8th UDP FINAL Approved

L.D COLLEGE OF ENGENEERING

“Design of drilling fluid using polymers along with

soil-fluid interaction.”

GUIDED BY: – Dr. M.V. SHAH

SUBMITTED BY

Name (Enrollment no.)

SARANG V.PATEL (110280106005)

ANIRUDH S. SABOO (110280106008)

NILIPT A. PATEL (110280106019)

SHOBHIT D.DUBEY (110280106044)

YEAR : 2014-15

CIVIL ENGINEERING DEPARTMENT

L.D. COLLEGE OF ENGINEERING, AHMEDABAD.


CERTIFICATE OF EXAMINER

The project report entitled

Design of drilling fluid using polymers along with

soil-fluid interaction

Submitted By

SARANG PATEL(110280106005)

ANIRUDH SABOO (11020106008)

NILIPT PATEL (110280106019)

SHOBHIT DUBEY(110280106044)

As a partial fulfilment of the requirement

For the

Subject: PROJECT-II (180605)

Semester – VIIIth

Of Gujarat Technological University in the field of

“CIVIL ENGINEERING”

is hereby approved.

Internal Examiner External Examiner

Date:

Place:


L. D. COLLEGE OF ENGINEERING

Civil Engineering

2015

CERTIFICATE

Date:

This is to certify that the Report of Project work entitled “Design of

drilling fluid using polymers along with soil-fluid interaction” has been

successfully completed by SARANG PATEL, ANIRUDH SABOO, NILIPT

PATEL AND SHOBHIT DUBEY, under my guidance, in the partial

fulfilment of the degree of Bachelor of Engineering in CIVIL (8th

semester) of

Gujarat Technological University, Ahmedabad during the academic year 2015.

Dr M V Shah Dr S P Dave

Internal Guide Head of Department


ACKNOWLEDGEMENT

We are thankful to Dr S. P. DAVE (Head of Department, Applied

Mechanics Department) for giving this opportunity. It was possible due to

her co-operation and help. I would like to place on record appreciation for

all those who are connected with this report. With great pleasure, I

express my deep sense of gratitude to respected Dr. M.V.SHAH and all

other staff members of Applied Mechanics Department for the co-

operation.

PROJECT CONDUCTED BY

STUDENT OF CIVIL

8TH

SEMESTER


ABSTRACT

Drilling fluids are used for drilling oil/gas from high density underground geological

formations. Water based drilling fluid are most extensively used nowadays everywhere in

India because they are easy to design, economic to maintain and can be applied to a high

versatile areas. Any drilling fluid should be designed in such a way that proper control over

pressure can be done, should be able to transport cuttings and finally it should support and

stabilize the well-bore. For depths greater than 600m, polymers fluids are mostly used,

because of the fluid dispersion problems encountered in shale. The aim of the present

research work is to formulate low cost polymer drilling fluid on the basis of soil-fluid

interaction with good dispersion efficiency. It is aim to design low cost drilling fluid by

adding polymers which are highly soluble in water and which can cover more specific area .

The objective of present study is to enhance various fluid properties like mud density,

viscosity, rheology, gel strength, filtration, pH of drilling fluids by using locally available low

cost polymers. The above objective will be satisfied in two phases. In 1st phase, detail

laboratory investigation will be carried out only on bentonite fluids with water as a medium.

In 2nd

phase the investigation will be carried out on polymer fluids and its dispersion

efficiency will be verified on shale specimens. Overall results of phase I and phase II indicate

that bentonite as a drilling fluid has very less dispersion efficiency in shale and it can be

better improved by using low cost polymers based on soil-fluid interaction.

The main objective of this project

To design bentonite and polymer based drilling fluid using soil fluid interaction and to study

its effect on shale rocks having dispersivity problems.


