Project_Report[2]

1

PROJECT REPORT ON

RADIAL DRILLING: A NEW WELL ENHANCEMENT

TECHNIQUE

SUBMITTED TO

SAVITRIBAI PHULE PUNE UNIVERSITY

IN PARTIAL FULFILLMENT OF

BACHELOR’S DEGREE

IN

PETROLEUM ENGINEERING

BY

K. Prerna (Exam No B80026738)

Ankit Priye (Exam No B80026709)

Gaurav Saxena (Exam No B80026730)

DEPARTMENT OF PETROLEUM ENGINEERING

MAHARASHTRA INSTITUTE OF TECHNOLOGY

PUNE – 411038

2014-2015

i

MAEER’S

MAHARASHTRA INSTITUTE OF TECHNOLOGY

PUNE

CERTIFICATE

This is to certify that K Prerna, Ankit Priye and Gaurav

Saxena of Maharashtra

Institute of Technology, Pune have satisfactorily and

successfully

completed the Project work on

RADIAL DRILLING: A NEW WELL ENHANCEMENT

TECHNIQUE

in partial fulfilment of Bachelor’s Degree in Petroleum

Engineering under the Savitribai Phule Pune University in the

year 2014-2015.

Dr. P.B. Jadhav Prof. Sanjay Joshi

Head, Internal Guide,

Dept. of Petroleum Engineering, M.I.T., Pune.

M.I.T., Pune.

ii

ACKNOWLEDGEMENT

Firstly we would like to convey our sincere thanks to Mr. Ajay Ray, President GeoEnpro

Petroleum limited, for giving us the oppurtunity to work on this project.

We would like to use this opportunity to express our gratitude to Prof. Sanjay Joshi, who

supported us throughout the course of this project. We are thankful for his aspiring guidance,

invaluably constructive criticism and friendly advice during the project work. We are sincerely

grateful to him for sharing his truthful and illuminating views on a number of issues related to

the project.

In addition, we want to thank Prof. Dr. P. B. Jadhav, Head Of Department, Petroleum

Engineering, MIT Pune, without whom our project wouldn’t have been a success.

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List of Figures

Sr. No Figures Page

No

Figure

1.1

The Radial Drilling Technique

4

Figure

1.2

Typical bottom hole assembly illustrating components used to create

jet drills laterals.

5

Figure

4.1

Coiled tubing surface unit.

11

Figure

4.2

Radial Drilling BHA deflector sub, centralizer and gyro tool.

12

Figure

4.3

Milling bit for Radial drilling.

13

Figure

4.4

Jetting nozzle for Radial drilling.

13

Figure

4.5

Radial drilling procedure for a single lateral.

15

Figure

4.6

Coil Tubing Units used to deploy Radial Jetting Drilling Technology

16

Figure

4.7

‘Macaroni’ Straight Pipe Tubing arrangement used to deploy Radial

Jetting Drilling Technology

17

Figure

4.8

A sample piece of 4½ in. casing with multiple 1 in. holes milled with

cutting system

18

Figure

4.9

Jet Bit nozzle under pressure

19

Figure

4.10

Typical type cutting pattern from jet bit

19

Figure

4.11

Mechanism of Penetration.

21

Figure

4.12

This chart shows the relationship between penetration rates

associated with jet bit pressure

22

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Figure

4.13

This chart shows the relationship between penetration rates

associated with jet bit flow rates

22

Figure

4.14

Relationship between flow rate and extended limit of horizontal well

26

Figure

4.15

Effect of pump pressure

27

Figure

4.16

Effect of well roughness

28

Figure

4.17

Effect of flow rate ratio

29

Figure

4.18

Effect of mother-well depth

30

Figure

4.19

The effect of well diameter

31

Figure

4.20

Sensitivity Analysis

32

Figure

6.1

Production profile XYZ#01

49

Figure

6.2

Well schematic of XYZ#01

50

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List of Tables

Sr. No. Tables Page No

Table 4.1 Structural parameters of jet nozzle

25

Table 4.2 Specification of Base Oil

38

Table 6.1 Holes details for well 1#.

42

Table 6.2 Production comparison of well 1# before and after Radial Drilling

43


44


45

Table 6.5 Production profile of well XYZ#01

49

Table 6.6 Previous well interventions of well XYZ#01

51

Table 6.7 Well details of XYZ#01

53

Table 6.8 Operations performed on well XYZ#01

53

Table 6.9 Laterals details drilled on well XYZ#01

66

Table 6.10 Equipments on the field

74

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Table of Contents

Chapter No Title Page No

List of figures iii

List of tables v

Abstract viii

1. Introduction 1

2. Literature Survey 6

3. HSE 7

4. Radial Drilling Technique 10

5. Indian Scenario 40

6. Case Study

6.1 Belayim Field, Egypt

6.2 Kharsang Field, India

41

7. Results 76

8. Conclusion 77

9. References 79

vii

RADIAL DRILLING: A

NEW

WELL ENHANCEMENT

TECHNIQUE

viii

ABSTRACT:

With a world context of high oil prices and a rate of increase in reserves from new discoveries,

that is not enough to compensate the rate of extraction, in addition to the high maturity of

oilfields currently being developed across all the world, companies have been working to

improve recovery factor of reserves, as a strategy to extend the useful life of the existing assets.

Working in this direction, radial drilling technology seems to be an alternative, which, in spite of

the fact that it currently raises uncertainty since it has never been tested in the past in or

currently, can be adapted to the existing wells thus becoming a low investment alternative.

The technology involves drilling lateral horizontal bores of small diameter and up to one hundred

meters long, with the possibility of placing several within the each productive layer. The laterals

are made in two steps:

The casing is milled with a ¾” milling bit.

The lateral extension is carried out by high pressure water jetting.

For this evaluation, pilot tests were performed in different oilfields, with the intention of

covering a wide range of possible scenarios and being able to evaluate the best applications for

this new alternative.

Radial Drilling (RD) is an economic, environmentally friendly technique to drill numerous micro

diameter lateral horizontal wells from different levels from an existing well. In this project

emphasis has been given to study the process of radial drilling technology, its advantages,

overcoming its limitation, its usage in the recovery of left out crude oil from exiting reservoirs

especially those from brown fields. It also provides ways to implement RD to such oil & gas

ix

fields before implementing the expensive IOR-EOR methods and also an analysis of its

economic feasibility is discussed. The Indian prospects of Radial Drilling technique has also

been analysed and recommendations has been given based upon the possibility of implementing

in the brown/ depleted fields of India.

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1. INTRODUCTION:

It is extremely important to have the possibility of increasing production and raising usable

reserves from the known horizons; due to these facts, the search for new technologies to increase

production was started, and it was then that the radial drilling technique appeared as a promising

one.

This process consists of making small diameter horizontal perforations by using water jets at

high pressure (jetting). The diameter of these lateral horizontal perforations is approximately 2

in. and up to 330 ft of extension each, at the same productive level. Each one has a bending

radius as small as 1 ft and is made in two steps:

1. The casing is perforated with a 0.75 in. milling bit.

2. Horizontal extension is made with high pressure fluid jetting.

This application combines the following important factors:

Low cost, it is applied to existing wells.

Low geological uncertainty.

Low environment risk.

Among various reasons for this technique to increase production, the following could be

highlighted:

Improves the conductivity of an important area around the well.

Possibility to define direction of the perforations.

Helps the mobilization of viscous oils.

Connects to areas of better petrophysical conditions.

Allows intervention of oil reservoirs limited by close aquifers.

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Radial Drilling Services Inc. (RDS), which is a registered Texas Corporation for the design,

manufacture, installation and provision of services related to radial drilling technology in North

America and worldwide, was founded by acting President Henk Jelsma in November 2004. Carl

Landers invented the radial drilling technology process and registered the patent in 1995 (Patent

No. 5413184). RDS obtained a license to the technology, improved the original technology and

added additional patented technologies. A wholly owned subsidiary of Radial Drilling Services

was set up in Calgary, Alberta Canada as RadCan Energy Services in 2006. The operations are

currently fully licensed in Alberta, Saskatchewan and British Colombia.

Radial Drilling Technology involves a method and apparatus for horizontal milling through the

walls of a vertically extending well casing at a 90º angle to provide horizontally jetted radials

into the earths strata for a substantial distance radially from the vertically extending well casing.

It provides an .extended perforation, or creates an ultra short radius horizontal application. The

technology uses a combination of coil tubing operations, high pressure jet drilling and analytical

reservoir evaluation. Originally designed for stripper wells in the US, the technology was

enhanced by the RDS group in Houston and California with special focus on reliability and

repeatability. Additional applications include gyro-directed acid placement, new well production

optimization (in lieu of perforating), salt production and CO2 sequestering methods, steam

injection, radial “huff and puff”, water disposal, injection for pressure maintenance and

enhancement of water well production. Additionally, the technology is applicable to salt dome

gas storage projects, water well improvement and mineral leaching processes.

The process basically involves utilizing downhole mechanics and hydraulics to ‘pull’ a high

pressure jet hose horizontally up to 100 metres into the producing formation. Overburden

combined with matrix porosity acts as a dynamic balance to the pressures exerted by the surface

system resulting in a ‘blast effect’ which pulverizes the formation ahead of the jet nozzle.

Reverse jets provide thrust as well as a cleaning effect for the horizontal lateral.

3

The difference between conventional drilling and radial drilling technology is that, during the

primary application, it can get past the near well-bore well damage, allowing the drill to access

the virgin part of the formation. Under the present technology, the system can operate reliably

and repeatedly to 2,500 metres total depth. However, a recent well has been completed in March

2006 to a total depth of 3,500 metres. Lateral distances of 100 metres are standard. Four laterals

are generally installed at the same depth, placed 90° apart. Additional levels can be jetted upon

request. Depending on target depth, the process takes generally 2-4 days for four laterals. A key

factor for the successful application of the technology is well selection where the client provides

information relating to formation type, vertical and horizontal permeability, casing design, and

production history. An assessment then is made to proceed with the drilling based on this data.

The radial drilling process can radically affect the entire value chain of production for any

company. Benefits of this process exceed what conventional drilling offers due to its efficiency

and economic nature. The main reasons to use radial drilling technology are: less wells drilled

therefore increased well spacing, less surface equipment used, and less environmental impact.

