Provide real‐time data (e.g., temperature, pressure, fluid flow, phase composition)
(P5) Enable selective zonal isolation, independent modulation and multi‐zone/field‐wide
deployments
(P6) Optimize production and increase ultimate reservoir recovery
(P7) Accelerate cash flow, reduce overall costs and maximize net present value (NPV)
(P8) Provide well integrity monitoring; improve health, safety and environmental (HSE) issues
The concept of intelligent casing‐intelligent formation is used in the following sense. intelligent casing‐
intelligent formation systems are systems deployed in the casing, on the external surface of the casing,
external to the casing and/or in the formation that possess such fundamental principles and
characteristics P1‐P8.
2.4 References ‐ Chapter on Intelligent Systems
Abay, H., Garbahan, G., Nyhavn, F. and Husebo, S. 2013. Monitoring Multilateral Flow and Completion Integrity with Permanent Intelligent Well Tracers. Paper SPE‐166076‐MS presented at the SPE Annual Technical Conference and Exhibition held in New Orleans, Louisiana, USA. 30 September – 2 October.
Al‐Asimi, Mohammad et al. (2003). “Advances in Well and Reservoir Surveillance,” Oilfield Review, Winter 2002/2003, pp. 14‐35.
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Al‐Jasmi, A., Goel, H. K., Nasr, H., et al. (2013). A Surveillance “Smart Flow” for Intelligent Digital Production Operations. Paper SPE‐163697‐MS presented at SPE Digital Energy Conference and Exhibition held in the Woodlands, Texas, USA. 5‐7 March.
Al‐Mohanna, K., Jacob, S., Ma, L. and Shafiq, M. 2013. New Generation Intelligent Completion System Integrates DownHole Control with Monitoring in Multilateral Wells. Paper SPE‐164147‐MS presented at the SPE Middle East Oil and Gas Show and Exhibition held in Manama, Bahrain. 10‐13 March.
Al Omair, Abdullatif A. (2007). Economic Evaluation of Smart Well Technology, Thesis, Master of Science, Petroleum Engineering, Texas A&M University, May 2007.
Almeida, Luciana Faletti, Vellasco, Marley M.B.R. and Pacheco, Marco A.C. (2010). “Optimization system for valve control in intelligent wells under uncertainties,” Journal of Petroleum Science and Engineering, Volume 73, Issues 1–2, August 2010, Pages 129–140.
Angel, Jack (2003). “Intelligent well systems‐Where we’ve been and where we’re going,” World Oil, March 2003, vol. 224 (No. 3).
Anoze, A. and Cunha, R. 2007. Production Optimization with Intelligent Wells. Paper SPE‐107261‐MS presented at the SPE Latin American and Caribbean Petroleum Engineering Conference held in Buenos Aires, Argentina. 15‐18 April.
BakerHughes website (2014). (www.bakerhughes.com) Chris, J., Azrul, N., Farris, B., NurHazrina, K., Aminuddin, M., Saiful, M., Gordon, K., Premjit, K., Darren, T.
and Eddep, A. 2011. Implementation of Next Generation Intelligent Downhole Production Control in Multiple‐dipping Sandstone Reservoirs, Offshore East Malaysia. Paper SPE‐145854‐MS presented at the SPE Asia Pacific Oil and Gas Conference and Exhibition held in Jakarta, Indonesia. 20‐22 September.
Cullick, A. and Sukkestad, T. 2010. Smart Operations with Intelligent Well Systems. Paper SPE‐126246‐MS presented at the SPE Intelligent Energy Conference and Exhibition held in Utrecht, The Netherlands. 23‐25 March.
Davies, David R. and Aggrey, George Hayford (2007). “Tracking the State and Diagnosing Downhole Permanent Sensors in Intelligent‐Well Completions with Artificial Neural Network,” 107198‐MS SPE Conference Paper.
Esmaiel, Talal Ebraheem (2005). “Applications of Experimental Design in Reservoir Management of Smart Wells,” 94838‐MS SPE Conference Paper.
Gao, Chang Hong, Rajeswaran, Raj Thanabalasingam, and Nakagawa, Edson Yoshihito (2007). “A Literature Review on Smart‐Well Technology,” 106011‐MS SPE Conference Paper.
Glandt, Carlos A. (2003). “Reservoir Aspects of Smart Wells,” 81107‐MS SPE Conference Paper. Glandt, Carlos A. (2005). “Reservoir Management Employing Smart Wells: A Review,” SPE Drilling &
Completion Journal, December 2005. 20(4): p. 281‐288. Going, W.S., Anderson, A.B., Vachon, G.P. ( 2006). ” Intelligent Well Technology—The Evolution to
Closed‐Loop Control ” 17796‐MS OTC Conference Paper. Halliburton website (2014). (www.halliburton.com) Hembling, D., Salamy, S., Qatani, A., Carter, N. and Jacob, S. 2006. Swell Packers: Enabling Openhole
Intelligent and Multilateral Well Completions for Enhanced Oil Recovery. Paper SPE‐100824‐MS presented at the IADC/SPE Asia Pacific Drilling Technology Conference and Exhibition held in Bangkok, Thailand. 13‐15 November.
Jalali, Y., Bussear, T., Sharma, S. (1998). “Intelligent Completion Systems‐‐The Reservoir Rationale,” 50587‐MS Conference Paper.
Khan, Mohd. Yunus and Chetri, H. 2014. Waterflood Optimization and its Impact Using Intelligent Digital Oil Field (iDOF) Smart Workflow Process: A Pilot Study in Sabriyah Maudoud, North Kuwait. Paper
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IPTC 17315 presented at the International Petroleum Technology Conference held in Doha, Qatar. 20‐22 January.
Konopczynski, M., Moore, W. and Hailstone, J. 2002. ESPs and Intelligent Completions. Paper SPE‐77656‐MS presented at the SPE Annual Technical Conference and Exhibition held in San Antonio, Texas, USA. 29 September – 2 October.
Lacy, Rodger, Neumann, Juergen, and Tough, Gary (2007). “A Combination of Expandable Sand Screens and Intelligent Control Systems in the Okwori Completions Offshore Nigeria,” 18484‐MS OTC Conference Paper.
Loermans, T. and Kelder, O. 2006. Intelligent Monitoring? …. Add Borehole Gravity Measurements! Paper SPE‐99554‐MS presented at the SPE Intelligent Energy Conference and Exhibition held in Amsterdam, The Netherlands. 11‐13 April.
Mateeva, A., Lopez, J., Hornman, K., Wills, P., Cox, B., Kiyashchenko, D., Berlang, W., Potters, H. and Detomo, R. 2014. Recent Advances in Seismic Monitoring of Thermal EOR. Paper IPTC 17407 presented at the International Petroleum Technology Conference held in Doha, Qatar. 20‐22 January.
Muradov, K. and Davies, D. 2012. Temperature Transient Analysis in a Horizontal, Multi‐zone, Intelligent Well. Paper presented at the SPE Intelligent Energy International held in Utrecht, The Netherlands. 27‐29 March.
Muradov, K. and Davies, D. 2013. Some Case Studies of Temperature and Pressure Transient Analysis in Horizontal, Multi‐zone, Intelligent Wells. Paper SPE‐164868‐MS presented at the EAGE Annual Conference and Exhibition incorporating SPE Europec held in London, United Kingdom. 10‐13 June.
Oberwinker, C., Mayfield, D., Dixon, D. and Holland, J. 2006. Automated Production Surveillance. Paper SPE‐96645‐PA presented to SPE Projects, Facilities and Construction Journal. June.
Olowoleru, D., Muradov, K., Al‐Khelaiwi, F. and Davies, D. 2009. Efficient Intelligent Well Cleanup using Downhole Monitoring. Paper SPE‐122231‐MS presented at the SPE European Formation Damage Conference held in Scheveningen, The Netherlands. 27‐29 May.
Patricio, A., Morooka, C. and Rocha, A. 1997. An Intelligent System for Process Plant and Well Production Control with Problem Diagnosis. Paper SPE‐38992‐MS presented at the Fifth Latin American and Caribbean Petroleum Engineering Conference and Exhibition held in Rio de Janeiro, Brazil. 30 August – 3 September.
Peringod, C., Al‐Ruheili, S., Kerecin, Z., Sonti, K. and Sukkestad, T. 2011. Successful Auto Gaslift using Intelligent Completion Boosted Oil Production – A Case History from Petroleum Development Oman. Paper SPE‐148474‐MS presented at the SPE/IADC Middle East Drilling Technology Conference and Exhibition held in Muscat, Oman. 24‐26 October.
Piovesan, O. and Kozman, J. 2009. An Intelligent Platform to Manage Offshore Assets. Paper SPE‐124514‐MS presented at the SPE Annual Technical Conference and Exhibition held in New Orleans, Louisiana, USA. 4‐7 October.
Potters, H. and Kapteijn, P. 2005. Reservoir Surveillance and Smart Fields. Paper IPTC‐11039‐MS presented at the International Petroleum Technology Conference held in Doha, Qatar. 21‐23 November.
Rahman, Mahmood, Reed, Daniel A., and Allan, Malcoln E., “The Challenges of Full‐Field Implementation of Fiber Optic DTS for Monitoring Injection Profiles in Belridge Field, California,” SPE 163694, Aera Energy, 2013 SPE Digital Energy Conference and Exhibition, The Woodlands, Texas, 5‐7 March 2013.
Robinson, M. 2003. Intelligent Well Completions. Paper SPE‐80993‐JPT, Journal of Petroleum Technology. Technology Today Series. August.
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Saeverhagen, E., Bouillouta, F., Baksh, N., Vettical, C. and Dagestad, V. 2013. Utilization of Key Performance Indicators and Benchmarking Improves Drilling Performance for Several Operators. Paper SPE‐166742‐MS presented at the SPE/IADC Middle East Drilling Technology Conference and Exhibition held in Dubai, UAE. 7‐9 October.
Schiozer, Denis Jose and Silva, Joao Paulo Quinteiro G. (2009). “Methodology to Compare Smart and Conventional Wells,” 124949‐MS SPE Conference Paper.
Schlumberger website (2014). (www.slb.com) Shaw, J. 2011. Comparison of Downhole Control System Technologies for Intelligent Completion. Paper
CSUG/SPE‐147547 presented at the Canadian Unconventional Resources Conference held in Calgary, Alberta, Canada. 15‐17 November.
Shevchenko, S., Navozov, V., Mironov, D., Pchelnikov, E. and Muslimov, Y. 2012. Oil Production Process Optimization Resultant from Intelligent Field Technologies Implementation in Samotlorskoe Field. Paper SPE‐161978‐MS presented at the SPE Russian Oil and Gas Exploration and Production Technical Conference and Exhibition held in Moscow, Russia. 16‐18 October.
Silva, M., Muradov, K. and Davies, D. 2012. Review, Analysis and Comparison of Intelligent Well Monitoring Systems. Paper SPE‐150195‐MS presented at the SPE Intelligent Energy International held in Utrecht, The Netherlands. 27‐29 March.
Stian Bærheim (2009). “Use of Expandable Pipe Technology to Improve Well Completions,” Master Thesis, Petroleum Technology, Universitetet I Stavanger, Spring 2009.
Stolboushkin, Eugene, Zuklic, Steve N., Peterson, Rick Elmer, Stretton, John (2013). “Novel Electro‐Hydraulic Intelligent Firing Head for Tubing Conveyed Perforating,” 166248‐MS SPE Conference Paper.
Sun, K., Constantine, J., Tirado, R., Eriksen, F. and Costa, L. 2009. Intelligent Well Systems – Providing Value or Just another Completion? Paper SPE‐124916‐MS presented at the SPE Annual Technical Conference and Exhibition held in New Orleans, Louisiana, USA. 4‐7 October.
Temizel, C., Dursun, S., Purwar, S. and Hancioglu, B. 2013. A system of Key Performance Indicators in Intelligent Fields. Paper SPE‐166019‐MS presented at the SPE Reservoir Characterization and Simulation Conference and Exhibition held in Abu Dhabi, UAE. 16‐18 September.
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Vachon, Guy (2004). “Intelligent well systems advance toward maturity,” Drilling Contractor, March/April 2004, pp. 34‐35.
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Van der Linden, R., Reijn, H., Noordzee, W., Muñoz, E., De Wolff, F. and Renes, W. 2010. Real‐Time Intelligent Production Monitoring of a North Sea Asset. Paper SPE 128300‐MS presented at the SPE Intelligent Energy Conference and Exhibition held in Utrecht, The Netherlands. 23‐25 March.
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Williams, B. and Nyhavn, F. 2012. Wireless Reservoir Surveillance Using Intelligent Tracers. Paper OTC 23282‐MS presented at the Offshore Technology Conference held in Houston, Texas, USA. 30 April – 3 May.
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3. Fiber Optic Sensors and Real-Time, Distributed Sensing
Clowes, McInnes et al. (1998) reported on the effects of high‐temperature and pressure on Silica Optical
Fiber Sensors. Clowes, Syngellakis et al. (1998) reported on the pressure sensitivity of side‐hole optical
fiber sensors. Clowes et al. (1999) reported on the low drift fibre‐optic pressure sensor for oil field
downhole monitoring. Eck et al. (2000) reported on the initial downhole monitoring capability of fiber
optic sensing. Qi et al. (2002) described the use of fiber optic pressure and temperature sensors for oil
downhole applications. De Costa (2004) describes how the next‐generation fiber optic sensors capture
vital information to guide intelligent decision making. Fryer et al. (2005) report on using permanent
fiber‐optic distributed temperature systems in monitoring of real‐time temperature profiles across
multizone reservoirs during production and shut‐In periods. Xu (2005) presents research conducted on
high temperature high bandwidth fiber optic pressure sensors.
3.1 Early History of Fiber Optic Sensing
Fiber optic communication and Fiber optic sensing have a history going back to the 1960s and 1970s,
(Culshaw, 2000). The seminal papers of (Kao et al. 1966) and (Simon et al. 1963) showed that optical
signals could be transmitted along glass or silica fibers with a loss potentially below that experienced in
coaxial copper cables. In the late 1960s and early 1970s, fiber optic sensing concepts and products
emerged and patents were filed on using optical fibers to make sensor measurements, (Menadier et al.
1967), (Dyott et al. 1970) and (Snitzer, 1971). Distributed optical fiber Raman temperature sensing was
reported on as early as 1985, (Dakin et al. 1985) and (Hartog, 1985). In the back‐scattered light of
Raman scattering, the ratio of the Anti‐Stokes and the Stokes light intensities provides the local
temperature measurement for single mode distributed temperature sensors (Shiota et al. 1991).
Brillouin scattering, the scattering of a light wave by an acoustic wave due to a nonelastic interaction
with the acoustic phonons of the medium, provides a method for sensing both distributed temperature
and strain, but not both simultaneously, (Culverhouse et al. 1989). Other early Brillouin scattering
treatments include a number of studies (Horiguch et al. 1990; Bao et al. 1993; Bao et al. 1994; Bao et al.
1995; Niklès et al. 1995; Shimizuet et al. 1995; Garus et al. 1997; Parker et al. 1998). John Dakin and
Brian Culshaw documented the basic theory, concepts, components, systems, subsystems, and
applications of fiber optic sensors in their four volumes of Optical Fiber Sensors: (Dakin and Culshaw
1988, 1989, 1996, and 1997).
Fiber Bragg grating‐based sensing utilizing Fiber Bragg gratings (FBGs) for use in fiber laser sensors
configurations has been developed for ultrahigh strain sensitivity applications, especially distributed
strain sensor systems for monitoring application in smart structures systems. Fiber Bragg grating (FBG)
is a periodic perturbation of the refractive index along the fiber length which is formed by exposure of
the core to an intense optical interference pattern. The formation of permanent gratings in an optical
fiber was first demonstrated in 1978, (Hill et al. 1978) and (Kawasaki et al. 1978). Fiber grating
technology and its broad range of applications are briefly reviewed in (Hill et al. 1997) and (Kersey et al.
1997).
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3.2 Fiber Optic Distributed Temperature System (DTS) Sensing
In oil and gas wells, DTS is used to monitor the temperature log of a well where it has wide spread
applications that include, in particular, the effects of liquid and gas flows, (Ukil et al. 2012). Distributed
fiber optic sensing has the ability to measure temperature and strain at about 1 meter intervals along a
single fiber. As such, it has a manifold of applications for the monitoring of temperature and strain in
large structures such as bridges, pipelines, flow lines, oil wells, dams and dikes. A comparison of the two
different DTS technologies Raman and Brillouin scattering are given below in Table 3.1; this comparison
is taken from Table I in (Ukil et al. 2012). The results due to Rayleigh scattering are not included since
the range is limited to 170 m.
Table 3.1 Comparison of Different DTS Technologies
Scattering Raman Brillouin
Temp. Sensitivity (%/ºC) 0.8 0.01
Temp. range (ºC) 0 to 70 -30 to 60
Accuracy (ºC) 10 1
Spatial resolution (m) 3 3-5
Fiber length range (m) 1000 51,000
Measurement time (s) 40 4
Strain (μm) - 100
The above results show that scattering Brillouin provides best length range, with highest temperature
sensitivity and relatively good measurement time. Brillouin scattering can also detect distributed strain.
However, it cannot possibly measure the distributed temperature and strain simultaneously. Typically,
the applications of the Brillouin scattering are either for distributed temperature measurement or strain,
but not both simultaneously. Therefore, Brillouin scattering would likely be a preferred choice in future
developments, as a replacement for the Raman scattering as already seen in the commercial systems,
(Lecoeuche et al. 2000). But, more recent efforts based on spontaneous Raman scattering and coded
OTDR (optical time domain reflectometry) have improved the ranges for Raman‐based distributed
temperature measurements.
(Skinner et al. 2004) reviews what sensing technologies are being adopted downhole and the drivers for
such deployment. In particular, the extensive review covers various aspects of performance
expectations including accuracy, resolution, stability and operational lifetime that the oil companies and
the oil service companies have for fiber‐optic sensing systems. The environmental conditions (high
hydrostatic pressures, high temperatures, shock, vibration, crush, and chemical attack) are also
discussed that these systems must tolerate in order to provide reliable and economically attractive
reservoir‐performance monitoring solutions.
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Bolognini et al. (2007) implemented a high performance scheme using amplitude modulation according
to Simplex coding, direct detection and additional use of lumped Raman amplification to further extend
the sensing range of Raman‐based distributed temperature sensing. An efficient and cost‐effective
distributed temperature sensing system was developed operating along 30 km of dispersion‐shifted
fibre with 17 m spatial resolution and 5 K temperature resolution. It was achieved using 255 bit Simplex
coding and low‐power commercially available laser diodes (80 mW CW power). The use of lumped
Raman amplification to produce high‐power coded pulses allows further 10 km distance enhancement,
resulting in a total measurement range of 40 km.
Another new Raman‐based distributed measure technique allows for temperature sensing over nearly
40‐km graded index multimode optical fiber, (Signorini et al. 2010). The novel technique employs a
hybrid scheme with two different peak power values and operates in non‐linear regime, achieving about
a 9 dB improvement with respects to standard techniques and attaining a temperature accuracy better
than 3ºC with an acquisition time shorter than 5 min and a meter‐scale spatial resolution.
Fiber optic sensors for temperature and pressure measurements were tested in a steamflood area,
(Karaman et al. 1996). Fiber optic sensors were used to determine accurate reservoir temperature
profiles in a permanent installation on the outside of casing in temperature observation wells,
(Carnahan et al. 1999). In order to provide real time reservoir surveillance and monitoring about well
and reservoir performance, fiber optic distributed temperature systems (DTS) were installed on two
extended reach drilling wells, (Brown et al. 2000). A fiber optic DTS system, installed in a horizontal well
bore located within a 2 degree Celsius geothermal temperature range, provided real‐time measurement
of the temperature profile along the well bore and open hole producing section for the purpose of
inferring the inflow production profile of the well, (Lanier et al. 2003). Fiber optic distributed
temperature sensing (DTS) was used to provide useful real time information for thermal analysis of
distributed temperature data in water injection and gas lift optimization wells, (Brown et al. June 2005).
In offshore wells in the Caspian Sea, fiber‐optic distributed temperature systems, installed from surface
to total depth, were used to analyze the producing well temperature profiles and calculate the flow
contribution from each of the producing zones, (Brown et al. October 2005); the results showed that
permanently installed fiber‐optic distributed temperature monitoring is cost effective compared to
conventional production logging.
Fiber optic distributed temperature sensing technology is deployed behind the casing providing full‐
access to the interior of the borehole under a wide range of conditions, (Henninges et al. 2005);
continuous temperature profiles were registered with high spatial and temporal resolution (0.3ºC
accuracy). With a permanent DTS installation behind the casing, even abandoned and sealed wells can
be monitored, which makes the cased‐hole method especially suitable for long‐term thermal
monitoring. It is emphasized that the cladding of the sensor cables has to be designed to protect the
delicate optical fiber and to withstand high temperature and pressures, strongly corrosive formation
fluids, as well as high mechanical stress during installation. For the well completion, custom designed
fastenings, lead‐throughs and optical connectors are required.
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The designs and test results of distributed strain and temperature sensors from the embedding of fiber
optic sensors in composite tubing is presented in (Inaudi et al. March 2006); the results show that
sensing systems based on Brillouin scattering are an effective method to monitor integrity and
operational parameter of a composite coiled‐tubing. The optical fiber sensors were pre‐packaged in a
novel sensing cable design, combining strain‐ and temperature‐sensing fibers in a single profile, called
SMARTProfile. (Inaudi et al. July 2006) presents different cable designs for high‐temperature sensing,
strain sensing and combined strain and temperature monitoring, as well as relevant application
examples to the monitoring of civil and oil & gas structures.
