SCSSV Full Report

Tubing Retrievable Sub Surface Safety Valve Page 4

Project Report

On

“Tubing Retrievable Sub-Surface

Safety Valves”

Summer Internship

1st June-25th July2008

At

Submitted To:

Mr. Cecil Antao

(Ops/Mktg Account Manager)

Submitted By:

Ashwin Soni Abhishek Bansal

Metallurgical Engineering & Material Science Gas Engineering

2005-2010 2005-2009

IIT Bombay, Powai UPES, Dehradun


ACKNOWLEDGEMENT

We sincerely thank Mr. C.K. Pathak (Country Manager, India & Bangladesh, BOT) for

providing us with this opportunity to learn and be part of this prestigious organization.

We would give our special thanks to Mr. Cecil Antao (Ops/Mktg Account Manager, BOT) for

guiding us throughout the eight week summer internship program and helping us in each

and every aspect as our mentor regardless of the busy schedule he had which kept our

morals high.

We give special thanks to Mr. Abhishek Kaushic (Sales Manager, BOT), Mr. Sushil Keshkar

(Ops/Mktg Account Manager, BOT), Mr. D.K. Shayamal (Ops/Mktg Account Manager, BOT)

and Mr. Rudappan Silvaguru (Field Service Manager, BOT) for providing us support and a

platform to interact with the BOT team.

We extend our sincere thanks to the Field Engineers, Commercial Team, Logistics and

Supply Chain Management Team, IT and Finance Department for providing us with the

knowledge of the operations and sharing their vast experiences with us.

This summer internship has been a valuable learning experience and has helped us gain a

perspective of the MNC culture and the corporate environment. We respect the core values

of the company “Integrity, Teamwork, Performance and Learning “and will try our best to

incorporate them into our actions. We thank Baker Oil Tools for providing us all the

information required and allowing us to use it in this report.

All in all being a part of Baker Hughes has been memorable and overwhelming.


CERTIFICATE

This is to certify that the project entitled

“Tubing Retrievable Sub-Surface Safety Valves”

Submitted by

Mr. Abhishek Bansal

B.Tech., Gas Engineering (2005-09)

from

University of Petroleum & Energy Studies, Dehradun

&

Mr. Ashwin Soni

Dual Degree, Metallurgical Engineering & Material Science (2005-10)

from

IIT Bombay, Powai

is an approved record of work carried out by them at

Baker Oil Tools, Baker Hughes, India Project Office, Mumbai

under proper guidance for a period of eight weeks

(w.e.f. 1st June to 25th July, 2008).

____________

Cecil Antao

(Ops/Mktg Account Manager)

Baker Oil Tools, Baker Hughes Asia Pacific Ltd.

Mumbai


1. A Brief Review of the Summer Internship

The summer internship at Baker Oil Tools started w.e.f. 1st June to 25th July i.e. for a period

of eight weeks. On the first day, the HSE orientation took place wherein we were told about

the Safety Policies of BOT. It was followed by a presentation on the core values of Baker

Hughes “Learning, Performance, Teamwork and Integrity”. In the following two weeks

presentations were delivered by the Finance Team, IT Team, Logistics and Supply Chain

Management Team and the Commercial Team. They envisioned us about the task their

team performs in order to carry out smooth and unrestricted operations in BOT.

For the next 6 weeks we were taken to workshops at ITS (International Tubular Services)

at Ghansoli and British Gas, Wadala situated in Mumbai. In the workshops we gained

valuable experience by working along with the Field Engineers. We learned about various

products of Baker Oil Tools such as Liner Hangers, Multilateral Assembly, Full Bore

Isolation Valve, External Casing Packer etc. We also assisted the Field Engineers working

on live project for the BOT customers like GSPC, BG and ONGC and participated in breaking

and redressing of various tools.

We also were taken to Baker INTEQ workshop for one day visit to have a glance of the

equipments available there.

On the last day of the Internship we delivered a presentation on the project to the BOT

team on the Project assigned to us i.e. “Tubing Retrievable Sub Surface Safety Valves”.


2. CONTENTS

ACKNOWLEDGEMENT ........................................................................................................................................ 5

1. A Brief Review of the Summer Internship ......................................................................................... 7

2. CONTENTS ..................................................................................................................................................... 8

3. LIST OF FIGURES AND TABLES .......................................................................................................... 12

4. INTRODUCTION ........................................................................................................................................ 13

5. BAKER HUGHES INCORPORATED ..................................................................................................... 14

5.1 About Baker Hughes ........................................................................................................................ 14

1.1.1 Drilling & Evaluation .................................................................................................................... 14

1.1.2 Completion & Production ........................................................................................................... 16

1.1.3 Reservoir Technology and Consulting................................................................................... 17

5.2 Financial Highlights ......................................................................................................................... 19

6. BAKER OIL TOOLS .................................................................................................................................... 20

6.1 THE Completion Company ............................................................................................................ 20

6.2 THE Workover Company ............................................................................................................... 20

6.3 THE Fishing Company .................................................................................................................... 20

7. SUB-SURFACE SAFETY SYSTEMS ....................................................................................................... 22

7.1 Introduction ........................................................................................................................................ 22

7.2 Overveiw .............................................................................................................................................. 23

Rating Envelope ........................................................................................................................................ 23

RBT Threads ............................................................................................................................................... 23

Unique Flapper Design ........................................................................................................................... 24

Chemical Injection Capabilities ........................................................................................................... 26


Control Line Connection ........................................................................................................................ 27

7.3 Basic Principle ................................................................................................................................... 29

1. Sub-Surface Controlled SSSV’s: ............................................................................................... 29

2. Surface Controlled SSSV’s: ........................................................................................................ 29

Contrast between SSCSV’s and SCSSV’s: .......................................................................................... 30

Versions of Safety Valves: ...................................................................................................................... 30

7.4 Industry Standards for Subsurface Safety Valves ................................................................ 31

8. Tubing Retrievable Surface Controlled Sub Surface Safety Valve (TRSCSSV) .................. 34

8.1 Assembly Drawing and Component List ................................................................................. 34

8.2 Working of a TRSCSSV .................................................................................................................... 36

8.3 Models Available ............................................................................................................................... 37

CEMENTSAFE™ SERIES SUBSURFACE SAFETY VALVE ........................................................... 38

Onyx™ SERIES SUBSURFACE SAFETY VALVES ............................................................................. 39

REALM™ SERIES SUBSURFACE SAFETY VALVE ........................................................................ 41

TITAN™ SERIES SUBSURFACE SAFETY VALVE ............................................................................ 42

SelecT™ SUBSURFACE SAFETY VALVE ............................................................................................ 44

NEPTUNE™ SERIES NITROGEN-CHARGED SUBSURFACE SAFETY VALVE ....................... 45

TRITON™ SERIES BALANCE LINESUBSURFACE SAFETY VALVE .......................................... 47

T-SERIES™ SUBSURFACE SAFETY VALVE ...................................................................................... 49

8.4 Models available in T-Series ......................................................................................................... 50

T (E) Series .................................................................................................................................................. 50

TM (E) Series .............................................................................................................................................. 50

TSM (E) Series and TUSM (E) Series ................................................................................................. 50

8.5 The Basic Hydrostatic Pressure Calculations ........................................................................ 51

8.6 Fail-Safe Setting Depth ................................................................................................................... 51


Fail-Safe Setting Depth Calculations ................................................................................................. 52

Opening and Closing Pressure Calculations ................................................................................... 53

8.7 Design Principles and Philosophy .............................................................................................. 56

Flow Tube Design Features .................................................................................................................. 56

Debris Exclusion/Control Design Consideration:- ...................................................................... 57

Scale Deposition prevention: ............................................................................................................... 57

Flow Tube Closure Assist Tool ............................................................................................................ 57

How side loading and torsional forces on a rod piston are perceived and designed for-

......................................................................................................................................................................... 58

Dual opposite wound Power Spring.................................................................................................. 59

8.8 Technical Evaluation of the ‘T’ Series SSV Equipment ....................................................... 59

Outer Housing thread seal design philosophy .............................................................................. 59

Permanent Lock Open Features.......................................................................................................... 60

Evaluation of dynamic seal assembly and metal-to-metal stop seals .................................. 60

Components of dynamic seal assemblies and metal-to-metal stop seals: .......................... 61

Baker Oil Tools' Detent System for the 'T'-Series Safety Valves ............................................ 63

Flapper and hinge pin design ............................................................................................................... 64

Table 3- Features and Benefits of Wedge Shape Flapper ......................................................... 65

Table 4- Features and Benefits of Curved (Slim line) Flapper ................................................ 66

Self-Equalizing Mechanism ................................................................................................................... 68

Control Line Jam Nut Connection ....................................................................................................... 72

Debris and Sand exclusion barriers .................................................................................................. 73

8.9 ‘T’ Series accessory tools ............................................................................................................... 74

Flapper Lock Open Tool ......................................................................................................................... 74

Wireline Insert Safety Valve ................................................................................................................. 75


Separation Sleeve ..................................................................................................................................... 76

Control Pressure Communication Tool............................................................................................ 77

9. CONCLUSION .............................................................................................................................................. 78

10. BIBLIOGRAPHY ...................................................................................................................................... 79


3. LIST OF FIGURES AND TABLES

Table 1- List of TE 5 (5.5") Components ................................................................................................... 35

Table 2- Fail Safe Setting Depth Calculations for the T (E) - 5 (5.5”) model (7) ........................ 55

Table 3- Features and Benefits of Wedge Shape Flapper ................................................................... 65

Table 4- Features and Benefits of Curved (Slim line) Flapper ......................................................... 66

Figure 1- RBT Thread Performance Envelope ........................................................................................ 24

Figure 2- Self Equalizing Mechanism ......................................................................................................... 25

Figure 3-Curved Flappers ............................................................................................................................... 26

Figure 4-Chemical injection feature simplifies the completion and maximizes the benefits

from injection process ............................................................................................................................ 27

Figure 5- Control line and its connections ............................................................................................... 28

Figure 6- A Sub Surface Safety Valve .......................................................................................................... 29

Figure 7- Model "T (E)-5" Safety Valve (Assembly Drawing) (7) .................................................... 34

Figure 8- Subsurface Safety Valve Type .................................................................................................... 37

Figure 9- RBT Thread connection................................................................................................................ 59

Figure 10- Dynamic Seal Assembly ............................................................................................................. 61

Figure 11- Location of Metal to Metal Stop Seal .................................................................................... 62

Figure 12- Detent System/Shock Absorber ............................................................................................. 63

Figure 13- Wedge Shaped Flapper (Three point contact shown above) ...................................... 64

Figure 14- Curved Flapper Design .............................................................................................................. 66

Figure 15- Single Hinge Flapper Assembly .............................................................................................. 67

Figure 16- Baker Jam Nut ............................................................................................................................... 72

Figure 17- Debris and Sand Exclusion Barriers ..................................................................................... 73

Figure 18- Flapper Lock Open Tool ............................................................................................................ 74

Figure 19- Wireline Insert Safety Valve .................................................................................................... 75

Figure 20- Control Pressure Communication Tool ............................................................................... 77


4. INTRODUCTION

The safety systems are required for the protection of the personnel around the platform,

the environment and to prevent any production losses. It is also required for shutting in a

well, in case of emergency shut down due to catastrophe, production testing, inspection

and other routine operations. The safety valves keep the well shut in when the control line

pressure is released and open up when the pressure is again maintained (in surface

controlled type safety valves). There are various versions of such subsurface safety valves

available with Baker Oil Tools. They are either surface controlled or subsurface controlled.