Also, the extended drainage radius obtained by this application results in additional recoverable

reserves per well drilled.

4

Figure 1.2 illustrates the drilling apparatus for Radial Jet Drilling. For producing wells the

completion equipments are removed from the well. A diverter (or shoe) is then placed onto the

bottom of the producing string and lowered to the depth of formation to be jet drilled. This

diverter has curved path to enable the jet bit and flexible hose to turn from going straight down

the tubing in the well and to approximately 90° towards the oil/gas formation. The jet bit is

attached to a 10000 psi or higher pressure rated flexible hose that has the flexibility to pass

through a typical 3 in. radius diverter path. One end of this flexible hose is attached to a high

pressure fluid filter, which in turn is connected to either coiled tubing or straight tubing pipe

conveying the high pressure fluid from the top of the wellbore down to the filter. This tubing

conveys the high pressure fluid from the high pressure pump at the surface and through the

tubing with the fluid passing sequentially through the flexible hose, the jet bit and through the

Figure 1.1: The Radial Drilling Technique

5

orifices of the jet bit to jet drill a lateral. An operator controls the jet drilling rate by controlling

the rate that the conveying tubing is lowered into the top of the vertical well. Some wells contain

steel casing and cement that must be penetrated before jet drilling. Other wells do not have steel

casing at the zone of interest; these are referred to as uncased wells- they are much more readily

jet drilled.

Figure 1.2: Typical bottom hole assembly illustrating components used

to create jet drills laterals.

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2. LITERATURE SURVEY

Radial drilling guidelines by Radial Drilling Services Inc. is a major help in understanding the

basic rules a and guidelines to be followed during radial drilling. It explains all the operations,

candidate selection, fluids used and describes various considerations or rules and regulations to

be followed during the drilling process.

Various SPE papers were referred to get the correct idea of the radial drilling technology.

SPE paper named, SPE 164773 Radial Drilling Technique for Improving Well Productivity in

Petrobel-Egypt by Adel M. Salem Ragab, Ph. D., American University in Cairo and Suez Canal

University, and Amr M. Kamel, B.Sc. Petrobel Company is the major source for understanding

the process of radil drilling, its mechanism and its effects. Radial drilling was first successfully

implemented for improving well productivity in Egypt. This paper gives us the details of this

radial drilling project in Egypt and the results obtained.

SPE paper headed, Extending Ability Of Micro-Hole Radial Horizontal Well Drilled By High-

Pressure Water Jet by Chi Huanpeng, Li Gensheng, Huang Zhongwei, Tian Shouceng, Di Fei,

presented at 2013 WJTA-IMCA Conference and Expo September, Houston, Texas refers to the

sensitivity analysis. A sensitivity study is carried out to identify the parameters controlling the

well extended limit. The sensitivity study includes the effect of flow rate, pump pressure, ratio

between the flow rate of the forward and backward orifices of the jet nozzle, well roughness,

well depth, and well diameter.

Presentation by Radial Drilling Services gave a major hand in understanding the Radial drilling

job step by step. It explains the bottom hole assembly (BHA) used for Radial Drilling, the fluids

used for RD, the various surface units and facilities used and the future aspects and growth of

radially drilled wells.

RDS field training manual describes the various operations and the health and safety

considerations taken care of while drilling a well. Its also sheds light on the abnormal activities

that could take place while radial drilling and the possible well damage that could take place.

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3. HSE CONSIDERATIONS

PPE(Personnel Protective Equipment)

a) All RDS personnel shall wear their PPE at all times on location.

b) Fall protection shall be worn any time personnel are 1m off the ground if no hard

rails are present.

c) Consult RDS safety website for PPE requirements when handling hazard products.

Safety meetings

a) Prior to start-up and at the beginning of all shifts, a technical/safety meeting shall

take place before the start of the operations regarding the tasks to be performed.

b) Coordinate operations between RDS operators and workover teams. This meeting is

fundamental for a safe and efficient work and to lessen risks and times of operation.

c) Discuss radial drilling hazards, location hazards and RDS safety policies.

d) Instruct all involved people of the (high) system pressures and safety issues.

e) Instruct all people that are NOT RDS Inc. employees that access to the unit is only

available upon invitation and NOT during operating times.

f) Local emergency numbers shall be posted in doghouse or unit.

g) All RDS employees present at well Site must sign a safety meeting document.

No jewelry of any kind shall be worn by RDS personnel during operations.

Drugs and Alcohol

a) Notify supervisor if you are taking any prescription drugs and insure all personnel

are aware of the side effects if needed.

b) NO alcohol is to be consumed 8 hours prior to commencing operations.

c) NO illegal drugs are to be used by RDS personnel at any time.

8

Cautions and warnings

a) Any danger zone around RDS equipment shall be clearly marked and the hazard

identified.

b) The area between the unit and well shall be cautioned off with cones or tape.

Policies

a) No unauthorized personnel shall enter RDS units without permission and must be

accompanied by an RDS supervisor.

Material Safety Data Sheets (MSDS)

a) MSDS’s shall be available to all personnel and must be complete and up to date

according to Inventory.

First Aid Kits

a) Must be complete, certified and up to date.

b) Clearly mounted and location identified.

Fire Extinguisher

a) Must be ABC.

b) Clearly mounted and location identified.

c) Inspected annually and tagged.

9

Zone 1 and Zone 2 Restrictions

a) Identified as: Zone 7.5m radius and Zone 2 15m radius.

b) NO cell phones, lighters, or smoking in Zone 1 and 2.

c) Further in line with client restrictions and guidelines.

Guards and Shields

a) To be removed only for repair and/or maintenance purposes and shall be replaced

immediately after completion of maintenance.

Communication

a) Have in place communication equipment for each RDS operator and assure constant

open lines from the operators to the supervisor and back.

Accidents and near misses

a) Report all accidents and near misses to supervisor and management as soon as

possible after occurrence.

10

4. THE RADIAL DRILLING TECHNIQUE

Definition :

RD is an unconventional drilling method which utilizes Coil Tubing conveyed drilling to create

micro diameter holes by expending the energy of high velocity jet fluids. A small section of

casing of the mother well is cut and then lateral holes are drilled in desired direction.

The Equipment Used:

The hardware used are bottom hole assembly consisting of Casing cutter, small diameter bit,

mud motor, hydraulic piston along with auxiliary tools of tubing end connector, anchor, orienter,

steering tool, controller. Also a coil tubing unit is used to convey the drilling process from the

surface.

4.1 Radial Drilling Surface Equipment.

The surface equipment of radial drilling is a simple coiled tubing unit this unit includes all the

required equipment for this job such as a high pressure pump up to 10000 psi, goose nick,

monitoring equipment and injector head as shown in Figure 4.1.

11

4.2 Radial drilling bottom hole assembly

The bottom hole assembly (BHA) of radial drilling is consist of deflector sub or shoe, one

side centralizer, and gyro tool as shown in Figure 4.2. This equipment is lowered into the

hole connected with work string.

The function of this assembly is to guide the tool from vertical to horizontal through,

maintained the deflector sub on the side of the casing.

Figure 4.1: Coiled tubing surface

unit.

12

4.3 Radial drilling Process and Field operation

Before starting the three steps of Radial drilling, we first run in hole with deflector sub, one side

centralizer to fit and guide the tool form vertical to horizontal and gyro tool for orientation on

drill pipes.

The three steps are performed as follow.

a) First step (milling the casing).

Is consisting mainly of a milling bit with a specific size the used size was 1 ¾" bit

connected with flexible shaft both are rotated by conventional mud motor connected

Figure 4.2: Radial Drilling BHA deflector sub,

centralizer and gyro tool.

13

to coiled tubing up to surface connected to coiled tubing unit with its monitoring

system. The milling bit is shown in Figure 4.3.

b) Second step (jetting formation)

Jetting the formation with nozzle has three opening oriented forward and three

oriented from backward connected to a 0.5” hose. The jetting is performed with a

pressure greater than fracture pressure of the formation, the pressure range from 7000

psi to 10000 psi. The jet nozzle is shown in Figure 4.4.

c) Third step ( washing out the formation)

Washing out the formation accomplished by pulling out the hose. While pull out of

hole we keep pumping through the operation.

4.4 Technical Parameters & Specification:

Generally lateral hole of about 300ft-500ft length are drilled having a diameter of 30mm-50mm

(1.2 inches-1.9inches). The bit size is about 1 ¾ inches connected to deflector shoe with flexible

shaft via end connector to the coil and then to a conventional mud motor. Some observation

made were that well with deepest lateral hole show significant increase production rate.

Consolidated rock shows better results of this technique than unconsolidated. Rock mechanics

Figure 4.3: Milling bit for Radial

drilling.

Figure 4.4: Jetting nozzle

for Radial drilling.

14

need to be studied properly in lieu of the decrease of rate before RD job is done. Also penetration

mechanism testing needs to be done along with penetration direction. For unconsolidated

formations gravel packing and slim tubes can be used to control blockage of holes. The

maximum working depth is about 10,000ft. Bottom hole temperature should be of maximum 248

degree Fahrenheit. Drilling fluids varies depending on reservoir lithology and formation fluid

properties. Water is generally used in most operations. For water sensitive formations diesel fuel

may be used which also is useful when dealing with waxy reservoir fluids. Hydraulic acid can be

used as a drilling fluid in carbonate formation. Because of high jet fluids, casing and formation

get eroded for which abrasives are used.

4.5 Candidate Recognition:

1) Gathering and organize well data provided by the client to include logs, well records,

reservoir characteristics and information on previous work over and treatments.

2) Reservoir information- OWC, GOC, zone thickness, dips and faults.

3) Tubular information: casing ID, OD, casing grade and cement quality.

4) Consider rat-hole / use of casing cutter.

5) Tailor coil length to formation / depth with onsite re-spooler.

6) Determine the well potential by considering cumulative production, remaining

recoverable reserves and available formation pressure.

7) Deviation survey: maximum inclination and inclination at zone of interest.

8) Check the logs- CBL, CCL and Gama-ray log.

9) Consider the implications of both the well bore and formation geometry.

10) Determine “safe” lateral length based on these factors.