TABLE OF CONTENTS

CHAPTER 1

INTRODUCTION

1.1 GENERAL.......................................................................................................................................10

1.2 MOTIVATION OF THE STUDY...................................................................................................11

1.3BRIEF DESCRIPTION....................................................................................................................12

1.4SCOPE & OBJECTIVE OF WORK…………………………...………….…………………..…..14

CHAPTER 2

LITERATURE REVIEW.........................................................................................................15

CHAPTER 3

EXPERIMENTAL SETUP

3.1 EXPERIMENTAL PROGRAMME

PART I : MATERIAL…………………………………………………………………...……………21

PART II : METHODOLOGY………………………………………………………….……………..24

3.2 STANDARD CODES USED…..……………………………..…………………....….…….……25

CHAPTER 4

EXPERIMENTAL INVESTIGATION

PHASE: I BENTONITE-WATER SYSTEM…………………….………………………………..…26

PHASE: II POLYMER-WATER SYSTEM……………………….……………………….................27

PHASE: III SHALE FLUID INTERACTION…………………………………..……………………28

4.1 SPECIFIC GRAVITY OF BENTONITE CLAY…………………………………….…………...29

4.2LIQUID LIMIT ON BENTONITE CLAY………………………………….………………….…30

4.3 PLASTIC LIMIT ON BENTONITE CLAY………………...........................................................32

4.4 FREE SWELL INDEX ON BENTONITE CLAY…..................................................................... 33

4.5 MUD WEIGHT OF BENTONITE SLURRY................................................................................ 34


4.6MUDVISCOSITY OF BENTONITE SLURRY……..………………………………….....…..…36

4.7PLASTIC VISCOSITY OF BENTONITE SLURRY….................................................................37

4.8 YIELD POINT OF BENTONITE SLURRY…............................................................................. 38

4.9 GEL STRENGTH OF BENTONITE SLURRY…………………………………………....……..39

4.10 FILTRATION (WATER LOSS) IN BENTONITE SLURRY…...……..…………………….....40

4.11 pH VALUE OF BENTONITE SLURRY………...……………………………..……………….41

4.12 CEC VALUE OF BENTONITE SLURRY………....……………………..…………………….42

CHAPTER 5

RESULT & ANALYSIS& DISCUSSION

5.1.1 SPECIFIC GRAVITY OFBENTONITECLAY,,,…………...………..…………....…….…….43

5.1.2LIQUID LIMIT OF BENTONITE CLAY ….............................................................................43

5.1.3 PLASTIC LIMIT OF BENTONITE CLAY……………….........................................................44

5.1.4 FREE SWELL INDEX OF BENTONITE CLAY..................................................................... ..44

5.1.5 MUD WEIGHT OF BENTONITE SLURRY…………………………………………..………45

5.1.6 MUD VISCOSITY OFBENTONITE SLURRY..………………...…………….……..…..…....45

5.1.7 PLASTIC VISCOSITY OF BENTONITE SLURRY .................................................................46

5.1.8 YIELD POINT OF BENTONITE SLURRY…...........................................................................46

5.1.9 GEL STRENGTH OF BENTONITE SLURRY………………….…………………………….47

5.1.10 FILTRATION (WATER LOSS) IN BENTONITE SLURRY………….……….…..…….…..47

5.1.11 pH VALUE OF BENTONITE SLURRY…………………………….………….….………...48

5.1.12 CEC VALUE OF BENTONITE SLURRY……………………………………………….…..48

5.2.1 MUD WEIGHT OF BENTONITE SLURRY………………………………….………………50

5.2.2 MUD VISCOSITY OFBENTONITE SLURRY..…………………….……..…………...….....50

5.2.3 PLASTIC VISCOSITY OF BENTONITE SLURRY ................................................................51

5.2.4 YIELD POINT OF BENTONITE SLURRY…..........................................................................52


5.2.5 GEL STRENGTH OF BENTONITE SLURRY…………………………….………………….53

5.2.6 FILTRATION (WATER LOSS) IN BENTONITE SLURRY…………………………….……53

5.2.7 pH VALUE OF BENTONITE SLURRY…………………………….…….…………………...54

5.3.1 CEC VALUE OF SHALE………………………………………………………..……………..55

5.3.2 SHALE DISPERSION TEST…………………………………………….……………………..56

5.3.3 SOIL-FLUID INTERACTION…………………………………………….…………….……...57

5.3.4 COMPARATIVE PLOTS OF BENTONITE MUD PROPERTIES………….………....……...58

5.3.5 COMPARATIVE PLOTS OF POLYMER MUD PROPERTIES……………………..……….59

CHAPTER 6

CONCLUSION………………………………………………………………………………61

REFERENCES………….........................................................................................................64