The surface controlled one is available in two types, one is tubing retrievable and other is

wireline retrievable. The tubing retrievable subsurface safety valves are most widely used

in the oil industry and are available in various models for various applications. They are

available in various designs offering different features which have been discussed further.


5. BAKER HUGHES INCORPORATED

5.1 About Baker Hughes

(1)Baker Hughes provides the worldwide oil and natural gas industry products and

services for drilling, formation evaluation, completion and production. We create value for

oil and gas producers by providing advanced, reliable technology to find, develop, produce

and manage oil and gas reservoirs. We also provide reservoir engineering and other

consulting services. Baker Hughes operates in over 90 countries serving independent,

international and national oil companies.

Baker Hughes is the only major oilfield service company structured around strong product-

line divisions that are focused on Best-in-Class products and services. Our divisions are

organized in two segments -- Drilling & Evaluation and Completion & Production -- which

share common opportunities in developing and delivering technology solutions during

distinct phases of oil and gas development.

The newly-formed Reservoir Technology and Consulting Group includes two consulting

firms – Gaffney, Cline & Associates and GeoMechanics International – that provide technical

and commercial consulting, with unique capabilities in reservoir engineering and

geomechanics.

1.1.1 Drilling & Evaluation

Our Drilling & Evaluation segment includes divisions that apply their products and services

primarily during the drilling process to improve efficiency, reduce risk and acquire

accurate information. The segment includes Baker Atlas, Baker Hughes Drilling Fluids,

INTEQ and Hughes Christensen.

http://www.gaffney-cline.com/

http://www.geomi.com/


Baker Atlas

Baker Atlas offers a complete range of down-hole well logging services for every

environment including advanced formation evaluation, production and reservoir

engineering, petro-physical and geophysical data acquisition services. In addition,

perforating and completion technologies, pipe recovery, and processing and analysis of

open and cased hole data complete the service range.

Baker Hughes Drilling Fluids

Baker Hughes Drilling Fluids provides fluids systems and services that help optimize the

drilling and completion processes maximize hydrocarbon production and manage drilling

waste. Leading technologies include environmentally compliant water-based and

synthetic-based mud systems and remediation fluids that can restore productivity from

damaged wells.

INTEQ

INTEQ provides real-time services to help oil companies drill more efficiently, evaluate

geologic formations, and place wells in productive zones within the reservoir. Important

technologies include automated rotary steerable directional drilling systems, high

performance drilling motors, and integrated logging-while-drilling assemblies. INTEQ also

provides data communications, data management and expert centers to improve drilling

operations and enhance formation evaluation.

Hughes Christensen

Hughes Christensen is the leader in Tricone™ and PDC drill bit, ream-while-drilling and

casing drilling technology. Hughes Christensen application and design engineers work with

customers to provide the best drill bit for the application to continuously improve drilling

performance.

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http://www.bakerhughesdirect.com/cgi/hcc/myHomePage/welcome.jsp?func=cert&goto=%2fresources%2fExternalFileHandler.jsp&linkNames=Hughes+Christensen&path=%2fprivate%2fHCC%2fcontentHTML%2fhome%2fHCC_homepage.html


1.1.2 Completion & Production

Our Completion & Production segment includes divisions that apply their products and

services primarily during the well completion, field production, transportation and refining

processes. The segment includes Baker Oil Tools, Baker Petrolite, Centrilift, and the

Production Optimization business unit.

Baker Oil Tools

Baker Oil Tools provides completion and intervention solutions that help manage cost and

reduce risk while optimizing production. The division has a comprehensive line of

completion systems, which maximize performance and safety from the reservoir to the

surface. Wellbore intervention solutions address issues ranging from temporary well

abandonment and fishing to casing exits, wellbore cleaning, and isolation, remediation and

stimulation operations.

Baker Petrolite

Baker Petrolite provides chemical technology solutions for hydrocarbon production,

transportation and processing, and also delivers pipeline integrity services. Baker Petrolite

is a leader in oil/water separation technology and in solutions to control corrosion,

deposition, bacteria and H2S in producing wells and production facilities. To serve refinery

and petrochemical customers, Baker Petrolite provides chemicals and technical support to

enhance plant processes, improve productivity, manage water treatment, and resolve

environmental issues.

Centrilift

Centrilift provides artificial lift systems, including electric submersible pumps (ESP) and

progressive cavity pump systems, as well as specific engineering, project management and

well monitoring services. Centrilift has expanded the applications for ESP systems to harsh

downhole environments that include high gas to oil ratio, heavy oil, high temperatures and

abrasive laden fluids. New systems also address the needs of coalbed methane and subsea

production.

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http://www.bakerhughesdirect.com/cgi/bpc/myHomePage/welcome.jsp?func=cert&goto=%2fresources%2fExternalFileHandler.jsp&linkNames=Baker+Petrolite&path=%2fprivate%2fBPC%2fcontentHTML%2fhome%2fBPC_homepage.html

http://www.bakerhughesdirect.com/cgi/clift/myHomePage/welcome.jsp?func=cert&goto=%2fresources%2fExternalFileHandler.jsp&linkNames=Centrilift&path=%2fprivate%2fCLIFT%2fcontentHTML%2fhome%2fCLIFT_homepage.html


ProductionQuest

Baker Hughes formed its ProductionQuest business unit to provide technology and services

that help maximize recovery from both new and mature fields. The unit provides

production optimization services centered on the well bore, including permanent

monitoring, chemical automation, intelligent production systems, and consulting services.

The unit also includes the Baker Hughes Integrated Operations group, which manages

projects and combines technologies and services from Baker Hughes divisions and

subcontractors to meet customer objectives for both well construction and production

optimization.

1.1.3 Reservoir Technology and Consulting

Baker Hughes recently formed the Reservoir Technology and Consulting Group to enhance

the company’s capabilities in reservoir engineering, geomechanics and energy consulting

services. The group currently includes Gaffney, Cline & Associates and Geomechanics

International, Inc., which continue to operate as stand-alone consulting firms.

Gaffney Cline & Associates

Gaffney Cline & Associates is an international advisory firm focused on providing

integrated technical and managerial services to all sectors of the oil and gas industry. For

more than 45 years GCA has provided strategic and detailed advice aimed at achieving

practical and commercially viable results. In addition to reservoir engineering, GCA advises

a wide group of clients in exploration, reservoir evaluation, field development, drilling and

production, pipeline, refining and LNG projects throughout the world.

GeoMechanics International

GeoMechanics International is a leader in consulting, training and software in the field of

geomechanics and its application to oil and gas reservoirs. GMI was founded in 1996 by a

team of experts from Stanford University's Department of Geophysics, and each of its

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consultants is a recognized leader in the field of geomechanics. GMI methods are focused

on applying geomechanics modeling to the entire life of a reservoir and are based on 20

years of R&D and more than 12 years of practical application to oilfield problems. These

methods have been proven to reduce exploration risk, save Non-Productive Time (NPT)

and help increase production and recoverable reserves.


5.2 Financial Highlights

(2)

Price & Volume

Recent Price $ 81.36

52 Week High $ 100.29

52 Week Low $ 62.65

Average Vol (Mil) (RTMA) 89.629

Beta 1.36

Share Related Items

Market Cap. (Mil) $ 25,060.540

Shares Out (Mil) 308.020

Float (Mil) 305.600

Dividend Information

Yield % 0.64

Annual Dividend 0.52

Payout Ratio (TTM) % 10.69

Financial Strength

Quick Ratio (MRQ) 1.87

Current Ratio (MRQ) 2.79

LT Debt/Equity (MRQ) 16.87

Total Debt/Equity (MRQ) 25.09

Mil = Millions RTMA = Rolling Three Month Average

TTM = Trailing Twelve Months MRQ = Most Recent Quarter

Asterisk (*) indicates numbers are derived from Earnings Announcements

Pricing and volume data as of Jul 11, 2008.


6. BAKER OIL TOOLS

(3)Baker Oil Tools leads the world in completion, workover and fishing solutions that help

exploration and production companies maximize value from their hydrocarbon-bearing

assets. Since its earliest days, the Baker name has been synonymous with excellence in

down-hole and surface technology, performance and reliability. In the current era of riskier

environments and higher stakes, those qualities are more valuable than ever.

6.1 THE Completion Company

Baker Oil Tools′ undisputed role as the industry leader in reliable, performance-based

completion solutions is based on the world′s most reliable sealing and anchoring

technologies, meticulous planning, and a no-nonsense approach to risk avoidance. From

the Model D Packer to the FORMation Junction™ Multilateral Completion System, H2O-

PAQSM and H2O-FRAQSM production enhancement processes, and InForce™ and

InCharge™ Intelligent Well System and High-pressure/high-temperature environments –

Baker has built a track record second to none by working closely with its customers to

meet or exceed their needs in virtually every completion application.

6.2 THE Workover Company

When well maintenance or remediation operations become necessary, Baker Oil Tools

applies more than five decades of industry-leading mechanical and inflatable packer

technologies to provide integrated solutions that maximize productivity and minimize cost.

At the forefront of Baker′s capabilities are its award-winning through-tubing workover

technologies, which allow zonal isolations, water shutoffs and well cleanouts to be

performed simply, without killing the well or pulling the production tubing.