11) Select formation compatible drilling fluids.

12) Consider chemical treatments / use of acid.

13) Complete a well specific plan to include all available information.

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4.6 Procedure of the Job:

Briefly it has three parts consisting of Milling, Jetting & Washing. The steps for performing the

drilling are as follows:

Run in hole (RIH) with deflector sub on the drill string to the depth as per as log data.

The drill string is oriented to correct direction through a gyro tool.

RIH with a milling tool to cut the desired casing location to start the lateral holes.

Figure 4.5: Radial drilling procedure for a single lateral.

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Pull out of hole (POOH) the milling tool.

RIH with jetting tool.

POOH with hose and jetting tool.

The deflector shoe is rotated and operation is repeated at each lateral hole for any horizontal

layer.

4.7 Radial Jet Drilling (RJD) System using Coil Tubing:

For jet drilling zones at depths over 4000 ft, it is best to use coil tubing since it can be run in and

out of the well rapidly, typically at rates of 100 ft/min. The coil tubing as shown in Figure 4.6

then conveys the high pressure fluid from the pump above ground down to the filter, which has

its bottom connected to the flexible tubing. With high pressures and the coil bending at the top of

the wellhead, the coil tubing will gain fatigue and have to be replaced after several cycles,

depending upon the pressure and the amount of curvatures at the top of the wellhead.

Unfortunately, the rental of coil tubing rigs can be very expensive and cost in excess of USD

$25000 per day.

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4.8 Radial Jet Drilling (RJD) using ‘Macaroni’ Straight Pipe Tubing:

A new jet drilling technique uses 1in. diameter Macaroni tubing to replace coiled tubing as

shown in Figure 4.7. The Macaroni tubing can be used with a PDM motor and milling bit to

bore 1in. holes in the casing. The tubing is retrieved to the surface and the flexible hose and jet

bit are attached to the bottom of the tubing and then lowered so the bit passes downhole, through

the diverter and drills a lateral. Due to the time it takes to the trip the 1 in. tubing in and out of

the wellbore, the system is employed to improve the efficiency. The basic operations are

unchanged except the bottom of the tubing is connected to a high pressure transfer hose that

travels with the pipe similar to traditional drilling techniques. A weight indicator is used on the

worker unit to control the penetration rate into the formation. This method eliminates the high

cost associated with coil tubing, lowers the upfront capital cost, significantly reduces the fatigue

of high pressure tubing and provides higher pressures of up to 20000 psi downhole to enable the

jet bit to drill hard rock.

Figure 4.6: Coil Tubing Units used to deploy Radial Jetting Drilling Technology

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4.9 Reaming the Casing:

Advanced casing cutting and casing reaming techniques have been developed. Figure 4.8 is a

photo of 1 in. holes drilled in a matter of minutes in thick P110 casing using a PDM motor, flex

shaft, and a milling bit (often referred to as a ballcutter). To be used in the process, the milling

bit needs to be able to bore four 1 in. holes in both thin and thick steel casings from shallower

depths to over 11000 ft deep. Internal reaming capabilities that ream complete windows in the

steel casing at the rate of about one inch per hour have been developed. By using this technique,

one can readily jet drill 10 laterals through one window into the formation.

Figure 4.7: ‘Macaroni’ Straight Pipe Tubing arrangement

used to deploy Radial Jetting Drilling Technology

19

4.10 Jet Bits and Penetration Rates:

Figure 4.9 illustrates the jet bit. It produces a full cone vortex of high pressure fluid in the front

that erodes and shears the rock to produce a hole in front with a diameter larger than the jet bit.

Rear thrusters on the bit provide forward force propulsion (typically 10 to 50 lbf of thrust). These

thrusters also cut the deep slots or ‘fins’ into the rock which greatly increase the flow area to the

vertical.

Figure 4.10 illustrates the hole produced by a jet bit in sandstone, which measures 7 in. from tip

to tip. This bit is designed to operate at pressures up to 20000 psi and at flow rates from 8 to 40

gpm. To employ the high pressures and flow rates, special flexible tubing and special proprietary

short crimps are used to enable the 3 in. turn radius in the diverter.

Figure 4.8: A sample piece of 4½ in. casing with multiple 1 in.

holes milled with cutting system

20

Mechanism of Penetration:

Four main penetration mechanisms were identified in radial drilling operation as shown in

Figure 4.11. These are as follows:

Surface Erosion: This is the process where the rock fragments are removed from the surface

of the rock due to the shear and compression forces exerted on the rock surface due to jetting

force.

Hydraulic Fracturing: The same theory of hydraulic fracturing stimulation, as the pressure

increase at the stagnation point diffuses in to formation, the formation may fail or crack if

this pressure is higher than the stresses set by formation stresses.

Poroelastic Tensile Failure: A rapid fluid pressure decrease at the rock surface will induce

effective tensile stresses in the formation equal to the decrease. If this induced tension is

higher than the sum of the smallest effective stress in the formation and the tensile strength,

the rock will fail in tension. This induced tension occurs as the compressibility of the rock

grains and pore fluid is not equal, and any deviation from equilibrium between the rock

grains and pore fluid has to be restored by fluid flowing through the pore space. This flow

Figure 4.9: Jet Bit nozzle under

pressure

Figure 4.10: Typical type cutting

pattern from jet bit

21

takes time due to the finite permeability of the rock, and gives rise to this transient

poroelastic effect. However, for high permeability sandstones the time scale is around 1µs

which may be unrealistically fast. However, the time scales inversely with the permeability

and for chalk (1 mD) or shale (1 mD) this effect may be important.

Cavitation: When water accelerates to pass through corners of the nozzle, the pressure may

drop below the vapour pressure. This may cause vapour bubbles to form as the flow moves

into a larger area, the pressure recovers to a certain degree. This increases the pressure above

the vapour pressure, causing vapour bubbles to collapse or implode. The shock waves may be

extremely high and cause additional erosion and tension effect.

Figure 4.12 illustrates the improved rate of penetration for the medium flow rate bits versus

pressure. Note the rapid drilling rate increases through our Berea Sandstone as the bit pressure is

increased from 7000 psi to 12000 psi. The high flow bit with a bit pressure of 12000 psi

penetrated this 6 in. this Berea Sandstone in one second, which corresponds to a penetration rate

of 1800 ft/hr.

Figure 4.11: Mechanism of

Penetration.

22

Figure 4.13 shows correlation between increased flow rate and increased penetration rate. New

higher-flow jet bits are enabling economical advancement in tighter and harder formation types,

which is reducing the run time required to create laterals.

They have jet drilled core samples varying from 3.5% porosity Dolomite, Indiana Limestone

(16% porosity and 10 mD), German Limestone cores (9.2% porosity and 2.1 mD), Austin Chalk,

heavy oil sandstone cores, Barnet Shale cores, Mercellus Shale cores and others.

Figure 4.12: This chart shows the relationship

between penetration rates associated with jet bit

pressure

23

Mechanism of Pulling:

During drilling, forward force is generated by water jet from orifices on jet nozzle. There are 3

kinds of force on jet nozzle and flexible hose, that adds to the ‘pull’ effect. The net forces that

effect to drive jetting nozzle forward can be derive from three main mechanisms:

1. The Under Pressure Force

2. The Jetting Force

3. The Ejector Force

The Under-Pressure Force: Any flow emerging from a nozzle and impinging on a wall

will be deflected and create a static pressure lower than the pressure surrounding the area of

the nozzle perimeter. The radial velocity (Vr) is inversely proportional to the gap. Decreasing

the gap will increase the velocity; therefore the static pressure (Pstat) will decrease. The static

pressure can come down to the level of atmospheric pressure, creating a pressure differential

Figure 4.13: This chart shows the relationship

between penetration rates associated with jet bit

flow rates

24

between nozzle front area and the surrounding fluid; hence creating a “pull” effect caused by

the “under pressure”.

The Jetting Force: Similar to commercial applications of pipe cleaning, the nozzle has

radial outlets (jets) into the radial direction and reverses nozzles for pulling forces. The

nozzle configuration should have a net pulling force. With the jets acting in an annular

chamber (radial hole) they will act with an ejector effect that will suck away water from the

front end of the nozzle head thus supporting the under pressure mechanism.

The Ejector Force: The reverse jets create a ejector force as they react to the fluid in the

hole and the reaction of the jet velocity impact against the jetted hole in the formation. The

forward force is a function of the angle at which the fluid is jetted against the wall of the hole

and a function of the amount of jets in the nozzle. A differential between the forward impact

forces versus the reverse force adds to the pulling force of the nozzle. Once established, this

force is the main contributor of the pulling power of the system. Centralizing the reverse jet

force and considering the resultant forward forces that result from the vectors, the system

permits forward motion in a straight line once the connection to the surface remains in slight

tension.

The main mechanism is Jetting force mechanism.

Driving Mechanism: Jetting force calculation

𝐒𝐣𝐞𝐭𝐭𝐢𝐧𝐠 = 𝛒𝐮𝐨𝟐𝐀𝐨 − ∑ 𝛒𝐮𝐢

𝟐

𝟔

𝐢=𝟏

𝐜𝐨𝐬𝛗𝐢𝐀𝐢

Where:

𝐀𝐎 =𝛑

𝟒 𝐃𝐨

𝟐 = 𝐢𝐧𝐬𝐢𝐝𝐞 𝐡𝐨𝐬𝐞 𝐚𝐫𝐞𝐚

25

𝐀𝐢 = 𝛑

𝟒 𝐝𝐢

𝟐 = 𝐧𝐨𝐳𝐳𝐥𝐞 𝐚𝐫𝐞𝐚

𝐮𝐨 = 𝐐

𝐀𝐎 = 𝐢𝐧𝐬𝐢𝐝𝐞 𝐡𝐨𝐬𝐞 𝐯𝐞𝐥𝐨𝐜𝐢𝐭𝐲

4.11 Fluids Used in Jet Drilling:

All jet drilling fluids pass through small jet bit orifices so a high pressure filter downhole is

employed to prevent the fluid particles from plugging the orifices. Many different fluids and

additives have been used over the past decades to jet drill. They use 3% KCL in the fluid to

reduce clay swelling in the reservoir and a friction reducer to reduce the pressure loss in the

tubulars. Recent experiments with UltraFrac by Earthborn clean to replace hydrochloric acid

have been encouraging. It has performed as well or better than HCL, is earth friendly, safe and

does not deteriorate the pumping equipment.