TABLE OF FIGURES

1. OIL BASED DRILLING FLUID……………………….………………...…………..…...…10

2. WATER BASED DRILLING FLUID……………………………………………….....……10

3. BENTONITE SLURRY……………………………………………………………………...21

4. POLYMER SLURRY…………………………………….…………………………………..22

5. SHALE………………………………………………….…………………………………….23

6. SPECIFIC GRAVITY……………………..………….………………………………..…….29

7. LIQUID LIMIT……………………………………………………………….………………31

8. PLASTIC LIMIT……………………………………………………………………………..32

9. FREE SWELL VOLUME……………………………………………………………………33

10. MUD WEIGHT………………………………………………………………………………34

11. MUD VISCOSITY…………………………………………………………………………...36

12. PLASTIC VISCOSITY……………………………………………………………………....37

13. YIELD POINT…………………………………………………………………….………….38

14. GEL STRENGTH………………………………………………………………….………....39

15. FILTRATION LOSS…………………………………………………………………………40

16. pH VALUE……………………………………………………………………….…………..41

17. CEC VALUE……………………………………………………………………….………...42


LIST OF GRAPHS

PHASE: I BENTONITE - WATER SYSTEM

1. SPECIFIC GRAVITY (G) v/s NO. OF SAMPLES……………………………………….…43

2. LIQUID LIMIT (%) v/s NO. OF SAMPLES……………………………….………………..43

3. PLASTIC LIMIT (%) v/s NO. OF SAMPLES……………………………………….………44

4. FREE SWELL VOLUME v/s NO. OF SAMPLES………………………………….………44

5. MUD WEIGHT v/s NO. OF SAMPLES…………………………………………….………45

6. MUD VISCOSITY v/s NO. OF SAMPLES………………………………………….………45

7. PLASTIC VISCOSITY v/s NO. OF SAMPLES………………………………………….….46

8. YIELD POINT v/s NO. OF SAMPLES…………………………………………….………..46

9. NO. OF SAMPLES v/s GEL STRENGTH………………………….…………………...…..47

10. FILTRATION LOSS v/s NO. OF SAMPLES……………………………….……………….47

11. pH VALUE v/s NO. OF SAMPLES…………………………………….……………………48

12. CEC VALUE V/S NO. OF OBSERVATIONS……………………………………………...48

PHASE: II POLYMER – WATER SYSTEM

1. MUD WEIGHT v/s NO. OF SAMPLES………………………………………….…………50

2. MUD VISCOSITY v/s NO. OF SAMPLES……………………………………………….…50

3. PLASTIC VISCOSITY v/s NO. OF SAMPLES………………………………………….….51

4. YIELD POINT v/s NO. OF SAMPLES………………………………………………….…..52

5. NO. OF SAMPLES v/s GEL STRENGTH……………………………………………....…..53

6. FILTRATION LOSS v/s NO. OF SAMPLES……………………………………………….53

7. pH VALUE v/s NO. OF SAMPLES…………………………………………………………54

PHASE: III SHALE

1. CEC VALUE V/S NO. OF OBSERVATIONS………………………………………..…….55

2. PERCENTAGE RECOVERY V/S NO. OF OBSERVATIONS………………………….....57


CHAPTER 1

INTRODUCTION

1.1 GENERAL

Various crude oil oriented companies are indulged in extracting the crude oil

through the earth by using various kinds of drilling fluids and jetting technology. Up to

certain limit under the earth the usage of bentonite slurry as drilling fluid is sufficient but

after that it becomes difficult to extract the crude oil through the earth so to enhance the

properties of slurry (drilling fluid) polymers are added to it in some proportion which are

costly and limited upto some extent in some areas which is governed by the soil fluid

interaction and the basic soil properties of the drilling fluid.

OIL BASED MUD ( FIG A) WATER BASED MUD (FIG B)


1.2 MOTIVATION OF THE STUDY

Various types of drilling fluids are available in the market today

both water based and oil based having their own limitation and advantages.

Out of many drilling fluids Bentonite-Water drilling fluid system is very commonly

used for drilling oil from shallow depth i.e. up to600 m. After that as fine clay particles

increases with depth, the problem of dispersivity increases, the problem further

magnifies when shale is determined. To overcome this problem generally polymers are

used instead of bentonite for greater depths. (> 600-800 m). Though lot of research work

is done by various Indian companies including RIL, ONGC etc. still a lot of research

work is needed on drilling fluids penetrability and efficiency. Presently our aim by this

research project is to formulate a drilling fluid which is economical and versatile to used

when dispersivity problems are magnified. The dispersing of any drilling fluid is a

function of viscosity, mud weight and pH value which further plays a very important role

in soil-fluid interaction. Through this research project an attempt is made to design most

efficient drilling fluid using bentonite in first phase and polymer in second phase based

on soil-fluid interaction. The aim is to design a drilling fluid based on physical and

rheological behavior of this fluids. The role of soil-fluid interaction helps in estimating

best polymer based drilling fluids which mitigate dispersivity issues.