6.3 THE Fishing Company

Fast, reliable solutions and around-the-world/around-the-clock service make Baker Oil

Tools the preferred provider for both traditional and through-tubing fishing and re-entry

projects. Baker engineers apply practical field experience to industry-leading cutting,


fishing and milling capabilities to provide a range of solutions that are the most advanced

and comprehensive available.


7. SUB-SURFACE SAFETY SYSTEMS

7.1 Introduction

(4)In 1969, an operator lost control of a platform and spilled 4.2 million gallons of crude

into the ocean, killing birds and contaminating beaches. Over 10,000 Loons and Western

Grebes were killed. This spill was off the coast of Santa Barbara, encircled Anacapa and the

eastern each of Santa Cruz Island, and earned the distinction of being the largest oil spill in

California not to mention the most publicised. The Santa Barbara oil spill is considered one

of the key events responsible for promoting the modern environmental movement.

A post-mortem on the accident showed that the well developed a leak in the tubing and

casing between the ocean floor and ocean surface. This allowed the oil to flow, unchecked,

into the ocean. Several attempts to regain control proved to be unfruitful. The well was

finally brought under control by drilling a relief well and pumping in heavy fluids. This

highly visible spill brought public attention to the need of safety equipment. A Subsurface

Safety Valves would have allowed the operator to regain control of the oil flow

immediately.

Shortly after the Santa Barbara oil spill, the petroleum industry began an accelerated

program for the development of standards in relation to safety valves. The American

Petroleum Institute’s Production Department in Dallas, took the lead in developing

specifications and funding an independent test laboratory. Initial testing was done from

1973 - 1974 at Southwest Research Institute in San Antonio, Texas.


7.2 Overveiw

Baker Oil Tools (BOT) is one of the leading suppliers of subsurface safety system

equipment. Full line of subsurface safety valves are available for surface-controlled and

subsurface-controlled tubing retrievable and wireline retrievable applications. Each valve

includes Baker's proven technologies and innovations that have set many industry

standards.

Rating Envelope

The combination of innovative computer programs and exhaustive laboratory testing has

enabled Baker Oil Tools to develop an industry standard for predicting safety valve housing

performance capabilities under all loading conditions. This conservative design approach

ensures the thread's ability to withstand aggressive down-hole environments. The results

of this evaluation are plotted in a graphical format which provides visual indication of the

safe operating range for the safety valve. With this load envelope, operators can safely plan

their completions with confidence that Baker Oil Tools' safety valves will protect their

people and investments.

RBT Threads

Through extensive FEA analysis and technical research, Baker Oil Tools offers RBT

premium thread connections. The efficiency of the RBT thread design allows Baker Oil

Tools to offer the smallest OD's for a given tubing size across the safety valve portfolio. The

RBT premium thread connections bring the superior protection and life extending

advantages of metal-to-metal sealing technology to thousands of Baker safety valves. The

connection's two-step design distributes thread load to impart greater strength than

single-step designs. The metal-to-metal seal points at the box and pin noses provide

enhanced pressure-containing capabilities. The combination of this two-step, ultra slim-

profile thread and the use of high tensile strength materials allows for the slimmest outside

diameters on the market.


Figure 1- RBT Thread Performance Envelope

The RBT thread also includes an innovative center torque shoulder design. The torque

shoulder provides superior resistance to back-off in down-hole service. In addition,

damage is prevented to the metal-to-metal seals during high torque loads and precisely

controls make-up loss.

Unique Flapper Design

Focusing on providing customer solutions along with using state of the art engineering

practices, Baker Oil Tools has introduced several industry firsts relating to its unique

flapper design. Baker Oil Tools was the first to offer a patented through the flapper self-

equalizing feature which has proven to reduce operating costs for operators. The self-

equalizing feature allows operators to open subsurface safety valves against differential

pressure.


Figure 2- Self Equalizing Mechanism

This unique design is resilient to debris and erosion which provides ultimate long-term

reliability. The equalizing system has been used successfully in HP/HT and Big Bore

applications where equalizing high pressures and large volumes can prove challenging.

Baker Oil Tools also provided the industry's first wireline damage resistant flapper design.

This design was created after careful review of mean-time-to-failure statistics relating to all

subsurface safety valve designs. This analysis revealed that a good portion of failures could

be eliminated with a wireline damage resistant flapper. The new flapper design protects

the seal surface from wireline damage if an operator accidentally closes the valve during

wireline operations. The protection offered by the wireline damage resistant flapper

extends the safety valve life for operators.

Baker Oil Tools was the first company to design a 4-1/2 in. safety valve to be installed

inside 7 in. casing and a 7 in. safety valve to be installed inside 9-5/8 in. casing. The key

ingredient to this success was the unique curved flapper design. The curved flapper design

was made possible by advanced machining processes, innovative engineering practices,

and exceptional quality control. These ultra-slimline curved flappers allow operators to

reduce their overall costs and maximize their return on investment by maintaining a large

bore ID while reducing the casing sizes needed for the completion.


Figure 3-Curved Flappers

For high flow rate natural gas applications, Baker Oil Tools recognized the need to design

and manufacture one of the world's most rugged flapper designs. Every flapper design goes

through an intricate engineering process to ensure the flapper can meet the demands of

high gas velocities. Baker Oil Tools' flapper designs have been verified by gas slam tests to

the highest rates available in the world.

Chemical Injection Capabilities

Scale, paraffin, or hydrate formation continues to pose significant risks to operators in

obtaining desired returns on their investments. Formation of these solids can jeopardize

safety valve function by impeding flow tube movement, thereby requiring intervention.

With this in mind, it is the culture within Baker Oil Tools to look for ways to simplify

completion designs that will increase system reliability and decrease operator cost while

maximizing performance.


Figure 4-Chemical injection feature simplifies the completion and maximizes the benefits from injection process

A result of this culture is the optional chemical injection feature available with the Titan™

Series Subsurface Safety Valve. This innovative design incorporates a field-proven double-

poppet system that permits chemical injection directly into the safety valve. Combining this

feature with a Titan Valve will virtually eliminate the need for any chemical injection

mandrel in the tubing string above the safety valve. This will save the customer money and

simplify the completion by reducing the number of components and tubing connections.

Injecting chemicals directly into the spring cavity also ensures that the customer will

receive the maximum benefit of the injection process by allowing injection directly where it

is needed. For valve designs that do not offer the integral chemical injection feature, Baker

Oil Tools offers a chemical injection sub that can be mounted directly on top of the Tubing

Retrievable Safety Valve (TRSV).

Control Line Connection

Baker Oil Tools offers control line in a variety of lengths and materials. The standard

control line provided is welded and drawn and complies to ASTMA269 specifications.

Seamless and encapsulated control line is available upon request. Encapsulation improves

the crush and abrasion resistance of the control line and can be offered in a variety of

materials to suit the customers' down-hole environment. Baker Oil Tools offers a variety of

control line connections to match the application. The Baker metal-to-metal jam nut, which


is standard for valve working pressures of 10,000 psi (689 bar) and below, provides

reliable control line connections at the safety valve. This jam nut features a front and rear

ferrule design that reduces the potential leak path from control line to annulus. For

working pressures greater than 10,000 psi (689 bar), Baker Oil Tools offers Autoclave

connections. (5)

Figure 5- Control line and its connections


7.3 Basic Principle

Depending on the environment and on the type and pressure of the produced effluent, it

may be necessary to place a SubSurface Safety Valve, SSSV, inside the well itself. It

supplements the one(s) on the wellhead if they should happen to be out of order (valve

failure, wellhead torn off, etc).

(6)There are two types of SSSV’s:

1. Sub-Surface Controlled SSSV’s:

These valves that were often called storm chokes are now termed SSCSV (SubSurface

Controlled Subsurface Safety Valves). They are set and retrieved by wireline. They close the

well following a modification in flow conditions where they are located:

a) Either when the ambient flow rate increases (and so the pressure loss across the

valve also increases)

b) When there is a pressure drop opposite the valve.

Baker Oil Tools Manufactures injection valves and velocity valves which fall under

SSCSV’s

2. Surface Controlled SSSV’s:

The SCSSV’s (Surface Controlled Subsurface Safety Valve), of the fail safe type, are

controlled from the surface by hydraulic pressure in the control line and are normally

closed (i.e. closed when no pressure is applied in the control line). The control pressure

acts n a jack which pushes a sleeve back thereby opening the valve. At the same time it

compresses a powerful return spring. As long as the control pressure is kept at the set

Figure 6- A Sub Surface Safety Valve


operating value, the valve remains open. However, if it falls below a certain threshold then

the valve will close automatically solely under the effect of the return spring.

Contrast between SSCSV’s and SCSSV’s:

The SCSSV does not depend directly on ambient flow conditions in the well, but rather on

one or more parameters measured at the well head. This also allows the subsurface valve

to be controlled via a number of safety systems connected to process facilities. The well’s

safety can therefore be achieved manually or automatically whether the trouble is directly

related to the well or not: fire, explosion or impact, process problem, etc. Depending on the

degree of safety required, the wellhead safety valve alone can be closed or, in conjunction

with it, the subsurface safety valve can also be closed.

Due to the design of the hydraulically controlled valve, the depth at which it can be

installed in the well is limited by the capacity of its running string. The spring must be

sufficiently compressed to overcome the opposing force due to the weight of the

hydrostatic column of the hydraulic fluid in the control line that governs the valve and acts

directly on the jack.

Also due to its design, the valve could not be opened as long as the pressure difference

between above and below the closing and sealing mechanism exceeds an average of 0.7

MPa (100 psi), so that the valve will not be damages when it opens. Some valves are

equipped with an internal equalization device. Here, all that is required to reopen the

valves is to increase the pressure in the control line with the well head closed. Otherwise it

is also necessary to recompress the tubing above the valve (by means of a pump, a nearby

well, etc.)

The SCSSV closing and sealing mechanism is either a flapper valve or a ball valve. For a long

time preference was given to ball valves, mainly because of the sealing quality, even though

the sleeve weldment (pivot cage) is complex and fragile. Currently check valves seem to be

preferred choice as they are much simpler, more rugged and robust (i.e. safer). Also, a lot of

progress has been made regarding the reliability and tightness of flappers.

Versions of Safety Valves:

1. Wireline Retrievable: Set in a special landing nipple and retrieved by wireline.


2. Tubing Retrievable: Screwed onto the tubing and pulled out with all or part of the

equipment in the well.