26

4.12 Sensitivity Study:

Based on the method established above and the parameters of jet nozzle in Table 1, a sensitivity

study is carried out to identify the parameters controlling the well extended limit. The sensitivity

study includes the effect of flow rate, pump pressure, ratio between the flow rate of the forward

and backward orifices of the jet nozzle (flow rate ratio for short), well roughness, mother-well

depth, and well diameter.

Table 4.1: Structural parameters of jet nozzle

Parameter Value Parameter Value

forward orifice diameter /mm 0.5 backward orifice diameter /mm 0.262

angle between forward orifice axis

0.524

angle between backward orifice

15

and jet nozzle axis /rad axis and jet nozzle axis /rad

the number of forward orifices 6 the number of backward orifices 8

inner diameter /mm 10 outer diameter /mm 18

inlet angle of the orifice /rad 0.236

27

1) Effect of the Flow Rate

The extended limit of the well decreases along with the increase of flow rate (Figure 4.14). To

make the well extend longer, a lower flow rate should be selected. But the rock-breaking

efficiency is low with a lower flow rate. There is an optimum value of flow rate 60L/min to

balance the well extension and rock-breaking efficiency combining with the research of Liao H.

L. et al. (2012).

Figure 4.14: Relationship between flow rate and extended

limit of horizontal well

28

2) Effect of the Pump Pressure

Figure 4.15 illustrates how the extended limit changes with the change in pump pressure from

30MPa to 60MPa. Pump pressure can increase the well extended limit significantly because of

the increasing inlet fluid pressure of the jet nozzle. Then, to increase the pump pressure is

recommended if the operation equipment and security condition allow in field operation.

Figure 4.15: Effect of pump

pressure

29

3) Effect of the Well Roughness

The roughness of the well has an important effect on both annulus pressure loss and pressure

drawdown during production. In Figure 4.16, the well extended limit decreases with a more and

more high speed that is because both the friction force on the flexible hose and the ambient

pressure around the jet nozzle increase as the roughness increases. Thus, the ejecting force

decreases, resulting in the decrease of well extended limit.

Figure 4.16: Effect of well

roughness

30

4) Effect of the Flow Rate Ratio

The well extended limit can change a lot when the flow rate ratio- k changes by changing the

ejecting force of the jet nozzle at the same pumping flow rate. The well extended limit of the

ideal condition (nozzle discharge coefficient = 1.0) and the actual condition (nozzle discharge

coefficient = 0.7-0.8) for different flow rate ratios are shown in Figure 4.17. The semi-log plots

in the figure are like downward parabola. The optimum flow rate ratio is about 1.0. And the

extended limit of ideal condition is about two times as that of actual condition. Improving the

nozzle discharge coefficient can help to extend the well length.

Figure 4.17: Effect of flow rate ratio

31

5) Effect of Mother-Well Depth

The radial drilling is generally applied in shallow wells, and seldom is the application in deep

wells. The influence of mother-well depth on the well extended depth for two kinds of CT are

shown in Figure 4.18. The extended limit of 1.75 in CT is a bit larger than that of 1.5 in CT

because of less pressure loss in CT. The plots are nearly parallel to the abscissa axis and there is

only two meters decease from mother-well depth 800 m to 3800 m, indicating that the effect of

mother-well depth on the well extended limit is negligible.

Figure 4.18: Effect of mother-well depth

32

6) Effect of the Well Diameter

The well extended limit increases by increasing the well diameter, but the increasing speed decreases

as shown in Figure 4.19. That is because small well diameter will result in large pressure loss in well

annulus and large resistance from ambient fluid around the jet nozzle.

Figure 4.19: The effect of

well diameter

33

7) Sensitivity Analysis

By sensitivity analysis method, we quantify the level that how changes in the different parameters

above impact the extended limit of the well. The relationship of the dimensionless changing rate of the

four parameters and the well extended limit is shown in Figure 4.20. The pump pressure, flow rate,

well roughness and flow rate ratio of jet nozzle are dominant parameters that influence the extended

limit, which indicates that the pumping capacity and jet nozzle performance are of great importance to

radial drilling technique. Meanwhile, the extended limit is not sensitive to changing of the mother-well

depth, revealing that the radial drilling technique is feasible in deep wells.

Figure 4.20: Sensitivity

Analysis

34

4.13 Key Benefits Of Radial Drilling:

1) Extended horizontal penetration (max. 100m), therefore reach beyond near wellbore damaged

zone.

2) Controllable length and direction of penetration (perpendicular deviation from the vertical

wellbore), thereby overcoming the limitations of hydraulic fracturing.

3) Reduced formation damage risk when applied as completion method, alternative for traditional

perforating.

4) Alternative to traditional injection and disposal applications.

5) No mud pits required (no environmental side effects).

6) Time and cost efficient application (drilling 4 laterals takes 2 to 4 days).

4.14 Limitations Of Radial Drilling

Difficulties of penetration under porosity of 3-4%.

Maximum working depth about 3000m.

Maximum tensile strength 1,00,000psi – maximum API grade that can be milled N80.

Maximum wellbore inclination 30 degrees and no more than 15 degrees at the target zone of

interest.

Bottom hole temperature not to exceed 120ᴼC.

Bottom hole pressure not to exceed 6500 psi.

Minimal wellbore OD & ID 5.5” and 120mm respectively.

35

4.15 Fluid Selection:

Proper fluid selection and identification and selection of a reservoir compatible fluid system are of key

importance to achieve the optimal result of the application of the Radial Drilling Technology.

The following criteria for fluid design criteria:

1) Low viscosity: the small nozzle size and high jetting velocities require <20Cp.

2) Fluids need to be filtrated through 5µ filters

3) Fluid blending

4) Adjustable density

5) Chemical stability

Application of a fluid system should prevent the following:

1) Formation damage

2) Clay swelling

3) Wettability change

4) Emulsion production

5) Solids invasion

6) Hydrate development

36

Compatibility requirements:

1) Reservoir fluids & rocks.

2) Inhibitors: corrosion, emulsion and scale.

3) Completion fluid brine.

4) Non corrosive and non-degrading.

Base fluids for milling phase:

1) Base: Fresh water (filtered down to 10 micron)

2) Organic lubricant Polymer (for lubrication)

3) Volume per Lateral 1,000 lts

4) Total volume 4 laterals: 4,000 lts

Base Fluids for jetting phase:

1) Base: Fresh water (filtered down to 10 micron)

2) Additive: e.g. clay inhibitors and/or other reservoir compatible additives

3) Organic Lubricant: Polymer (for lubrication)

4) Volume per Lateral: 750 lts

37

As fluid selection is one of the critical aspects in Radial Drilling, RDS recommends that the

appropriate fluid specialists together with the reservoir engineers identify and design the optimal fluid

system depending on reservoir properties, fluid criteria’s as described above, and compatibility

requirements as described above.

4.16 Recommendation For Post Radial Drilling Activities:

Swabbing (flowing) of the wells after completion of radials

Post Radial Drilling activities are as important as the Radial Drilling itself. They include the cleaning

of the spend fluids during Radial Drilling by means of swabbing (flowing). This will provoke the

formation fluids to flow after stagnation during the radial drilling operations. Swabbing (flowing) is

a prerequisite to:

a) eliminate any of the spend fluids from the laterals;

b) eliminate any of the formation cuttings from the lateral;

c) Stimulate the formation after the operations.

It is recommended to calculate the spend fluids and acids that have been used during the Radial drilling

operations and to swab back one and a half times of these spend fluids.

It is recommended to perform the swabbing (flowing) within a closed system, with a tubing/packer

system:

38

Method 1: Dual packer Method 2: Single packer

Wells will require a few days to settle on a basic flow level. This is normally between 10 to 15 days.

Generally there is a slow increase during that period and then the well will settle. This is mainly a

function of available (remaining) reservoir pressure.

Perforated

Lateral

Packers

Swabbing

tool

Perforated

Lateral

Packer

Swabbing

tool

39

4.17 Specification Of Indian Base Oil

Table 4.2: Specification of Base Oil

4.18 Abnormal Events:

Abnormal events or problems that can be encountered while drilling..

1) Broken flex shaft;

2) Broken bits;

40

3) Lost tools in well;

4) Stuck CT or tools;

5) Unit malfunctions;

6) CT over pulls above normal;

7) CT breakage;

8) Unsuccessful milling;

9) Unsuccessful jetting;

10) Loss of well control.

41

5. INDIAN SCENARIO

RD has been done by Selan Exploration Technology Limited recently for the first time in India for

lateral jet drilling. The zone where it was done were mostly of Kalol VIII reservoir, Ahmedabad,

Gujarat. Three wells were selected and each well was performed with 6 numbers of lateral wells. The

reservoir is a silty sandstone layer having low permeability and porosity. The operation was done in

two steps: casing cutting using a tungsten carbide bit of size 22 mm and then performing jet drilling

using high pressure jet hose in variety of jet angles to drill the lateral holes. Coil tubing unit has been

used for the surface equipment. Hence from this it can be seen that RD jobs have been started and can

be applied in other states of India. The cost is low and dead fields can be reused to produce leftover

crudes.

Proposal for implementation of RD technology in India:

In many Indian states, especially that of Assam, Maharashtra & Gujarat many of the fields are either in

late of their production life or are nearly brown and dead. Such fields can be revived with RD

techniques. Many such fields are being produced with artificial gas lifts, SRP, Water Flooding

techniques, EOR processes etc. These methods are moderately costly job. So it is proposed that RD

technique can be taken as a sub step in field development strategy after primary recovery and before

applying IOR methods. Also various work-over jobs are being done to stimulate damaged producing

zone. So before any work-over jobs for improving skin are being performed Radial Drilling jobs can

help as it is a bypassing method. It bypasses the damaged skin zone and reaches to the virgin zones

beyond the damaged region from where newer unexploited existing crudes can be extracted.

This will help reduce the number of work-over jobs per field/reservoir. After radial drilling is done the

filed can be produced for other one-two years without much of workover/IOR-EOR jobs mostly. After

that work-over jobs can be taken up to stimulate the previously damage zone as well as zone extracted

through radial drilling techniques.