Transient temperature analysis of DTS profiles provide added value for oil and gas wells under
production, injection, and treatment conditions, (Johnson et al. 2006). DTS technology was shown to
improve analytical capabilities relative to production/injection layer contributions, reservoir flow
properties, tubular leaks, and steam breakthrough locations; and it was shown that cost and safety
advantages were gained by using DTS transient analysis techniques. Permanent fiber‐optic distributed
temperature monitoring systems were installed in gravel‐packed sand‐screen completions producing
from multilayered reservoirs to monitor production rates and changes over time, providing flow profile
and reservoir layer pressures, (Pinzon et al. 2007).
Used during matrix treatments to monitor temperature profiles along the wellbore in real time,
distributed temperature sensing (DTS) showed that fluid distribution can be quantified both before and
after a diverter stage so that the diversion effect can be evaluated, (Glasbergen et al. 2007).
A fiber optic distributed temperature sensor system based on spontaneous Raman scattering with Golay
coding is developed, (Soto et al. 2007), for applications up to 8 km sensing distance. CC‐coding
techniques and the use of multimode fibers in a single receiver scheme provided for high spatial and
temperature resolution sensing with high repeatable measurement using low power semiconductor
lasers.
(Sierra et al. 2008) presents experiences in the analysis of transient DTS data acquired during high‐rate,
multi‐stage hydraulic fracturing in vertical, deviated, and horizontal oil and gas wells; the results show
that the location of fiber, conveyed with coiled tubing inside the flow path or cemented behind casing,
has a major impact in the temperature response. Where the fiber was placed inside the casing,
determination of the fluid distribution was found to be challenging. In locations where the fiber was
cemented behind the casing, results based on the temperature value provided well‐defined patterns,
and gave discrimination between flow inside and behind casing, allowing out‐of‐zone fracture
assessment.
(Yamate, 2008) reviews fiber‐optic sensors for exploration for oil and gas including Schlumberger’s fiber
optic pressure sensor which provides low temperature sensitivity with a Bragg grating pressure sensor
using a single mode side‐hole fiber. Other fiber optic sensors include optical probes for multiphase
flows and distributed dynamic strain measurement with Fiber Bragg gratings (FBGs) for integrity
monitoring of risers.
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(Huckabee, 2009) summarizes applications of optic fiber distributed temperature sensing (DTS)
technology for hydraulic fracturing stimulation diagnostics and well performance evaluation in
unconventional gas well completions. The DTS installations included temporary “call‐out” deployments,
velocity string installations, and permanent "behind casing" installations in vertical and horizontal
wellbores; results provided quantitative inflow distribution measurement for well performance
evaluations in commingled multiple interval completions. The results also validated hydraulic fracture
containment in disposal well injection applications. The many uses for a well’s temperature profile are
taking fiber‐optic technology (e.g., DTS) into the forefront of production monitoring and diagnostics,
(Brown, 2009).
DTS analysis helps determine what acidizing procedure should be made, (Reyes et al. 2010).
(Rahman et al. 2011) is a case study of the application of DTS technology in solving surveillance issues in
an old field, presenting many examples of injection profiles derived from DTS measurements and a
comparative evaluation of different interpretation techniques. (Rahman et al. 2013) presents results of
field tests with Fiber‐Optic Distributed Temperature Sensing (DTS) in a five‐well permanent installation
pilot followed by a 30‐well survey acquisition program in which the injection profiles from over 70
injection strings with DTS fibers are being routinely surveyed and the interpreted results are being pro‐
actively used for waterflood surveillance and optimization. The field tests confirmed that the DTS
technology has the potential to replace conventional Radio‐Active Tracer (RAT) technology for
continuous monitoring of injection profile; RAT had faced limitations and/or challenges due to its
inability to access wellbores for logging because of scale build‐ups and casing deformations. DTS surveys
provided temperature measurements spaced equally along the length of an optical fiber at
approximately 1 meter intervals. The DTS technical issues resolved successfully in the field tests
included the following: The fiber optic cable contained inside a ¼ inch stainless steel tube was deployed
outside the casing and cemented in place. The fiber optic cable and its control line were installed in a
way that permitted perforation for completion without damaging the fiber. The control line and fiber
was pulled through the wellhead mandrel and was secured from damage during rig move‐out, and
installation of the well‐head and injection manifold. The whole installation procedure was made simple
and fast enough to be integrated into lean manufacturing style of drilling process that takes less than
three days to complete a well from spud to rig release. The acquisition and interpretation of DTS
technology for monitoring of injection profile was made cheap enough to be incorporated in a “low‐
cost” environment where a producer makes less than 20 BOPD. In achieving a “low‐cost” installation,
own surveys were made and own software was developed for processing and interpreting the data for
hundreds of injectors surveyed and analyzed yearly.
3.3 Fiber Optic Distributed Sensing: DTS, DPS, DSS, DAS, and DCS
Fiber‐optic technology which provides for distributed temperature sensing (DTS) is a means for
measuring temperature along the length of an optical fiber in a well, (Al‐Asimi et al. 2002). (Wang, et al,
2003) successfully developed optical fiber sensors for measurement of pressure, temperature, flow and
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acoustic waves and show successful demonstrations in three field tests in the oil fields of
Chevron/Texaco in Coalinga, California and at the world class oil flow loop facilities at the University of
Tulsa, in Tulsa, Oklahoma. Successful demonstrations showed the following results.
(a) Deployability of fiber optic sensors; no sensors failed in any of the three field tests during
deployment;
(b) Pressure sensor resolution of 0.03psi, repeatability of 0.15% full scale and stability of 0.01%;
(c) Flow sensor resolution of 0.26% and stability better than 1.56%;
(d) Developed sensor and hermetic packaging that can be deployed through 0.25inch O.D.,
0.125 inch I.D. high pressure steel tubing; packaged sensor is less than 1mm in diameter;
(e) Developed remote monitoring and control systems so that all the computers in the field site
at Coalinga, Ca could be monitored and controlled from virtually anywhere in the world through
remote internet access;
(f) Successfully developed and tested acoustic sensors.
Hybrid fiber‐optic cable is used in permanent monitoring (e.g., pressure and temperature) in the
sandface, (Algeroy et al. 2010). Fiber optic sensor technologies offer a wide range of subsurface
measurements that includes distributed temperature sensing (DTS), distributed strain sensing (DSS),
distributed pressure sensing (DPS), distributed acoustic sensing (DAS), and distributed chemical sensing
(DCS), (Koelman, 2011). Field tests have demonstrated that fiber optic distributed temperature sensing
systems have potential for continuous monitoring of the reservoir. Full‐field implementations have
been able to overcome both technical and economic challenges. For example, a full‐field
implementation showed that (a) perforating a well for completion could be managed without damaging
the DTS fiber and (b) that DTS could be deployed successfully outside the casing without any damage,
(Dennis, 2013) and (Rahman et al. 2013). These latter references point out that approximately 70
permanent and semipermanent DTS installations have been run and no fiber has failed because of
temperature or hydrogen degradation or because of formation shear. Furthermore, four wells with
external fiber optic cable have been hydraulically fractured with a large volume of sand proppant
without any harm done to the fiber.
Many environmental applications of DTS demand very accurate temperature measurements, with
typical RMSE<0.1K, (van de Giesen, et al. 2012). A number of DTS application issues are described in
(Tyler et al. 2009) including repeatability, resolution, cable options, instrument operations, and
performance.
3.4 Fiber Optic Distributed Sensing Products
The following list of manufacturers of DTS systems is taken from (Ukil et al. 2012); it is not an exhaustive
list, and the order does not signify any relative measure.
• Sensa® (Manuals, whitepapers. (Online). Available: http://sensa.org.): DTS systems like SUT‐® family,
DTS‐® family for applications like power T&D, leakage detection in oil and gas, fire detection, etc.
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• omnisens® (Manuals, whitepapers. (Online). Available: http://www.omnisens.ch.): distributed
monitoring systems for temperature, strain, fatigue, etc., like DITEST‐® LTM®, AIM®, SHM®, DSM®,
STA‐R®, DLIGHT series®, etc.
• es&s® (Manuals, whitepapers. (Online). Available: http://www.esands.com.): DTS system like DiTeSt®
for distributed temperature and strain measurement.
• LIOS TECHNOLOGY® (Manuals, whitepapers. (Online). Available: http://www.lios‐technology.com.):
stand alone DTS systems, integrated Real Time Thermal Rating (RTTR) package.
• sensornet® (Manuals, whitepapers. (Online). Available: http://www.sensornet.co.uk.): fiber optic
sensors and digital monitoring systems.
• SensorTran® (Manuals, whitepapers. (Online). Available: http://www.sensortran.com.): DTS product
families like ASTRA®, CENTUARUS®, GEMINI®, NEPTUNE®, CABLES®.
• Weatherford® (Manuals, whitepapers. (Online). Available: http://www.ep‐solutions.com.): optical DTS,
optical pass‐thru pressure/temperature gauge.
• AP SENSING® (Manuals. (Online). Available: http://www.apsensing.com.): DTS system like EN54‐5®.
• Promore Engineering Inc.® (Manuals, whitepapers. (Online). Available: http://www.promore.com.):
reservoir monitoring systems.
• sabeus® (Manuals, whitepapers. (Online). Available: http://www.sabeus.com.): Field Sense™ MPT
temperature sensing systems, BHPt pressure sensing systems.
• LUNA Technologies® (Manuals, whitepapers. (Online). Available: http://www.lunatechnologies.com.):
Distributed Sensing System™ (DSS) 4300 for making distributed measurements of temperature and
strain.
• HALLIBURTON® (Manuals, whitepapers. (Online). Available: http://www.halliburton.com.).
• MAXIM® (Application Note 687. (Online). Available: http://www.maxim‐ic.com/an687.).
The list included the following nonprofit professional societies as well.
• The Fiber Optic Association Inc. (The Fiber Optic Association, Inc., Tech. information,
whitepapers.(Online). Available: http://www.thefoa.org.).
• Subsea Fiber Optic Monitoring Group (Subsea Fiber Optic Monitoring Group, Publications,
whitepapers. (Online).Available: http://www.seafom.com.).
• IEEE Photonics Society (IEEE Photonics Society, Journals, Conf. Publications. (Online). Available:
http://www.photonicssociety.org.).
Hottinger Baldwin Messtechnik GmbH, Germany developed products based on photonic Bragg sensors,
(Haase, 2007), including fiber optical Bragg sensors for strain measurements. Products include special
software modules and hardware components for signal processing of photonic sensors linking electrical
and optical systems as well as high strain level applications.
The Distributed Temperature Sensing technology in use by Schlumberger uses fiber optic temperature
sensors to determine the temperature distribution down the well at resolutions near 1 meter. By pulsing
laser lights down an optic cable and reflecting the light scattered due to Raman scattering, a log is
produced that accurately depicts the thermal conditions (Brown 2008). Schlumberger uses a resonant
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pressure transducer in its WellWatcher tool that uses microchips cast on synthetic sapphire plates. The
result is a pressure transducer that can withstand the high temperatures expected in most drilling
scenarios (Culurciello 2010). These gauges are rated to withstand pressures over 10,000kPa and 110°C
(Schlumberger 2008). Schlumberger reports on the development of its permanent fiber‐optic pressure
gauge, (Algeroy et al. 2010). As an example of what oil and gas service companies provide,
Weatherford’s “Downhole Optical Cable” is a standard cable that consists of two single‐mode fibers for
pressure gauges, flowmeters, and seismic systems and one multimode fiber for DTS systems. Pressure
gauges and seismic stations are multiplexed on a single fiber, while a downhole cable splitter can be
used to further enable multi‐zone sensing architectures that deliver enhanced production monitoring
capabilities.
Yokogawa has developed the DTSX200 distributive temperature sensor (DTS) to facilitate the efficient
recovery of unconventional resources by monitoring temperature distribution underground, (Fukuzawa,
2012).
Future systems and products must be capable of withstanding higher and higher temperatures and
operate on less and less dependency of a “down‐the‐hole” power source, (Avant et al. 2012). Many
applications of fiber optic distributive sensing do not require a power source except at the surface.
Optical fibers for DTS applications are under development for withstanding temperatures in geothermal
wells where temperatures can range from 350‐380°C wells to 550‐600°C wells producing geothermal
fluids, (Reinsch et al. 2010).
3.5 U. S. Patents on Fiber Optic Sensing Technology
The abstracts of 57 collected U.S. patents on fiber optic sensing technology are summarized in Appendix
A. The issue dates of the patents range over a 24 year period from 1990 to 2014. The sampling of
patents shows the potential breadth and depth of fiber optic sensing applications and the recent
exponential growth of patents in the area of fiber optic sensing technology.
3.6 References ‐ Chapter on Fiber Optic Sensing
Al‐Asimi, Mohammad et al. “Advances in Well and Reservoir Surveillance,” Oilfield Review, Winter 2002/2003, pp. 14‐35.
Algeroy, John, Lovell, John, Tirado, Gabriel, Meyyappan, Ramaswamy, Brown, George, Greenaway, Robert, Carney, Michael, Meyer, Joerg H., Davies, John E., and Pinzon, Ivan D., 2010. “Permanent Monitoring: Taking it to the Reservoir,” Oilfield Review, Spring 2010, 22, no. 1, pp. 34‐41.
Avant, Chris, Behera, Bijaya K., Danpanich, Supamitta, Laprabang, Waranon, De Santo, IIaria, Heath, Greg, Osman, Kamal, Khan, Zuber A., Russell, Jay, Sims, Paul, Slapal, Miroslav, Tevis, Chris, 2012. “Testing the limits in Extreme Well Conditions,” Oilfield Review Autumn 2012, 24, no. 3.
Bao, X., Webb, D. J., and Jackson, D. A., 1993. “32‐km Distributed temperature sensor using Brillouin loss in optical fibre”, Optics Lett., Vol. 18, No. 7, pp. 1561‐1563, (1993).
Bao, X., Webb, D. J., and Jackson, D. A., 1994. “Combined distributed temperature and strain sensor based on Brillouin loss in an optical fiber,”Opt. Lett., vol. 19, no. 2, pp. 141–143, 1994.
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Bao, X., Dhliwayo, J., Heron, N., Webb, D. J., and Jackson, D. A., 1995. “Experimental and theoretical studies on a distributed temperature sensor based on Brillouin scattering,” J. Lightwave Technol., vol. 13, no. 7, pp. 1340–1348, 1995.
Bolognini, Gabriele, Park, Jonghan, Soto, Marcelo A., Park, Namkyoo and Di Pasquale, Fabrizio, 2007. “Analysis of distributed temperature sensing based on Raman scattering using OTDR coding and discrete Raman amplification,” Measurement Science and Technology, vol. 18, no. 1, 2007, pp. 3211‐3218.
Brown, G.A., Kennedy, B., and Meling, T., ‘Using Fibre‐Optic Distributed Temperature Measurements to Provide Real‐Time Reservoir Surveillance Data on Wytch Farm Field Horizontal Extended‐Reach Wells,” SPE paper 62952, SPE Annual Technical Conference and Exhibition, 1‐4 October 2000, Dallas, Texas.
Brown, G., Carvalho, V., Wray, A., Sanchez, A., and Gutierrez, G., 2005. “Slickline With Fiber‐Optic Distributed Temperature Monitoring for Water‐Injection and Gas Lift Systems Optimization in Mexico,” SPE paper 94989, SPE Latin American and Caribbean Petroleum Engineering Conference, 20‐23 June 2005, Rio de Janeiro, Brazil.
Brown, G., Field, D., Davies, J., Collins, P., and Garayeva, N., 2005. “Production Monitoring Through Openhole Gravel‐Pack Completions Using Permanently installed Fiber‐Optic Distributed Temperature Systems in the BP‐Operated Azeri Field in Azerbaijan,” SPE paper 95419, SPE Annual Technical Conference and Exhibition, 9‐12 October 2005, Dallas, Texas.
Brown, George, 2009. “Downhole Temperatures from Optical Fiber,” Oilfield Review Winter 2008/2009:20, no. 4, 2009, pp. 34‐39.
Carnahan, B.D., Clanton, R.W., Koehler, K.D., Harkins, G.O., and Williams, G.R., 1999. “Fiber Optic Temperature Monitoring Technology,” SPE paper 54599, SPE Western Regional Meeting, 26‐27 May 1999, Anchorage, Alaska.
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Clowes, J. R, Edwards, J, Grudini, I, Kluth, E. L. E, Varnham, M. P, Zervas, M. N, Crawley, C. M, Kutlik, R. L, 1999. “Low Drift Fibre‐Optic Pressure Sensor for Oil Field Downhole Monitoring,” Electronics Letters, Vol. 35, No. 11, pp. 926‐927.
Culshaw, Brian, 2000. “Fiber Optics in Sensing and Measurement,” IEEE Journal of Selected Topics in Quantum Electronics, Vol. 6, No. 6, November/December 2000, pp. 1014‐1021.
Culverhouse, D., Farahi, F., Pannel, C. N., and Jackson, D. A., 1989. “Potential of stimulated Brillouin scattering as sensing mechanism of distributed temperature sensors,” Electron. Lett., vol. 25, pp. 913–914, 1989.
Dakin, J. P., Pratt, D. J., Bibby, G. W., and Ross, J. N., 1985. “Distributed optical fiber Raman temperature sensor using a semiconductor light source and detector,” Electron. Lett., vol. 21, pp. 569‐570, 1985.
Dakin, John and Culshaw, Brian, 1988. Optical Fiber Sensors: Principles and Components, Artech House, Boston, 1988.
Dakin, John and Culshaw, Brian, 1989. Optical Fiber Sensors II: Systems and Applications, Artech House, Boston, 1989.
Dakin, John and Culshaw, Brian, 1996. Optical Fiber Sensors III: Components and Subsystems, Artech House, Boston, 1996.
Dakin, John and Culshaw, Brian, 1997. Optical Fiber Sensors IV: Applications, Analysis, and Future Trends, Artech House, Boston, 1997.
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De Costa, William J. 2004.“Next‐Generation Fiber Optic Sensors Capture Vital Information To Guide Decision Making,” The American Oil & Gas Reporter, January 2004.
Denney, Dennis, 2013 (written by senior editor Dennis Denney based on paper SPE 163694 authored by Rahman, Mahmood, Reed, Daniel A., and Allan, Malcoln E.,) , “Implementation Challenges: DTS Injection Profiles in the Belridge Field, California,” JPT, June 2013, pp. 120‐123.
Dyott, R. B. and Stern, J. R., 1970. “Group delay in glass fiber waveguides,” in IEE Conf. Trunk Telecommunications by Guided Waves, London, U.K., Sept.‐Oct. 1970, pp. 176–181.
Eck, Joseph et al. 2000. “Downhole Monitoring: The Story So Far,” Oilfield Review, Winter 1999/2000, pp. 20‐33.
Fryer V, Shuxing D, Otsubo Y, Brown G and Guilfoyle P, 2005. “Monitoring of Real‐Time Temperature Profiles Across Multizone Reservoirs During Production and Shut‐In Periods Using Permanent Fiber‐Optic Distributed Temperature Systems,” SPE 92962, SPE Asia Pacific Oil & Gas Conference and Exhibition, Jakarta, April 5‐7.
Fukuzawa, Toru, 2012. “DTSX200 Distributed Temperature Sensor for Oil and Gas Production, Yokogawa Technical Report, Vol. 55, No. 2, 2012.
Garus, D., Gogolla, T., Krebber, K., and Schliep, F., 1997. “Brillouin optical fiber frequency‐domain analysis for distributed temperature and strain measurements,” J. Lightwave Technol., vol. 15, no. 4, pp. 654–662, 1997.
Glasbergen, Gerard, Gualtieri, Dan, Trehan, Rakesh, Van Domelen, Mary, and Nelson, Micky, 2007. “Real‐Time Diversion Quantification and Optimization Using DTS,” SPE paper 110707, SPE Annual Technical Conference and Exhibition, 11‐14 November 2007, Anaheim, California.
Haase, K., 2007. “Strain sensors based on Bragg gratings,” Joint IMEKO TC3, TC16 and TC22 International Conference, November 27‐30, 2007, Merida, Mexico.
Hartog, A. H., 1985. “Distributed temperature sensing in solid‐core fibers,” Electron. Lett., vol. 21, pp. 1061–1062, 1985.
Henninges, Jan, Zimmermann, Günter, Büttner, Grit, Schrötter, Jörg, Erbas, Kemal, and Huenges, Ernst, 2005. “Wireline distributed temperature measurements and permanent installations behind casing,” Proceedings World Geothermal Congress 2005, Antalya, Turkey, 24‐29 April 2005.
Hill, K. O., Fujii, Y., Johnson, D. C., and Kawasaki, B. S., 1978. “Photosensitivity in optical fiber waveguides: Application to reflection filter fabrication,” Appl. Phys. Lett., vol. 32, pp. 647–649.
Hill, Ken and Meltz, Gerry, 1997. “Fiber Grating Technology Fundamentals and Overview,” Journal of Lightwave Technology, 15, 8, August, 1263‐1276, 1997.
Horiguch, T., Kurashima, T., and Tateda, M., 1990. “Distributed‐temperature sensing using stimulated Brillouin scattering in optical silica fibers”, Opt. Lett., 15, N°8, pp.1038‐10‐140, (1990).
Huckabee, Paul, 2009. “Optic Fiber Distributed Temperature for Fracture Stimulation Diagnostics and Well Performance Evaluation,” SPE paper 118831, SPE Hydraulic Fracturing Technology Conference, 19‐21 January 2009, The Woodlands, Texas.
Inaudi, Daniele and Glisic, Branko, 2006. “Integration of distributed strain and temperature sensors in composite coiled tubing,” SPIE Smart Structures and Materials Conference in San Diego. 2006 February 27, March 2, 2006.