1.3 BRIEF DESCRIPTION

Bentonite is a locally available soil in Gujarat so it is generally used as a main constituent of

drilling fluid.

Due to its inherent properties like swelling after coming in contact of water it perfectly suits

as a drilling fluid.

Following are the properties of bentonite slurry:

1. Mud Weight

2. Mud Viscosity

3. Rheology

4. Yield point

5. Gel Strength

6. Filtration properties

7. pH value

1.3.1 Polymers to be used

XC POLYMER

PAC-LV POLYMER

PAC-RG POLYMER

PHPA POLYMER


1.3.2 Ingredients to be used

• Hydration agent : Caustic soda

• Weighing agent : Barite ( specific gravity :- 4.26)

• Viscofying agent : Xanthan Gum

• Liquefying agent : Polyanionic cellulose

LVG RG

(Low viscosity grade) (Regular grade)

1.3.3 SCHEME OF WORK

PHASE – I

BASIC TESTS ON BENTONITE AND BENTONITE SLURRY.

PHASE – II

BASIC TESTS ON POLYMER BASED DRILLING FLUIDS.

STUDYING THE INTERACTION OFPOLYMERS BASED DRILLING

FLUIDS ON THE SHALEROCK.


1.4 SCOPE& OBJECTIVE OF WORK

The scope of the research work is to design most economical drilling fluid based

on soil fluid interaction so as to remediate dispersivity problems.

In the first phase our aim is to determine various physical and rheological

properties of raw drilling fluid viz. Specific gravity, Liquid limit, Plastic limit,

Free Swell Index, Mud Weight, Mud Viscosity, Plastic Viscosity, Yield Point,

Gel Strength, Filtration (water loss), pH value using bentonite and water as basic

constituents.

To compare the various physical and rheological properties of raw fluid using

bentonite and water to obtain most efficient proportioning of drilling fluids. Also

to verify the efficiency/applicability of drilling fluid with respect to depth of well.

In second phase the efficiency of drilling fluid will be further announced using

locally available polymers viz. XC POLYMER, PAC-LV,PAC-RG, PHPA.

To determine the various physical and rheological properties of raw drilling fluid

using polymers and to compare their value with bentonite drilling fluid.

To verify the efficiency of polymer based drilling fluid by applying on shale rock

with major dispersivity problems.

To observe the solid-fluid interaction between shale rock and drilling fluids.

OBJECTIVE OF THE WORK

To design bentonite and polymer based drilling fluid using soil fluid interaction and to study

its effect on shale rocks having dispersivity problems.


CHAPTER 2

LITERATURE REVIEW

TITLE OF PAPER:- “Flow properties of water-based drilling fluids”

AUTHOR:-Aleksander Kristenen

NAME OF JOURNAL:-Thesis of master of science(Norwegian University

Of Science & Technology), 2013

• The objective of this master paper was to investigate the flow properties of water

based drilling fluids, utilizing measurements in both the micro and macro scale.

Rheology is defined as the science of deformation and flow of matter. Important

properties of drilling fluid are viscosity (PV, YP, GS), mud weight, filtration. Mud

shearing concept is adopted for fluidity which results in breaking of structure of

water-based drilling fluids.

• Viscosity is the representation of the internal resistance to deformation, a fluid shows

under stress. Thixotropic fluids are showing signs that the viscosity is reduced when

the shear force is constant for some time, i.e. the fluid flows easier with time under

static shear stress. They develop a solid state structure when at rest or with decreasing

shear rate, like a gel.

• The gel structure strength depends on the time at rest and when sheared. The gel will

begin to break as shear is initiated, and will ultimately break completely when

exposed higher and prolonged shear. There are different methods and equipment for

measuring the rheological properties of a fluid. In the drilling business the most

common way is by using a Fann 35 Viscometer.


TITLE OF PAPER :- Polymer systems for fluid supported excavations

AUTHOR: - Stephan Jefferies, Carlos Ram, VirTroughton

NAME OF JOURNAL: -Geotechnical Issues in Construction, 2009

Excavation support fluids are used in a wide variety of civil engineering operation

including piling, ·diaphragm walling, slurry tunneling, horizontal directional drilling,

oil and water well drilling, drilling site investigation boreholes and the formation of

cutoff walls and drainage walls.