42

6. CASE STUDY

6.1: BELAYIM FIELD, EGYPT:

Radial drilling technique applied for the first time in Egypt in Belayim land oil field in Petrobel

Company, Belayim oil field is located in the central part of the Gulf of Suez along of Sinai Peninsula.

Belayim oil fields are characterized by multiple layered reservoirs generally formed from sand with

interbedded shale and anhydrite from different ages. Belayim oil field manly production now depends

on artificial lift, secondary recovery is used (water injection).

Three pilot wells were selected to evaluate radial drilling technique from layered reservoir zones II-A,

IV. And Zone IV currently contains about 23% of Belayim OOIP and contributes about more than

27% of production

The first pilot well radially drilled to evaluate the radial drilling technique on 2010, the well was

producing from zone II-A and zone IV with daily average rate 40 cubic meter per day, static reservoir

pressure about 900 psi and productivity index is 2 barrel per day per psi, average porosity 20%,

heterogeneous permeability, well depth below 3000 meter and net pay thickness is 25 meter. Radial

drilling job were performed on this well by milling and jetting six lateral holes with 50 meter lateral

length at different depths from zone IV

43

Table 6.1: Holes details for well 1#.

REMARKS JETTING

PRESS. ,Psi

LENGTH OF

PENET RETION

, MT.

DEPTH OF

THE HOLE ,

MT

No. OF

HOLE

7000 50 2340 No.1

7000 50 2339 No.2

7000 50 2338 No.3

7000 50 2337 No.4

7000 50 2336 No.5

TRIED TWO TIMES TO

DRILL, NO SUCCESS

7000 -- 2335 No.6

DURING POH FOUND

THE BIT AND FLEX

SHAFT IN SIDE

DEFLECTOR SHOE

7000 50 2334 No.7

7000 50 2333 No.8

44

An easy test called vacuum test was performed on this well before and after radial drilling job to

evaluate this technique. Production rate show a little increased after stimulating the well with this

technique.

Table 6.2: Production comparison of well 1# before and after Radial Drilling

BEFORE RADIAL DRILLING AFTER RADIAL DRILLING

RATE (B/D) WC% NET OIL RATE WC% NET OIL

251 12 35 346 16 46

Second pilot well was selected to evaluate radial drilling technique is well 2 #, the well was producing

from zone II, II-A and zone IV with daily average rate 75 cubic meter per day, static reservoir pressure

about 1990 psi at top of perforation 7126 feet sub sea level and productivity index is 1 barrel per day

per psi from last vacuum test before applied radial drilling, average porosity 20%, heterogeneous

permeability, well depth below 3000 meter and net pay thickness is 40.5 meter.

An easy test called vacuum test was performed on this well before and after radial drilling job to

evaluate this technique. Production rate show obviously increased after stimulating the well with this

technique. However the static well pressure decreased which mean a decrease in fluid level. and

productivity index still the same.

45



RATE (B/D) WC% NET OIL

(CM/D) RATE (B/D) WC% NET OIL (CM/D)

471 1.6 74 818 16 109

The third pilot well was selected to evaluate radial drilling technique is well 3 #, the well was

producing from zone IV with daily average rate 30 cubic meter per day, static reservoir pressure about

970 psi at datum 7900 feet sub sea level and productivity index is 2 barrel per day per psi from last

vacuum test before applied radial drilling, average porosity 20%, heterogeneous permeability, well

depth below 3000 meter and net pay thickness is 26.5 meter.

Radial drilling job was performed on this well by milling and jetting four lateral holes at two depths

with 50 meter lateral length from zone IV. tried many time to make another two holes at another depth

but the holes were canceled due to 1 ¾” bit and flexible shaft lost in hole several time, and that cause

more lost time.

The third pilot well was selected to evaluate radial drilling technique is well 3 #, the well was

producing from zone IV with daily average rate 30 cubic meter per day, static reservoir pressure about

970 psi at datum 7900 feet sub sea level and productivity index is 2 barrel per day per psi from last

vacuum test before applied radial drilling, average porosity 20%, heterogeneous permeability, well

depth below 3000 meter and net pay thickness is 26.5 meter.

Radial drilling job was performed on this well by milling and jetting four lateral holes at two depths

with 50 meter lateral length from zone IV. tried many time to make another two holes at another depth

46

but the holes were canceled due to 1 ¾” bit and flexible shaft lost in hole several time, and that cause

more lost time.



RATE (B/D) WC% NET OIL (CM/D) RATE (B/D) WC% NET OIL (CM/D)

189 3.2 34 252 3.2 39

47

6.2 RADIAL DRILLING PROGRAM

KHARSANG FIELD

WELL: XYZ#01

10th

Mar, 2015

48

GENERAL WELL INFORMATION

Location XYZ#01 is proposed as a candidate for radial drilling operations. The well is

currently producing from the zones 905-912m BRT; 934-940m BRT & 937-940m BRT. A

total 04Nos. of laterals are planned to be drilled from this well. The complete well details with

its current production and well history is given below in this document. Well XYZ#01 is

producing from G layer and the laterals are planned for the same sand.

1. Well Objectives

Geological/ Production Objectives

1) To increase the formation exposure in G sands for enhancing the production of oil.

2) Evaluate well deliverability, reservoir pressures and increase in production rates observed

in this pilot project in order to assess the same for carrying out future radial drilling

operations in other wells.

Well Construction Objectives

1) To carry out radial drilling operations with Zero LTI frequency

2) Achieve all geological and production objectives of the well

3) Maintain hole quality and minimize formation damage

4) Achieve HSE objectives and stay within company HSE targets

5) To carry out operations within planned AFE budget and time

49

2. Well Data Summary

1) Area / Block : MIT Oil Field

2) Well No. : XYZ#01

3) Operator : MIT Petroleum Ltd

4) RT / GL Elevation (Above MSL) : 196.41m / 192.35m

5) 7” Casing (26ppf, N-80, BTC) shoe : 1430.63m BRT

6) Float Collar : 1405.96m BRT

7) Bridge Plug Depth : 960m BRT

8) Open perforation interval : 905-912m BRT; 934-940m BRT & 937-940m

BRT (G)

9) Well Status : Well is currently producing 3KLOPD w/ SRP

assistance

10) Well Coordinates : Surface

Latitude: 27° 24' 15 N

Longitude: 96° 01' 48 E

Northing: 3,034,704.87m

Longitude: 206,318.82m

11) Directional Profile : Vertical well

12) Operating Base : MIT, PUNE

13) Expected date of Start of Operations : 10th

Mar, 2015

14) Planned Number of laterals : 04 Laterals

15) Expected no. of days for 4 laterals : 4.7 days (w/ 24 hour workover operations)

50

a) Production Profile XYZ#01

Table 6.5: Production profile of well XYZ#01

Reservoir Perf Depth (MD) Perf Date Current Prod Cum oil Prod

G

934-940

905-912

21-11-1984

28-03-1998

Oil : 3 kl

Water : 0 kl

40,800 kl

0

2

4

6

8

10

12

14

16

18

0

20

40

60

80

100

120

1980.0 1985.0 1990.0 1995.0 2000.0 2005.0 2010.0 2015.0 2020.0

Ga

s r

ate

(Mscf/

d)

Oil

/ W

ate

r R

ate

s (

bb

l/d

)

Year

Production Rates

Oil Rate, bbl/d Water Rate, bbl/d Gas Rate, Mscf/d

G-00

SRP

Figure 6.1: Production profile

XYZ#01

51

3. Well Schematic

WELL KSG # 16 (KHP)

Present completion:

Cambrian layer

G-00

General Data

Drilled :19.12.83 to 25.01.84

Bit size 20" 16 " CSG , 65 ppf DF : 196.41m amsl GL : 192.35 m amsl

to 54m H-40 STC @ 50.6 m. TD : 1561m dr. , 1562m Log

Status : SRP

Crude type : HWC API Gravity: 28.66 deg API

Last WOJ :Feb-11

Bit size 13-3/4" 10-3/4" CSG 40.5 ppf Technical Data

to 309 m. K-55 STC @ 300.88 m. Well Head

WF10" (5000 psi) x 6" (5000psi)

HF 6" (5000psi) x 3" (3000psi)

Production string ( 23.02.2011 )

FB shoe 0.19

Cement rise behind casing 2 X 2-7/8" EUE Tbg 18.52

605 m from surface PSN 0.34

92 X 2-7/8" EUE Tbg 862.44

1 sgl tbg w ith TH 8.79

DF-HF diff. 4.06

Total string length (m) 894.34 m

PSN @ 875.29 m Sucker Rod Completion :

2-7/8" tbg shoe @ 894.34 m 1* 3/4" SR w ith Sub-surface pump

52 x 3/4" Plane Sucker Rods

905m-912m (G-00) 28.3.98 60 x 3/4" Sucker Rods w ith spiral scrapers

934m-940m (G-00) on 18.8.88 Cumulative production from July'84 to Feb'11

937m-940m (G-00) 21/11/84 Oil: 37,054 kls, Gas:8,20438 m3

BP @ 960 m on 17.02.2011

963m-966m (G-00) 5/2/84 & 21/11/84

968m-972m(G-00) 28.3.'98 Remarks

Present Production Rate :

C/L : 1058.5 m on 15.11.03

TOC @ 1071m on 14.2.84 Reservoir data :

BP @ 1115m on 4.2.84 On 25.11.87 SBHP @ 951.5m = 104 ksc (STHP -25.1 ksc

shut in since 14.11.87)

1120m-1126m 31/1/84 On 28.09.01 FBHP @ 939m = 64.9 ksc (thru' 5.5 mm bean

at the rate of 8 klopd w ith 0-3 ksc of THP

Bit size 9-5/8"

to 1561 m.

7" CSG @ FC 1405.96 m

1430.63 m. N80 TD 1562m

LTC 26 ppf

Found

casing

damage in

the collar @

966m bdf

(28.04.10)

WELL XYZ#01

Figure 6.2: Well schematic of

XYZ#01

52

4. Well History and Present Status

Table 6.6: Previous well interventions of well XYZ#01

G 905-912, 934-940. Well completed in SRP. Produced

clean oil 5 KLOPD & no water

BP @ 960m 17/02/11

G 905-912m 28.03.98 Produce clean oil @ 7-8 KLOPD by

control production. After that

production decline due to increase

water cut, sand ingression & coal

particles.