Inaudi, Daniele and Glisic, Branko, 2006. “Distributed Fiber optic Strain and Temperature Sensing for Structural Health Monitoring,” IABMAS'06 The Third Int'l Conference on Bridge Maintenance, Safety and Management, 16 ‐ 19 July 2006, Porto, Portugal.
Johnson, D., Sierra, J., Gualtieri, D., and Kaura, J., 2006. “DTS Transient Analysis: A New Tool To Assess Well Flow Dynamics,” SPE paper 103093, SPE Annual Technical Conference and Exhibition, 24‐27 September 2006, San Antonio, Texas.
Kao, C. K. and Hockham, G., 1966. “Dielectric fiber surface waveguides for optical frequencies,” Proc. IEE, vol. 113, pp. 1151–1158, July 1966.
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Karaman, Osama S., Kutlik, Roy L., and Kluth, Ed L., 1996. “A Field Trial to test Fiber Optic Sensors for Downhole Temperature and Pressure Measurements, West Coalinga Field, California,” SPE paper 35685, SPE Western Regional Meeting, 22‐24 May 1996, Anchorage, Alaska.
Kawasaki, B. S., Hill, K. O., Johnson, D. C., and Fujii, Y., 1978. “Narrow‐band Bragg reflectors in optical fibers,” Opt. Lett., vol. 3, pp. 66–68, 1978.
Kersey, Alan D., Davis, Michael A., Patrick, Heather J., LeBlanc, Michel, Koo, K. P., Askins, C. G., Putnam, M. A., and Friebele, E. Joseph, 1997. “Fiber Grating Sensors,” Journal of Lightwave Technology, 15, 8, August, 1442‐1463, 1997.
Koelman, J. Vianney, 2011. “Fiber‐Optic Sensing Technology Providing Well, Reservoir Information‐‐Anyplace, Anytime,” JPT, July 2011, pp. 22‐24.
Lanier, G.H., Brown, G., and Adams, L., 2003. “Brunei Field Trial of a Fibre Optic Distributed Temperature Sensor (DTS) System in a 1,000m Open Hole Horizontal Oil Producer,” SPE paper 84324, SPE Annual Technical Conference and Exhibition, 5‐8 October 2003, Denver, Colorado.
Lecoeuche, V., Hathaway, M. W., Webb, D. J., Pannell, C. N., and Jackson, D. A., 2000. “20‐km distributed temperature sensor based on spontaneous Brillouin scattering,” IEEE Photon. Technol. Lett., vol. 12, no. 10, pp. 1367–1369, 2000.
Menadier, C., Kissinger, C., and Adkins, H., 1967. “The fotonic sensor,” Instruments and Control Systems, vol. 40, p. 114, 1967.
Niklès, M., Thévenaz, L., Robert, Philippe A., 1995. “Simple distributed fiber sensor based on Brillouin gain spectrum analysis", Optics Lett., 21, pp. 758‐760, (1995).
Parker, T. R., Farhadiroushan, M., Feced, R., Handerek, V. A., and Rogers, A. J., 1998. “Simultaneous distributed measurement of strain and temperature from noise‐initiated Brillouin scattering in optical fibers,” IEEE J. Quantum Electron., vol. 34, no. 4, pp. 645–659, 1998.
Pinzon, I.D., Davies, J.E., Mammadkhan, F., and Brown, G.A., 2007. “Monitoring Production from Gravel‐Packed Sand‐Screen Completions on BP's Azeri Field Wells Using Permanently installed Distributed Temperature Sensors,” SPE paper 110064, SPE Annual Technical Conference and Exhibition, 11‐14 November 2007, Anaheim, California.
Qi, Bing et al. 2002. “Fiber Optic Pressure and Temperature Sensors for Oil Down Hole Application,” Fiber Optic Sensor Technology and Applications, Proceedings of SPIE, Vol. 4578, pp. 182‐190.
Rahman, Mahmood, Zannitto, Peter J., Reed, Daniel A., and Allan, Malcolm E., 2011. “application of Fiber‐Optic Distributed Temperature Sensing Technology for Monitoring Injection Profile in Belridge Field, Diatomite Reservoir,” SPE paper 144116, SPE Digital Energy Conference and Exhibition, 19‐21 April 2011, The Woodlands, Texas.
Rahman, Mahmood, Reed, Daniel A., and Allan, Malcolm E., 2013. “The Challenges of Full Field Implementation of Fiber‐Optic DTS for Monitoring Injection Profile in Belridge Field, California,” SPE paper 163694, 2013 SPE Digital Energy Conference and Exhibition, Mar 05 ‐ 07, 2013, The Woodlands, TX.
Reinsch, Thomas and Henninges, Jan, 2012. “Temperature dependent characterization of optical fibres for distributed temperature sensing in hot geothermal wells,” Measurement Science and Technology, 21 (2010) 094022 (http://dx.doi.org/10.1088/0957‐0233/21/9/094022), arXiv:1206.1853 (physics.geo‐ph), 8 June 2012.
Reyes, Robert, Glasbergen, Gerard, Yeager, Valerie, and Parrish, Joseph, 2010. “Distributed temperature sensing yields lessons for acid treatment,” World Oil, July 2010, pp. 91‐100.
Shimizu, K., Horiguchi, T., and Koyamada, Y., 1995. “Measurement of distributed strain and temperature in a branched optical fiber network by use of Brillouin optical time‐domain reflectrometry,” Opt. Lett., vol. 20, no. 5, pp. 507–509, 1995.
Shiota, T. and Wada, T., 1991. “Distributed temperature sensors for single mode fibers,” Proc. SPIE, vol. 1586, pp. 13–18, 1991.
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Sierra, Jose, Kaura, Jiten, Gualtieri, Dan, Glasbergen, Gerard, Sarkar, Diptabhas, and Johnson, David, 2008. “DTS Monitoring of Hydraulic Fracturing: Experiences and Lessons Learned,” SPE paper 116182, SPE Annual Technical Conference and Exhibition, 21‐24 September 2008, Denver, Colorado.
Signorini, A., Faralli, S., Soto, M.A., Sacchi, G., Baronti, F., Barsacchi, R., Lazzeri, A., Roncella, R., Bolognini, G., and Di Pasquale, F., 2010. “40 km long‐range Raman‐based distributed temperature sensor with meter‐scale spatial resolution,” IEEE 2010 Optical Society of America, Optical Fiber Communication, National Fiber Optic Engineers Conference, 21‐25 March 2010, San Diego, CA.
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4. Instrumented Casing
Instrumented casing is defined as a casing containing sensors or possessing the ability to communicate
with or interrogate remote sensors. The sensed data may be communicated to the surface by means of
a casing telemetry system, or stored for later retrieval by another tool. This section gives a brief history of instrumented casing technologies, and describes several attempts to create such a system.
4.1 Brief History ‐ Instrumented Casing
Cooke et al. (1984) introduced instrumented casing. The main objective of their investigation was real‐
time measurement of downhole temperature and pressure during cementing in order to monitor and
predict mud losses, mud displacement efficiency, mud setting time, cementing operations, cross flow in
the annulus, gas migration, forecast well behavior, and reduce remedial costs. They proposed attaching
temperature and pressure sensors externally to the production casing and connecting them by a cable
that extended to the surface in order to transmit the valuable data to the surface.
In 2000, other inventors (Ciglenec and Tabanou 2000) proposed a system that measures formation
pressure with remote sensors in cased boreholes. They presented a system that takes information from
sensors placed in the formation during drilling operations. To achieve this, sensors will be placed in the
formation by means of gunfire, drilling, or hydraulically forcing them prior to installation of the casing.
The system would communicate with these sensors using an antenna installed on the casing. Given the
uncertainty in sensor location, they proposed attaching pip‐tags to these sensors that would emit
gamma radiation. A wireline tool could then detect the pip‐tag depth and azimuth. This tool would then
create a hole in the casing, and insert an antenna in the casing wall to allow communication with and
data collection from the sensors. Although this patent focuses specifically on detecting formation
pressure, it is obvious that other types of sensors could as easily be employed by this or a similar
system; the focus on formation pressure is understandable considering its vital role in formation
monitoring, production lifetime, and ensuring continuous production. The casing antenna could then
either communicate this information to the surface or store it in memory for later collection. The
greatest disadvantage of this system appears to be the time required to detect and mount antennas on
the casing. A preferable embodiment, assuming all other factors are equal, would be a casing system
with preinstalled antennas, thereby eliminating the non‐productive time (NPT).
During 2002 and 2004, Beique and Morris (2004) proposed the idea of placing pressure sensor in the
casing for future measurements and monitoring. Sensors should be attached to transmitters that send
the measurements to receivers, which collect and transmit the sensor information to the surface or
MWD/LWD and/or wireline tools.
Recently, Vinegar et al. (2006) developed wireless communication system using well casing. The system
uses well casing as a power and communication path between the surface and downhole modules, and
the formation as the ground (return path to complete the electrical circuit). Communications are
implemented using spread‐spectrum transceivers at the wellhead and downhole modules. The
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communication enables transmission of measurements from downhole sensors placed outside the
casing to the surface, and control of downhole devices.
More recently, Liang et al. (2009) presented a method that utilizes downhole sensor networks using
wireless communication. The goal of this invention would be to create a denser sensing structure near
the borehole to provide information vital to drilling, completions, and production operations. It
recognizes that elastodynamic waves can be employed for both subterranean power transfer and
communication with the sensor. Those sensors are located in the vicinity of a producing wellbore
receive power and communicate with one or more hubs located in the well or at the outer surface of a
casing by means of elastodynamic waves. These hubs could then log the sensor information for later
retrieval by a wireline type tool, or communicated directly to the surface by means of a cable attached
to the casing. The interrogating hubs could either harvest energy from the surrounds (such as from
downhole vibration or fluid flow) or could draw power directly from a casing cable. Given the
uncertainty in the relative hub and senor locations, they propose a type of searching function that would
allow the hub to locate a sensor (or sensor cluster) by steering the elastodynamic beam until a response
is detected; sensor locations could then be stored in memory. Furthermore, these sensor clusters could
increase communication range and signal strength by acting together to create a stronger combined
signal, so called beam forming. It is interesting to note that they disdain the use of RFID for the sensors
because of the short communication distance and power transfer problems.
In summary, a number of attempts have been made to create instrumented casing systems. The
commercial success of these systems, however, has been limited. Presently, instrumented casing
systems have a limited number of sensing elements at only a few discrete locations in the wellbore. A
number of the systems discussed here would satisfy a loose definition of an ICIFT system; however,
there are significant gaps in the intellectual property in this area, specifically there exist not patents at
present known to the authors that would prohibit the creation and commercialization of the system and
methods considered in this project.
4.2 U. S. Patents ‐ Instrumented Casing
The review of instrumented casing technology highlights the developments that have been made in
intelligent property as well as the review of articles published in journals and other resources.
U.S. Patent 4120166 (October 17, 1978) [Cement monitoring method; Exxon Production Research
Company] proposes a method for monitoring the location and set of a cement slurry within a support
member of an offshore structure. The location and setting properties of the cement are determined by
monitoring the electrical resistivity of the fluid within the support member. Preferably, a plurality of
electrical probes mounted along the length of the support member can be used to measure the
electrical resistivity of fluid within the member. Normally, the presence of cement would be indicated by
an abrupt change of resistivity as the cement displaces the original fluid (air or sea water) present in the
support member. Resistivity of the cement slurry will also change gradually as the cement sets.
Cooke et al. (1984) investigated real‐time measurement of downhole temperature and pressure during
cementing in order to monitor and predict mud losses, mud displacement efficiency, mud setting time,
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cementing operations, cross flow in the annulus, gas migration, forecast well behavior, and reduce
remedial costs. They proposed attaching temperature and pressure sensors externally to the
production casing and connecting them by a cable that extended to the surface in order to transmit the
valuable data to the surface. Even though little experimental work on instrumented casing has been
published since Cooke’s work in1984, a number of U.S. patents have been issued related to
instrumented casing since that time. These are reviewed next.
U.S. Patent 4839644 (June13, 1989) [System and method for communicating signals in a cased borehole
having tubing; Schlumberger Technology Corporation] proposes a system and method are for wireless
two‐way communication in a cased borehole having tubing extending there through. A downhole
communications subsystem is mounted on the tubing. The downhole subsystem includes a downhole
antenna for coupling electromagnetic energy in a TEM mode to and/or from the annulus between the
casing and the tubing. The downhole subsystem further includes a downhole transmitter/receiver
coupled to the downhole antenna, for coupling signals to and/or from the antenna. An uphole
communications subsystem is located at the earth's surface, and includes an uphole antenna for
coupling electromagnetic energy in a TEM mode to and/or from the annulus, and an uphole
receiver/transmitter coupled to the uphole antenna, for coupling the signals to and/or from the uphole
antenna. In accordance with a feature of the invention, the annulus contains a substantially non‐
conductive fluid (such as diesel, crude oil, or air) in at least the region of the downhole antenna and
above.
U.S. Patent 4845493 (July 4, 1989) [Well bore data transmission system with battery preserving switch;
Hughes Tool Company] proposes an improved method and apparatus of transmitting data signals within
a well bore having a string of tubular members suspended within it, employing an electromagnetic field
producing means to transmit the signal to a magnetic field sensor, which is capable of detecting
constant and time‐varying fields, the signal then being conditioned so as to regenerate the data signals
before transmission across the subsequent threaded junction by another electromagnetic field
producing means and magnetic sensor pair; the method and apparatus also having a battery saving
switch that extends the life of the battery carried by the tubular member in a compartment that shields
the battery from the well bore environment.
U.S. Patent 6028534 (February 22, 2000) [Formation data sensing with deployed remote sensors during
well drilling; Schlumberger Technology Corporation] proposes a method and apparatus for acquiring
data representing formation parameters while drilling a wellbore is disclosed. A well is drilled with a drill
string having a drill collar that is located above a drill bit. The drill collar includes a sonde section having
transmitter/receiver electronics for transmitting a controlling signal having a frequency F and receiving
data signals at a frequency 2F. The drill collar is adapted to embed one or more intelligent sensors into
the formation laterally beyond the wall of the wellbore. The intelligent sensors have electronically
dormant and active modes as commanded by the transmitter/receiver circuitry of the sonde and in the
active mode have the capability for acquiring and storing selected formation data such as pressure,
temperature, rock permeability, and the capability to transmit the stored data to the
transmitter/receiver of the sonde for transmission thereby to surface equipment for processing and
display to drilling personnel. As the well is being drilled the sonde electronics can be positioned in
selected proximity with a remote sensor and, without tripping the drill string, formation data can be
acquired and transmitted to the surface to enable drilling decisions based thereon.
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In 2000, Ciglenec and Tabanou were issued the U.S. patent 6070662 (June 6, 2000) [Formation pressure
measurement with remote sensors in cased boreholes; Schlumberger Technology Corporation] that
proposes the following: The present invention relates to a method and apparatus for establishing
communication in a cased wellbore with a data sensor that has been remotely deployed, prior to the
installation of casing in the wellbore, into a subsurface formation penetrated by the wellbore.
Communication is established by installing an antenna in an opening in the casing wall. The present
invention further relates to a method and apparatus for creating the casing wall opening, and then
inserting the antenna in the opening in sealed relation with the casing wall. A data receiver is inserted
into the cased wellbore for communicating with the data sensor via the antenna to receive formation
data signals sensed and transmitted by the data sensor. Preferably, the location of the data sensor in the
subsurface formation is identified prior to the installation of the antenna, so that the opening in the
casing can be created proximate the data sensor. The antenna can then be installed in the casing wall
opening for optimum communication with the data sensor. It is also preferred that the data sensor be
equipped with means for transmitting a signature signal, permitting the location of the data sensor to be
identified by sensing the signature signal. The location of the data sensor is identified by first
determining the depth of the data sensor, and then determining the azimuth of the data sensor relative
to the wellbore.
U.S. Patent 6429784 (August 6, 2002) [Casing mounted sensors, actuators and generators; Dresser
Industries, Inc.] proposes a casing sensor and methods for sensing using a casing sensor are disclosed.
The casing sensor includes a casing shoe and a sensor coupled to the casing shoe. A casing data relay
includes a downhole receiver coupled to a well casing and a transmitter coupled to the receiver. The
casing sensor may be coupled to the transmitter. A drill string actuator may be controllable through the
downhole receiver.
In 2004, Beique and Morris were issued the U.S. patent 6693554 (February 17, 2004) [Casing mounted
sensors, actuators and generators; Halliburton Energy Services, Inc.] wherein they proposed the
following: A casing sensor and methods for sensing using a casing sensor are disclosed. The casing
sensor includes a casing shoe and a sensor coupled to the casing shoe. A casing data relay includes a
downhole receiver coupled to a well casing and a transmitter coupled to the receiver. The casing sensor
may be coupled to the transmitter. A drill string actuator may be controllable through the downhole
receiver.
In 2006, Vinegar et al. were issued the U.S. patent 7114561 (October 3, 2006) [Wireless communication
using well casing; Shell Oil Company]; they proposed the following: A petroleum well having a borehole
extending into a formation is provided. A piping structure is positioned within the borehole, and an
induction choke is positioned around the piping structure downhole. A communication system is
provided along the piping structure between a surface of the well and the induction choke. A downhole
module is positioned on an exterior surface of the piping structure and is configured to measure
characteristics of the formation. The formation characteristics, such as pressure and resistivity, are
communicated to the surface of the well along the piping structure.
U.S. Patent 7380597 (June 3, 2008) [Deployment of underground sensors; Schlumberger Technology
Corporation] proposes a method of installing a sensor located in a chamber on the out‐side of a casing,
comprising the steps of positioning the casing in a well, cementing the casing in position, positioning a
drilling tool inside the casing level with the chamber, drilling through the casing, chamber and cement
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into the formation surrounding the well so as to create a fluid communication path, and sealing the hole
drilled in the casing.
U.S. Patent 7477162 (January 13, 2009) [Wireless electromagnetic telemetry system and method for
bottomhole assembly; Schlumberger Technology Corporation] proposes a wireless electromagnetic
telemetry system for broadcasting signals across a bottomhole assembly disposed in a borehole drilled
through a subterranean formation includes an insulated gap at a first point in the bottomhole assembly,
at least one magnetic field sensor at a second point in the bottomhole assembly which measures a
magnetic field, and a circuitry which modulates a voltage across the insulated gap, wherein the voltage
creates an axial current along the bottomhole assembly that results in the magnetic field.
U.S. Patent 7518528 (April 14, 2009) [Electric field communication for short range data transmission in a
borehole; Scientific Drilling International, Inc.] proposes an application of a unique conductive electrode
geometry used to form an efficient wideband, one‐ or two‐way wireless data link between autonomous
systems separated by some distance along a bore hole drill string. One objective is the establishment of
an efficient, high bandwidth communication link between such separated systems, using a unique
electrode configuration that also aids in maintaining a physically robust drill string. Insulated or floating
electrodes of various selected geometries provide a means for sustaining or maintaining a modulated
electric potential adapted for injecting modulated electrical current into the surrounding sub‐surface
medium. Such modulated current conveys information to the systems located along the drill string by
establishing a potential across a receiving insulated or floating electrode.
In 2009, Liang et al. were issued the U.S. patent 7602668 (October 13, 2009) [Downhole sensor networks using wireless communication; Schlumberger] wherein they proposed the following: Sensors located in the vicinity of a hydrocarbon‐producing well receive power and communicate with one or more hubs located in the well or at the outer surface of a casing by means of elastodynamic waves. Each hub incorporates a plurality of transducers which permit focusing of the emitted elastodynamic waves. In order to concentrate the energy on a single sensor, or a group of sensors arranged in a cluster. Hubs and sensors communicate by exchanging, modulated elastodynamic waves. Sensors belonging to a cluster may transmit, properly time‐shifted elastodynamic waves, in order to collectively focus their energy in the direction of a hub. Time synchronization between the sensors within a cluster may be accomplished by means of electromagnetic fields which travel much faster than elastodynamic waves, but can only propagate over short distances in typical formations. U.S. Patent 7880640 (February 1, 2011) [Wellbore communication system; Schlumberger Technology
Corporation] proposes a gap collar for an electromagnetic communication unit of a downhole tool
positioned in a wellbore. The downhole tool communicates with a surface unit via an electromagnetic
field generated by the electromagnetic communication unit. The gap collar includes a first collar having
a first end connector and a second collar having a second end connector matingly connectable to the
first end connector. The gap collar further includes a non‐conductive insulation coating disposed on the
first and/or second end connectors, and a non‐conductive insulation molding positioned about an inner
and/or outer surface of the collars. The insulation molding moldingly conforms to the shape collars. The
connectors are provided with mated threads modified to receive the insulation coating. Measurements
taken by the downhole tool may be stored in memory, and transmitted to the surface unit via the
electromagnetic field
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U.S. Patent 8141631 (March 27, 2012) [Deployment of underground sensors in casing; Schlumberger
Technology Corporation] proposes a subsurface formation fluids monitoring system, and a method
thereof, integrated on a casing or tubing sub having an inner and an outer surface and defining an
internal cavity. The system also includes a sensor mounted on the outer surface and wireless data
communication between an interrogating tool located in the internal cavity and the sensor. The system
also able to provide fluid communication between the sensor and fluids of the formation with a tool that
can be moved through the well to a number of locations.
U.S. Patent 8164475 (April 24, 2012) [Downhole communication; Expro North Sea Limited] proposes a
downhole signal receiving system where a pair of setting devices are used to electrically connect with
downhole structure and are connected to one another by a bulk conductor. Signals are extracted by
using a detecting means (53) that does not interrupt the conduction path. The tool provides a low
impedance conduction path along which signals from the surrounding structure can flow to facilitate
detection.