In each of these applications the role of the fluid is to keep the hole open until a

permanent element (concrete, lining etc.) is installed. This paper will focus on the use

of polymer excavation fluids for piling though polymers can and have been used in all

the applications cited except for low permeability cut-off walls, which remain an area

of need and opportunity .Polymer is good because it is bio degradable. (Xantham

gum and guar gums).It should be designed to prevent dispersion of fines from the

soil into the fluid.


TITLE OF PAPER:-“Shale Stability: Drilling Fluid Interaction and

Shale strength

AUTHOR :- Manohar Lal

NAME OF JOURNAL: - Special publication on petroleum engineering

by Society of Petroleum Engineers (Amoco-SPE 54356), 1999

• This paper presents main results of a shale stability study, related to the understanding

of shale/ fluid interaction mechanisms, and discusses shale strength correlation. The

major shale/ fluid interaction mechanisms: Capillary, osmosis, hydraulic, swelling and

pressure diffusion. Shale make up over 75% of the drilled formations, and over 70%

of the borehole problems are related to shale instability.

• The problems include hole collapse, tight hole, stuck pipe, poor hole cleaning, hole

enlargement, plastic flow, fracturing, lost circulation, well control. While drilling,

shale becomes unstable when the effective state of the stress near the drilled hole

exceeds the strength of the hole. Shale stability is affected by properties of both shale

(e.g. mineralogy, porosity) and of the drilling fluid contacting it.

• Shale with certain properties (including strength) normally lies buried at depth. It is

subjected to in situ stresses and pore pressure, with equilibrium established between

the stress and strength. When drilled, native shale is exposed suddenly to the altered

stress environment and foreign drilling fluid.

• The main fluid interactions are as follows: Capillary pressure, Osmosis,

Swelling/Hydration pressure, Fluid penetration. The main objective to improve

shale stability is to prevent, minimize, delay or use to our advantage the interaction of

the drilling fluid with shale. For fractured shale stability, use effective sealing agents,

thixotropic drilling fluid (high viscosity for low shear rates), and lower mud weight.

PHPA and strongly adsorbing cationic polymers and components like poly glycerol

can limit the dispersion of shale cuttings or spallings in the well.


TITLE OF PAPER :- Development of water based drilling fluids

customized for shale reservoirs

AUTHOR:-Jay P Deville, Brady fritz, Michael Jarrett

NAME OF JOURNAL: -Special publication on petroleum engineering by

Society of Petroleum Engineers(Amoco-SPE), 2011

• Customized WBMs have been developed for three major North American shale plays:

Haynesville, Fayetteville and Barnett. The WBMs were customized with a rational,

bottom-up approach that allowed for precise matching of the chemistry of the fluid to

the formation being drilled. Excellent laboratory data and field performance for the

fluids customized for these three shale plays have validated the effectiveness of the

fluid design approach. The success of these fluids gives operators an environmentally

advantageous and potentially economically advantageous alternative to NAFs, which

had previously dominated the unconventional shale drilling market.


TITLE OF PAPER :-Experimental Analysis of Shale for Evaluating

. Shale Drilling Fluid Interaction in Agbada Formation

AUTHOR:- Okoro Emeka Emmanueland Adewale Dosunmu

NAME OF JOURNAL:- British Journal of Applied Science

&Technology4(35):2014

Wellbore instability in shale formations has been a significant problem in the

petroleum industry for over a century. It is believed that the main cause of shale

instability stems from unfavourable interactions between the drilling mud and shale

formations. Shale instability is generally caused by pore pressure changes and

mechanical property alterations around the wellbore, induced by both chemical and

hydraulic effects. All of these alterations are caused by water and ion movement into

or out of the shale formations.

The shale dispersion test (rolling test) is a common procedure that is used to measure

the interactions between drilling fluids and shales. The shale rolling test depend on

the moisture content of the shale, the shale composition, the viscosity of the test fluid,

the rotation speed of the rollers, and the test temperature. This test is used to design

fluids and screen the effectiveness of inhibitor additives to maintain the integrity of

the cuttings and minimize the interaction of fluids with the shale sections during the

drilling and completion operations. It gives an indication of how the cuttings might

survive in the drilling fluid as they travel up the annulus and it does provide some

measure of the ability of the drilling fluid to inhibit shale. Shale dispersion is a

process by which shale cuttings disintegrate into smaller sizes.