G1 968-972m 28.03.98

G 934-940m 18.08.88

G 937-940m 21.11.84

G1 963-966m 05.02 &

21.11.84

After re-perforation produced clean

oil @ 24 KLOPD thru 24mm bean.

till 11.07.87

TOC @ 1071m 14.02.84 Presence of oil was detected during

swabbing, but leakage in BP was

suspected and therefore cement

dumped on Top of BP.

BP @ 1115m 04.02.84

H 1120-1126m 31.01.84 Produced formation water(salinity

220 ppm and bi-carbonate 1067

ppm)

53

WELL DETAILS

1. Rig, BOP and Wellhead Details

Workover Rig Specifications:

Name of Rig : XJ-250

Type : Mobile Well Service Unit

Derrick Height : 95 ft

Static Hook Load : 440000 lbs

D/Works : 350 HP (Driven by 1 x CAT C-9 Engine)

Drilling Line : 7/8”

Mud Pumps : 1 x 220HP NOV

R/Table : 11-1/2”

Clear Height Below R/beams : 10.8 ft (3.29 m)

Drill Floor Difference : 0.66m

(Original drilling RT to workover RT)

Kelly : 3” square kelly

Well Head

Wellhead Make : BHEL

Wellhead Type : Conventional flange type

BOP

7-1/16” – 5M BOP stack : 7-1/16”x5M Dual Ram

54

2. Time Depth- XYZ#01

Well Name :XYZ #01

No. of Laterals : 04

Table 6.7: Well details of XYZ#01

OH size Depth (MD) Casing Size Depth (MD)

20" 54 16" 50.60

13.3/4" 309 10.3/4" 300.88

9.5/8" 1562 7" 1430.63

Planned Days on Well : P10 : 3.9 P50 : 4.7

Table 6.8: Operations performed on well XYZ#01

S.No RADIAL DRILLING Program and

Details of Activities

Depth

m

(MD)

BRT

Cum

Most

Optimistic

days

(P10)

AFE

Time

Hrs

(P50)

Cum

AFE

Time

Days

(P50)

Actual Activity

Date & Time

Lateral # 1 hrs day hrs day

0 R/U workover rig on location. Carry

out HOC job. Pump WDM & allow

6 0.00 0.0 0.00 0.0 11/Mar/15 06:00

55

soaking time. POOH sucker rods and

2.7/8" tubing completion to surface.

N/U BOP & carry out scrapping job.

Make arrangements to RIH w/ RDS

BHA.

1

M/U RDS BHA (2.3/8" pup jt. +

deflector shoe + 2.3/8" pup jt. +

XO to tubing + UBHO) and RIH

along with 2.7/8" tubing to depth

of lateral

939.0 5.00 0.2 6.00 0.3

11/Mar/15 12:00

2 R/U wireline to RIH CCL-GR for

depth correlation 939.0 0.50 0.2 0.60 0.3

11/Mar/15 12:36

3

Carry out CCL-GR run for depth

correlation. POOH & R/D wireline

sheaves

939.0 3.00 0.4 3.60 0.4

11/Mar/15 16:12

4 R/U slickline 939.0 0.75 0.4 0.90 0.5 11/Mar/15 17:06

5

RIH gyro and orient the deflector

shoe to desired Azimuth

(Proposed depth: 939m w/ 313deg

in Azimuth- Lateral Length- 50m)

& R/D slickline

939.0 4.00 0.6 4.80 0.7

11/Mar/15 21:54

6 Casing Milling Operations- Lateral

#1 939.0 0.00 0.6 0.00 0.7

11/Mar/15 21:54

7

R/U CT surface equipment (flow

cross, BOP, pipe injector &

gooseneck)- calibrate "0" at

939.0 3.00 0.7 3.60 0.8

12/Mar/15 01:30

56

surface for the depth sensor

8 M/U bit + motor onto the Coil tubing

& surface test motor 939.0 0.50 0.7 0.60 0.8

12/Mar/15 02:06

9 RIH milling BHA on coil tubing to

the depth of deflector shoe 939.0 1.25 0.8 1.50 0.9

12/Mar/15 03:36

10 Carry out casing milling operations 939.0 1.25 0.8 1.50 1.0 12/Mar/15 05:06

11

POOH Milling BHA + Coil tubing to

surface- re test motor on surface, B/O

& L/D same.

939.0 2.00 0.9 2.40 1.1

12/Mar/15 07:30

12 Radial Drilling Operations -

Lateral # 1 939.0 0.00 0.9 0.00 1.1

12/Mar/15 07:30

13

M/U high pressure rubber hose onto

the Coil tubing. Pump @ low

discharge and surface test at surface

and start RIH to the deflector shoe

depth

939.0 1.50 0.9 1.80 1.1

12/Mar/15 09:18

14

M/U additional pump connections

with CT Unit. Pump base oil to fill

CT (total 135gal vol.). B/O pump

connections

939.0 1.25 1.0 1.50 1.2

12/Mar/15 10:48

15

Start radial drilling- jetting operations

and drill 50m of lateral in the desired

sand and direction

939.0 0.75 1.0 0.90 1.2

12/Mar/15 11:42

16 POOH with jetting BHA (hose + CT)

to surface. B/O hose from CT and

939.0 1.50 1.1 1.80 1.3 12/Mar/15 13:30

57

L/D same.

17

R/D gooseneck and injector head in

order to P/U/ orient to the required

depth/ direction for the next lateral

939.0 0.50 1.1 0.60 1.3

12/Mar/15 14:06

18

Lateral # 2

Proposed Depth: 937m w/ 133deg

in Azimuth-

Lateral Length: 35m

937.0 0.00 1.1 0.00 1.3

12/Mar/15 14:06

19 P/U the string to the required lateral

depth 937.0 0.75 1.1 0.90 1.4

12/Mar/15 15:00

20 R/U slickline for gyro orientation 937.0 0.75 1.2 0.90 1.4 12/Mar/15 15:54

21


shoe to desired Azimuth & R/D

slickline

937.0 4.00 1.3 4.80 1.6

12/Mar/15 20:42


# 2 937.0 0.00 1.3 0.00 1.6

12/Mar/15 20:42

23

R/U injector head and gooseneck.

calibrate "0" at surface for the depth

sensor

937.0 0.75 1.4 0.90 1.7

12/Mar/15 21:36



12/Mar/15 22:12



12/Mar/15 23:42


58

26



& L/D same.

937.0 2.00 1.6 2.40 1.9

13/Mar/15 03:36


Lateral # 2 937.0 0.00 1.6 0.00 1.9

13/Mar/15 03:36

28





depth

937.0 1.50 1.6 1.80 2.0

13/Mar/15 05:24

29




connections

937.0 1.25 1.7 1.50 2.0

13/Mar/15 06:54

30



sand and direction

937.0 0.75 1.7 0.90 2.1

13/Mar/15 07:48

31

POOH with jetting BHA (hose + CT)

to surface. B/O hose from CT and

L/D same.

937.0 1.50 1.8 1.80 2.2

13/Mar/15 09:36

32




937.0 0.50 1.8 0.60 2.2

13/Mar/15 10:12

33

Lateral # 3


in Azimuth-

909 0.00 1.8 0.00 2.2

13/Mar/15 10:12

59

Lateral Length: 60m


depth 909.0 0.75 1.8 0.90 2.2

13/Mar/15 11:06

35 R/U wireline to RIH CCL-GR for

depth correlation 909.0 0.50 1.9 0.60 2.2

13/Mar/15 11:42

36

Carry out CCL-GR run for depth

correlation. POOH & R/D wireline

sheaves

909.0 3.00 2.0 3.60 2.4

13/Mar/15 15:18


38



slickline

909.0 4.00 2.0 4.80 2.5

13/Mar/15 21:00


# 3 909.0 0.00 2.0 0.00 2.5

13/Mar/15 21:00

40



sensor

909.0 0.75 2.1 0.90 2.5

13/Mar/15 21:54



13/Mar/15 22:30



14/Mar/15 00:00


44 POOH Milling BHA + Coil tubing to


909.0 2.00 2.3 2.40 2.7 14/Mar/15 03:54

60

& L/D same.


Lateral # 3 909.0 0.00 2.3 0.00 2.7

14/Mar/15 03:54

46





depth

909.0 1.50 2.3 1.80 2.8

14/Mar/15 05:42

47




connections

909.0 1.25 2.4 1.50 2.9

14/Mar/15 07:12

48



sand and direction

909.0 0.75 2.4 0.90 2.9

14/Mar/15 08:06


to surface and L/D same. 909.0 1.50 2.5 1.80 3.0

14/Mar/15 09:54

50




909.0 0.50 2.5 0.60 3.0

14/Mar/15 10:30

51

Lateral # 4


in Azimuth-

Lateral Length: 40m

907 0.00 2.5 0.00 3.0

14/Mar/15 10:30


depth 909.0 0.75 2.5 0.90 3.1

14/Mar/15 11:24

61


54



slickline

909.0 4.00 2.7 4.80 3.3

14/Mar/15 17:06


# 4 909.0 0.00 2.7 0.00 3.3

14/Mar/15 17:06

56



sensor

909.0 0.75 2.8 0.90 3.3

14/Mar/15 18:00



14/Mar/15 18:36



14/Mar/15 20:06


60



& L/D same.

909.0 2.00 3.0 2.40 3.6

15/Mar/15 00:00


Lateral # 4 909.0 0.00 3.0 0.00 3.6

15/Mar/15 00:00

62





depth

909.0 1.50 3.0 1.80 3.7

15/Mar/15 01:48

63 M/U additional pump connections 909.0 1.25 3.1 1.50 3.7 15/Mar/15 03:18

62



connections

64



sand and direction

909.0 0.75 3.1 0.90 3.8

15/Mar/15 04:12


to surface and L/D same. 909.0 1.50 3.2 1.80 3.8

15/Mar/15 06:00

66 POOH RDS BHA to surface, B/O &

L/D same. 909.0 5.00 3.4 6.00 4.1

15/Mar/15 12:00

Handover the well to production

for well activation 907.0 0.00 3.4 0.00 4.1

15/Mar/15 12:00

SUB- TOTAL 85.00 3.5 102.00 4.3 15/Mar/15 12:00

Contingency @ 10% 8.50 0.4 10.20 0.4 15/Mar/15 22:12

TOTAL TIME 93.50 3.9 112.20 4.7 15/Mar/15 22:12

62

A. RADIAL DRILLING PROGRAMME

1. Pre-Radial Drilling Preparation:

1) Have a pre job safety meeting with the crew & all parties involved & explain the job

procedure prior to every major job during the operations.