U.S. Patent 8215164 (July 10, 2012) [Systems and methods for monitoring groundwater, rock, and casing
for production flow and leakage of hydrocarbon fluids; HydroConfidence Inc.] proposes a system
comprising one or more subsystems, which can be practiced alone or in combination, which together
allow for monitoring of groundwater, rock, and casing for production flow and leakage of hydrocarbon
fluids. A flow measurement subsystem measures flow of hydrocarbons in the horizontal casing string. A
well mechanical integrity monitoring subsystem monitors the mechanical integrity of the natural gas
production well, including the junctures of a completed well. An aquifer monitoring subsystem directly
monitors water aquifer(s) underneath and surrounding a natural gas production well or pad, including
monitoring wells or existing water wells. A communication subsystem is used to communicate
measurements taken downhole to the surface. The present invention may be used to enhance the
production from a gas bearing shale formation, mitigate liability associated with hydrocarbon migration,
and monitor for a loss of mechanical integrity of a well.
U.S. Patent 8237585 (August 7, 2012) [Wireless communication system and method; Schlumberger
Technology Corporation] proposes a wireless communication system for use in well, subsea, and oilfield‐
related environments employs one or more wireless network devices that offer short‐range wireless
communication between devices without the need for a central network which may have a device using
a BLUETOOTH protocol. The system may be used for telemetry, depth correlation, guidance systems,
actuating tools, among other uses.
U.S. Patent 8269648 (September 18, 2012) [System and method to remotely interact with nano devices
in an oil well and/or water reservoir using electromagnetic transmission; Lockheed Martin Corporation]
proposes electromagnetic transmission and reception used in detecting relative changes associated with
nano devices existing within an oil reservoir. The system enables monitoring of the relative movement
of the nano devices in the oil and/or water over a given area based on the incremental or relative
changes of the intensity of the reflections over time. In one embodiment, a source of electromagnetic
energy from an array of antennae transmitting immediately in the far field recharges a power source
embedded in the nano devices. In another embodiment, the return signals from the nano devices maps
the morphology of ensembles of nano devices. In yet another embodiment the transmission controls
the movement of the nano devices and controls the function performed by the nano devices relative to
effecting changes in the well to improve production of oil.
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U.S. Patent 8305229 (November 6, 2012) [System for wireless communication along a drill string; The
Charles Machine Works, Inc.] proposes a system of wireless communication along a drill string for
communication between a boring tool and boring machine. The method of communication is an
insulated gap placed in the drill string with a soil‐engaging electrode. This would allow for wireless
communication between different elements of a drilling string.
U.S. Patent 8312320 (November 13, 2012) [Intelligent field oil and gas field data acquisition delivery
control and retention based apparatus program product and related methods; Saudi Arabian Oil
Company] proposes an apparatus, program product, and methods for data management. An exemplary
apparatus includes one or more PDHMS surface units each having a serial interface to provide a
continuous real‐time data stream of captured data, a data storage medium for storing collected
downhole process data during a downstream communication link failure, a controller configured to
cause the PDHMS surface unit to store recovery data during the downstream communication failure,
and a broadband interface to provide recovery file transmission of recovery data stored during the
downstream communication link failure. The apparatus can also include a RTU configured to collect the
continuous real‐time data collected by the PDHMS surface unit and to transmit the collected data to a
SCADA system, which can function as a time synchronization master for the RTU and PDHMS surface
units, and which can forward the collected data to other systems.
U.S. Patent 8327932 (December 11, 2012) [Recovering energy from a subsurface formation; Shell Oil
Company] proposes a method of recovering energy from a subsurface hydrocarbon containing
formation that includes introducing an oxidizing fluid in a wellbore positioned in at least a first portion
of the formation. At least a portion of the first portion of the formation has been subjected to an in situ
heat treatment process. The portion includes a treatment area having elevated levels of coke
substantially adjacent the wellbore. The pressure in the wellbore is increased by introducing the
oxidizing fluid under pressure such that the oxidizing fluid substantially permeates a majority of the
treatment area and initiates a combustion process. Heat from the combustion process is allowed to
transfer to fluids in the treatment area. Pressure decreases in the wellbore such that heated fluids from
the portion of the formation are conveyed into the wellbore. The heated fluids are transferred to a heat
exchanger configured to collect thermal energy.
U.S. Patent 8330617 (December 11, 2012) [Wireless power and telemetry transmission between
connections of well completions; Schlumberger Technology Corporation] proposes an intelligent well
system that may include a first main bore transmission assembly disposed in a main bore and a first
lateral bore transmission assembly disposed in a lateral bore. The first main bore transmission assembly
may include a first main bore transmission unit, and the first lateral bore transmission assembly may
include a first lateral bore transmission unit. The first main bore transmission unit and the first lateral
bore transmission unit may be configured to establish a wireless connection there between, such that at
least one of power or telemetry can be wirelessly transmitted. The first main bore transmission
assembly may be configured to be communicatively connected to a surface communication device.
U.S. Patent 8342242 (January 1, 2013) [Use of micro‐electro‐mechanical systems MEMS in well
treatments; Halliburton Energy Services, Inc.] proposes a method comprising placing a Micro‐Electro‐
Mechanical System (MEMS) sensor in a subterranean formation, placing a wellbore composition in the
subterranean formation, and using the MEMS sensor to detect a location of the wellbore composition. A
method comprising placing a Micro‐Electro‐Mechanical System (MEMS) sensor in a subterranean
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formation, placing a wellbore composition in the subterranean formation, and using the MEMS sensor
to monitor a condition of the wellbore composition. A method comprising placing one or more Micro‐
Electro‐Mechanical System (MEMS) sensors in a subterranean formation, placing a wellbore
composition in the subterranean formation, using the one or more MEMS sensors to detect a location of
at least a portion of the wellbore composition, and using the one or more MEMS sensors to monitor at
least a portion of the wellbore composition. A method comprising placing one or more Micro‐Electro‐
Mechanical System (MEMS) sensors in a subterranean formation using a wellbore composition, and
monitoring a condition using the one or more MEMS sensors.
U.S. Patent 8358220 (January 22, 2013) [Wellbore communication downhole module and method for
communicating; Shell Oil Company] proposes a wellbore communications system comprising a surface
computing unit. The surface computing unit comprises a processing module and a communications
module, one or more downhole modules arranged within the wellbore, and a wireless communications
channel communicatively coupling one or more the downhole modules and the surface computing unit.
The surface computer unit and one or more of the downhole modules are configured to encode data
with an iterative code prior to transmission on the wireless communications channel.
U.S. Patent 8390471 (March 5, 2013) [Telemetry apparatus and method for monitoring a borehole; Chevron U.S.A., Inc.] proposes a system, method and device may be used to monitor conditions in a borehole. Energy is transmitted to a pulse generator located proximate a position to be interrogated with a sensor. The pulse generator stores the energy, and then releases it in a pulse of electromagnetic energy, providing the energy to resonant circuits that incorporate the sensors. The resonant circuits modulate the electromagnetic energy and transmit the modulated energy so that it may be received and processed in order to obtain the desired measurements.
4.3 References ‐ Chapter on Instrumented Casing
Beique, J. M. and Morris, B. R. 2004. Casing Mounted Sensors, Actuators and Generators, US Patent number: 6693554.
Ciglenec, R. and Tabanou, J.R. 2000.Formation pressure measurement with remote sensors in cased boreholes, US Patent # 6070662.
Cooke, C.E. Jr., Kluck, M. P. and Medrano, R. 1984. "Annular Pressure and Temperature Measurements Diagnose Cementing Operations." SPE Journal of Petroleum Technology no. 36 (12):2181‐2186. doi: 10.2118/11416‐pa.
Liang, K. K., Jacques, J., and Philippe, S. 2009. Downhole sensor networks using wireless communication. Schlumberger Technology Corporation.
Vinegar, H., Robert, R. B., William M. S., Frederic, G.C. and Ilya, E.B. 2006. Wireless Communication Using Well Casing. Shell Oil Company.
The U.S. Patents referenced in this section are listed below in chronological order. U.S. Patent 4120166: Cement monitoring method Exxon Production Research Company Issued October
17, 1978, Filed March 25, 1977. U.S. Patent 4845493: Well bore data transmission system with battery preserving switch Hughes Tool
Company Issued July 4, 1989, Filed November 4, 1987. U.S. Patent 4839644: System and method for communicating signals in a cased borehole having tubing
Schlumberger Technology Corporation Issued June 13, 1989, Filed June 10, 1987.
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U.S. Patent 6028534: Formation data sensing with deployed remote sensors during well drilling Schlumberger Technology Corporation Issued February 22, 2000, Filed November 5, 1998.
U.S. Patent 6070662: Ciglenec, R. and Tabanou, J.R., Formation pressure measurement with remote sensors in cased boreholes Schlumberger Technology Corporation Issued June 6, 2000, Filed August 18, 1998.
U.S. Patent 6429784: Casing mounted sensors, actuators and generators Dresser Industries, Inc. Issued August 6, 2002, Filed February 19, 1999.
U.S. Patent 6693554: Beique, J. M. and Morris, B. R., Casing mounted sensors, actuators and generators Halliburton Energy Services, Inc. Issued February 17, 2004, Filed June 11, 2002.
U.S. Patent 7114561: Vinegar, H., Robert, R. B., William M. S., Frederic, G.C. and Ilya, E.B. 2006, Wireless communication using well casing Shell Oil Company Issued October 3, 2006, Filed March 2, 2001;
U.S. Patent 7380597: Deployment of underground sensors Schlumberger Technology Corporation Issued June 3, 2008, Filed April 10, 2003.
U.S. Patent 7477162 & 7477162 B2: Wireless electromagnetic telemetry system and method for bottomhole assembly Schlumberger Technology Corporation Issued January 13, 2009, Filed October 11, 2005.
U.S. Patent 7518528: Electric field communication for short range data transmission in a borehole Scientific Drilling International, Inc. Issued April 14, 2009, Filed February 13, 2006.
U.S. Patent 7602668: Liang, K. K., Jacques, J., and Philippe, S., Downhole sensor networks using wireless communication Schlumberger Issued October 13, 2009, Filed November 3, 2006.
U.S. Patent 7880640: Wellbore communication system Schlumberger Technology Corporation Issued February 1, 2011, Filed May 24, 2006.
U.S. Patent 8141631: Deployment of underground sensors in casing Schlumberger Technology Corporation Issued March 27, 2012, Filed June 21, 2005.
U.S. Patent 8164475: Downhole communication Expro North Sea Limited Issued April 24, 2012, Filed November 28, 2005.
U.S. Patent 8215164: Systems and methods for monitoring groundwater, rock, and casing for production flow and leakage of hydrocarbon fluids HydroConfidence Inc. Issued July 10, 2012, Filed January 2, 2012.
U.S. Patent 8237585: Wireless communication system and method Schlumberger Technology Corporation Issued August 7, 2012, Filed October 17, 2007.
U.S. Patent 8269648: System and method to remotely interact with nano devices in an oil well and/or water reservoir using electromagnetic transmission Lockheed Martin Corporation Issued September 18, 2012, Filed October 22, 2009.
U.S. Patent 8305229: System for wireless communication along a drill string The Charles Machine Works, Inc. Issued November 6, 2012, Filed January 18, 2010.
U.S. Patent 8312320: Intelligent field oil and gas field data acquisition delivery control and retention based apparatus program product and related methods Saudi Arabian Oil Company Issued November 13, 2012, Filed August 25, 2009.
U.S. Patent 8327932: Recovering energy from a subsurface formation Shell Oil Company Issued December 11, 2012, Filed April 9, 2010.
U.S. Patent 8330617: Wireless power and telemetry transmission between connections of well completions Schlumberger Technology Corporation Issued December 11, 2012, Filed September 11, 2009.
U.S. Patent 8342242: Use of micro‐electro‐mechanical systems MEMS in well treatments Halliburton Energy Services, Inc. Issued January 1, 2013, Filed November 13, 2009.
U.S. Patent 8358220: Wellbore communication downhole module and method for communicating Shell Oil Company Issued January 22, 2013, Filed March 26, 2008.
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U.S. Patent 8390471: Telemetry apparatus and method for monitoring a borehole Chevron U.S.A., Inc. Issued March 5, 2013, Filed September 7, 2007.
5. Borehole Telemetry
5.1 Well Logging Methods
In their 2008 2nd edition of the book “Well Logging for Earth Scientists,” Ellis and Singer describe well
logging methods in great detail. For the most part, measurement techniques for well logging methods
are developed from the three broad disciplines ‐ electrical, nuclear, and acoustic. Such measurements
are sensitive to the properties of the rock and/or to the pore‐filling fluid. Wireline logging,
measurement while drilling (MWD) and logging while drilling (LWD) methods are used in making
formation evaluations and completion evaluations. A formation evaluation determines the following:
(1) location of oil‐bearing and gas‐bearing formations, (2) an estimate of their producibility, and (3) an
assessment of the quantity of hydrocarbon in place in the reservoir. Completion evaluation focuses on
critical things such as cement quality, pipe and tubing corrosion, pressure, temperature and flow
measurements, etc. as well as a whole host of production logging services. For an in depth treatment of
the well logging methods that are used in making formation evaluations and completion evaluations, the
reader is referred to Ellis and Singer’s book.
5.2 Wireline Telemetry
In 1927, the Schlumberger brothers developed the first electrical log in France. The instrument
measures the electrical resistivity of the formation at different depths. This information can give an
indication of what is in the ground. Oil soaked rock generally has a high resistivity; while water soaked
rock has lower resistivity. This information was useful to people looking for oil at that time (SEED 2012).
In addition, wireline telemetry provides an enormous improvement in studying subsurface geology. It
uses a single‐ or multi‐strand cable in order to send information from downhole tools to the surface at
high speed and quality.
Since the Schlumberger brothers, wireline telemetry has provided high quality information from
formations, but not in real‐time while drilling. Drilling assemblies must be pulled out of the borehole in
order to give wireline tools room to be lowered down into the formation. Reservoir, geological and
petro‐physical analyses are performed using wireline logs because it provides high confidence to
reservoir engineers and geologist.
5.3 RF Signal Transmission in Rock Formations
The communications potential of radio wave propagation through rock strata in the earth's crust is
treated by Ames, et al. (1963). Included are geological and geophysical considerations pertinent to
communications. The work addresses electrical properties of media and antenna characteristics in
describing wave propagation in dissipative medium. Conductivity and attenuation are considered for
rock strata with pore spaces containing water, fluids, etc. The conductivity of rock with water‐filled pore
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is known to vary exponentially with the porosity. Small changes in rock porosity have a large effect on
radio wave attenuation. The work addressing deep‐strata communication with ranges extending over
10s and 100s miles emphasizes that the frequency range of interest is limited to 1‐20 KHz.
Information on RF signal transmission in rock formations largely focuses on applications that include EM
telemetry, borehole and cross‐borehole EM radar systems, and mining communication systems. A few
general properties that have been widely observed are noted.
The frequency range for a particular downhole EM system is critical. For EM MWD, this has been shown
to be about 1‐10Hz. While for cross‐borehole radar, the operating range is around 100 MHz. The major
factor here is the distance through the rock strata that these signals must travel. While for EM MWD this
involves thousands of feet, for borehole radar this is only a couple hundred feet allowing a much larger
frequency. For distances less than what borehole radar requires, higher signal frequencies may be
possible. It is important to use the highest frequency that can reliably communicate over the required
distance since higher frequencies lead to high data transmission rates. In general, each component of an
ICIFT system will have a particular operating frequency range depending on a host of factors and
conditions.
5.4 Electromagnetic Telemetry
The Electromagnetic Telemetry concept was first introduced in the 1940s with the objective of
transmitting information from the bottom of a borehole to the surface during the drilling process. Using
electromagnetic signals would do away with the need for an electrical conduit inside the drill pipe (Arps
and Arps 1964).
A field study (Smith 1983) demonstrated the potential use of electromagnetic data transmission method
for the application downhole telemetry. Measurements showed successfully transmission of data from
depth of 10,000 ft. at the rate of 2 to 50 bits per second. It was found that, by varying frequencies,
depths in excess of 16,000 ft. could be obtained.
Thawley and Scott (1984) introduced a downhole digital power amplifier, which is used in a
measurements‐while‐drilling telemetry system. Using digital means, this system provided a sinusoidal,
variable frequency, variable power, and phase shifted output for the transmission of data from a sensor
arrangement to a coupling transfer device, for ultimate transmission of downhole data to the surface by
electromagnetic waves.
As more difficult well trajectories and profiles were drilled, conventional wireline and mud pulse
telemetry started facing disadvantages. For example, in horizontal boreholes, the difficulty of inserting
tools and logs in the absence of a large gravitation force component reduces the success rate of the
wireline runs. In addition, in the absence of large mud windows, wells need to be drilled using
compressible fluids that prohibit mud pulse telemetry. Harrison et al. (1990) conducted study on the
needs of the industry regarding downhole telemetry. They concluded that electromagnetic telemetry is
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capable of 8 bits/second in most common borehole depths in average conductivity, and 1 bit/second is
feasible in all known worst cases at a depth of 10,000 ft.
Recently, Schnitger and Macphers (2009) modeled the signal strength of an electromagnetic telemetry
system where the skin depth effect and the exponential attenuation for higher frequencies were
confirmed by real measurements. The constant attenuation at lower frequencies was also confirmed. In
fact, EM telemetry actually involves transmitting through the formation adjacent to the wellbore, and
formation, mud and surface properties therefore greatly influence the attenuation of the signal. So it
was concluded that repeater‐less EM telemetry is a reliable means of transmission only in depths
shallower than 9,000 feet, although, there have been some exceptions where it has been achieved to
depths greater than 15,000 ft. Additionally, because measured signal amplitudes depend on mud and
formation resistivity, which vary with time and depth, accurate predictions of signal amplitudes are
difficult.
5.5 Wired Drill Pipe Telemetry
Wired drill pipe telemetry was first introduced in the later part of the 1930’s as a continuous insulated
electrical conduit attached to the drill pipe from surface to the bottom portion of the drill string.
However, those designs faced some problems with the lack of leakage resistance to the ground of
electrically connected, insulated conductors located in a fluid‐filled well, which resulted in current
leakage (Polk 1935).
In 1965, Brandt designed an invention to prevent current leakage to ground by providing a direct electric
potential on the insulated conductors to cause electrolysis through the drilling mud at the connecting
joints of the conductor, which results in the formation of an insulating gas film on the electrical contacts
of the connected insulated conductors. This was one of the first of many steps to eventual creation of a
commercial viable wired pipe system (Brandt 1965).
In 1988, Howard developed an invention to overcome the major drawback with wire pipe telemetry: the
Drill Pipe Compound (DPC). Exxon Production Research Company, Shell Development Company, R.
Meador, and other scientists have made efforts to improve telemetry through the tool joints, but none
of the previous works had achieved commercial success. Howard found that an electromagnetic field
generation source, such as a wire coil and ferrite core, can be employed to transmit electrical data
signals across a threaded junction utilizing a magnetic field (Howard 1988).
Fay et al. (1992) performed field tests in 1992 while drilling with the high‐data‐telemetry system,
indicating reliable behavior of its components. The electromechanical connectors inside the drill pipes
performed well and did not cause any disturbances during standard data transmission, and their results
seemed very attractive due to number and accuracy of data collected.
More recently, Allen et al. (2009) presented the advantages of the wired pipe telemetry systems to‐
date. It was concluded that ECD management enhancement, vibration diagnostics for drilling
optimization, instantaneous downlink commands to rotary steerable systems, elimination of data linking
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related NPT, directional control improvements, and memory quality of formation evaluation
measurements allowed more effective reservoir navigation, drilling performance and wellbore
placement. In addition, the learning curve associated with the implementation of the combined wired‐
pipe and downhole tools in real time does not represent a threat to the operations, and the risk
associated with its adoption is low.
Today, National Oil Well Varco (NOV) is one of the providers in Wired pipe technology. The NOV wired
pipe consists of a high‐speed wired drill pipe telemetry system, allowing bi‐directional data flow along a
drilling string. The current state of wired drill pipe allows a 57.6 Kbps bi‐directional data rate. Along the
string of pipe, assembly (BHA) interfaces exists for communication with most of the major service
providers (Pink et al. 2012).
The wired pipe platform is comprised of 5 main components:
The interface sub connects to the MWD/LWD and RSS tools to allow bi‐directional
communication of logs and commands.
The wired pipe “Booster subs” enhances the signal to improve the signal to noise ratio and
improves communication efficiency between subs. First generation “Measurement Subs”
positioned along the drill string currently measure bore and annular pressure as well as
electronics board temperature.
The wired pipe “Broadband Network” is the heart of the system, allowing high reliability data
transmission through the drill pipe.
The Top Drive swivel allows for data to be extracted to the surface system while the drill pipe
rotates.
The wired pipe network, in its current state, is capable of providing data at a sufficient telemetry speed
(57 kbps) to automate all parameters except the vibration data. To achieve a full high speed vibration
related optimization, a future state telemetry speed will be required (Pink et al. 2012).
5.6 Acoustic Methods
First introduced in the 1940’s, acoustic methods transmit seismic or acoustic signals through the drill
pipe, the earth, or the mud stream. Since then, several attempts have been made to develop a reliable
acoustic telemetry technology as an alternative to mud pulse in drilling applications. However, most of
them have subsequently been abandoned (ARPS and ARPS 1964, Azari et al. 2006).