Percent recovery, a measure of shale recovered after dispersion tests were calculated.

The dispersion is a function of changes in structure of the shale matrix and in the

bound and crystalline water caused by the hydration of the cores.


TITLE OF PAPER :-Characterization of Egyptian Smectitic Clay

Deposits by Methylene Blue Adsorption

AUTHOR:- Salwa D. Abayazeed and Essam El-Hinnawi Department

Of Geological Sciences, National Research Centre, Dokki, Cairo, Egypt

NAME OF JOURNAL:- American Journal of Applied Sciences 8 (12):

1282-1286, 2011 ISSN 1546-9239 © 2011 Science Publications

• The characterization of smectitic clays has been traditionally made using physical and

chemical methods which are time-consuming and require costly equipment.

Adsorption of methylene blue by these clays has been introduced as a quick and

cheap method for the estimation of cation exchange capacity.

• Methylene blue is a large polar organic molecule which is adsorbed onto the

negatively charged surfaces of clay minerals. It has high selectivity for adsorption by

smectite and is also adsorbed by the smectite component of mixed-layer clays, but is

largely unaffected by other clay minerals. Adsorption of methylene blue is a common

method used to estimate the cation exchange capacity. The methylene blue test has

been used routinely by the drilling industry to estimate the percentage of bentonite

mud in the circulation of fluids.


CHAPTER 3

EXPERIMENTAL SETUP

3.1 EXPERIMENTAL PROGRAMME:

PART : I MATERIAL

BENTONITE

Bentonite is a locally available soil in Gujarat so it is generally used as a main constituent of

drilling fluid. Bentonite is an absorbent aluminium phyllosilicate, impure clay consisting

mostly of montmorillonite.

Due to its inherent properties like swelling after coming in contact of water it perfectly suits

as a drilling fluid.

Following are the properties of bentonite

slurry:

1. Mud Weight

2. Mud Viscosity

3. Rheology

4. Yield point

5. Gel Strength

6. Filtration properties

7. pH value

8. CEC value

Bentonite Slurry


POLYMER

Polymers to be used

XC POLYMER

PAC-LV POLYMER

PAC-RG POLYMER

PHPA POLYMER

Ingredients to be used

Hydration agent : Caustic soda

Weighing agent : Barite ( specific gravity :- 4.26)

Viscofying agent : Xanthan Gum

Liquefying agent : Polyanionic cellulose

LVG RG

(Low viscosity grade) (Regular grade)

Polymer Slurry


SHALE

Shale is a fine-grained, sedimentary rock composed of mud that is a mix of flakes of clay

minerals and tiny fragments ( silt-sized particles) of other minerals, especially quartz and

calcite . The ratio of clay to other minerals is variable. Shale is characterized by breaks along

thin laminae or parallel layering or bedding less than one centimetre in thickness, called

fissility. Mudstones, on the other hand, are similar in composition but do not show the Shale

is a fine-grained, sedimentary rock composed of mud that is a mix of flakes of clay minerals

and tiny fragments ( silt-sized particles) of other minerals, especially quartz and calcite . The

ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae

or parallel layering or bedding less than one centimetre in thickness, called fissility.

Mudstones, on the other hand, are similar in composition but do not show the fissility.

SHALE PROBLEMS

Borehole instability

Cuttings instability

Bit balling


PART : II METHODOLOGY

E

X

P

E

R

I

M

E

N

T

A

L

P

R

O

G

R

A

M

M

E


3.2 STANDARD CODES USED:-

1. ISO 9001:2008 QMS

2. OHSAS 18001:2007

3. ISO 14001:2004 EMS

4. IS:2720 (PART 3/ SEC 1)1980 (SPECIFIC GRAVITY OF

BENTONITE)

5. IS:2720 (PART 5) 1985 ( LIQUID LIMIT OF BENTONITE)

6. IS:2720 (PART 5) 1985 (PLASTIC LIMIT OF BENTONITE)

7. IS:2720 (PART 40) 1977 ( FREE SWELL INDEX OF BENTONITE)

8. API (AMERICAN PETROLEUM INSTITUTE) 18th

Edition 2010


CHAPTER 4

EXPERIMENTAL INVESTIGATION

Phase I

Bentonite-Water system

Preparation of sample:

Bentonite clay used during the experiment was collected locally from Ahmedabad region in

powder form. Bentonite sample prepared by us consisted of 8% of bentonite in 100% water

by volume. The mixture prepared is agitated until thorough mixture is formed.