2) No oil dripping or spill is allowed within the well site.

3) Complete rig equipment & personnel are mobilized as per contract

4) All railings & work platforms must be in place.

5) All guy ropes are properly anchored.

6) All high pressure lines including mud pump, pop off valve line and discharge lines are

properly secured/ clamped.

7) Complete rig instrumentation is rigged up & functional

8) High pressure lines are pressure tested to 1000psi.

9) Ensure that the mast and rotary are perfectly centered with Xmas tree.

10) Ensure all instrumentation is hooked up, calibrated and verified jointly by Rig DIC and

Company representative.

11) Pre-radial drilling ops equipment check will be completed by the Company

representative, along with the representative of Radial Drilling Services.

12) Ensure the low discharge high pressure pump required to fill base oil into CT with the

required crossovers to connect to the CT reel are available. Additionally, also ensure that

the pump required for transferring oil from one barrel to another is also available and in

working condition with the required hose etc. available at location.

13) Ensure all rig equipment are serviced and in good operating condition, tanks are clean

and mud pump is also serviced to carry out all operations smoothly.

14) All tanks are properly cleaned and filled with clean water.

15) All personnel are wearing PPE. Eyewash units and showers are available at chemical

loading point.

16) Derrick man escape device is installed.

17) Derrick man climb assist is installed.

18) All required crossovers and tools are available.

63

19) Sufficient spare parts to support the rig are available.

2. Chemical Requirements during the operations:

KCl brine is the formulation of fluid to be used during the radial drilling operations for

only casing milling operations.

For well killing/ circulation, processed oil is to be used.

The casing would be filled with processed oil and circulation during sand cleaning and

scrapper trip would be carried out using HOC. KCl brine would be used for casing milling.

For jetting the laterals, base oil would be used.

For quantities of chemicals to be used the following assumption is made:

1) KCl = 5-7% (1.03-1.04SG)

2) Base Oil = Total volume of CT is to be filled using base oil (CT Volume = 135gal)

3) Base oil requirements would be based on pumping rates and lateral length.

Flowrates suggested during casing milling & jetting operations would be around 5-8gpm,

but the final concentration of chemicals and flowrate required for the operations would be

confirmed at the time of operations by the RDS Supervisor.

3. Radial Drilling Operations:

A. Removal of Completion:

Prior to handing over well for radial drilling operations

1) Carry out pre-job safety meeting with all personnel involved.

64

2) Connect kill line to casing and pressure test the line up to 1000psi.

3) Prepare workover fluid by using Potassium Chloride KCl (SG = 1.03-1.04 and pH = 7.5,

KOH may be added to maintain pH).

4) N/D horse head.

5) Bleed of casing and tubing pressure & Observe for 30 minutes for well activity and ensure

that well is dead.

6) Once the well is confirmed for no activity, then connect suitable pony rod over polished

rod.

7) N/D polished rod with stuffing box assembly.

8) N/U SR BOP.

9) POOH all sucker rods (113Nos.) with sub-surface pump and fill up workover fluid thru

tubing during POOH SRs. Observe for any swabbing effect during POOH of sucker rods.

10) After the sub-surface pump comes out of hole, clamp it properly with plunger rod and

barrel. L/D pump on the catwalk. Check the pump visually for any damage.

11) N/D SR BOP with SRP well head fittings.

12) N/U tubing BOP and function test BOP

13) Connect 2-7/8” Pup joint with safety valve to the Tubing Hanger. Pick up TH slowly and

remove TH.

14) Make arrangements to RIH with 2.7/8” tubing to clear down to bottom @ 960m BRT

while circulating with hot oil.

15) Once the well is confirmed as clear to bottom, POOH tubing with PSN and fill up WOF

(processed oil) in casing to maintain liquid level up to top of BOP at all the time during

pulling out. Rack back all tubing joints while POOH.

16) Make arrangements and carry out a scrapper trip down to 960m BRT. Ensure no rotation is

done with the scrapper and the string is run carefully while the scrapper is going past the

perforations @ 905-912m & 934-940m BRT. Once the string is at bottom @ 960m BRT,

P/U string by 2m and carry out circulation using hot oil.

17) Make surface arrangements and hand-over the well for carrying out radial drilling

operations.

65

18) Assistant Driller to strap all tubing being RIH for radial operations. AD to measure all

components of the RDS BHA, make fishing schematics of all components and prepare

tally prior to RIH.

19) Ensure, the pump required for filling CT reel with base oil is available with all

required connections.

20) Ensure pump required for transferring base oil from one barrel to another is

available with the required length of hose, fittings etc.

21) Place RDS unit as per RDS supervisor instructions

22) Ensure, wireline unit & slickline unit are available on site to be used as and when required.

23) Ensure all chemicals required during radial drilling operations viz: KCl, processed oil &

base oil are available on site.

24) Ensure all tubing are drifted from the monkey board while RIH- Drift dia. for 2.7/8”-

6.5ppf tubing is 2.347”.

66

B. Radial Drilling Procedure:

Following are the laterals proposed to be drilled in this well:

Table 6.9: Laterals details drilled on well XYZ#01

Well

Name

No. of

Laterals

Details of Lateral

Depth (MDBRT) Azimuth Length

XYZ 04

907m 213° (± 3°) 40m

909m 292° (± 3°) 60m

937m 133° (± 3°) 35m

939m 313° (± 3°) 50m

1) M/U RDS BHA (2.3/8" pup jt. w/ centralizer + deflector shoe + 2.3/8" pup jt. w/

centralizer + UBHO + XO to tubing) and RIH along with 2.7/8" tubing to depth of

lateral (935m BRT- depth of deflector shoe)

2) R/U wireline to RIH CCL-GR for depth correlation.

3) Carry out CCL-GR run for depth correlation. POOH & R/D wireline sheaves.

4) R/U slickline

5) RIH gyro and orient the deflector shoe to desired Azimuth (Proposed Depth: 939m w/

313deg in Azimuth, Lateral Length: 50m) and R/D slickline

Casing Milling Operations- Lateral #1:

6) R/U CT surface equipment (flow cross, BOP, pipe injector & gooseneck)- calibrate "0"

at surface for the depth sensor

7) M/U bit + motor onto the Coil tubing & surface test motor

8) RIH milling BHA on coil tubing to the depth of deflector shoe

9) Carry out casing milling operations (using KCl brine)

67

10) POOH Milling BHA + Coil tubing to surface- re test motor on surface, B/O & L/D

same.

Radial Drilling Operations - Lateral # 1

11) M/U high pressure rubber hose onto the Coil tubing. Pump @ low discharge and surface

test at surface and start RIH to the deflector shoe depth. While RIH pump @ low

flowrates of 3gpm to 200m above lateral depth using KCl brine. Once the deflector shoe

is tagged, jet the lateral for about 5m and pull back into the tubing shoe.

12) M/U additional pump connections with CT Unit. Pump base oil to fill CT (total 135gal

vol.). B/O pump connections (remember to fill CT with base oil for the lateral length to

be drilled- remaining volume of fluid is KCl brine. For this lateral of 50m the volume of

base oil to be filled = ~ 135gal)

13) Start radial drilling- jetting operations and drill 50m of lateral in the desired sand and

direction

14) POOH with jetting BHA (hose + CT) to surface and L/D same.

15) R/D gooseneck and injector head in order to P/U/ orient to the required depth/ direction

for the next lateral

Lateral # 2 (Proposed depth: 937m w/ 133deg in Azimuth, Lateral Length: 35m)

16) P/U string by 2m to 937m BRT.

17) R/U slickline for gyro orientation

18) RIH gyro and orient deflector shoe to desired Azimuth (Proposed: 937m w/ 133deg in

Azimuth)

19) R/U injector head and gooseneck. calibrate "0" at surface for the depth sensor

20) Repeat Steps 7 to 15 for casing milling & radial drilling operations for 35m in this

lateral.



22) R/U wireline to RIH CCL-GR for depth correlation.

23) Carry out CCL-GR run for depth correlation. POOH & R/D wireline sheaves.


68


Azimuth).


27) Repeat Steps 7 to 15 for casing milling & radial drilling operations for 60m in this

lateral.





Azimuth)


32) Repeat Steps 7 to 15 for casing milling & radial drilling operations for 40m in this lateral

33) POOH RDS BHA to surface, B/O & L/D same.

34) Handover the well to production for well activation.

35) RIH final completion with tail pipe & production tubing as per running tally. Tubing

shoe @ 894.34m BRT & PSN @875.29m BRT as per the following sequence:

a) 2-7/8” OD, EUE, 6.5 ppf, N-80 FB Shoe.

b) 02 nos. 2-7/8” OD, EUE, 6.5 ppf, N-80 Tubing

c) 01 no. PSN

d) 2-7/8” OD, EUE, 6.5 ppf, N-80, tubing as per requirement up to surface

e) 01 no 2-7/8” OD, EUE, 6.5 ppf, N-80 tubing hanger with handling pup joint.

36) N/D tubing BOP & N/U SR BOP with necessary wellhead fittings.

37) RIH New Sub-surface pump with 3/4”SR with spiral scrappers. Test downhole pump on

surface prior to R/I.

38) Space out pump after seating on PSN.

39) ND SR BOP.

40) Complete the well with polished rod & stuffing box.

69

41) Release Rig to next location.

42) Install horse head and commission the surface unit with proper spacing of stroke length

43) Start SRP and Pressure tests the downhole pump at 500 psi surface pressure.

44) Carry out production testing of well at WHT.