In 2006, a new Acoustic Telemetry system (ATS) was presented by Azari et al. (2006) to obtain real‐time
bottom hole pressure and temperature data without the use of wireline during Drill Stem Test (DST)
operations. This was particularly important to eliminate any potential problems that could occur with
the wireline or slick line operations. This particular system uses generated acoustic energy to transmit
real‐time data to the surface through the tubing wall. The maximum transmission distance at the
current stage was 12,000ft using a single repeater. In addition, the downhole transmitter uses three
quartz sensors, each of which have the capacity to store up to 440,000 data sets.
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52 | P a g e
In 2011, Reeves et al. published a SPE Paper where it is shown that a Canadian engineering company
(XACT Downhole Telemetry Inc.) has overcome key technical hurdles to develop successful acoustic
telemetry technology. With the help of repeaters placed in the drillstring, acoustic signals could reach
the surface without problems. However, drill string vibrations such as stick and slip, as well as rig noises
affected acoustic signals at surface. Therefore, more work must be done on this technology in order to
reduce the amount of surface noise and vibrations that could cause data loss. Up to 30 bits per second
could be reached and decoded at the surface using this technology, and it is not depth‐dependent
(Reeves, Camwell, and Mcrory 2011).
5.7 Mud Pressure Pulses
First introduced by Arps and Scherbatskoy (1964), mud pressure pulsing mainly focused on utilizing
logging methods for detecting and measuring the variations in formation characteristics or in
measurement values of other physical quantities at a point in the borehole adjacent the drill bit while
drilling is in progress. This makes continuous measurements of such characteristics located in the drill
stem adjacent to the drill bit, converts the measurements into pressure wave impulses in the drilling
fluid which travel to surface where pressure sensors located in the surface lines detect those signals and
relay them to a main decoding apparatus for their surface interpretation.
In 1964, Arps discussed the benefits of his invention. He explained that in this system, the resistance to
flow of the mud stream through the drill string is modulated by means of a valve device mounted in a
special drill collar sub directly above the bit. Utilizing the flowing mud stream as the communication
channel, this system requires no major modifications to the drill string to establish contact between the
downhole instruments and the surface (ARPS and ARPS 1964)
In the later part of 1980’s, mud pulse tools were able to send data from downhole to the surface at the
rate of 1.5 to 3 bits per second. Also, the mud pulse signal was noted to lose half its amplitude every
1,500 to 3,000 feet of depth, as mentioned by Howard in the U.S Patent #4788544 (Howard 1988).
Today, MWD tools in the industry are capable of transmitting close to 15 bits per second of data from
downhole to surface using high‐speed measurement while drilling tools.
5.8 References – Chapter on Borehole Telemetry
Allen, S., McCartney, C., Hernandez, M., Reeves, M., Baksh, A. and MacFarlane, D. 2009. Step‐Change Improvements with Wired‐Pipe Telemetry, paper SPE‐ 119570‐MS, presented at the SPE/IADC Drilling Conference and Exhibition, 17‐19 March, Amsterdam.
Ames, L. A., DeBettencourt, J. T., Frazier, J. W., and Orange, A. S., 1963. “Radio Communications via Rock Strata,” IEEE Transactions on Communications Systems, June, Volume 11, Issue 2, 159‐169.
Arps, J.J., and Arps, J.L. 1964. The Subsurface Telemetry Problem‐A Practical Solution. Journal of Petroleum Technology, Vol. 16, Num. 5, Pages 487‐493.
Arps, Jan J., and Serge A. Scherbatskory. 1952. Logging While Drilling. edited by USPTO. United States.
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53 | P a g e
Azari, M., Salguero, A.M., Almanza, E. and Kool, H. 2006. Data Acquisition with Advanced Acoustic Telemetry Improves Operational Efficiency in Deep‐water and Land‐Well Testing, Paper SPE‐ 101182‐MS, presented at the SPE Asia Pacific Oil & Gas Conference and Exhibition, Adelaide, Australia.
Brandt, H. 1965. Method of Improving Electrical Signal, United States Patent 3170137. Ellis, Darwin V. and Singer, Julian M., 2008. Well Logging for Earth Scientists, 2nd Edition, Springer. Fay, J.B., Fay, H. and Couturier, A. 1992. Wired Pipes for a High‐Data‐Rate MWD System. In European
Petroleum Conference. Cannes, France: 1992 Copyright 1992, Society of Petroleum Engineers Inc. Harrison, W.H., R.L. Mazza, L.A. Rubin, and A.B. Yost II. 1990. Air‐Drilling, Electromagnetic, MWD System
Development, paper SPE‐ 19970, presented at the SPE/IADC Drilling Conference, 27 February‐2 March, Houston, Texas.
Howard, Mig A. 1988. Well bore data transmission system, US Patent number: 4845493. Pink, T., Bruce, A., Kverneland, H. and Applewhite, B. 2012. Building an Automated Drilling System
Where the Surface Machines are Controlled by Downhole and Surface Data to Optimize the Well Construction Process, paper SPE‐ 150973, presented at the IADC/SPE Drilling Conference and Exhibition, San Diego, California.
Polk, J.V. 1935. Insulated Electrical Connection. United States Patent US2000716. Reeves, M.E, Camwell,P.L. and Mcrory J. 2011. High Speed Acoustic Telemetry Network Enables Real‐
Time Along String Measurements, Greatly Reducing Drilling Risk., paper SPE‐145566, presented at the Offshore Europe Conference, 6‐8 September 2011, Aberdeen, UK.
Schnitger, J. and Macpherson, J.D. 2009. Signal Attenuation for Electromagnetic Telemetry Systems, Paper SPE‐ 118872, presented at SPE/IADC Drilling Conference and Exhibition, Amsterdam.
SEED. 2012. Build An Electrical Logging Tool. Schlumberger Excellence in Educational Development, Inc. 2012, Available at www.planetseed.com/node/20391, lasted accessed Dec. 02.
Smith, H.C. 1983. Toroidal Coupled Measurements While Drilling, paper SPE‐ 11361, presented at the IADC/SPE Drilling Conference, 20‐23 February, New Orleans, Louisiana.
Thawley, S. T, and Craig, M.S. 1984. Downhole Digital Power Amplifier for Measurements‐While Drilling Telemetry System, United States Patent: 4468665.
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54 | P a g e
6. Borehole Telemetry – Capabilities and Reliability
Telemetry measurements obtained from different wells are summarized by the service companies that
provide the respective technology (Schlumberger, Baker Hughes, Halliburton, Weatherford), and are
presented here, as they provide a better understanding of the reliabilities and capabilities of their
existing systems. While reliability data on telemetry systems other than wireline is rare in the literature,
the available data is discussed and the conclusions are summarized below.
6.1 Hardwired Telemetry
High quality and valuable memory data can be sent to surface while drilling which helps the drilling team
to make more informed decisions than ever before possible. Three types of hard‐wired telemetry in the
Industry are wireline, wired casing and wired pipe.
Wire line is well used in almost all drilled wells. It has been the standard method to get downhole
information since the 1930’s. The main advantage is the high resolution of the logs. However, in high
angles and deep wells, wireline in open‐hole logging is challenging due to drag, low tool weight,
formation washouts, wellbore tortuosity, fluid condition, and wellbore deterioration. Therefore, in some
wells it is preferred to avoid wire line operation and work with the logs taken while drilling, alone.
In wired casing, the wire is placed outside the casing, and runs from downhole to surface. Its use began
in the 1980’s in order to prevent remedial cementing jobs by providing real time information related to
pressure and temperature while cementing (Cooke, Kluck, and Medrano 1984). However, there is no
recognized system that can provide the same technical and economic advantage comparable to the
wired system.
Wired drill pipe consists of a wire normally placed inside the drill pipe, and runs the entire well length
from downhole to surface. It is manufactured in double‐shouldered drill pipe connections to meet the
demands of tough drilling applications. Its application has increased since 2000, promoted by extreme
drilling programs and high rig costs.
Wired pipe communication does not require mud circulation and it can be used simultaneously with
mud pulses. Therefore, in drilling scenarios in which the mud pulser stops working, data can continue
being received at the surface from the wired drill pipe at a high rate of 10,000 bits per second. Allen et
al (2009) showed the difference between mud pulse and wired pipe telemetry data acquisition that can
be observed:
We see from Figure 6.1 that the wired pipe system offers a much effective sampling rate than the mud
pulse system (by this we mean the number of sample available at the surface while drilling). However,
this technology is only applicable to very specific projects. Because of its high costs, it is not commonly
used in the industry. Regarding costs, wired drill pipe rental costs around ten times more than a
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57 | P a g e
from downhole. The entire process is almost instantaneous, which enables workers to make informed
decisions during the drilling process.
The superior cost effectiveness of MWD logging is especially true for medium‐ to high‐cost wells and
high‐risk drilling applications where problems with hole geometry, displacement, and logging
environment do not allow wire line logs to reach bottom. In fact, current researches focus on reducing
the use of wireline equipment and replacing them with downhole drilling and measurement tools.
The mud pulse tool can send information to surface at 10 to 15 bit per second in most applications. In
addition, it has a memory that stores data at higher rates to enable enhanced definition following bit
trips. Thus, once the tool is pulled back to the surface, memory data has to be recovered prior running it
back into the hole. Memory information can then be analyzed and important decisions made about
future work.
Some MWD tools have a battery system supplied by lithium chloride batteries. This enables the tool to
operate without circulation in the hole (tripping). The recovered information is stored into its memory
and recovered only when the tool is pulled back to the surface.
The most common inconvenience with this technology is that it is very sensitive to downhole vibrations
that are generated by the drilling activity. In some situations, downhole vibrations and shocks are close
to the working range of the tool. When this occurs, the MWD stops sending mud pulses to surface due
to downhole failure. Battery systems and downhole sensors can continue working, but no real‐time
communications are available. In all cases, the drilling assembly must be pulled to the surface in order
to check and replace the MWD tool to be able to continue drilling ahead. Moreover, hole caliper data
measured by LWD tool is stored into the memory because of the large number of bytes that would be
required if they were sent to the surface. Regarding costs, the MWD has the cheapest rental and
operating costs.
6.5 Telemetry Data Rates
The data rates of various wired/wireless telemetry systems have approximate ranges as follows:
Wireline System (100‐500 Kb/s)
Wired Drill Pipe Telemetry System (50‐500 Kb/s)
Fiber Optic System (10‐100 Mb/s)
Mud Pulse Telemetry (1.5‐40 b/s)
Acoustic Telemetry (10‐30 b/s)
Electromagnetic Telemetry (10‐100 b/s)
Accuracy, resolution, maximum values, sensitivity and other quantities of single‐point, quasi‐distributed
and distributed type sensors are reviewed in Silva et al. (2012), particularly for electronic and fiber‐optic
type sensors. The reader is referred to that article for the quantitative values and details.
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58 | P a g e
6.6 References ‐ Chapter on Borehole Telemetry – Capabilities and Reliability
Allen, S., McCartney, C., Hernandez, M., Reeves, M., Baksh, A. and MacFarlane, D. 2009. Step‐Change Improvements with Wired‐Pipe Telemetry, paper SPE‐ 119570‐MS, presented at the SPE/IADC Drilling Conference and Exhibition, 17‐19 March, Amsterdam.
Azari, M., Salguero, A.M., Almanza, E. and Kool, H. 2006. Data Acquisition with Advanced Acoustic Telemetry Improves Operational Efficiency in Deep‐water and Land‐Well Testing, Paper SPE‐ 101182‐MS, presented at the SPE Asia Pacific Oil & Gas Conference and Exhibition, Adelaide, Australia.
Cooke, C.E. Jr., M.P. Kluck, and Medrano, R. 1984. "Annular Pressure and Temperature Measurements Diagnose Cementing Operations." SPE Journal of Petroleum Technology no. 36 (12):2181‐2186. doi: 10.2118/11416‐pa.
Reeves, M.E, Camwell,P.L. and Mcrory J. 2011. High Speed Acoustic Telemetry Network Enables Real‐Time Along String Measurements, Greatly Reducing Drilling Risk., paper SPE‐145566, presented at the Offshore Europe Conference, 6‐8 September 2011, Aberdeen, UK.
Silva, M., Muradov, K. and Davies, D. 2012. Review, Analysis and Comparison of Intelligent Well Monitoring Systems. Paper SPE‐150195‐MS presented at the SPE Intelligent Energy International held in Utrecht, The Netherlands. 27‐29 March.
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59 | P a g e
7. Sensor Technologies Applicable to Producing Wells
The ability to sense physical characteristics of the drilling environment is an important part of making
informed decisions about drilling and production operations. These parameters include pressure,
temperature, and flow among many others. Each of these can be measured in a variety of ways by
different sensing instruments depending on the physical law applied to that measurement. This section
will discuss the suitability of particular sensing elements to a downhole system, and provide some
insight into the theory of operation of these sensors.
One characteristic of marketed sensors that must be discussed is the ostensible nature of the sensors.
Although a sensor or gauge may be labeled to measure pressure, temperature, etc., measurement is
normally performed on a supervenient property. The most common supervenient property observed in
data acquisition is a voltage difference. This is because electronic devices are only stimulated by one
property: voltage. All measurement parameters must therefore be implemented in such a way so a
calibrated voltage source, or voltage reference is altered predictably by the desired property (Fraden
2010).
The ideal measurement case is measurement calibration. In this process, the tested unit is compared to
a declared standard for the property of interest (Carr 2002). For example, if we place a meter‐stick
alongside the standard accepted by the International Committee for Weights and Measures, then
determination of the length of the meter‐stick is made by observing the differential length between the
two. There are no degrees of separation between the desired measurand and measured property and,
assuming the meter‐stick will be a tool for visual inspection, insignificant complexity generated by the
influence of other properties.
However, it is safe to assume we will never be afforded the ideal case for downhole measurement. For
non‐ideal cases, the effective use of the sensor will be largely determined by the influence other
properties have on the supervenient property.
7.1 Sensor Technologies
To explore sensor technologies for their ultimate applicability to producing wells, layers of abstraction
must be removed from the sensors with which we are familiar. In this section, the focus will be on the
underlying measurement technology in common sensors and their applicability in downhole
environments.
7.2 Sensor Selection
The selection of the measurement categories discussed in the proceeding sections was made by
evaluating the popular technologies currently offered by Schlumberger, Weatherford, and Baker‐
Hughes. The measurements most common to the list of products are chosen as the topics for analysis.
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60 | P a g e
7.3 Basic Sensing Technologies
7.3.1 Temperature There are a number of physical properties that are influenced by temperature. This means that there are
a number of ways to measure temperature, but it also means that undesirable temperature effects on
the measurement system can complicate the measurement. These effects will be discussed for some
measurement technologies below. The primary technologies discussed here are thermocouples, RTDs,
and fiber optics.
7.3.1.1 Thermocouples Thermocouples are strands of two different materials fused together at an end. The resulting effect, also
known as the Seebeck effect, is a potential difference (voltage) measurable at the free ends. As
measured, the voltage is the result of mostly temperature, but is also influenced by the resistances in
the wires composing the thermocouple, the wires leading from the thermocouple to data acquisition
system, and the junctions where all parts make some type of contact. These resistances are measurable
in a lab prior to the sensor’s deployment, and are therefore errors for which critical users may
compensate.
Further noticeable are variations of the resistances, and therefore error, at changes in temperature. For
this reason, the voltages produced by thermocouples may not be considered linear with temperature.
However, resistances are predictable and so is the non‐linearity.
The thermocouples are appealing for precise measurement because of the predictable nature of the
imperfections. The resistances that would affect the voltage measurement could change downhole as
parts degrade, but it is predictable that the measurements will remain within a margin that may be
determined experimentally. However, if the distance between the thermocouple and measurement
device is variable then error will be present in the wire that connects the two. Wire of any material has a
resistivity that is a function of its cross‐sectional geometry, length, and temperature. If a wire were
extended, for example, down to the bottom of a 10,000ft well, then it would have a resistivity profile
predictable only if the temperature were known for every linear unit of travel (the resolution of such a
profile would be dependent on the size of the linear unit). It is therefore recommended that
thermocouples be very close to the measurement device for acceptable accuracy (Pollock 1971).
In additional to the benefit of predictability of error, thermocouples also do not require excitation
sources for operation. Sensors discussed later in this section will require a voltage source to determine
the temperature, but the thermocouple generates its own measurable voltage, eliminating the need for
a battery pack or other power supply.
7.3.1.2 Resistance Temperature Detectors (RTDs), Thermistors Resistance Temperature Detectors (RTDs) are devices that house a sample of known resistivity over a
particular temperature range, Figure 7.3.1. Manufacturers of RTDs will publish the predictable range
with the sensor’s data sheet as per their results in experimental trials.
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or scheme (W
le by measur
mperature wi
ect. The mo
pulsing a lase
ckscattered li
ered light is m
e optic cable
of the RTD w
element ar
ture, and will
which they
Within this w
rvenient prop
oltage to the
e. Circuits to
ore compon
erein. The v
, so any situa
nced by ambi
sely construc
as ‐90°C to 1
Wikipedia, 201
ring light bac
ill cause parti
st common f
er down the
ight returnin
measured for
e at which th
61 | P
whose resistan
e also sourc
result in inco
may be depl
window, RTD’
perty is resist
RTD to dete
achieve this
ents that ma
voltage suppli
ation in whic
ient tempera
cted and pro
130°C (Therm
12b)
kscattered ba
icular wavele
form, Optical
optical cable
g to the em
temperature
he event occ
a g e
nce is
ces of
orrect
loyed,
’s are
tance,
rmine
result
ay be
ied to
ch the
tures.
oduce
mistors
ack to
engths
Time
e and
ission
e, and
curred
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7.3.2 PrePressure
Displacem
piezoresis
piezoresis
7.3.2.1 PiSystems t
can be re
across tw
pressure
equipmen
Piezoelect
therefore
7.3.2.2 PiPiezoresis
module w
7.3.3. The
For use in
gauges so
the accura
ssure is a property
ment is the m
stive transdu
stive, capaciti
iezoelectric Stthat use som
ead by a volta
o nodes cem
is applied to
nt. This form
tric strain ga
be classified
Figure 7
iezoresistive Sstive devices
will house a
e resistance c
n an automat
o that the cha
acy of the vo
y that is mea
most common
ucers. The p
ive, electrom
train Gauges e form of co
age. The mo
ented to its e
the material
of sensor is m
auges are sim
as useful in c
.3.2: Piezoele
Strain Gauges are character
piezoresistive
changes as th
ted measurem
anges in resis
ltage referen
asured less d
n in tradition
pressure gau
agnetic, pote
mputer to m
odules house
ends upon th
the voltage c
most commo
milar to ther
cases where t
ectric Strain G
rized by an o
e membrane
e membrane
ment system,
stance may b
ce is paramo
irectly than t
nal measurem
uges discuss
entiometric, re
measure and l
a piezo‐ ele
e application
changes; thes
nly found in v
rmocouples i
thermocouple
Gauge schem
bservable cha
that will flex
flexes.
, an excitatio
be read and lo
unt to this se
temperature
ment method
ed in this
esonant, and
log pressure,
ment that ge
n of mechanic
se changes c
vibration sens
in their supe
es would like
me (Ashauer a
ange in resist
x with chang
on voltage mu
ogged. Not u
ensor’s integri
in most prac
ds such as in
section inclu
d optical.
use pressure
enerates a po
cal stress, Fig
an be measu
sors.
ervenient pro
wise prove u
and Konrad 2
tance. In typ
ges in applied
ust be applie
unlike the RT
ity.
62 | P
ctical applica
manometer
ude piezoele
e transducers
otential diffe
ure 7.3.2. W
ured by monit
operties, and
seful.
002)
ical applicatio
d pressure, F
d to piezores
TDs or thermi
a g e
ations.
rs and
ectric,
s that
erence
When a
toring
d may
ons, a
Figure
sistive
istors,
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7.3.2.3 CaCapacitan
electronic
and then
measurab
inversely
measured
In downh
changes i
the prope
changes i
and temp
and the m
This devic
discussed
Figure
apacitive Meance is the po
cs will have tw
removed, th
ble on the no
proportiona
d to determin
hole measure
n resistance o
erties of the
n the capacit
perature. If th
measurement
ce additionall
.