7.4 Industry Standards for Subsurface Safety Valves

The recognized industry standard for Subsurface Safety Valve systems is published in the

American Petroleum Institute Specifications, API Spec 14A and API RP 14B. These two

documents prescribe the minimum standards for quality assurance and performance to provide

the maximum reliability of Subsurface Safety Valve equipment. They also provide guidelines for

the design, installation and operations of safety valve systems. The following is a brief overview

of these standards.

API 14A

The API 14A specification covers Subsurface Safety Valves, Safety Valve Locks, Safety Valve

Landing Nipples, and all components that establish tolerance and/or clearances which may affect

performance or interchangeability.

Classes of Service

Subsurface safety valves, safety valve locks and safety valve landing nipples must meet

acceptable standards for materials manufacturing and testing for one of four classes of service.

Class 1 - Standard Service is for use in oil or gas wells which do not exhibit the

detrimental effects caused by sand or stress corrosion cracking.

Class 2 - Sandy Service is for use in oil or gas wells where a substance such as sand

could cause valve malfunction or failure (this valve must also meet the Class 1 service

requirements).

Class 3 - Stress Corrosion Cracking Service is for use in oil or gas wells where corrosive

agents could cause stress corrosion cracking. This valve must meet the requirements for a

Class 1 and Class 2 valve and be manufactured from materials which are resistant to

stress corrosion cracking.

Within this service class there are two sub-classes, 3S for sulfide stress cracking service and 3C

for chloride stress cracking service. Metallic material, suitable for a 3S environment, shall be in

accordance with NACE MR0175.


Class 4 - Weight Loss Corrosion Service is for use in oil or gas wells where corrosive

agents could be expected to cause weight loss corrosion. Class 1 or Class 2 and be

manufactured from materials which are resistant to stress corrosion cracking.

A Subsurface safety valve which has qualified for Class 1 or Class 2 service will be considered

qualified for Class 3 service without requalification testing, when it is manufactured from

materials resistant to stress corrosion cracking.

Traceability

All components, weldments, subassemblies and assemblies of SSSV equipment shall be

traceable except, Springs, Beans, Common hardware.

Hardness

Each pressure containing part shall be hardness tested in accordance with API.

Equipment Marking

SSSV equipment marking on the exterior surface with the manufacturer’s name or trademark,

monogram, rated working pressure, class of service, model number, serial number, date of

manufacture, and pressure classifications. This list is a general requirements, see specification of

specific requirements.

Supplied Documentation

Each monogrammed SSSV, SV Locks and Nipples shall be delivered to the operator with a

Manufacturer’s Shipping and Receiving Report and an Operating Manual.

Dimensional Inspection

All traceable components, except elastomeric seals, must be dimensionally inspected to assure

proper function and compliance with design specifications and drawings.

Welding

No Welding is performed on a Broken Arrow SSSV.


API RP 14B

The API RP 14B specification covers considerations for system design, instructions for safe

installation, repair, and guidelines for operating and testing to assure sage and efficient

performance of the SSSV system. Also included are procedures for reporting failures. This

recommended practice is directed toward wireline, tubing retrievable and pumpdown SSSV

systems.

Inspection and Testing

Safety valve inspection begins on location where documentation should be checked to verify

serial numbers, size in accordance with the design, and that the safety valve lock for a retrievable

safety valve is compatible with the landing nipple in the well.

Before running the SCSSV in the well, connections should be tightened or checked in

accordance with operating manual. Ascertain that all visible sealing elements are not damaged or

deformed, and that all other visible features do no exhibit marring distortion that may interfere

with safety valve operation.

On new and replaced SSSVs, the opening and closing hydraulics pressures should be verified

according to the operating manual. Ascertain that the SSSV will operate fail-safe at the setting

depth before installation.

After installation of the SSSV in the well, the valve should be closed under minimum no-flow

conditions by operations of the surface control. Verification of closure may be accomplished by

wire-line, pressure build-up or flow test. If the well is capable of flow, the SSSV can be tested

for leakage by opening the surface valves to check the flow. The SSSV is then reopened

following the operation manual.

The SSSV should be operated at least every six months. (4)


8. Tubing Retrievable Surface Controlled Sub Surface Safety

Valve (TRSCSSV)

8.1 Assembly Drawing and Component List

Figure 7- Model "T (E)-5" Safety Valve (Assembly Drawing) (7)


Table 1- List of TE 5 (5.5") Components

S.NO Component Name Quantity

1 Top Sub 1

2 Sliding Manderal Nut 1

3 Dynamic Seal Assmbly 1

4 Coupling Jamnut 2

5 Piston 1

6 Thread Protector 1

7 Cylinder Sub 1

8 Bearing 1

9 Set Screw 1

10 Coupling 1

11 Power Spring 1

12 Flow Tube 1

13 Spring Stop 1

14 C-Ring 1

15 Flapper Stop 1

16 Flapper Base 1

17 Spring Housing 1

18 Flapper Stop Seal Assembly 1

19 Flapper Pin 1

20 Torsion Spring 1

21 Equalizer Flapper Assembly 1

22 Flange Face Spacer 1

23 Resilience Seal 1

24 Rear Ferrule 2

25 Front Ferrule 2


8.2 Working of a TRSCSSV

The working principle for all TRSCSSV is same. These valves are controlled from the

surface via a small diameter hydraulic control line connecting the safety valve to the

surface Emergency Shut-Down System. Since the valve is of the normally closed type, when

the applied control line pressure is removed, the valve returns to the closed position thus

shutting in the well.

The control line is connected to the top sub through the jam nut connection. The control

line allows the control line fluid to fill inside the control chamber. The hydraulic oil used as

the control line fluid is used to pressurize the piston in the control chamber. The piston in-

turn pushes down the power spring. The piston is connected to the flow tube through

coupling thus allowing it to move down as the spring is compressed.

As soon as the flow tube comes in contact of the closed flapper, it pushes the plunger of the

equalizing port. The equalizing port allows the differential pressure across the flapper to

equalize. As soon as the differential pressure is equalized, the flow tube pushes down the

flapper to open position.

To again close the flapper, the pressure in the control line is bled off. This decompresses

the spring and the flow tube moves up. The flapper then closes and the metal to metal seal

doesn’t allow any fluid to pass through it. Thus the flow from the well is suspended and the

well is shut in.


8.3 Models Available

[Source: Baker Oil Tools Catalog]

Figure 8- Subsurface Safety Valve Type


CEMENTSAFE™ SERIES SUBSURFACE SAFETY VALVE

DESCRIPTION

The CEMENTSAFE™ Series tubing retrievable surface controlled subsurface safety valve is

designed specifically for use in cement-through and frac-through applications. In addition,

the CEMENTSAFE offers superior performance in applications that require the exclusion of

flowing debris from the working components of the TRSV.

The CEMENTSAFE utilizes a piston with non elastomeric dynamic seals to isolate the

control chamber and spring cavity from cement and produced fluids. This exclusion feature

not only protects the sealing surfaces of the actuation system but also excludes cement or

other debris from entering the flapper cavity of the safety valve.

The CEMENTSAFE incorporates the successful features from the T-Series™ product offering

such as metal-to-metal housing seals, metal-to-metal containment below the flapper, thru-

the-flapper self equalizing, and secondary puncture communication. This combination of

features ensures the performance required to meet the demands of harsh environments in

cement-through and frac-through applications.

FEATURES/BENEFITS

• Complete exclusion of well bore fluids from the spring and flapper cavity - Ensures

smooth and reliable operation in cement-through and frac-through applications

• Non elastomeric piston actuator system - elimination of elastomers and their inherent

problems

• Unique curved flapper - optimizes OD to ID relationships

• Metal-to-metal seal technology - 100% metal-to-metal sealing and containment of well

bore fluids when the valve is in the closed position

• Patented thru-the flapper equalizing system - most successful and widely used system

available to the market

• RBT Housing Seals - two step metal-to-metal sealing system provides strength and sealing

under the harshest conditions

• Patented radial punch control fluid communication system – eliminates accidental

communication primarily associated with linear shifting sleeves


Onyx™ SERIES SUBSURFACE SAFETY VALVES

DESCRIPTION

The Onyx™ Series, is the industry's first 7 in. tubing Retrievable Safety Valve (TRSV) that

can fit inside a 9-5/8 in. casing with cable bypass capabilities. In addition, Baker Oil Tools

has designed the industry's first 4-1/2 in. TRSV to fit inside a 7 in. casing.

The Onyx Series of tubing retrievable surface controlled subsurface safety valves are

specifically designed for big bore applications. Onyx Series safety valves are based on the

successful T-Series™. The Onyx Series combines a patented, state-of-the-art closure

mechanism and premium housing threads to produce the industry's first tubing retrievable

safety valves that offer full-opening production in smaller casing sizes. As a result,

operators get multiple benefits: the lower cost of smaller-OD casing, flexibility in designing

their completions, and higher production rates typical of larger tubing sizes.

FEATURES/BENEFITS

• Slimline OD - enables larger tubing to be installed without sacrificing the full opening for

maximized production

• Reduces completion cost (CAPEX) - the valve permits operators to use smaller casing

programs

• Broader application coverage - ability to run capillary lines for downhole instrumentation

or chemical injection and/or cables for electric submersible pump operation as well as dual

completion installations



• Non elastomeric dynamic seal assembly - withstands extreme pressures and

temperatures exceeding 28,000 psi and 450°F






• Ultra strong curved flapper design - resistant to high impact loads in high flow rate

applications


REALM™ SERIES SUBSURFACE SAFETY VALVE

DESCRIPTION

The new REALM™ Series tubing retrievable surface controlled subsurface safety valves are

specifically designed for high pressure / high temperature (HP/HT) applications. REALM

Series safety valves build upon the success of the T-Series™ and use state-of-the-art

technology to provide the industry's most reliable safety valve for these critical

applications.

The REALM Series reduces operating expenses by providing absolute pressure ratings. The

control chamber, dynamic seal system and rod piston are capable of withstanding full

differential pressures. This capability eliminates the requirement to stage tubing pressures

during installation, thus reducing installation cost and risk of over pressuring the valve.

Baker Oil Tools utilizes a unique design approach combining cutting edge design

techniques with the industry's most rigorous test program to provide safety valves

specifically designed for HP/HT applications.

FEATURES/BENEFITS

• Absolute pressure ratings - no staging of tubing pressure







• Ultra strong curved flapper design - designed to withstand extreme differential pressures



• HP/HT Leader - successful field experience minimizes operating risk


TITAN™ SERIES SUBSURFACE SAFETY VALVE

DESCRIPTION

Baker Oil Tools' commitment to innovation has resulted in the Titan™ Series surface

controlled subsurface safety valve. Innovative field-proven technology that reduces the

number of typical safety valve failure modes has been a hallmark of Baker Oil Tools' safety

valves through the years. Titan standard features include: wireline damage resistant

flapper, non elastomeric seal technology, and metal-to-metal containment of wellbore

fluids in the closed position. These standard features deliver unprecedented reliability,

efficiency, and adaptability.