SUPPORT DATA

1. List of Equipment required during the radial drilling operations:

Following are the list of equipment supplied by RDS & GEPL during the radial drilling

operations:

A. RDSY 5:

Following are the parameters of the offered unit:

1) Coil Tubing size: 5/8” (15.9mm)

2) CT Length: 12138ft (3699m)

3) Size of Hole for Casing Exit: 22mm

4) Unit Weight: 16T

5) Power Supply: CAT C6.6 202HP, 2200rpm water cooled engine

6) Transmission: Direct Drive Hydraulic

7) Maximum Pump Pressure (Primary Pump): 15000 psi

8) Operating Pressure: 13000 psi

9) Maximum Pump Pressure (Secondary Pump): 20000 psi

10) Operating Pressure: 18000 psi

11) System Design: 15000psi

70

12) Diesel Fuel Consumption: 20.80 ltrs/hr

13) Air Pressure: 120 psi

14) Length of Hose Supplied: 100m

15) Hole Size with Jetting: 50-60mm

B. Operating Details:

1) Unit Location: 100ft (33m) from wellhead

2) Coil Tubing Guide System: At well head

3) Max Grade of Casing: 80

4) Maximum Wall Thickness: 11mm

5) Maximum Depth: 3600m

6) Air System: 38 ltrs

7) Diesel Fuel: 1136 ltrs

C. Operating Fluid Volume:

1) Water System: 1700ltrs

2) Air System: 38 ltrs

3) Diesel Fuel: 1136 ltrs

D. Filtering System:

1) Mesh size: 5 microns and 10 microns available with the unit

71

E. Downhole motor:

1) PDM Size: 1.1/16”

2) Mud Flowrate: 0.2-0.5 l/sec

3) Output shaft at no load conditions: 2.0-4.9 rpm

4) Pressure Drop at no load conditions: 1.0-2.4 MPa

5) Differential pressure during operation: 1.8-2.7 MPa

6) Maximum Efficiency: 40%

7) WOB: 6KN (0.6T)

F. Gyro Offered:

1) Gyro Size: 1.75” OD

2) Overall Length: 11feet including top crossover and mule shoe stinger assembly

3) Running Gear:

a) 1.75” Dia. 17-4 Ph Heat Treated Stainless Steel

b) Top Connector Crossover

c) Gyro Instrument Pressure Barrel

d) Alignment Sub

e) Probe Pressure Barrel

f) Internal Spring Landing Assembly

g) Bull Plug

h) Crossover adjustable for orientation of mule shoe stinger

i) Mule Shoe Stinger- 7/8” Diameter

j) Pressure Rating: 12000-14000 psi

4) UBHO provided

72

5) Surface readout system: Well-Nav

6) Operates on single conductor and multiple conductor wireline

7) Temp. range: -55° F to 257° F (125° C)

8) Directional Data Measured:

a) Gyro tool face wellbore inclination hole

b) Direction (Azimuth)

c) High-Side

d) Orientation Wellbore Temperature

e) Optional Water level Contact

f) 35V DC minimum at probe cable head

RDS has vide queries asked has confirmed provision of the following with the

Gyroscope Equipment:

1) Crossovers to connect the gyro tool with the cable head provided by the

Company provided slickline services

2) Suitable connectors to make the gyro system compatible with the depth encoder

system of the wireline unit

3) Connector cable between logging cable and the gyro system

G. Accessories Offered:

Along with the above mentioned equipment, RDS will provide the following

with their RDS package:

1) Deflector shoe

2) Pup joint 2.3/8” EUE connection- 4 feet

3) UBHO for Gyro

4) Hydraulic Injector

73

5) PDM (As specified above)

6) Flex Shaft

7) 22mm Bit

8) Nozzle

9) Jet Hose

10) Coil Tubing package

11) Pack-off

12) Coil Tubing BOP

13) Crossovers: to connect CT to 22mm tungsten bit

14) Crossovers to connect RDS BHA to 2.7/8” EUE Tubing

15) Centralizers 02Nos. available (in RDS BHA)

16) Pup joint above and below

17) 5 & 10 microns filtration screens

Equipment required to be provided by the Company:

1) Workover rig

2) Full access to location for RDS system

3) Adequate work platform

4) Wireline Equipment

5) Water Truck with around 15m3 water requirement for 4 laterals

6) Good illumination to the workover site for carrying out 24 hours operations

during radial drilling

74

2. Equipment Matrix:

Table 6.10: Equipments on the field

Sl.

No. Item Status GEPL RDS

1 Well service unit on site X

2 Slickline equipment to run Gyro on site X

3

Wireline Equipment to run CCL-

GR for depth corelation on site

X

4

Tanks to store drill water to be

supplied for casing milling &

radial drilling operations

On site available 2

tanks of 30KL

capacity X

5

Mud pump to transfer workover

fluid for radial operations on site X

6 2-7/8" EUE tubing pup joints on site X

7 Potassium Chloride (KCl) on site X

8 Base Oil

on site (available

total 40 drums) X

9

Night illumination between W/O

rig and RDS unit

Already installed

on the well service

unit X

10

Additional Crew for 24 hrs.

operations On Site X

11

Chiksan pipe for transferring

workover fluid from tanks to

RDS unit. on site X

12

Crossover to connect 2” Fig 602

to RDS filters (1” NPT) On site X

75

13 RDS Coil Tubing Unit On site X

14

RDS BHA (2.3/8" pup joints w/

centralizers + deflector shoe +

UBHO + XO to connect to

2.7/8" tubing + PDM + rubber

hose) on site X

15 5 micron & 10 micron filters on site X

16

CT BOP + flow cross + pack-

off+ gooseneck+ injector head

etc. on site X

17 Crane- 30MT on site X

18 Memory Gyro On site X

19 Pump for base oil transfer to CT On site X

20

Pump for base oil barrel to barrel

transfer On site X

3. Unit of Measurements

All reporting from the well shall have following units:

1) Depth : m MDRT (m, Measured depth below rotary table)

2) Depth : m TVDRT (m, True vertical depth below RT)

3) Length : m (meter)

4) Diameter : in (inch)

5) Temperature : ºF (degree Fahrenheit)

6) Pressure : psi (pounds per square inch)

7) Workover Fluid Weight : gm/cc (gram per cubic centimeter i.e. SG)

8) Flow-rate : gpm (gallons per minute)

9) Hook Load : MT (metric ton)

10) Casing Weights : ppf (pounds per foot)

11) Torque : lbf-ft (pounds force foot)

76

7. RESULT

Radial drilling is implememted to enhance the well produactivity. The case study on belayim

field shows successful radial drilling operation.

The enhancement of net oil production ranges from 12.5 % to 47%:

Well no. RATE BEFORE RD (B/D) RATE AFTER RD (B/D)

1 251 346

2 471 818

3 189 252

As the number of holes increase results show a good results than those of less number of

holes.

In Kharsang field, in well XYZ#01, before radial drilling the well was producing 3kl/d

(KiloLitres/day), and after implementing Radial Drilling technology well is delivering 4kl/d.

We can conclude that the well deliverability of well XYZ#01 is quite less.

77

8. CONCLUSION

Radial drilling technique proved a lot of advantages from these advantages we can mention

that radial drilling technique can improve productivity index by different means by-passing

possible damaged zone, extending drainage area in productive formation, connecting fracture

in wellbore and improving drainage from low permeability, heterogeneous and layered

reservoirs.

On the other hand this technique proved some limitations like Maximum tensile strength

100,000 psi – maximum API grade that can be milled N-80, not suitable for highly deviated

and deep wells.

Despite its limitations, RJD can be effective for completing both new and workover wells

with radial up to 1,000 ft due to its low environmental impact, economical enhancement of

reservoir productivity, suitability for many formation types, enhanced effectiveness of

subsequent well stimulation treatments, and the speed at which laterals can be drilled.

Future work might focus on comparing the productivity of jet-drilled laterals to traditionally

drilled horizontal wells, skin factors, and comparison of theoretical productivity predictions

of horizontal wells to actual productivity of horizontal jet drilled laterals.

The various studies and experiments had drawn following conclusions:

Improved RJD technology is enabling more economical enhancements of both new

and older wells.

Based on the above results, radial drilling technique becomes a solution for a mature

oilfield and low oil production. With radial drilling technique we can decrease

damage radius and increase drainage radius and as a result we can increase production

to 200% to 400% from the previous one. Radial drilling operation is depending on

several parameters such as, cutting transport, borehole position and reservoir

characteristics.

Using this technique in consolidated rock is better than unconsolidated ones in order

to maintain the hole open.

78

The screening criteria about Radial Drilling must be taken in consideration before the

operation specially depth & degree of consolidation.

Radial drilling by high pressure jet flow techniques can greatly increase oil recovery

and oil production rate.

79

9. REFERENCES:

M.A.; Siso,M.; Hassan,A.M.; Pierpaolo,P; and Roberto, Abdel-Ghant, C.2011, “New

Technology Application, Radial Jet Drilling Petrobel, First Well in Egypt,” SPE 164773

2011-163, 10th Offshore Mediterranean Conference and Exhibition, Ravenna, Italy,

March 23-25.

Bruni,M.; Biassotti,H.; and Salomone, G.2007,“Radial Drilling in Argentina,” SPE

107382, SPE Latin American and Caribbean Petroleum Engineering Conference, Buenos

Aires, Argentina, April 15 -18.

Buckman Jet Drilling, 2010, Leading Innovators in Jet Drilling Technology,

www.buckmanenergyservices.com.

Marburn,B.; Sinaga,S.; Arliyando,A.; and Putra, S.2012, “Review of Ultra Short-Radius

Radial System(URRS),” Marburn,B.; Sinaga,S.; Arliyando,A.; and Putra,S.2012,

“Review of Ultra Short-Radius Radial System(URRS)”, International Petroleum

Technology Conference (IPTC), Bangkok, Thailand, February7-9. RadJet.2012, “Rad-Jet

Technology,” http://www.radjet.com/technology/radjet-vs-competitors/.

Radial Drilling Guidelines-march 2008, Radial Drilling Services Inc., page:3-6

Well Productivity Manual 2012 Radial Drilling Services, Inc.

WELL PRODUCTIVITY MANUAL 2012 | RADIAL DRILLING SERVICES, INC

WELL PRODUCES, IN

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