The following physical and rheological properties of bentonite-water system are

determined and their observations are noted.

Table 1


Phase II

Polymer-Water system

Composition of sample:

FOR 1 LITRE OF WATER

45 gram of NAHCO3 (To remove hardness of water)

Caustic soda (pH: 8.5-9)

KCL (5 -7 % by volume or 50-70 gm by weight)

PAC-LVG (0.8% by volume or 8 gm by weight)

PAC-RVG (0.4% by volume or 4 gm by weight)

XC polymer (0.25% – 3% by volume or 2.5 to 3 gm by weight)

PHPA (0.3%-0.4% by volume or 3 to 4 gm by weight)

Preparation of sample:

The constituents of polymer-water system were taken in proportions given

above. They were added one by one and agitated simultaneously until

homogeneous solution was formed.

The following physical and rheological properties of polymer-water system are


Table 2


Phase III

Shale fluid Interaction

The following physical and chemical properties of Shale-XC polymer system are


Table 2


4.1 SPECIFIC GRAVITY OF BENTONITE CLAY

CONCEPT: The specific gravity of the clay is known as the ratio of weight density

of the clay to the weight density of the water.

PURPOSE: The specific gravity of the bentonite clay is determined to know the

quantity of bentonite to form slurry for drilling.

FIG 4.1.1 Determination of Specific gravity

APPARATUS: Density Bottle, Weighing Balance, Bentonite clay, Kerosene, Water

& MATERIALS


4.2 LIQUID LIMIT ON BENTONITE CLAY

CONCEPT: Liquid limit is the water content at which the soil changes from liquid

state to plastic state.

PURPOSE: Bentonite used in drilling mud has to flow like liquid through annular

spacing, but while return flow it forms mud-cakes, which keeps wellbore stable.

These properties depend on liquid limit of bentonite.

Results: The flow index of the bentonite clay is 363.37%.

0

100

200

300

400

500

600

700

1 10 100 1000

liquid limit

liquid limit

Log. (liquid limit)


Fig 4.2.1 Determination of Liquid limit

Fig 4.2.2 Determination of Liquid limit

APPARATUS: Casagrande’s liquid limit device, Grooving tool, Oven, Glass sheet

&MATERIALS Spatula, 425 micron IS sieve, Weighing Balance, Wash bottle, Bentonite

Clay, Water.


4.3 PLASTIC LIMIT ON BENTONITE CLAY

CONCEPT: Plastic limit is the minimum water content at which soil remains in

plastic state. It is the water content at which the soil thread of 3 mm diameter starts

crumbling.

PURPOSE: Plastic limit of the bentonite clay is determined to find the plasticity

index of the bentonite clay.

Fig 4.3.1 Determination of Plastic Limit

APPARATUS : Flat glass plate, Oven, Spatula, Bentonite clay, Water

& MATERIALS


4.4 FREE SWELL INDEX ON BENTONITE CLAY

CONCEPT: Free swell index is the increase in volume of soil, without any external

constraints, on submergence in water.

PURPOSE: The free swell index is determined to know the swelling properties of the

bentonite clay used as a drilling mud.

Fig 4.4.1 Determination of Shrinkage Limit

APPARATUS: Graduated glass cylinder, Oven, Balance, Sieve, Bentonite

& MATERIALS Clay, Water, Kerosene etc


4.5 MUD WEIGHT OF BENTONITE SLURRY

CONCEPT: Mud Weight is the weight per unit volume of the mud. In water base

Mud density can be regarded as a measure of the suspended solids.

PURPOSE: Mud Weight property of drilling fluid is determined to design the drilling

fluid in such a way that the hydrostatic force developed by the mud in the drilled hole

will balance the formation pressure and thus support the surrounding hole.

Fig 4.5.1 Determination of Mud Weight


Fig 4.5.2 Determination of Mud Weight

APPARATUS : Mud balance, Bentonite slurry etc

& MATERIALS


4.6 MUD VISCOSITY OF BENTONITE SLURRY

CONCEPT: The viscosity of drilling mud may be defined as it’s resistance to flow.