One-quarter of all safety valve failures occur due to wireline damage during interventions

into the wellbore. The Titan incorporates the damage resistant characteristics of the

successful SelecT™ flapper design to virtually eliminate this failure mode. This design

ensures all seal surfaces are protected from wireline contact even during accidental closure

of the valve during wireline operations.

The Titan can be tailored to your specific needs, with available options such as integral

chemical injection capability, wireline damage resistant seal bores, and various control

system stop seal versions. An optional thru-the-flapper self equalizing system is also

available to minimize operational expenses while maximizing productivity.

FEATURES/BENEFITS

• Field-proven technology - basic design features have been carried over from the highly

successful T-Series™ and SelecT portfolios

• Patented thru-the-flapper self-equalizing - most successful and widely used system




• Wireline damage resistant flapper - design protects sealing integrity during wireline

operations

• Patented lock open system - achieved via one wireline trip and allows flow through the

locked open valve with no ID restriction


• No shifting sleeves required to communicate - impossible to inadvertently communicate

the hydraulic chamber

• Metal-to-metal seal technology - 100% metal-to-metal sealing and containment of

wellbore fluids when the valve is in the closed position

• Optional chemical injection capability - injection mandrel within the TRSV eliminates the

need for a mandrel above the valve and allows injection of fluids directly into spring cavity

for maximum effectiveness

• Optional damage resistant seal bores - ensures seal bore integrity when it is needed


SelecT™ SUBSURFACE SAFETY VALVE

DESCRIPTION

The SelecT™ is a tubing retrievable surface controlled subsurface safety valve that is

designed to address the unique challenges that shallow set safety valves (typically <1,000 ft

) must endure. An ultra strong power spring delivers high closing forces needed to provide

reliable and consistent closings in the presence of paraffin and other produced solids.

One-quarter of all safety valve failures occur due to wireline damage during interventions

into the wellbore. The SelecT design team developed an advanced flapper design to

virtually eliminate this failure mode. This design ensures all seal surfaces are protected

from wireline contact even during accidental closure of the valve during wireline

operations.

Combining design enhancements with the successful features of the industry leading T-

Series™, the SelecT addresses applications for smaller tubing sizes ranging from 2-3/8 in. -

3-1/2 in.

FEATURES/BENEFITS

• Ultra strong power spring - ensures smooth and reliable closures

• Wireline damage resistant flapper - design protects sealing integrity during wireline

operations

• Patented thru-the-flapper self-equalizing - most successful and widely used system






• Metal-to-metal seal technology - 100% metal-to-metal sealing and containment of

wellbore fluids when the valve is in the closed position


NEPTUNE™ SERIES NITROGEN-CHARGED SUBSURFACE SAFETY VALVE

DESCRIPTION

The Neptune™ Series nitrogen charged tubing retrievable surface controlled subsurface

safety valve is designed for completions requiring low operating pressures due to control

system limitations. The Neptune operating system contains many patented features that

provide simple, reliable, and fail-safe operation in the most critical applications.

The Neptune Series incorporates integral nitrogen charged systems within the valve, which

oppose the hydrostatic pressure acting on top of the piston. The dynamic seal configuration

used for the operating piston is a significant engineering achievement that utilizes the

industry's first non elastomeric seal technology for nitrogen charged safety valves. Unlike

other nitrogen charged designs, the Neptune Series' patented operating system is designed

to be fail-safe closed in all applications even if the primary nitrogen chamber pressure is

lost. The operating system is also far less susceptible to failing due to debris in the control

line or hysteresis as all ball check seats, Belleville washers, and collets have been

eliminated.

The Neptune Series comes standard with two totally independent operating systems and

an integral control line filter. These features deliver the redundancy and assurance

required in remote subsea wells. When it comes to your critical applications, the Neptune's

innovative design and simple operation make it the only logical choice to protect your

investment.

FEATURES/BENEFITS

• Two independent and operating systems - offers redundancy to maintain dependable

valve operation

• Simple operation - uses the same moving parts of a conventional TRSV

• Patented fail-safe operating system - ensures fail-safe operation in all applications

• Innovative non elastomeric seal technology - an industry first for nitrogen-charged valves

• Operating system is free of ball check seats - virtually eliminates failure due to control

line debris

• Low operating pressure at any setting depth - reduces operating system investment


• Optional integral control line filter - provides clean and trouble free operation


under the harshest conditions.


TRITON™ SERIES BALANCE LINESUBSURFACE SAFETY VALVE

DESCRIPTION

The Triton™ Series balance line tubing retrievable surface controlled subsurface safety

valve is designed for completions requiring low operating pressures due to control system

limitations. The Triton combines the field-proven technology of the industry leading T-

Series™ with a hydrostatically balanced rod piston to achieve simple, reliable and fail-safe

operation.

Baker Oil Tools used a revolutionary design approach focusing on the elimination of

previous balance line failure modes. As a result, the Triton Series offers fail-safe operation

in every application. The non elastomeric rod piston design is also configured to make the

operating pressure insensitive to tubing pressure.

These design features are essential in providing a low-operating-pressure safety valve for

deepwater completions.

Failure to close due to the buildup of wellbore debris and in-service friction is one of the

most common failure modes of TRSV's. The Triton Series rod piston configuration is

designed to reduce the potential of this failure mode. Pressure can be applied to the

balance line to assist in closure if the valve is unable to close due to the buildup of debris

and additional friction.

Baker Oil Tools is committed to being the industry leader in offering versatile solutions for

demanding applications. The Triton Series teams with the Neptune™ Series and Titan™

Heavy Sprung designs to deliver reliable solutions for almost every deepwater/subsea

application.

FEATURES/BENEFITS

• Low operating pressure at any setting depth - reduces operating system investment

• Simple operation - uses the same moving parts of a conventional TRSV

• Patented fail-safe operating piston - previous balance line failure modes eliminated and

ensures fail-safe operation in all applications




T-SERIES™ SUBSURFACE SAFETY VALVE

DESCRIPTION

Baker Oil Tools' T-Series™ tubing retrievable safety valves offer unmatched protection

from low end standard service through HP/HT applications. With T-Series Safety Valves,

one can count on premium performance and long-term reliability for the life of the well

which is attributed to complete removal of elastomeric compounds and elimination of

linear shifting sleeves. Incorporating non elastomeric dynamic seals and metal-to-metal

housing connections eliminates the possibility of explosive decompression which is

commonly associated with elastomeric compounds. Extensive studies by operators and

independent research institutes have shown that accidental actuation of shifting sleeves

and subsequent control fluid communication is one of the primary causes for safety valve

failures. By removing all shifting sleeves from the T-Series valve, Baker Oil Tools has

eliminated one of the most common failure modes found in safety valves.

The T-Series versatile design is ideal for a variety of applications including deepwater

completions. The T-Series Heavy Sprung Safety Valve features an extra strong power spring

to overcome the additional hydrostatic pressure associated with deep setting depths. The

reliability and simplicity of the T-Series have made it one of the most successful safety

valves in the industry. The high spring closure force guarantees performance in the

presence of paraffin or other produced solids.

FEATURES/BENEFITS

• Subsurface safety valve leader - successful field experience minimizes operating risk









• Deep-set capability - ultra strong power spring ensures smooth and reliable closures


8.4 Models available in T-Series

There are various versions of T-Series safety valves available, depending upon the valve OD

and the rated working differential pressure.

The rated working pressure varies from 5000 psi to 13500 psi. The OD’s are available

ranging from 23/8 in. to 7 in.

In all, the different versions of T series can be broadly classified as follows:

T (E) Series

The Models “T(E)-5” and “T(E)-10” Tubing Retrievable Safety Valves are non-equalizing or

self equalizing flapper-type subsurface tubing mounted safety valves. The self-equalizing

version utilizes an Equalizing Flapper Assembly. The “TE-5” and “TE-10” are similar except

for rated working pressure. The “T (E)-5” is rated for 5,000 psi working pressure, and the

“T (E)-10” is rated for 10,000 psi.

TM (E) Series

The Model TM (E)-5 Tubing Retrievable Safety Valves are non-equalizing and self-

equalizing flapper-type subsurface tubing mounted safety valves rated for 5,000 psi

working pressure. The TM series valves utilize a redundant full open and full closed static

metal to metal seal on the dynamic actuator.

TSM (E) Series and TUSM (E) Series

The TSM (E) and TUSM (E) series have all the features of the TM (E) series and apart from

that they have a slim line outside diameter and ultra slim line outside diameter

respectively. These valves have a curved slim line flapper installed instead of a wedge

shaped flapper (present in T and TM series).

Curved shape of flapper allows for smaller O.D. of flapper housing or larger I.D. of flow tube

compared to wedge shape flapper valve.


Reduced O.D. or increased I.D. allows user more liberty in safety valve applications. A larger

diameter TRSV can be run inside casing that would normally require a down-sized tubing

string. A smaller pressure drop can be anticipated for a wireline valve application.

8.5 The Basic Hydrostatic Pressure Calculations

Hydrostatic pressure is created by the weight of a column of fluid. It is measured in psi or

pounds per square. It always acts on down-hole tools when they are run in liquids. There

can also be differences between the hydrostatic pressure in the annulus and tubing of a

well, due to the use of different weight fluids in the tubing and casing. Such differences can

elastically collapse or balloon, and therefore, lengthen or shorten; the tubing string.

Another example is the effect of hydrostatic pressure in the opening and closing of sub-

surface safety valves. The hydrostatic pressure or the tubing pressure opposes the opening

pressure of the safety valve and this, to open the safety valve; the opening pressure mist

offset the tubing pressure. Thus, the opening pressure of the valve is the tubing pressure +

normal opening pressure of the safety valve. In the closing of the safety valve, the

hydrostatic pressure or the tubing pressure actually helps to close the valve, due to the

hydrostatic force acting on the valve actuator’s hydraulic piston area.

Hydrostatic pressure has to be calculated using the fluid gradient. This number has the

units of psi/ft. Using data such as lbs/gal. Or API Gravity (if dealing with hydrocarbon

liquids), one can calculate the hydrostatic pressure by:

1) Finding the fluid gradient in the Packer Calculations Handbook

2) Multiplying this by the depth of interest.