7.3.3: Piezo
asurement otential capa
wo sheets se
e applied vol
des of the ca
l to their se
e a pressure
ements, these
of the wires a
dielectric m
tance assume
he sensor is p
corrected.
y requires a v
Figure 7.3.
resistive Pres
city of cond
eparated by a
ltage (up to t
apacitor, Figu
eparating dis
applied to on
e devices wo
as temperatu
media separat
ed to have be
paired with a
voltage sourc
.4: Capacitiv
ssure Sensor
uctors separ
a nonconduct
the documen
re 7.3.4. The
tance, and t
ne of the plat
ould be susce
res changed
ting the plate
een by pressu
temperature
ce, and is the
e Pressure Se
(Ashauer and
ated by a di
tive material,
nted limitation
theoretical c
thus is the
es.
eptible to a
is the most o
es will also b
ure, when it
e sensor, then
erefore limite
ensor (USGS,
d Konrad 200
ielectric med
, and when a
ns of the cap
capacitance o
supervenient
number of in
obvious, but a
be altered.
is the combi
n this factor
ed by all limit
2012)
63 | P
02)
dia. Capacito
voltage is ap
pacitor) will s
of a set of pla
t property th
nterferences.
also the chan
The result w
nation of pre
may be acco
ing factors al
a g e
ors in
pplied
till be
ates is
hat is
The
ges in
will be
essure
unted
ready
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7.3.2.4 ElElectroma
When a f
coil chang
be pressu
Again, the
7.3.2.5 PoIn potent
one end,
reposition
the wiper
calibrated
like the p
voltage di
7.3.2.6 ReResonant
change in
Figure 7.3
What is p
measurem
pressure
Temperat
predictab
transduce
lectromagnetagnetic press
erromagnetic
ge proportion
rized to a cal
e electromagn
Figure
otentiometriciometric pres
and connec
ned along the
r’s placement
d source is no
hilosophy of
ivision, rathe
esonant pressure tra
pressure. Co
3.6.
particularly n
ment over bo
sensors will
ture variatio
le resistive
ers from dow
ic ure transduc
c core is pass
nately. For th
ibration pres
netic pressur
e 7.3.5: Electr
c ssure transdu
cting the oth
e strip. If on
, and therefo
ot used, then
the electrom
r than induct
ansducers use
ommon media
noteworthy a
oth time and
plastically d
ns will also
characteristic
nhole applica
cers are yet a
sed through t
his apparatus
sure so that a
e transducer
romagnetic (I
ucers, a wipe
er to comm
e side of the
ore the voltag
n the sensor
magnetic pres
ion.
e the change
a found in tra
bout this for
d temperatur
deform, ther
change the
cs of the m
ations. Reson
another mean
the eyelet of
to measure
a pressure ma
requires a po
Inductive) Pr
r is positione
on ground, t
e wiper has a
ge will be a fu
will serve to
ssure transdu
es in a mater
ansducers inc
rm of pressu
re. Over tim
eby changing
mechanical
aterial. Bot
nant transduc
ns of measur
coiled wire,
pressure, on
ay be inferred
ower supply.
ressure Senso
ed on a resist
the voltage
a constant ap
nction of the
indicate diff
cer, but the
rial’s resonan
clude quartz,
ure measurem
me, the film o
g their read
properties
th of these
cers, however
ring displacem
the inductive
e direction o
d by the core
or (USGS, 201
tive strip. App
at the wiper
pplied calibrat
e opposing ap
ferential pres
potentiomet
nt frequency
silicon, and s
ment is the c
or membrane
ings under a
responsible
disqualify m
r, remain a go
64 | P
ment, Figure
e properties i
of movement
’s displaceme
12)
plying a volta
r will vary as
ted pressure,
plied pressur
ssure. This is
ric operates u
to determin
synthetic sap
consistency o
e in piezores
applied press
for the nor
most piezores
ood candidate
a g e
7.3.5.
in the
must
ent.
age to
s it is
, then
re. If a
much
under
ne the
phire,
of the
sistive
sures.
rmally
sistive
e.
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7.3.2.7 OOptical pr
they do n
cable with
are reflec
2010) , Fig
Optical p
necessity
Optical ressure senso
not transmit e
h a known sp
cted, which c
gure 7.3.7.
ressure tran
for an optic c
Figure 7.3
ors again use
electrical sign
pectral profile
communicate
Figure 7.3.7
sducers are
cable to trans
3.6: Resonant
e displacemen
nals to the me
e. As the light
e to the read
7: Optical Pre
consistent a
smit the data
t Pressure Sen
nt as the sup
easurement d
t passes thro
der what pre
essure Sensor
across tempe
to the surfac
nsor (OG&E,
pervenient pr
device. Light
ugh the optic
essures the s
r (Wikipedia,
erature range
ce.
1997)
roperty, but a
t is channeled
cal sensor, ce
sensor is enc
, 2012a)
es, but their
65 | P
are unique in
d through an
ertain wavele
countering (F
r caveat is i
a g e
n that
optic
engths
rench
n the
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A ‘middle
their phil
radio wav
operation
7.4 Real‐T
Measurem
effective
transmit
necessary
instrumen
7.4.1 InstThere are
produced
their nove
7.4.1.1 DThe Distri
sensors to
laser light
produced
7.4.1.2 WSchlumbe
synthetic
expected
over 10,0
7.5 Brief S
Sensor te
are summ
Table 7.1:
Note: RTD
resonant
Measurem
prelimina
ground’ cou
osophies. A
ves could be
n of Surface A
Time, Distribu
ment of dow
practices. To
data quickly
y to remote
ntation techn
trumentatione currently a
effective res
el use of supe
Distributed Temibuted Temp
o determine t
ts down an o
that accurat
WellWatcher Serger uses a r
sapphire plat
in most drill
00kPa and 11
Summary of S
chnologies, w
marized in Tab
Pressure Sens
D may becom
system.
ment using th
ry set of rest
ld possibly be
resonant sen
e monitored
Acoustic Wave
ted Instrume
wnhole prope
o achieve re
y and effectiv
ely reconstru
iques will be
n Techniques couple notab
sults with reg
ervenient pro
mperature Senerature Sens
the temperat
optic cable a
ely depicts th
Sapphire Gaugresonant pres
tes. The resu
ing scenarios
10°C (Schlumb
Sensor Techno
which have th
bles 7.1 and 7
sor Summary
me passive fo
he shear stres
trictions: pow
e found betw
nsor responsi
consistently
e (SAW) devic
ntation Techn
erties at rea
eal‐time mea
vely, while t
ct a data‐im
explored for
ble instrumen
gards to real
perties in the
nsing, DTS (Scing technolog
ure distributi
and reflecting
he thermal co
ge (Schlumberssure transdu
lt is a pressu
s (Culurciello
berger 2008)
ologies
he potential t
7.2.
r the case th
ss in the wall
wer requirem
ween the optic
ible for refle
and reliably.
ces, which wil
niques
l‐time is cru
surement, th
the measure
mage of the
their applica
ntation techn
l‐time data a
e determinati
chlumberger)gy in use by
ion down the
g the light sc
onditions (Bro
rger) ucer in it Wel
re transduce
2010). Thes
.
to measure p
Table 7
hat the resista
s of the pipe
ents, invasive
cal and reson
ecting lower f
. This is the
ll be discusse
ucial for loss
he transmiss
ement metho
e target are
bility in futur
niques in use
acquisition. Th
ion of proper
Schlumberge
e well at resol
cattered due
own 2008).
llWatcher too
r that can wi
se gauges are
pressure and t
7.2: Temperatu
ance is gauge
appears to b
eness, and re
nant transduc
frequency lig
foundation
ed in detail lat
s prevention
sion method
od(s) gather
ea. In the fo
re, real‐time s
e by large com
heir appeal c
ties of intere
er uses fiber
lutions near 1
e to Raman s
ol that uses m
ithstand the
e rated to w
temperature
ure Sensor Sum
ed as a damp
be the most f
equired forek
66 | P
cers if we hyb
ght in the fo
of the theor
ter in this pap
and to max
must be ab
as much da
ollowing sec
systems.
mpanies that
comes prima
st.
optic temper
1 meter. By p
scattering, a
microchips ca
high tempera
ithstand pres
in producing
mmary
pening factor
easible based
knowledge. B
a g e
bridize
rm of
retical
per.
ximize
ble to
ata as
ctions,
t have
rily in
rature
ulsing
log is
ast on
atures
ssures
g well,
r for a
d on a
Based
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67 | P a g e
on existing techniques, sensor technologies are summarized in Table 7.3; they have the potential to
measure flow in producing well.
Table 7.3: Flow Sensor Summary
7.6 References – Chapter on Sensor Technologies Applicable to Producing Wells
Ashauer, M. and Konrad, B. 2002. Demystifying Piezoresistive, Pressure Sensors, Application Note 871, Jul 17, 2002, http://www.maximintegrated.com/app‐notes/index.mvp/id/871, last accessed Dec. 26, 2012.
Brown, G. 2008. "Downhole Temperatures from Optical Fiber." Oilfield Review no. Winter 2008/2009 (4):34‐39.
Carr, J. J. 2002. Practical radio frequency test and measurement (electronic resource) : a technician's handbook / Joseph J. Carr: Boston : Newnes, c2002.
Culurciello, E. 2010. Silicon‐on‐sapphire circuits and systems : sensor and biosensor interfaces / Eugenio Culurciello: New York : McGraw Hill, c2010.
Fischer, R. E., Tadic‐Galeb, B., Yoder, P. R. and Galeb, R. 2008. Optical system design / Robert E. Fischer, Biljana Tadic‐Galeb, Paul R. Yoder, 2nd Edition, McGraw‐Hill, New York.
Fraden, J. 2010. Handbook of modern sensors: physics, designs, and applications, 4th Edition, Springer Verlag, New York.
French, M., Jackson, S., Jokisuu, E. 2010. Diverse Engagement: Drawing in the Margins. In Proceedings of the University of Cambridge Interdisciplinary, Graduate Conference 2010: University of Cambridge.
García, M.R. Vilas, Carlos , Banga ,J.R. and Alonso, A. A. 2007. Optimal field reconstruction of distributed process systems from partial measurements, Ind. Eng. Chem. Res., 2007, 46 (2), pp 530–539.
OG&E,1997 Resonant Pressure Sensor Pollock, D. D. 1971. The Theory and Properties of Thermocouple Elements, ASTM, STP 492. Schlumberger. 2008. WellWatcher Sapphire Gauge, NDPG Multidrop Pressure and Temperature Gauge,
available at http://www.slb.com/~/media/Files/completions/product_sheets/sapphiregauge_ps.pdf, last accessed on Dec. 26, 2012.
Thermistors, NTC. 2012. Micro‐Chip Technologies for Industrial Electronic Components. Available at http://www.microchiptechno.com/ntc_thermistors.php, last accessed Oct. 30 2012.
Wikipedia 2012a. Fiber Bragg grating, http://en.wikipedia.org/wiki/Fiber_Bragg_grating, last accessed on Dec. 26, 2012.
Wikipedia 2012b. Resistance thermometer, http://en.wikipedia.org/wiki/Resistance_thermometer, last accessed on Dec. 26, 2012.
USGS 2012. Use of Submersible Pressure Transducers in Water‐Resources Investigations, http://pubs.usgs.gov/twri/twri8a3/, last accessed on Dec. 26, 2012.
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68 | P a g e
8. RFID Sensor Technology, Borehole Telemetry Applications
Radio Frequency Identification (RFID) technology is an attractive option for borehole telemetry. Surface
acoustic wave (SAW) sensor technology has a multitude of benefits for downhole applications of RFID‐
based sensors. One is the utility of being passive (i.e., unpowered) wireless remote sensors, Brocato et
al. (2007). They can small sizes similar to that of RFID tags and even smaller. State‐of‐the‐art SAW
sensors can have a footprint size as small as 2 mm by 1mm for width and length with even smaller
thicknesses, Härmä et al. (2008). Just to give a perspective, a U.S. dime is about 18 mm in diameter and
has a surface area of over 250 mm2; more than 100 such SAW sensors could fit on the surface of a dime.
Another benefit is very low cost. Another important characteristic of SAW sensor technology is its
ability to withstand high temperatures, Hauser et al. (2003), even as high as l000 C if appropriate material combinations are employed for assembly, interconnects and packaging, Hornsteiner et al.
(1998) and Zhang et al. (2011). It can withstand harsh environmental conditions (e.g., shocks,
accelerations, vibrations, high temperatures, temperature gradients, radiation). High temperature
applications include combustion chambers, Hauser et al. (2003), car exhausts, Tourette et al. (2009), and
piston temperatures, Plum et al. (2011). SAW sensor technology is simple, robust and provides for high
performance. SAW sensor technology can be used in a wide range of sensing applications since it can be
used to read any type of unpowered low or high impedance varying sensor, e.g., temperature, pressure,
light level, mechanical switch, acoustic emission, acceleration, Brocato et al. (2007). SAW sensors report
physically measurable data in the same manner as do similar conventional sensors, but they can do it
remotely and without any local power source. The measurement information (e.g., temperature,
pressure) contained in SAW sensors can be obtained remotely using a radar‐like interrogation device,
and the sensors and their related communication electronics draw all of the power needed for
communicating from the radar pulse, Brocato et al. (2007).
Radio Frequency Identification (RFID) technology is an attractive option for borehole telemetry and
sensing applications. This is due to the ability of RFID devices to function without onboard power,
although it is possible to improve some aspects of device performance with the addition of a battery.
For the purposes of this review, RFID encompasses two types of devices. These are Inductive Coupling
RFID and Surface Acoustic Wave (SAW) RFID.
Inductive coupling RFID is short‐range (typically <1m) telemetry method operating on the same
principles as a transformer. SAW RFID, on the other hand, utilizes a dipole antenna and tends to have
longer read ranges at significantly lower power levels (~10m).
8.1 Inductive Coupling RFID
Inductive Coupling RFID has found widespread use in inventory control, including some use in the oil and
gas industry. The main advantage of inductive coupling RFID is its ability to form a passive sensing
device. Because it inductively couples to the interrogating device, it is able to draw all the power it
needs to communicate and power its sensors from the interrogating signal.
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Because R
they cann
the carrie
would be
tags typic
The theor
derivation
RFID coil
antenna c
coil is give
2
Where current th
the evalua
radius of
will likely
By Farada
magnetic
equation
∙
RFID tags typ
not utilize a d
er wave (usu
2.4 km; obv
ally use smal
ry of IC RFID
n of induced v
antennas uti
coils”(Lee 199
en by the follo
2
2 232
is the magne
hrough the co
ation of the B
the coil will l
be on the ord
ay’s Law, the
flux. The eq
(Knight 2004
∙
pically operat
ipole antenna
ally one‐qua
iously, this is
l coil antenna
is simple and
voltage on a t
ilize “near fie
98). For a co
owing equati
2
2
13
Figure 8.1:
etic flux dens
oil, and is thB‐Filed is large
ikely be on t
der of one me
voltage indu
uation for th
).
e in the Very
a. The length
rter or one‐h
s not a realist
as that resona
d easily deriv
tag to illustra
eld magnetic
il with N turn
on, Figure 8.1
≫
: B‐Field Prod
sity, is the he magnetic p
e compared t
he order of o
eter.
ced in the re
he magnetic f
y Low Freque
of an antenn
half (Ulaby 2
tic antenna le
ate at the car
ved from fund
te some stren
induction co
ns, the equat
1.
duced by Curr
number of t
permeability.
to the radius o
one centimet
eceiver due to
flux through
ency (VLF) ran
na is typically
2005)). The w
ength for an
rrier frequenc
damental phy
ngths and we
oupling betwe
tion for the m
rent Coil (Lee
turns, is th. The assump
of the coil is v
er or less wh
o a changing
the receiving
nge (typically
a fraction of
wavelength o
RFID tag. For
cy.
ysical laws.
eakness of IC
een transmit
magnetic field
e 1998)
e radius of t
ption that the
valid for our
hile the minim
magnetic fie
g coil is given
69 | P
y around 125
the waveleng
of a 125 kHz
r this reason,
We briefly sh
RFID.
tting and rece
d produced b
he coil,
distance bet
purposes sinc
mum read dis
ld depends o
n by the follo
a g e
kHz),
gth of
wave
, RFID
how a
eiving
by the
(1)
is the
tween
ce the
stance
on the
owing
(2)
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70 | P a g e
In the case that the transmitting and receiving coils are aligned such that the field is parallel to , and assuming the B‐field is uniform of the surface, the equation for the magnetic flux becomes.
2
21 2
21
(3)
where is the radius of the receiving antenna. Faraday’s Law predicts the voltage induced around the closed loop of the receiving coil and it is given by the following equation.
(4)
By combining Lenz’s Law, Faraday’s Law, and our previous equation for the magnetic flux through a
closed N‐turn loop, we obtain the following equation for voltage induced around the closed receiving
coil loop (Knight 2004).
2
21
(5)
where is the number of turns in the receiving coil. The important thing to note here is that the signal
falls off with the cube of the distance between coils. This best‐case scenario is probably an overly
optimistic estimate for downhole, since the perfect alignment we assumed here is difficult to accomplish
downhole.
As mentioned earlier and as we see from equation (5), IC RFID is a short‐range communication system
that falls off with the cube of the distance between reader and tag. The addition of a sensor to a passive
tag would further reduce this range. One solution to this problem is the addition of an onboard battery
to boost communication range. This will be discussed shortly. Furthermore, IC RFID which tends to be
more vulnerable to temperature than the SAW RFID systems discussed later.
8.1.1 Signal Modulation There are a number of standard signal modulation methods that are used and well understood in
industry. Among these are Amplitude Shift Keying (ASK, NRZ or Manchester), Frequency Shift Keying
(FSK), and Phase Shift Keying (PSK). The RFID tag modulates the interrogating signal via backscatter
modulation; by switching a transistor placed between two antenna pads it can transmit senor or ID
information on the interrogating signal itself. A detailed discussion of these modulation techniques
would be an unnecessary distraction; they are mentioned here for the sake of completeness only. Lee
provides a good starting point for readers desiring a more intensive discussion of these techniques (Lee
1998).
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71 | P a g e
8.1.2 Active Tags Active tags improve communication ranges by adding an onboard power supply. This allows the tag to
provide some of the power it needs to communicate with the interrogator (and to power its on‐board
sensors). The major disadvantages to active tags are that batteries place a maximum life expectancy on
the tag, batteries tend to be a limiting factor in temperature limits, and batteries increase the size of the
tags.
8.2 SAW RFID
SAW (Surface Acoustic Wave) RFID, like passive inductive coupling RFID, has the capability to operate
using only power received from the interrogating signal. Like many RFID devices, it also has the ability to
host a variety of sensors. However, unlike its IC counterpart, it tends to be far more rugged with the
ability to withstand extreme temperature and pressure environments as well as the ability to
communicate in metallic and other conductive environments. Furthermore, SAW RFID tends to have
long read distances with much lower power input.
8.2.1 A Brief History of SAW Devices The history of SAW RFID begins in the late 19th Century. In 1885, Lord Rayleigh discovered Surface
Acoustic Waves, for this reason, these waves are often referred to as Rayleigh waves. While in 1880, the
Curie brothers discovered the coupling of the elastic and electric fields in piezoelectric materials. In
1965, White and Voltmer demonstrate the uniform IDT (Interdigital Transducer); quickly followed by
Tancrell demonstrating the use of the Lithium Niobate substrate. Together these accomplishments
represent the core of modern SAW devices (Morgan 1998).
8.2.2 Principles of Operation The operation of a basic SAW device is pictured in Figure 8.2. An electromagnetic wave is transmitted
by the reader and received by an antenna on the tag. This electromagnetic wave is then converted into
a Surface Acoustic Wave (SAW) by way of the Interdigital Transducer (IDT). This SAW then propagates
along the piezoelectric substrate where it can be modified for signal processing or sensing application.
An IDT then transforms the SAW to an electrical signal sent to the tag antenna and propagated as an EM
wave which returns to the reader carrying tag information (Brocato et al. 2007).
While SAW devices also communicate with the reader using backscatter modulation, they can be read a
greater distance at significantly reduced power. This is because the SAW travels about 100,000 times
lower than the EM wave, allowing the environmental reflections of the reader signal to die down before
the SAW tag sends its own signal. This ability of the SAW RFID to create a clutter free environment for
communication is one of its primary advantages over its inductive coupling counterpart (Plessky and
Reindl 2010).
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8.2.2.1 ReOne of th
based on
Figures 8.
substrate
This show
reduction
Furtherm
number (
binary on
larger tag
There are
data and
frequency
telemetry
RDLs are t
Figur
eflective Delae two main t
resonators, w
.3 and 8.4. Th
. The distanc
ws that there
n, and SAW s
ore, the spac
longer period
es). Clearly,
.
e several adva
to build mu
y coding (OFC
y system if th
the same as t
e 8.2: Operat
y Lines ypes of wirel
which will be
he SAW from
e from the ID
is a direct tr
size, which w
cing of the fo
ds without re
a larger num
antages of RD
ulti‐sensor e
C) techniques
e data is to b
those of a gen
tion of a SAW
ess SAW sens
e discussed la
the IDT is re
DT to the first
rade‐off betw
we wish to m
ollowing refle
eflectors can
mber of tags w
DLs over reso
nvironment w
s (Kalinin 201
be interpreted
neric SAW RF
Figure 8.3: SA
W Tag System
sors is based
ater. The ope
flected off a
t reflector de
ween delay ti
minimize for e
ctors on the
be thought o
will require a
onators such
without colli
1). This is an
d as a functio
ID described
AW RDL(Kalin
m(Plessky and
on reflective
eration of an
number of re
etermines the
me, which w
easier transp
substrate de
of a binary ze
larger numbe
as the ability
ision using T
essential asp
on of depth a
earlier.
nin 2004)
Reindl, 2010
e delay lines (
n RDL is show
eflectors spac
e delay time
we wish to m
port and plac
etermines the
eroes while re
er of reflecto
y to attach an
TDMA, CDMA
pect of an int
at the surface
72 | P
0)
RDLs); the ot
wn schematica
ced along the
of the SAW s
aximize for c
cement down
e tag identific
eflectors repr
ors and theref
n ID to the se
A, and ortho
telligent form
e. The princip
a g e
ther is
ally in
e SAW
signal.
clutter
nhole.
cation
resent
fore a
ensed
ogonal
mation
ples of
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8.2.2.2 ReA resonat
the ability
resonator
sensing d
when des
individual
frequency
bandwidt
(~5000), p
advantage
8.2.2.3 ASAW devi
is theoret
We see th
by IC RFI
important
ranges of
For comp
larger tha
esonators tor, shown sc
y to attach an
rs in close pr
ata. This mak
signing an in
l oscillators tu
y range, it m
h for a large
potentially pr
e of the 433M
ntenna and Pces typically
tically governe
hat power inc
D. We also s
t in determin
a typical SAW
arison, Plessk
an that of a SA
hematically i
n ID to the SA
roximity simu
kes it difficult
telligent form
uned to differ
might be diffic
number of d
roviding muc
MHz ISM band
Figure 8.4:
ower use a dipole
ed by the rad
creases with t
see that ther
ning an optim
W device actin
Tab
Transm
1
100
10,000
ky and Reind
AW device(Ple
n Figure 8.4,
AW sensor in
ultaneously,
t or impossibl
mation telem
rent specific c
cult to create
downhole tag
h higher reso
d making man
: Schematic o
antenna ope
dar equation g
4 212
the forth root
re is an inver
mal downhole
ng at 69MHz
ble 8.1: SAW D
itted Power
l give the pow
essky and Rei
uses symmet
formation. W
unlike RDLs,
le to match s
metry system.
central freque
e sufficient in
gs. However,
olution data,
nufacturing c
of SAW Reson
erating in the
given as (Broc
1
t of distance,
rse relation b
e frequency
in air; these a
Detection RangDet
10.8
34.0
108
wer requirem
indl 2010).
try to increas
While it is pos
resonators
sensor data to
. One possib
encies. Depen
ndependent
, resonators d
and smaller
heaper (Kalin
nator(Kalinin
far‐field regi
cato et al. 200
which is muc
between freq
range. Broca
are listed in th
ge and Powertection Range (
8
0
8.0
ment for an IC
se data resolu
ssible to place
do not attac
o depth and l
ble solution w
nding on the
frequencies
do provide v
bandwidths
nin 2005).
n 2005)
ion. The rang
07).
ch more gene
quency and r
ato gives som
he Table 8.1
(m)
C RFID to be
73 | P
ution at the c
e and read se
ch a tag ID t
location dow
would be to
optimal dow
with the req
very high Q‐fa
allowing it to
ge of these de
erous than all
range, this w
me values for
below.