8.6 Fail-Safe Setting Depth

The fail-safe setting depth of a single line control SCSSV is defined as the maximum setting

depth at which the valve will close while opposing the hydrostatic pressure in the control

line. The fail-safe depth of a SCSSV is dependent on numerous factors, such as force of the

power spring, actuator piston area, pressure gradient of the control line fluid and the

annulus fluid, as well as friction force developed when actuating the SCSSV.


For a particular SCSSV, the piston area and the spring force are constant, although the

setting depth may increase by adding additional spring force, the pressure gradient of the

control line fluid is the determining factor. If the annulus fluid is heavier than the control

line fluid, and there is a possibility that the control line could break, the hydrostatic

pressure applied at the working fail-safe setting depth, the theoretical depth should be

modified by a safety factor of 1.2 to 1.5 to compensate for potential increase in mechanical

and seal friction. Per API 14A, Fail-Safe Setting Depths are calculated with salt water in the

control line plus and an additional 15% is factored in, thus the actual Fail-Safe Setting

Depth of a valve is normally 28% greater with hydraulic oil in the control line.

Increased setting depths can be important for several applications:

In areas where it is desirable to place a safety valve below the level at which

paraffin/scales occur

In the arctic, where the safety valve should be installed below permafrost zone

In platform, subsea, or arctic applications, where it is desires to ensure that no hydrates

will form at the valve

In areas where the threat of earthquakes could cause tubing to leak below a shallow set

safety valve.

Fail-Safe Setting Depth Calculations

The fail-safe setting depth calculation is based on the condition that the control line parts at

the surface controlled subsurface safety valve and annulus fluid is introduced into the

control chamber.

The fail-safe setting depth calculation is a force balance of the vertically downward acting

forces and the vertically upward acting forces.

Downward Acting Forces

1. Hydrostatic Head = (Setting Depth x Hydraulic Gradient) x (Maximum Piston Area) =

(Sd)(g)(A)

2. Weight of Moving Parts = W


3. Accumulated Friction = This factor includes all sources of friction such as spring friction,

seal friction, flow tube friction, etc., and is to be determined from testing or good

engineering judgment = Ff.

Upward Acting Forces

1. Minimum Power Spring Force with Valve in Closed Position - Fs.

2. Forces = (Sd)(g)(A) + W + Ff - Fs = 0

Vertical Direction = 0

Therefore …

(Sd)(g)(A) + W + Ff = Fs

and …

Sd = (Fs - W - Ff)/(g)(A)(SF)

where:

SF = Safety factor, generally 1.15

Minimum and maximum fail-safe depths are to be determined, considering the variation in

spring valves as well as component tolerances.

Opening and Closing Pressure Calculations

The full opening pressure is to be calculated based upon the power spring(s) force in the

full open position and the associated dynamic friction.

The full open pressure calculation is based on the assumption that only the pump pressure

from the surface is available to open the valve. That is, this calculation ignores the

hydrostatic head in the control line. The full open pressure calculation is a force balance of

the vertically downward acting forces and the vertically upward acting forces.


1. Pump Pressure Force = (Full Open Press) x (Minimum Piston Area) = (Po)(A)




1. Minimum Power Spring Force with Valve in Open Position - Fo



engineering judgment = Ff.

Forces = (Po) (A) + W - Fo - Ft = 0


Therefore:

(Po)(A) = Fo + Ft - W = 0

And

Po = (Fo + Ff- W)/ (A)

Minimum and maximum opening pressures are to be determined, considering the

variations in spring valves as well as component tolerances.

The full closed pressure is to be calculated based upon the power spring(s) force in the

fully closed position and the associated dynamic friction. The full closed pressure

calculation is a force balance of the vertically downward acting forces and the vertically

upward acting forces.


1. Pump Pressure Force = (Full Open Press) x (Minimum Piston Area) = (Pc)(A)




engineering judgment = Ff


1. Minimum Power Spring Force with Valve in Open Position = Fc

Forces = (Pc)(A) + W + Ff - Fc = 0



Therefore

(Pc) (A) = Fc - Ft - W = 0

and

Pc = (Fc - Ff- W)/ (A)

Minimum and maximum opening pressures are to be determined, considering the

variations in spring valves as well as component tolerances.

Table 2- Fail Safe Setting Depth Calculations for the T (E) - 5 (5.5”) model (7)


8.7 Design Principles and Philosophy

Flow Tube Design Features

(4)The flow tube is the component which transfers the linear force of the piston to the

closure mechanism. The design of this component must withstand the large forces

imparted during slam closing the flapper mechanism and during opening the closure

mechanism against differential pressure. Furthermore, the flow tube functions to restrict

the migration of well debris into the spring cavity and therefore provides critical protection

of the dynamic seals.

Stress Considerations-

The Baker flow tube is designed to withstand the following stress conditions:

1. Column Buckling: It is caused by the force of the piston while opening the closure

mechanism against differential pressure. The critical buckling load must be greater

than actual buckling load (piston area of the dynamic system times the maximum

rated control line pressure).

2. Bearing Failure: It occurs between the contact surface of the bottom of the flow tube

and the upper face of the flapper while opening the closure mechanism against

differential pressure. The bearing stress (contact stress) between the bottom face of

the flow tube and the upper face of the non-self-equalizing flapper is kept below the

minimum yield strength of flow tube and flapper, whichever is less. Furthermore,

when considering the self equalizing flapper, the bearing stress kept below the

minimum yield strength of the flow tube and the plunger whichever is less. This

expectance criteria ensures that the flow tube will not swell or swedge and impede

the free movement of the component.

3. Pressure Induced combined Stress: It is due to the possibility of pressure build up

across the flow tube. It is calculated by the means of the combined stress, API burst

and collapse calculations and a collapse stability calculation. Analyzing these

features the ability of the flow tube to withstand differential pressure loads in very

unlikely situation, where debris may impede the ability of debris exclusion gaps


from venting pressure or in the event of very rapid pressurization or

depressurization of the tubing, is ascertained.

For Baker 5.5” TSM (E)-5:

Burst and Collapse pressure (Combine stress analysis) = 5000 psi

Burst Pressure (from API 5CT) = 4947 psi

Collapse pressure (from API 5CT) = 2175 psi

Collapse stability pressure across flow tube = 2542 psi

Debris Exclusion/Control Design Consideration:-

Baker applies two philosophies when designing a safety valve for service in the presence of

debris. The first is that the debris should be excluded from certain areas of the valve,

specifically the spring cavity; the second is that certain areas of the safety valve will be in

contact with debris and measures must be taken to prevent this debris from fouling the

mechanism with which it comes in contact.

Scale Deposition prevention:

Scale build up can be prevented by the use of following coatings:

Teflon-PTFE coating

Xylan

Here Xylan also referred as Poly-amid-imid type coating is best suited for acids, release,

abrasion, and high load bearing resistance. But Xylan doesn’t tolerates high pH, thus not

recommended for water based drilling mud, water based hydraulic control line fluid etc.

For high pH applications Teflon-PTFE should be considered.

Work in this field is still going and researchers are striving hard to fabricate a thinner

coating.

Flow Tube Closure Assist Tool

Because of the effectiveness of Baker’s Debris exclusion considerations, failures to close

and high opening pressure due to debris accumulation are minimized. In the event that

excessive debris or scale is realized, Baker can provide a wireline run, jar-activated, closure

assist tool. The three-trip tool sets in the lock profile provided in the safety valve nipple

adapter and incorporates a set of retraceable slips to engage and shift the flow tube both


upward and downward. Once the flow tube is freed, the closure assist tool is jarred-up to

release from the flow tube and is retrieved to the surface.

How side loading and torsional forces on a rod piston are perceived and designed for-

Baker’s philosophy in this regard is the same used throughout the design of T-Series safety

valves:

Wherever possible, either eliminate undesirable phenomenon.

Make the mechanism affected by those phenomenons rugged enough to withstand

them.

Rather than incorporate additional mechanisms to protect weak points.

Eccentric loading of the flow tube by the single piston located offset from the valve’s

centerline, has two detrimental effects.

It causes resultant side loads at the points at the either end of the flow tube where the flow

tube is guided by the cylinder sub and the spring washer. This side loading can result in

excessive friction and wear at these points. This is addressed in the TM and TSM safety

valve by special surface treatments and coatings on these sliding surfaces.

The second effect is a bending moment applied to the flow tube between the two guide

points. Many valves have a two-piece flow tube which can flex at the connection between

the two pieces, substantially exaggerating the friction and wear. The TM and TSM have a

robust, one-piece flow tube which is stiff enough to be unaffected by the applied bending

moment.

Torsional Loading of the rod piston can result from the rotation of the flow tube caused by

the compression of the helical power spring. Other manufacturers address this by:

1. Adding rotational lock mechanisms to prevent the rotation of the flow tube.

2. Bearing systems to absorb the rotation at the end of the power spring

In earlier designs, Baker used this approach as well. However, these mechanisms add to

the complexity of the valve and introduce additional, unnecessary failure modes.


Dual opposite wound Power Spring

Baker’s latest generation of valves incorporate a simpler solution. The single power

spring is replaced by two stacked, counter wound springs. In the stacked spring system

is compressed the rotation occurs at the interface between the two springs rather than

at the ends. Thus no rotational load is applied to the flow tube.

8.8 Technical Evaluation of the ‘T’ Series SSV Equipment

The technical evaluation will include a detailed examination of the following:

Outer Housing thread seal design philosophy

Permanent lock open features – The elimination of shear sleeves from the I.D of the

valve

The dynamic seal assembly and metal-to-metal stop seals

Flapper and hinge pin design and integrity

Self Equalizing Mechanism

Outer Housing thread seal design philosophy

The seals used in the outer housings of the safety valve are critical to the reliability of the

safety valve system. Failure in these seals can lead to tubing to annulus leak and possibly a

work over. Baker Oil Tools recommends that all tubing mounted safety valves be provided

with metal-to-metal housing connections. The ’RBT’ is the name given to the metal-to-metal

housing thread connection that is used extensively in the Baker Oil Tools Safety Valve

Designs. The ‘RBT’ housing connections have recorded no failures since 1983 either by

leakage or due to tensile loads.

Figure 9- RBT Thread connection

External pressure increases the

sealing force at the box nose seal

Internal pressure increases the

sealing force at the pin nose seal


The box and pin sealing lips at each end of the thread (box and pin noses) are designed

with interference that provides a positive metal-to metal seal for containment of both

internal and external pressure.

The 'RBT' thread has a center locating shoulder that carries the torque of the made up

connection. The torque capacity of the connection is defined by the bearing area of this

shoulder. Experience has shown that this design provides excellent resistance to back off in

down-hole service.

This center locating shoulder also provides the proper metal-to-metal interference for the

seals at the box and pin noses. The pressure holding ability of the 'RBT' is not a direct

function of makeup torque. The pressure holding ability of the thread is defined by the

interference at the box and pin noses.

Permanent Lock Open Features

Important: In 1992 (25%) twenty five percent of tubing retrievable safety valve failures in

an independent study were caused directly by leakage between the hydraulic control line

chamber and the tubing well bore through the wireline insert valve communication feature.

One out of ever four failures was linked to a communication feature in the I.D. of the valve.

No matter how strong the shear sleeves in the Safety valves were wireline operators and

coil tubing units managed to find a way to prematurely shear any type of shear sleeve that

has been placed in a Safety Valve I.D.

Baker Oil Tools redesigned the permanent lock open feature for the 'T' series valves. The

sleeves that were shearing prematurely were completely eliminated from the I.D. of the

valve. There have been no recorded failures of the Baker puncture communication system

causing a premature leak or failure. There are no shear sleeves in the I.D. of the 'T' series

safety valves.

Evaluation of dynamic seal assembly and metal-to-metal stop seals

The use of rod piston type actuators reduces the number of possible leak paths, the friction

is reduced from the old style concentric piston designs (much smaller circumference) and

deeper setting depths are easier to achieve.

The dynamic actuator seal assemblies are designed to last the Test that each design is

required to complete – the Baker Endurance Test and/or Cyclic Hot Test, involves more


than 1200 cycles. This duplicates opening and closing the valve once a month for the next

100 years. The valve and control fluid temperature are also cycled. The temperature is

varied throughout the test from 100 F to the maximum rated temperature of the valve.

The dynamic seals used in the 'T' series valves have been proven with the metal to metal

stop seal design as well as the 'standard' non elastomeric assembly that does not utilize the

metal to metal stop seals.

Figure 10- Dynamic Seal Assembly

Components of dynamic seal assemblies and metal-to-metal stop seals:

The Baker Oil Tools system uses the following main components.

The dynamic seal assembly

The full open metal to metal stop seal

The full closed metal to metal stop seal

The detent / dampener system

Location of the Metal to Metal stop seals

The Baker metal to metal seat is made from MP159 material. This highly corrosion

resistant material provides the highest degree of sealing integrity.

The location of the metal to metal stop seals when the valve is in the full closed position is

an interesting discussion. Typically there are two choices. First-locating the seal in the

control line fluid or second - locating the seal at a point below the seal bore and other seals.

The arguments for each are given below:

Locating the 'full closed stop seal' inside the control line chamber


The advantage of the internal full closed stop seal is that the metal to metal seat is

'protected' by the hydraulic fluid - during the time that the valve is in the open position the

seat is bathed in control fluid.

The disadvantage of the internal closed stop seal is that the importance is placed on the

making sure that the full closed metal to metal seat (static seal) is protected. It ignores the

fact that the seal bore may be subject to increased corrosion, pitting and scale during the

time that the valve is in the closed position. If this type of corrosion begins it will be very

hard on the dynamic seal assembly. The corrosion generally forms a very rough surface and

will destroy the dynamic seal over time.

Figure 11- Location of Metal to Metal Stop Seal


Baker Oil Tools' Detent System for the 'T'-Series Safety Valves

The purpose of the detent spring system is to prevent the deformation of the two mating

metal-to metal surfaces during slam closures of the valve. During slam closures the impact

of the flow tube and piston being pushed into the metal to metal seat can render the metal

to metal stop seal ineffective. The impact is softened and any damage to the two surfaces is

eliminated by the use of the shock absorber (detent / dampener system). If the valves that

you are comparing do not have a detent system it is likely that the metal-to-metal seals will

be ineffective.

Figure 12- Detent System/Shock Absorber


Flapper and hinge pin design There are two types of flappers provided in the 'T' series valves. The first design is called

the 'wedge shaped flapper' found in the standard 'T' or 'TM' series. The second design is

referred to as the 'curved flapper' found in the 'TS' or 'TSM' series, the curved flapper is

used in slim line designs. Both designs are capable of utilizing the 'thru the flapper

equalizing system.

The wedge shape flapper started in 1980 when Baker Oil Tools set out to build an

indestructible flapper mechanism. The testing performed resulted in several patented and

original concepts that are still in use today. The wedge shape of the flapper is one of the

important features to consider. The wedge gains the advantage of leverage by moving the

first point of contact with the flow tube away from the hinge. This 'three point contact'

reduces the stress on the hinge pin during opening and during closures (the farther away

from the hinge that the contact occurs the lower the forces trying to bend or shear the

hinge). In addition, during the closure of a valve the 'three point contact' allows the impact

from a slam closure to be hydraulically absorbed by the flow tube- not the seat.

Figure 13- Wedge Shaped Flapper (Three point contact shown above)


Table 3- Features and Benefits of Wedge Shape Flapper

Features Benefits

Only two parts move to fully open the safety

valve

Simplicity in design relates directly to long life

operation. Once open, the closure mechanism is

out of the flow path and completely covered by

the flow tube.

Wedge shape flapper

By moving the initial flow tube contact point

away from the hinge pin, the wedge shape

assures the largest moment arm possible during

flapper opening and closing. This reduces hinge

and pin stresses to the very minimum.

Stainless or nickel steel flapper, machined from

solid bar

Stronger and more ductile than cast materials:

wider variety of suitable materials available in

bar form. Greater assurance of uniformity of

properties and overall quality of flapper

Dual hinge flapper Flapper pin is loaded in double shear only. Pin is

not subject to bending loads.

Large diameter, high strength hinge pin

Assures maximum shear resistance available to

resist damage over lifetime of valve. Premium

corrosion resistant material (MP35N) provides

unlimited down-hole life expectancy.

Single wire torsion spring

Torsion spring returns flapper to full closed,

sealing position without any assistance from

well pressure. Torsion spring is wound around

mid section of hinge pin, thus maximizing the

quantity of wire available for the given flapper.

Wedge shape flapper mechanism proven

repeatedly in high velocity gas slam testing

Baker was the first safety valve company to

subject a closure mechanism to repeated slam

closures without failure of the components.

The curved flapper also has the 'three point contact' advantage. The curved flapper allows

the sides to contact the flow tube before the flapper engages the seat. . The valve seat is


thus protected from damage due to stress so it will seal as effectively the next time.

Figure 14- Curved Flapper Design

Both systems utilize the concept of placing the hinge pin in shear rather that to place it in

bending. The hinge pin is manufactured of specially selected high-strength alloy. And

because of the unique hinge design, the hinge pin bending common in other valves is

completely eliminated.

Table 4- Features and Benefits of Curved (Slim line) Flapper

Features Benefits

Curved shape of flapper allows for

smaller O.D. of flapper housing

and/or larger I.D. of flow tube

compared to wedge shape flapper

valve.

Reduced O.D. / increased I.D. allows user more latitude in

safety valve applications. A larger diameter TRSV can be run

inside casing that would normally require a down-sized

tubing string. A smaller pressure drop can be anticipated for

a wireline valve application.

Unique geometry of flapper assures

only axial loads are transmitted to

the flow tube.

Flow tube is not bent or crimped by radial loads from the

flapper during opening and closing. This eliminates damage

which may cause wireline tool strings to hang-up in the valve.

Curved and angled seating surface

is not intersected by flow tube

during opening or closing.

Eliminates wear on sealing surfaces which would eventually

cause leakage.

Tight tolerance held on hinge and

pin components.

Eliminates use of external alignment devices that add friction

and complexity to the closure mechanism. This is the same,


proven philosophy used for the Baker wedge shape flapper

closure mechanism.

Sculptured flapper geometry.

Reduces inertial forces which come into play during slam

opening/closing of valve. Efficient, compact design.

Primary metal-to-metal flapper to

seat seal is backed-up by a resilient

seal on the flapper seat.

Torsion spring returns flapper to full closed, sealing position

without any assistance from well pressure. Torsion spring is

wound around mid section of hinge pin, thus maximizing the

quantity of wire available for the given flapper.

Both systems utilize the concept of placing the hinge pin in shear rather that to place it in

bending. The hinge pin is manufactured of specially selected high-strength alloy. And

because of the unique hinge design, the hinge pin bending common in other valves is

completely eliminated.

Figure 15- Single Hinge Flapper Assembly


Gas slam test

A gas slam test is designed to duplicate the condition when a well is flowing, the control

line is bleed off and the safety valve closes with the flow against the flapper. Gas slam test

are an excellent indication of the reliability of a subsurface safety valve. API test require

only the very minimum requirements regarding slam test. Baker Oil Tools has designed

flappers that are virtually indestructible and this allow the valves to be tested at flow rates

and velocities listed below.

These test represent real life conditions and need to be considered when evaluating

Subsurface safety valves. All sizes of 'T' series valves have complete High Velocity Gas Slam

Test 20 Slams, 15 of which are:

200 ft/sec (41 MMSCFD)for 2-3/8" Valves

200 ft/sec (58.5 MMSCFD)for 2-7/8" Valves




The Post slam leak rate following the slam test is the same leak rate that is required by the

API 14A functional test for 'new' valves.

Self-Equalizing Mechanism

A Self-Equalizing Safety Valve contains an integral equalizing mechanism which allows

shut-in pressure from below the safety valve to be vented to the tubing above the flapper.

This will decrease the differential pressure across the flapper (equalize) and allow the

valve to open. There is no need to fill the tubing above the flapper with fluid, hook-up a

pump to pressure down the tubing above the flapper to equalize the pressure across the

flapper. The self- equalizing system will equalize the valve and have the well back on

production quicker, safer and more efficiently. The simplicity and advantages of being able

to open a valve without having to mobilize pumps and fluids that are required to equalize a

non self-equalizing valve have made a tremendous market for self –equalizing valves. The

economics generally provide that a self -equalizing system will pay for itself in a matter of a

few months. In some applications the system pays for itself the first time that it is used.


Wide spread use of self equalizing valves is the industry standard. One of the main reasons

for the success is the system described below.

Evaluation of Self-Equalizing Designs

There are basically two types of self equalizing systems.