100 to 1000
a g e
ost of
everal
to the
wnhole
make
wnhole
quisite
actors
o take
evices
(6)
lowed
will be
r read
times
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8.2.2.4 SAA numbe
relevant t
connected
Temperat
Surprising
Since the
phase cha
Figure 8.5
Pressure S
Pressure
RFID geom
8.6).
AW Sensors r of sensors
to ICIFT shor
d to SAW dev
ture Sensor
gly, sensing t
temperature
ange in the re
5: Variation o
Sensor
measuremen
metry. This in
have been d
rtly. Further
vices whilst re
emperature w
e directly affe
eflected signa
of the continu
a func
ts are also po
nvolves the cr
Figure 8.6:
eveloped for
rmore, Broca
emaining pass
with SAW RF
ects the SAW
l (Reindl et a
uous phase d
ction of temp
ossible with S
reation of a p
SAW Substra
r SAW device
ato has show
sive.
FID devices c
W velocity, the
l. 2003), Figu
difference
perature (Rein
SAW RFID. Th
pressure‐isola
ate with Press
es, and we w
wn that impe
omes with n
e device tem
re 8.5.
between ndl et al. 200
hese, howeve
ated cavity in
sure‐Isolated
ill discuss a f
edance‐varyin
o changes to
perature can
the first and
03)
er, require a m
the SAW sub
d Cavity
74 | P
few them tha
ng sensors ca
o the device
n be read from
d third respon
modification
bstrate (see F
a g e
at are
an be
itself.
m the
nse as
in the
Figure
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The surfa
change in
indirectly
response
The dashe
While this
In Figure
pressure.
SAW, allo
Flow Sens
Measurem
of other p
propertie
determini
ce of this cav
n the path len
as a change
can be seen i
ed line after
s value can be
8.8, we see
We also no
wing the retu
sor
ment of flow,
physical prop
s such as flu
ing the flow r
vity will then
ngth of the SA
e in the cent
in Figures 8.7
Figure 8.7: T
T4 represent
e measured d
Figure 8.8:
here that th
ote that this c
urn signal to b
while possib
perties. This i
id properties
rate, we will f
be deformed
AW. This can
er frequency
7 and 8.8 belo
Time‐delay re
ts the delayed
directly, it is o
Frequency Re
he frequency
change in fre
be detected a
ble with SAW
is in part bec
s and flow ge
first demonst
d when expos
n be measure
y of the RFID
ow, respective
esponse of SA
d response c
often easier to
esponse of SA
y of SAW sig
equency is sm
and measured
RFID, proves
cause it requ
eometry. Bef
rate the poss
sed to higher
ed directly as
D. The time
ely.
AW Pressure
caused by the
o measure ins
AW Pressure
gnal is varyin
mall relative t
d with the ap
s to be more
uires a priori
fore going to
sibility for a si
r borehole pr
s a change in
delay respon
e Sensor
e exposure to
stead the cha
e Sensor
g linearly wi
to the carrier
propriate cho
challenging t
knowledge o
oo much into
imple system
75 | P
ressures, cau
the delay tim
nse and frequ
o higher pres
ange in freque
th changes i
r frequency o
oice of anten
than measure
of the certain
o the difficult
.
a g e
sing a
me, or
uency
ssure.
ency.
in the
of the
na.
ement
n flow
ties in
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It is well
boundarie
determine
strain. Giv
An examp
while Figu
We note
rate and w
known that
es adjacent t
ed analyticall
ven that SAW
ple of a SAW
ure 8.9 shows
Figure
that the flow
wall shear str
different flo
o the flow d
y for a numb
W devices can
device meas
s the SAW res
e 8.9: Schema
w shown here
ess is easily d
Figure 8.10:
ows exert a
irection. The
ber of flow typ
measure str
suring the flow
sponse to diff
atic of SAW M
e is simply Ha
derived from
SAW Sensor
shear stress,
e relationship
pes. This stre
rain, it is also
w rate of a s
ferent flow co
Measuring Pre
agen‐Poiseuill
classical equa
Response to
, known as t
p between w
ess can then b
possible to r
imple flow‐g
onditions.
essure Driven
le pipe flow.
ations.
o Changing Flo
the wall shea
wall shear and
be related to
relate this str
eometry is sh
n Laminar Flo
The relations
ow Rate
76 | P
ar stress, on
d flow rate c
both a force
rain to a flow
hown in Figu
ow
ship between
a g e
solid
an be
and a
w rate.
re 8.8
n flow
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Here we s
constant
advance i
While it is
the wide
measurem
uncertain
allowing a
fluid prop
from MW
Impedanc
Finally, w
sensors, w
paramete
Brocato h
expands t
function o
These sen
changes t
change in
see that the
over the ran
t is possible t
s reasonable
range flow ty
ments difficu
ty in flow ge
a known fluid
perties could
WD tools such
ce‐Varying Se
we come to a
which are att
er. This is show
Figur
has shown tha
the range of
of these impe
nsors change
the amplitud
the amplitud
SAW phase i
ge of flow ra
to measure th
to make cer
ypes experien
lt. One possi
ometry is eli
d geometry a
then be obt
as resistivity,
ensors
broader cate
tached at the
wn in Figure 8
e 8.11: SAW
at these type
sensing poss
edance‐varyin
the radar ap
e of the rec
de of the sign
s directly pro
ates. This me
he flow from t
tain assumpt
nced downho
ble solution
minated. Thi
nd eliminatin
tained from p
, and from the
egory of sens
e IDT, vary t
8.11 below.
Communicat
es of devices w
ibilities for SA
ng sensors in
perture of th
ceived signal,
al.
oportional to
eans that give
the phase of
tions about th
ole and the u
is to design
s would invo
ng the need t
prior knowled
e knowledge
sors, dubbed
heir impedan
tion Diagram
work for even
AW RFID. Wh
dividually, w
e SAW tags a
allowing the
the flow rat
en sufficient
the return sig
he borehole
ncertainty in
the RFID pac
olve creating
to make such
dge of the bo
of drilling flu
here as imp
nce in respon
from (Brocat
n very high im
hile we will n
we will discuss
as they chang
e physical pa
te while the f
information
gnal.
geometry an
device orien
ckaging in su
a sort of duc
h an assumpt
orehole envi
uids introduce
pedance‐varyi
nse to some
to et al. 2007
mpedance se
ot go into de
s their effect
ge their impe
arameter to
77 | P
frequency rem
about the fl
nd fluid prope
ntation makes
ch a way tha
ct in the pack
tion. Knowled
ronment obt
ed to the well
ing sensors. T
changing ph
7)
ensors. This fu
etail discussin
on the SAW
edance. This
be related t
a g e
mains
ow in
erties,
s flow
at the
kaging
dge of
tained
l.
These
hysical
urther
ng the
RFID.
s then
to the
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78 | P a g e
8.3 References – Chapter on RFID Sensor Technology, Borehole Telemetry Applications
Brocato, R. W., G. A. Wouters, E. Heller, J. Blaich, and D. W. Palmer. 2007. Re‐configurable Completely Unpowered Wireless Sensors. Paper read at Electronic Components and Technology Conference, 2007. ECTC '07. Proceedings. 57th, May 29 2007‐June 1 2007.
Härmä, Sanna, Plessky, Vickor P., Hartmann, Clinton S., and Steichen, William, 2008. “Z‐path SAW RFID tag,” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Vol. 55, No. 1, January 2008, pp. 208‐213.
Hauser, Robert, Bruckner, Gudrun, Stelzer, Andreas, Maurer, Linus, Biniasch, Jörg, Reindl, Leonhard, Teichmann, Rüdiger, 2003. “A high‐temperature stable SAW identification tag for a pressure sensor and a low‐cost interrogation unit,” Sensor 2003, Proc. 11th International Conference, 13‐15 May, 2003, Exhibition Centre, Nuremberg, Germany, pp. 467‐472.
Hausleitner, C., et al, 2001. “Cordless Batteryless Wheel Mouse Application Utilizing Radio Requestable SAW Devices in Combination with the Giant Magneto‐Impedance Effect,” IEEE Trans. on Microwave Theory and Techniques, vol. 49, no. 4, pp. 817‐822, Apr. 2001.
Hornsteiner, E. Born, Fischeraurer, G., Riha, E., 1998. “Surface acoustic wave sensors for high‐temperature applications”, Proceedings of the 1998 IEEE Frequency Control Symposium, 27‐29 May 1998, pp. 615‐620.
Kalinin, V. 2004. Passive wireless strain and temperature sensors based on SAW devices. Paper presented at Radio and Wireless Conference, 2004 IEEE, 19‐22 Sept.
Kalinin, V. 2005. Influence of receiver noise properties on resolution of passive wireless resonant SAW sensors. Paper presented at Ultrasonics Symposium, 2005 IEEE, 18‐21 Sept.
Kalinin, V. 2011. Wireless physical SAW sensors for automotive applications. Paper read at Ultrasonics Symposium (IUS), 2011 IEEE International, 18‐21 Oct. 2011.
Knight, R.D. 2004. Physics for scientists and engineers: a strategic approach. San Francisco: Pearson/Addison Wesley.
Lee, Y. 2012. RFID Coil Design 1998. Available at Microchip.com, http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en011766, last accessed October 31, 2012.
Morgan, D. P. 1998. History of SAW devices. Paper presented at Frequency Control Symposium, 1998. Proceedings of the 1998 IEEE International, 27‐29 May.
Plessky, V., and Reindl, L. 2010. Review on SAW RFID tags, Ultrasonics, Ferroelectrics and Frequency Control, IEEE Transactions, no. 57 (3):654‐668. doi: 10.1109/tuffc,1462.
Plum, T., Tourette, S., Loschonsky, M., Röbel, M., 2011. “Piston Temperature Measurement with SAW Sensors”, 2011 Joint Conference of the IEEE International Frequency Control and the European Frequency and Time Forum (FCS), 2‐5 May 2011.
Pohl, Alfred, “A Review of Wireless SAW Sensors,” 2000. IEEE Trans. on Ultrasonics, Ferroelectrics, and Frequency Control, vol 47, no. 2, pp. 317‐332, March.
Reindl, L.M., Pohl, A., Scholl, G., and Weigel, R., 2001. “SAW based radio sensor systems,” IEEE Sensors J. vol. 1, pp. 69‐78, June 2001.
Reindl, L., I. Shrena, S. Kenshil, and R. Peter. 2003. Wireless measurement of temperature using surface acoustic waves sensors. Paper read at Frequency Control Symposium and PDA Exhibition Jointly with the 17th European Frequency and Time Forum, 2003. Proceedings of the 2003 IEEE International, 4‐8 May 2003.
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Seindl, R., Pohl, A., and Seibert, F., 1999. “Impedance Loaded SAW Sensors Offer a Wide Range of Measurement Opportunities,” IEEE Int. Microwave Symp. Dig, Anaheim,, pp. 1453‐1456, June 1999.
Tourette, S., Collin, G., Le Thuc, P., Luxey, C., Staraj, R., 2009. “Small Meandered PIFA Associated with SAW Passive Sensor for Monitoring Inner Temperature of a Car Exhaust Header”, IEEE International Workshop on Antenna Technology, IWAT 2009, Santa Monica, California, 2‐4 March 2009.
Ulaby, F.T. 2005. Electromagnetics for engineers. Upper Saddle River, NJ: Pearson/Prentice Hall. Zhang, Shujun and Yu, Fapeng, 2011. “Piezoelectric Materials for High Temperature Sensors”, J. Am.
Ceram. Soc., 94 (10) 3153–3170.
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Appendix A: Summary of Collected U. S. Patents on Fiber Optic Sensors
The abstracts of 57 collected U.S. patents on fiber optic sensing technology are summarized below. The
issue dates of the patents range over a 24‐year period from 1990 to 2014. This sampling of patents
shows the potential breadth and depth of fiber optic sensing applications and the recent exponential
growth of patents in the area of fiber optic sensing technology.
U.S. Patent 4891640, January 2, 1990, proposes a high temperature and pressure fiber optic
feedthrough for borehole usage. A high temperature and high‐pressure fiber optic feed‐through is set
forth to enable communication to the interior of a pressure housing making up a downhole logging tool.
U.S. Patent 6233746, May 22, 2001, proposes a multiplexed fiber optic transducer for use in a well and
method. The optic sensor can be configured to sense downhole conditions, such as temperature,
pressure, or stress, either individually or in combination.
U.S. Patent 6355928, March 12, 2002, proposes a fiber optic tomographic imaging of borehole fluids. It
provides a method and an apparatus for fiber optic tomographic analysis and imaging of fluids and
includes a method for providing information on downhole fluid flowing in a hydrocarbon well, utilizing at
least one downhole tomograph chamber. It allows the generation of two or three‐dimensional images
of multiple phase flow in the wellbore and allows determination of production parameters of multiple
zones on an individual zone basis.
U.S. Patent 6531694, March 11, 2003, U.S. Patent 6787758, September 7, 2004, U.S. Patent 6828547,
December 7, 2004, U.S. Patent 7040390, May 9, 2006, and U.S. Patent 7201221, April 10, 2007, propose
wellbores utilizing fiber optic‐based sensors and operating devices. They provide a method for
controlling production operations using fiber optic devices. An optical fiber carrying fiber‐optic sensors is
deployed downhole to provide information about downhole conditions. Parameters related to the
chemicals being used for surface treatments are measured in real time and on‐line, and these measured
parameters are used to control the dosage of chemicals into the surface treatment system. The
information is also used to control downhole devices that may be a packer, choke, sliding sleeve,
perforating device, flow control valve, completion device, an anchor or any other device. Provision is
also made for control of secondary recovery operations online using the downhole sensors to monitor
the reservoir conditions.
U.S. Patent 6571046, May 27, 2003, proposes a downhole protector system for fiber optic system
components in subsurface applications. The device is designed to prevent the harsh downhole
environment from adversely affecting optical fibers themselves or optical components in the optical
fiber system.
U.S. Patent 6898339, May 24, 2005, propose multiple mode preloadable fiber optic pressure and
temperature sensor. It is a multiple mode pre‐loadable fiber optic pressure and temperature sensor. It
includes a generally cylindrical structure having at least one compression element, a fiber optic having a
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81 | P a g e
Bragg grating in contact with one side of the compression element, a diaphragm in contact with the
other side of the compression element, and a fluid port in fluid communication with the diaphragm.
U.S. Patent 6955218, October 18, 2005, and U.S. Patent 7163055, January 16, 2007, propose placing a
fiber optic sensor line. It is a method and an apparatus for placing fiber optic control line in a wellbore.
The method includes providing a tubular in the wellbore, the tubular having a first conduit operatively
attached thereto, whereby the first conduit extends substantially the entire length of the tubular. The
method further includes aligning the first conduit with a second conduit operatively attached to a
downhole component and forming a hydraulic connection between the first conduit and the second
conduit thereby completing a passageway therethrough. Additionally, the method includes urging the
line through the passageway. In another aspect, a method for placing a control line in a wellbore is
provided. In yet another aspect, it provides an assembly for an intelligent well.
U.S. Patent 7028543, April 18, 2006, proposes system and method for monitoring performance of
downhole equipment using fiber optic based sensors. It is a method and system for monitoring the
operation of downhole equipment, such as electrical submersible pumps. The method and system rely
on the use of coiled fiber optic sensors, such as hydrophones, accelerometers, and/or flow meters.
These sensors are either coupled to or placed in proximity to the equipment being monitored. As the
sensor is perturbed by acoustic pressure disturbances emitted from the equipment, the length of the
sensing coil changes, enabling the creation of a pressure versus time signal. This signal is converted into
a frequency spectrum indicative of the acoustics emissions of the equipment, which can then be
manually or automatically monitored to see if the equipment is functioning normally or abnormally, and
which allows the operator to take necessary corrective actions.
U.S. Patent 7155101, December 26, 2006, proposes manufacturing method for high temperature fiber
optic accelerometer. It includes (a) drawing an optical fiber through a resin; (b) winding the resin coated
fiber onto a disc mounted on an assembly having a central shaft; and (c) curing the resin‐coated fiber.
U.S. Patent 7165892, January 23, 2007, proposes downhole fiber optic wet connect and gravel pack
completion. In a described embodiment, a system for making fiber optic connections in a subterranean
well includes a first fiber optic connector positioned in the well and a second fiber optic connector
operatively connected to the first fiber optic connector after the first fiber optic connector is positioned
in the well. It is a method of monitoring a subterranean well. It includes the steps of positioning a fiber
optic line in the well. The fiber optic line extends in a formation intersected by the well. Positioning
another fiber optic line in the well, the fiber optic line extends to a remote location and operatively
connects the fiber optic lines while the fiber optic lines are in the well. It monitors a well parameter
using a sensor operatively coupled to the fiber optic line extending in the formation.
U.S. Patent 7208855, April 24, 2007, proposes a fiber optic cable as integral part of a submersible motor
system. Apparatus, systems and methods are proposed for transmission of optical signals through a
wellbore whereby optic fibers are protected from exposure to harsh downhole fluids and conditions.
The system comprises a power cable assembly running down hole from the surface. It comprises both
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electrical leads and at least one fiber‐optic lead. It includes an electric submersible motor apparatus
having optic fibers and optic fiber leads as an integral part of the motor and internal to the motor
casing. It includes connection(s) between the optic fibers internal to the motor casing and downhole
sensors and other equipment requiring optical communication.
U.S. Patent 7254999, August 14, 2007, and U.S. Patent 8020436, September 20, 2011, propose fiber
optic accelerometer based seismic sensing apparatus and associated method, all permanently installed
in well. Embodiments of the present invention include a fiber optic seismic sensing system for
permanent downhole installation. In one aspect, the present invention includes a multi‐station, multi‐
component system for conducting seismic reservoir imaging and monitoring in a well. Permanent
seismic surveys may be conducted with embodiments of the present invention, including time‐lapse
(4D) vertical seismic profiling (VSP) and extended micro‐seismic monitoring. Embodiments of the
present invention provide the ability to map fluid contacts in the reservoir using 4D VSP and to correlate
micro‐seismic events to gas injection and production activity.
U.S. Patent 7322421, January 29, 2008, proposes fiber optic deployment apparatus and method. A head
member having a piston provided thereon is connected to an elongate tube such as a micro‐tube. The
micro‐tube contains one or more optical fibres, preferably suspended therein by a protective fluid such
as a scavenging gel. The head member is preferably inserted into an already‐deployed downhole tubular
and fluid is pumped down that already deployed tubular behind the piston such that the head member
and attached micro‐tube and optical fiber(s) are pumped downhole. A sealing means such as a resin
material may be pumped downhole in the annulus between the outer circumference of the micro‐tube
and the inner circumference of the already‐deployed tubular downhole in low viscosity form and which
may be adapted to cure or harden after a passage of time and/or under application of heat.
U.S. Patent 7,515,781, April 7, 2009, proposes fiber optic, strain‐tuned, material alteration sensor. The
present invention includes a method and system of measuring alteration, alteration type, and alteration‐
causing species in process fluids and equipment and for controlling the process feeds and conditions to
maximize the yields and equipment lifetime by minimizing the alteration. The invention includes an
optical sensor comprising an optical fiber, a fiber grating written within the optical fiber, strain‐tuned
elements fixed to the optical fiber and an unaltered element, and an altered element fixed to the
unaltered element.
U.S. Patent 7736067, June 15, 2010, proposes fiber optic seal. A fiber sealing apparatus in which a seal
about an outer fiber optic cable may be formed relatively independently of a seal about an inner fiber
optic line.
U.S. Patent 7740064, June 22, 2010, proposes system method and apparatus for downhole submersible
pump having fiber optic communications. A downhole submersible pump system, method, and
apparatus utilizes fiber optic sensors and distributed temperature sensors below the submersible pump
to monitor pump discharge pressure and temperature, intake pressure and temperature, and motor
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temperature. In addition, distributed temperature sensors are used below the pump to monitor the
perforations within the well bore.
U.S. Patent 7,779,683, August 24, 2010, proposes tracking fluid displacement along a wellbore using real
time temperature measurements. A method of tracking fluid displacement along a wellbore includes the
steps of: monitoring temperature in real time in the wellbore; and observing in real time a variation in
temperature gradient between fluid compositions in the wellbore. Another method of tracking fluid
displacement along a wellbore includes the steps of: monitoring temperature along the wellbore; and
observing a variation in temperature gradient due to a chemical reaction in the wellbore. Another
method includes the step of causing a variation in temperature gradient in the fluid while the fluid flows
in the wellbore.
U.S. Patent 7852468, December 14, 2010, proposes fiber optic refractometer. A downhole
refractometer apparatus and method include a light source, an optical fiber that receives light emitted
from the light source and a fluid cell that receives a downhole fluid. A metalloid interface member is
disposed to provide an interface with the downhole fluid in the fluid cell, and a light detecting device
detects a light reaction at the metalloid interface member, the downhole fluid property being estimable
at least in part based on the light reaction.
U.S. Patent 7900699, March 8, 2011, proposes method and apparatus for logging a well using a fiber
optic line and sensors. It comprises a logging tool adapted to be deployed in a wellbore environment.
The logging tool includes at least one sensor for taking a measurement of the wellbore environment.
The sensor is a fiber optic sensor and the system includes a fiber optic line in optical communication
with the sensor. The data measured by the sensor is transmitted through the fiber optic line on a real
time basis to the surface, where the data is processed into a real time display. In one embodiment, the
fiber optic sensor is a passive sensor not requiring electrical or battery power. In another embodiment, a
continuous tube with one end at the earth's surface and the other end in the wellbore is attached to the
logging tool and includes the fiber optic line disposed therein.
U.S. Patent 7912333, March 22, 2011, proposes dual conductor fiber optic cable. It is a powered fiber
optic cable for use in a hydrocarbon well of extensive depth and/or deviation. The cable may couple to a
downhole tool for deployment to well locations of over 30,000 feet in depth while maintaining effective
surface communication and powering of the tool. The cable may be configured to optimize volume
within a core thereof by employing semi‐circular forward and return power conducting portions about a
central fiber optic portion. As such, the cable may maintain a lightweight character and a low profile of
less than about 0.5 inches in diameter in spite of powering requirements for the downhole tool or the
extensive length of the cable itself.
U.S. Patent 7969571, June 28, 2011, proposes evanescent wave downhole fiber optic spectrometer. It is
an apparatus for estimating a property of a fluid downhole. It includes the following: an optical fiber
that receives light emitted from a light source and including an unclad portion adapted for contacting
the fluid; a photodetector for receiving optical signals from the portion; and a spectrometer for
obtaining an evanescent spectrum of the fluid from the portion.
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U.S. Patent 8090227, January 3, 2012, proposes purging of fiber optic conduits in subterranean wells. A
downhole optical sensing system includes an optical line, at least two tubular conduits, one conduit
being positioned within the other conduit, and the optical line being positioned within at least one of
the conduits, and a purging medium flowed in one direction through one conduit, and flowed in an
opposite direction between the conduits. It is a method of purging a downhole optical sensing system. It
includes the steps of installing at least two conduits and an optical line in a well as part of the sensing
system. One conduit is positioned within the other conduit, and the optical line is positioned within at
least one of the conduits. A purging medium is flowed through the conduits in the well, so that the
purging medium flows in one direction through one conduit and in an opposite direction between the
conduits.
U.S. Patent 8155486, April 10, 2012, proposes flexural disc fiber optic sensor and method of forming
same. A fiber optic sensor employs at least two flexural discs that are spaced apart from one another
along a central axis. The fiber optic sensor can be used for OTDR measurements of acceleration for real‐
time oilfield monitoring applications as well as other fiber‐based interferometric measurement
applications. A coupling structure preferably couples the outer edges of the flexible disks, the mass
being attached to the coupling structure.
U.S. Patent 8177424, May 15, 2012, proposes fiber optic sensor for use on sub‐sea pipelines. The fiber
optic sensor assembly is coupled to remotely located equipment by fiber optic cable(s) which extend
outside of the pipeline. The fiber optic sensor assembly is affixed to a mounting point on the pipeline.
The mounting point is a pipe section having an internal conduit and at least one layer that surrounds the
internal conduit for protection and insulation of the internal conduit. A segment of the pipe section has
a portion of such layer(s) removed or omitted to define an annular recess. When installed, the assembly
has two semi‐cylindrical halves that are positioned with the annular recess and coupled together to
thereby surround and embrace the segment of the pipe section. The assembly houses a length of optical
fiber that is coupled to at least one externally accessible fiber optic connector.
U.S. Patent 8,210,252, July 3, 2012, proposes a fiber optic gravel distribution position sensor system.
The well condition during gravel packing is monitored and the gravel distribution condition is sent to the
surface in real time through the preferred technique of a fiber optic line that wraps around the screens
directly or indirectly on a surrounding tube around the screens. The fiber optic line has a breakaway
connection that severs when the completion inner string is removed. A production string can then be
run in to tag the fiber optic line through a wet connect to continue monitoring well conditions in the
production phase. The fiber optic line can also be coiled above the packer so that the relative movement
of the inner string to the set packer can be detected and communicated to the surface in real time so as
to know that the crossover has been moved the proper distance. One example is to get it from the
gravel packing position to the reverse out position.
U.S. Patent 8213756, July 3, 2012, Proposes breathable downhole fiber optic cable and a method of
restoring performance. A breathable downhole fiber optic cable is provided having an outer protective
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tube. It is a fiber optic tube having a plurality of optical fibers contained therein. It has at least one
annulus disposed between the outer protective tube and the fiber optic tube and it has at least one
path, extending through the length of the fiber optic cable, which provides a channel for a purge gas to
flow for removing a second gas, such as hydrogen, from the fiber optic cable.
U.S. Patent 8218916, July 10, 2012, proposes fiber optic temperature and pressure sensor and system
incorporating same. It is a sensing system that includes a sensor having an enclosure that defines a
chamber, a fiber and an optic segment extending from outside the enclosure into the chamber. It
includes a sequence of optical processing elements within the chamber. The elements include a fiber
Bragg grating, a polarizer, a side hole fiber, and a mirror. A light source is arranged to direct light to the
sensor(s). A spectral analyzer is arranged to detect light reflected back from the sensor(s). The fiber
Bragg grating substantially reflects a first spectral envelope while transmitting the remainder of the
optical spectrum to the polarizer and side hole fiber. The polarizer, side hole fiber, and mirror cooperate
to return an optical signal within a second spectral envelope. The characteristic wavelength of a peak in
the first spectral envelope is highly sensitive to temperature and relatively weakly sensitive to pressure.
The period of the optical signal within the second spectral envelope is highly sensitive to pressure and
relatively weakly sensitive to temperature. The spectral analyzer measures these spectral components
to simultaneously derive a measure of temperature and pressure that effectively compensates for
temperature‐pressure cross‐sensitivity of the sensor(s).
U.S. Patent 8,240,913, August 14, 2012, proposes a fiber optic sensing device and method that include a
stationary, rotary component, and a fiber optic sensing system. The fiber optic sensing system includes a
cable having one or more fiber optic sensors disposed on the stationary component, the rotary
component, or combinations thereof. The fiber optic sensing system is configured to detect one or more
first parameters including temperature, strain, pressure, vibration, torque; or combinations thereof
related to the stationary component, the rotary component, or combinations thereof. The one or more
first parameters is used to determine one or more second parameters including thermal expansion,
clearance, fluid flow rate variation, condensation, fluid leakage, thermal loss, life, thermal stress, or
combinations thereof related to the stationary component, the rotary component, or combinations
thereof.
U.S. Patent 8,274,400, September 25, 2012, proposes methods and systems for downhole telemetry.
Methods and apparatus for facilitating optical communications and sensing, with downhole optical or
other sensors, in high temperature oilfield applications. The apparatus can include a downhole
telemetry cartridge for downhole use at temperatures in excess of about 115 degrees Celsius. The
apparatus can also include a downhole light source optically connected to the telemetry cartridge. The
light source may include at least one remotely pumped laser optically connected to a surface pump laser
via optical fiber(s). The remotely pumped laser may drive the downhole optical or other sensors for their
operations.
U.S. Patent 8,280,202, October 2, 2012, proposes fiber‐optic dynamic sensing modules and methods. A
fiber‐optic dynamic sensing module comprises a support member, a beam extending from the support
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member, and a pre‐strained fiber Bragg grating sensor and a strain‐free fiber Bragg grating sensor
mounted on the beam. The pre‐strained and strain‐free fiber Bragg grating sensors each comprise a
Bragg grating inscribed in a fiber. The Bragg grating of the pre‐strained fiber Bragg grating sensor is
packaged more tightly along a longitudinal direction of the beam than the Bragg grating of the strain‐
free fiber Bragg grating sensor.
U.S. Patent 8,298,227, October 30, 2012, proposes temperature compensated strain sensing catheter.
A strain sensing assembly implements thermal management and/or temperature measurement
techniques to adequately mitigate against and compensate for temperature changes in optical fiber
strain sensors of a distal end of a catheter. In one embodiment, the distal end of the catheter includes
an end effector such as an ablation head that introduces significant thermal temperature changes
proximate the distal end of the catheter. In one embodiment, a plurality of temperature sensors is
utilized for accurate determination of each of a plurality of optical fiber strain sensors. In other
embodiments, a single temperature sensor may be utilized by implementing thermal management
techniques that adequately reduce temperature differences between the single temperature sensor and
the plurality of optical fiber strain sensors.
U.S. Patent 8,304,714, November 6, 2012, proposes chemical sensor using four wave mixing technique.
A sensor for measuring a property of a chemical, the sensor including: a light source; and a mixing
medium in optical communication with the light source and exposed to the chemical; wherein four wave
mixing of light interacting with the mixing medium provides a signal that indicates the property.
U.S. Patent 8,306,373, November 6, 2012, proposes fiber Bragg grating sensing package and system for
gas turbine temperature measurement. A fiber Bragg grating multi‐point temperature sensing system
comprises a fiber sensing cable package and a plurality of clamping devices distributed along an inner
surface of a wall in a circumferential direction for securing the fiber sensing cable package. The fiber
sensing cable package comprises a fiber Bragg grating based sensing cable comprising at least one
optical fiber, a plurality of Bragg gratings inscribed in the optical fiber, and a fabric layer and a sheath
tube surrounding the optical fiber. The multi‐point fiber temperature sensing system comprises a light
source for transmitting light to the Bragg gratings based sensing cable package, and a detector module
receiving reflected signal. Each clamping device comprises a radiation tee and defines at least one
mounting hole for securing the fiber sensing cable.
U.S. Patent 8,330,096, December 11, 2012, proposes an interrogator for a plurality of sensor fiber optic
gratings including a driver/modulator. An interrogator for a plurality of sensor fiber optic gratings. The
interrogator includes a broadband optical source; at least one beam splitter directing output of the
optical source to the sensor fiber optic gratings; at least one linear filter for converting changes in peak
reflection wavelength to changes in intensity; at least one optical receiver; and at least one amplifier
associated with each optical receiver. The interrogator also includes, alternatively, a driver/modulator
for the optical source providing on/off pulses; an analog integrator following the at least one amplifier;
or a mechanism compensating for masking of one sensor fiber optic grating by another.
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U.S. Patent 8,330,617, December 11, 2012, proposes wireless power and telemetry transmission
between connections of well completions. An intelligent well system may include a first main bore
transmission assembly disposed in a main bore and a first lateral bore transmission assembly disposed in
a lateral bore. The first main bore transmission assembly may include a first main bore transmission
unit, and the first lateral bore transmission assembly may include a first lateral bore transmission unit.
The first main bore transmission unit and the first lateral bore transmission unit may be configured to
establish a wireless connection there between, such that at least one of power or telemetry can be
wirelessly transmitted. The first main bore transmission assembly may be configured to be
communicatively connected to a surface communication device.
U.S. Patent 8,333,505, December 18, 2012, proposes methods and systems for extending the range for
fiber optic distributed temperature (DTS) systems. Systems and methods for extending the range of a
fiber optic DTS system are provided. In one respect, a method may provide steps for transmitting, in a
first time‐period, an optical signal at a first energy level through an optical fiber, collecting backscatter
signals because of the first transmission. The first energy level is adjusted to a second energy level,
transmitting, in an additional time‐period, the adjusted optical signal through the optical fiber.
Backscatter signals are collected because of the adjusted transmissions. The system uses a portion of
the collected backscatter as a result of the first transmission and a portion of the collected backscatter
as a result of the additional transmissions, determining one or more parameter profiles, such as a
temperature profile.
U.S. Patent 8,333,551, December 18, 2012, proposes embedded fiber optic sensing device and method.
A device operating in an environment includes a fiber optic sensing system having one or more fiber
optic sensors disposed in the device and configured to detect one or more parameters related to the
device. The parameters may include temperature, strain, pressure, vibration, or combinations thereof.
U.S. Patent 8,336,633, December 25, 2012, proposes System and method for connecting devices in a
well environment. A technique facilitates formation of communication line connections in a well
environment. An electro‐optic splitter enables communication line connections which comprise
electrical conductor connections and optical fiber connections. The electro‐optic splitter comprises a
universal block, which enables the electrical conductor and optical fiber to pass through the universal
block while also enabling splitting of at least one of the electrical conductor and optical fiber for
additional connection to one or more downhole gauges or other devices.
U.S. Patent 8,369,671, February 5, 2013, proposes a hermetically sealed fiber sensing cable. In one
aspect, the present invention provides a hermetically sealed fiber sensing cable comprising the
following. It has a core fiber comprising at least one Bragg grating region, an outer surface and a length.
It has a fiber cladding in contact with the core fiber along the entire length of the core fiber. The fiber
cladding has an outer surface and a length. A carbon layer is disposed upon the outer surface of the
fiber cladding along the entire length of the fiber cladding.
The carbon layer comprises diamond‐like carbon. A hydrogen ion absorption layer is in contact with the
carbon layer. The hydrogen ion absorption layer is disposed on the outer surface of the carbon layer. It
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has an outer sleeve. Also provided in another aspect of the present invention is a component for a
hermetically sealed fiber sensing cable.
U.S. Patent 8,371,372, February 12, 2013, proposes installation of tubular strings with lines secured
thereto in subterranean wells. It is a system which has at least one line attached to a tubular string and
it can include at least one clip pivotably secured on one side of a recess. At least one structure is
positioned on an opposite side of the recess. Rotation of the clip into engagement with the structure
secures the line in the recess. A method of attaching at least one line to a tubular string can include
securing the line to a support on the tubular string as the tubular string is being conveyed into a
wellbore. The securing step further includes rotating at least one clip into engagement with at least one
structure, thereby preventing removal of the line from a recess formed in the support.
U.S. Patent 8,402,789, March 26, 2013, and U.S. Patent 8,272,236, September 25, 2012, propose a high
temperature stable fiber grating sensor and a method for producing same. A method of producing a
thermally stable grating allows the grating to be placed in environments where temperatures reach
1000.degree. C. These gratings may be concatenated so as to form a sensor array. The method requires
a step of lowering the characteristic intensity threshold of a waveguide by at least 25%. That step is
followed by irradiating the waveguide with femtosecond pulses of light having a sufficient intensity and
for a sufficient duration to write the grating so that at least 60% of the grating remains after exposures
of at least 10 hours at a temperature of at least 1000.degree. C. Pre‐writing a Type I grating before
writing a minimal damage Type II grating lowers the characteristic threshold of the waveguide so that a
stable low damage type II grating can be written; alternatively providing a hydrogen or deuterium
loaded waveguide before writing the grating lowers the characteristic threshold of the waveguide.
U.S. Patent 8,402,834, March 26, 2013, proposes a fiber optic pressure sensor based on differential
signaling. It is a temperature‐compensated pressure gauge, which has a substrate having at least one
surface coupled to a source of pressure to be measured. The substrate’s first surface has a first fiber
Bragg grating from a first optical fiber attached in an appropriately sensitive region of the substrate. A
fiber Bragg grating from a second optical fiber is attached to the opposite surface from the first fiber
Bragg grating. The first and second fiber Bragg gratings reflect or transmit optical energy of decreasing
or increasing wavelength, respectively, in response to an applied pressure. The first and second fiber
Bragg gratings have nominal operating wavelength ranges that are adjacent to each other but are
exclusive ranges and the fiber Bragg gratings also have closely matched pressure coefficients and
temperature coefficients.
U.S. Patent 8,408,064, April 2, 2013, proposes a distributed acoustic wave detection method. A
distributed acoustic wave detection system and method is provided. The system may include a fiber
optic cable deployed in a well and configured to react to pressure changes resulting from a propagating
acoustic wave and an optical source configured to launch interrogating pulses into the fiber optic cable.
In addition, the system may include a receiver configured to detect coherent Rayleigh noise produced in
response to the interrogating pulses. The CRN signal may be used to track the propagation of the
acoustic wave in the well.
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U.S. Patent 8,417,084, April 9, 2013, proposes distributed optical pressure and temperature sensors.
Disclosed herein is a carrier for an optical fiber having a plurality of optical sensors located thereon. The
carrier has a test section comprising a cavity and at least one geometric discontinuity, wherein in
response to a pressure applied to the test section, a stress concentration is formed proximate to the
geometric discontinuity, and wherein the optical sensor is adhered to at least a part of the geometric
discontinuity. The cavity may be filled with a liquid or a gel. A temperature optical sensor may also be
provided adjacent to the pressure optical sensor.
U.S. Patent 8,422,021, April 16, 2013, proposes all‐fiber interferometric fiber optic gyroscope for
inhibiting zero drift. A method for inhibiting zero drift of an all‐fiber interferometric fiber optic
gyroscope and a corresponding all‐fiber interferometric fiber optic gyroscope are disclosed. The method
comprises: reversing the polarity of an AC voltage applied to a PZT piezoelectric ceramic phase
modulator according to a predetermined half‐cycle time period, and making half of the difference
between output rotation rates of the gyroscope in two adjacent half‐cycle time periods as the output
rotation rate of the gyroscope in a cycle. A phase reversal switch and a DSP chip are added to the all‐
fiber interferometric fiber optic gyroscope. The phase reversal switch is used for controlling the polarity
of the AC voltage, and the DSP chip is used for outputting a square wave signal to control the phase
reversal switch and for calculating the output rotation rate of the gyroscope according to the output
signal of a demodulation/amplifier circuit.
U.S. Patent 8,432,552, April 30, 2013, proposes a high intensity Fabry‐Perot sensor. It is a sensor
assembly having an optical fiber and a lens in optical communication with the optical fiber. It has a
reflective surface spaced from the lens for reflecting light from the beam back to the lens. It has a
partially reflective surface positioned between the reflective surface and the lens for reflecting light
from the beam back to the lens. It has an alignment device for aligning the lens and reflective surface
with respect to one another such that light from the beam of light transmitted from the lens reflects
from the reflective surface back to the lens. The alignment device can have a rotational component and
a base component, where the rotational component rotates to align a beam of light transmitted from
the lens. The rotational component can also cooperate with the base component to move axially with
respect to the reflective surfaces to align the beam for optimum power.
U.S. Patent 8,433,160, April 30, 2013, proposes smart fastener and smart insert for a fastener using fiber
Bragg gratings to measure strain and temperature. A measurement device including a fastener for use
in attaching a first member to a second member, in which the fastener has an aperture extending
through a length of the fastener, and a first optical fiber located within the aperture, in which the first
optical fiber includes at least one fiber Bragg grating sensor. At least a portion of the first optical fiber
can be secured within the aperture. A first end of the first optical fiber can be connected to an
associated first optical connector and a second end of the first optical fiber can be connected to an
associated second optical connector.
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U.S. Patent 8,445,841, May 21, 2013, proposes method and apparatus for a mid‐infrared (MIR) system
for real time detection of petroleum in colloidal suspensions of sediments and drilling muds during
drilling operations, logging and production operations. A first waveguide has a top face positioned in an
oil well borehole for wetting by returning drilling mud from a drill bit as drilling progresses. A second
waveguide is positioned in the borehole for wetting by new drilling mud being pumped to the drill bit.
MIR light rays are fed from an MIR light source into the first and second waveguides for causing
evanescent waves to be generated by each waveguide for reacting with the molecules of the associated
drilling mud, respectfully, whereby a modulated optical signal representative of spectra of components
and particles in the associated drilling mud, respectively, are emitted from each waveguide. The
modulated optical signals are converted to electrical signals. They are subtracted from one another to
remove common mode signals and passed into a processor programmed for extracting the spectra
hydrocarbon components contained in the returning drilling mud as the result of the drilling activity.
U.S. Patent 8,474,782, July 2, 2013, proposes system and method for effective isolation of an
interferometer. An interferometer has its performance enhanced by being suspended in a housing that
is optionally evacuated. The frame that supports the interferometer is secured to a cover for the
housing with a plurality of studs having mechanical vibration isolators. The frame comprises a support
flange with a foam layer beneath the interferometer. An optics tray is disposed above the
interferometer and holds the assembly to the support flange. The fibers that are connected to the
interferometer enter the side of the housing and the entry is sealed off to allow the interior of the
housing to be evacuated.
U.S. Patent 8,476,583, July 2, 2013, proposes system and method for wellbore monitoring. A system for
monitoring a borehole includes the following. A borehole string is disposed within the borehole and
configured to direct a fluid into the earth formation for storage in the earth formation, the fluid
including carbon dioxide. At least one optical fiber sensor is disposed on the borehole string at a fixed
location relative to the borehole string. The optical fiber sensor includes a plurality of measurement
units disposed therein along a length of the optical fiber sensor. The plurality of measurement units are
configured to cause a wavelength shift in an interrogation signal received in at least one optical fiber
sensor due to at least one of a strain and a deformation of the borehole string. A processor is configured
to transmit the interrogation signal to the at least one optical fiber sensor, and calculate at least one of
the strain and the deformation based on the wavelength shift.
U.S. Patent 8,672,539, March 18, 2014, proposes a method of sensing distributed temperature for a multiple sensor fiber optic sensing system.