1) Around the flapper

2) Thru the Flapper

The major disadvantage of 'around the flapper' type self-equalizing mechanisms is that

produced fluids containing debris, such as scale and sand, are introduced into the annulus

created between the valve's flow tube and outer housing. There is a tendency for the debris

to collect in the annulus of the valve and eventually block the movement of the flow tube as

it tries to return to the closed position. Valves that use 'around the flapper' equalizing

systems can fail in the "open" position due to the problems associated with the location of

this debris! Erosion problems are also a concern and can lead to leakage. The Baker Oil

Tools thru the flapper system is good for the working pressure of the valve that it is used

on. We have several systems rated above 10,000 psi.

Baker Oil Tools patented "THRU-THE FLAPPER, METAL-TO-METAL, SELF-EQUALIZING

SYSTEM" type equalizing system was developed to eliminate problems. The result is the

most popular, reliable equalizing system in the industry.

OPERATION

Simple opening procedure - Close the wing valve -then pressure up to the valve full opening

pressure. The equalizing feature will allow the pressure to equalize and open the safety

valve. The equalizing feature does not interfere with normal valve operations. After the

Subsurface safety valve is open, open the wing valve and flow the well as required. The

process is quick and simple. No staggering pressures or worries about damaging the valve.

This allows the wells to be put on production much sooner after a system test on

emergency shut-down, the increased production could pay for the feature the first time it is

used.


HOW THE SYSTEM WORKS

The system consists of an equalizing plunger, an equalizing spring and an equalizing type

flapper. As control line pressure is applied to the valve, the flow tube begins to move

downward until it contacts and depresses the equalizing plunger. This unseats the metal-

to-metal seal and exposes the ports in the plunger. The plunger location on the flapper has

been designed so that once equalization has occurred the plunger returns to its closed

position. This feature protects both the plunger and its metal-to-metal seat.

DESIGN FEATURES ( Thru the flapper equalizing system)

Sealing Mechanism

The primary metal-to-metal seal is achieved by the tapered portion of the plunger (on the

side with the ports) contacting the metal to metal seat in the flapper. Notice that the seat in

the flapper has a straight edge where it contacts the shoulder of the plunger. This gives a

higher contact force on the sealing diameter and prevents any debris from accumulating on

the sealing surface.

Plunger Location

The plunger is located so that the flow tube will make contact during the initial opening

and equalizing. Then it clears the flow tube completely during flow tube movement to the


full open position. The plunger does not interfere with the flapper housing in the full open

position.

The positioning of the ports is very important. These ports clear the seating surface on the

flapper during equalization. They are also positioned far enough below the bevel on the

plunger itself so that erosion of the seat is virtually eliminated. The equalizing flow does

not take the pressure drop across the poppet seat.

The pressure drop is taken through the throat of the poppet. The seat is protected. The

total area of the ports is greater than the poppet throat area. The system has passed over

one hundred separate class 2 sandy service tests in the various valve designs and has been

used for over a decade without erosion problems. The plunger is made from a erosion and

corrosion resistant material. The small size of the plunger makes it possible to use the very

best materials without influencing the overall cost of the system.

Equalizing Springs

The equalizing springs are designed from a high strength material, these springs will retain

a desired preload even after prolonged use. The spring force itself is determined by spring

length, plunger stroke and spring stress.

Equalizing Times

The thru the flapper equalizing system has a small flow area. This small flow area increases

the amount of time required to equalize the valve. The advantage to the small flow area is

that the operator can determine from the amount of flow if the well is producing through

the full open valve or thru the equalizing mechanism.

Several of the "Around the flapper systems' have failed because the operator flowed the

well through the equalizing mechanism for extended periods of time and completely

eroded and destroyed the valve. The small flow area allows the operator to have a positive

indication that the valve is fully open 100% metal-to-metal seal. No elastomeric materials

or soft seats are used which eliminates the risk of chemical degradation and explosive

decompression. All sizes are Class 2 Sandy Service.


Control Line Jam Nut Connection

Figure 16- Baker Jam Nut

A critical leak path in Sub surface controlled safety valves is where the control line

connects to the safety valve. Baker Oil Tools Jam Nut Connection uses metal to metal seals

and provides the most reliable seal available. The 1/8" NPT type connection has a helical

leak path around the thread root that must be plugged with Teflon tape or some type of

thread dope, therefore it is not used by Baker. The NPT connection is subject to leakage and

this type of connector adds an additional leak path. The control line connection is one of the

most critical connections because a leak at this connection cannot be remedied by putting

in an insert valve.


Debris and Sand exclusion barriers

Figure 17- Debris and Sand Exclusion Barriers

The T-series valves have a simple and effective method of preventing sand or debris from

entering the area behind the flow tube or around the flapper seat. As shown in the above

illustrations there is a close tolerance barrier at the top of the spring cavity and also one

towards the bottom of the spring cavity. These are controlled tolerances that are designed

to keep sand and debris out. These are not seals or wipers, but they do prevent any flow

around the flow tube. A small amount of fluid must pass through these barriers due to the

change in volume in the spring cavity caused by the piston / actuator moving up and down

as the valve opens and closes.

The T-series valves are all tested with sand slurries and are tested to the standards of the

API 14A class 2 sandy service test.


8.9 ‘T’ Series accessory tools

Flapper Lock Open Tool

(7)The Flapper Lock Open Tools allows retrieval of a Dry String. Flapper Lock

Open is also used in the event of Safety Valve malfunction. After the Safety Valve

has been permanently locked open, it may accept a Separation Sleeve or a

Wireline Retrievable Insert Safety Valve provided communication of the control

fluid to the interior of the valve has also been accomplished.

Two wireline runs are required to permanently lock the Flapper of a Tubing

Retrievable Valve open. On the first run, the Flapper Lock Open Tool is landed and

locked in the Nipple Profile of the Tubing Retrievable Safety Valve. Withdrawal of

the Wireline Running Tool which is attached to the Slide Assembly portion of the

Flapper Lock Open Tool actuates the Tool releasing the Lock Ring, which retains

the Flapper in the open position. A second run retrieves the Flapper Lock Open

Tool. The tool is designed such that the Lock Ring cannot be released into the

Flapper section if the Flow Tube of the Tubing Retrievable Safety Valve is not in

the fully closed position.

Figure 18- Flapper Lock Open Tool


Wireline Insert Safety Valve

The Baker wireline insert valves are hydraulically operated,

surface controlled, subsurface, through tubing retrievable safety

valves. The valves are normally closed type. When the applied

control chamber pressure is removed, the valves automatically

return to the closed position. In the event of a tubing retrievable

safety valve malfunction, the wireline retrievable safety valve can

be run into the Nipple Profile in the ID of the tubing retrievable

safety valve after control line communication has been established

and the malfunctioning valve has been locked open.

The Baker wireline insert valves are available in non-equalizing or

self-equalizing configuration. The particular insert safety valve

required depends on the lock profile of the model “T (E)-5” or “TE-

10”.

Figure 19- Wireline Insert Safety Valve


Separation Sleeve

The purpose of the Separation Sleeve is to blank-off the hydraulic chamber in a “T-Series”

Safety Valve after control line communication has been established between the control

line and the valve ID, to prevent contamination of the control line by well fluids. After

control line communication has been established, well pressure can communicate to the

surface through the control tubing until a Separation Sleeve or other appropriate wireline

tool is run into the Nipple Profile in the “T-Series” Safety Valve.

The Separation Sleeve should be used if control line communication has been established

and production of the well is scheduled to continue without an operable safety valve in the

well. The use of a Separation Sleeve is also recommended when pulling the string after

control line communication has been established.

The particular Separation Sleeve required depends on the Lock Profile of the Safety Valve.

The Flapper Lock Open Tool opens the Tubing Safety Valve and maintains it in that position

when the tubing is pulled, permitting retrieval of dry string. It is also run in the event of

Tubing Ret. Safety Valve malfunction. When the Safety Valve has been permanently locked

open, it will accept a Separation Sleeve or Wireline Insert Valve.

A separate Flapper Lock Open is required for each of the various lock profiles available for

the Tubing Retrievable Safety Valve.


Control Pressure Communication Tool

The Control Pressure Communication Tool is used to establish control line communication

into tubing retrievable safety valves containing the control line communication feature by

no-going into a Lock Profile. This enables the use of a control line actuated wireline insert

safety valve. A separate Control Pressure Communication Tool is required for each of the

various lock profiles available for the Tubing Retrievable Safety Valve.

Figure 20- Control Pressure Communication Tool


9. CONCLUSION

1. Stringent testing procedures are followed for the working of a TRSCSSV since it

stays in the well till the well lasts and can be in operation at any point of time.

2. Advancement in Design can be done by improvement of piston features and a

cylindrical piston again be looked upon as a possibility since it will eradicate the

problems of torsional loading, column buckling, flexing, eccentric loading and other

complexities in the design.

3. The TRSCSSV generally fails due to breaking up of the control line due to various

reasons. Thus a design which has no control line is being looked for which has

probably some other working mechanism, though no work has yet been done on it.


10. BIBLIOGRAPHY

1. BakerHughesDirect. About Baker Hughes. [Online] [Cited: July 20, 2008.]

http://www.bakerhughesdirect.com/cgi/bhi/resources/ExternalFileHandler.jsp?path=pri

vate/BHI/public/bakerhughes/about/index.html&bookmarkable=Yes&channelId=-

3000081. ISO-8859-1.

2. Baker Hughes - Investor Relations - Financial Highlights. Baker Hughes Direct. [Online]

[Cited: July 20, 2008.] http://investor.shareholder.com/bhi/financials-KeyRatios.cfm. UTF-

8.

3. About Baker Oil Tools. Baker Hughes - Baker Oil Tools. [Online] [Cited: July 20, 2008.]

http://www.bakerhughesdirect.com/cgi/bot/resources/ExternalFileHandler.jsp?path=pri

vate/BOT/public/about/index.html&bookmarkable=Yes&channelId=-

4198841&channelId=-4198841. ISO-8859-1.

4. Monica Wolf. Course 023 - Subsurface Safety Systems. IMPACT Module 023. 1999.

5. maxerhim. Catalog SSBOT-04-5809. Safety Systems. s.l. : Baker Oil Tools, 2004.

6. Perrin, D. Well Completion and Servicing. Paris : Technip, 1999. pp. 153-160.

7. Baker Oil Tools. Model T(E)-5 Deep Set Tubing Retrievable Flapper (5.5") Tech Unit. B-

153-5. 2003.

SCSSV Full Report

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