PURPOSE: The viscosity of the drilling fluid is determined effectively control the

cleaning at the bit face and rapid settling of cuttings at the surface. Sometimes drilling

fluid having low viscosity is desired at the toe of the bit and sometimes high viscosity

of drilling fluid is necessary to remove coarse sand from hole or to stabilize gravel.

Fig 4.6.1 Determination of Mud Viscosity

APPARATUS& MATERIALS: Marsh Cone funnel, Stop Watch, Measuring tub,

Bentonite Slurry etc.


4.7 PLASTIC VISCOSITY OF BENTONITE SLURRY

CONCEPT: Plastic viscosity is that part of the resistance to flow in mud caused by

the friction between suspended particle and the viscosity of the base liquid.

PURPOSE: Plastic viscosity is determined to control equivalent circulating density,

surge and swab pressure, differential sticking, rate of penetration etc. while drilling.

Fig 4.7.1 Determination of Plastic Viscosity

APPARATUS & MATERIALS: FANN Viscometer, Bentonite Slurry etc


4.8 YIELD POINT OF BENTONITE SLURRY

CONCEPT: Yield point is resistance of initial flow of fluid or stress required in order

to move the fluid. It is an attractive force among colloidal particles in drilling fluid.

PURPOSE: Yield point indicates the ability of the drilling mud to carry the cuttings

to the surface. Also frictional pressure loss is directly related to the yield point. If you

have higher Yield point, you will have high pressure loss while the drilling mud is

being circulated.

Fig 4.8.1 Determination of Yield Point

APPARATUS& MATERIALS: FANN viscometer, Bentonite Slurry


4.9 GEL STRENGTH OF BENTONITE SLURRY

CONCEPT: The gel strength is the shear stress of drilling mud that is measured at

low shear rate after the drilling mud is static for a certain period of time.

PURPOSE: The gel strength of the drilling fluid is determined because it

demonstrates the ability of the drilling mud to suspend drill solid and weighting

material when circulation is ceased.

Fig 4.9.1 Determination of Gel Strength

APPARATUS & MATERIALS: FANN viscometer, Bentonite Slurry


4.10 FILTRATION (WATER LOSS) OF BENTONITE SLURRY

• The filtration property of the drilling fluid is determined to estimate the filtration loss

in to the formation.

• Thus the objective of measuring the filtration properties is to design the fluid in such a

way that the tough filter cake is deposited on the walls of the hole which will prevent

the loss of the drilling fluid.

Fig 4.10.1 Determination of Filtration Loss

APPARATUS & MATERIALS: Filtration Measuring Equipment, Bentonite Slurry


4.11 pH VALUE OF BENTONITE SLURRY

CONCEPT: pH is a value representing the hydrogen ion conc. in liquid. It is used to

indicate acidity or alkalinity of drilling mud. The pH is presented in a numerical value

(0-14) which means an inverse measurement of hydrogen ion concentration in the

fluid.

PURPOSE: pH value is determined to indicate whether the drilling fluid is acidic or

alkaline so that it may not raise any serious consequences like rusting of drilling

assembly.

Fig 4.11.1 Determination of pH

APPARATUS & MATERIALS : pHydrion paper


4.12 CEC VALUE OF BENTONITE SLURRY

CONCEPT: In soil science, cation-exchange capacity or CEC is the number of exchangeable

cations per dry weight that a soil is capable of holding, at a given pH value and available for

exchange with the soil water solution.

PURPOSE: CEC is used as a measure of soil fertility, nutrient retention capacity, and the

capacity to protect groundwater from cation contamination.

Fig 4.12.1 Determination of CEC

APPARATUS & MATERIALS: Measuring flask, funnel ,glass rod, Methylene blue, filter

paper


CHAPTER 5

RESULT, ANALYSIS& DISCUSSION

5.1.1 SPECIFIC GRAVITY OF BENTONITE CLAY

Fig 5.1 Specific gravity G vs. No. of samples

Result: From the experiment performed on the density bottle, the specific gravity of

the bentonite clay is 2.66.

5.1.2 LIQUID LIMIT OF BENTONITE CLAY

Fig 5.2 Liquid Limit (%) v/s No. of samples

Result: From the experiment performed on the casagrande apparatus, the liquid limit

of the bentonite clay is 595%.

0

0.5

1

1.5

2

2.5

3

1 2 3

Spe

cifi

c G

ravi

ty (

G)

No. of samples

Specific Gravity

0%

100%

200%

300%

400%

500%

600%

700%

1 2

Liq

uid

Lim

it(%

)

No. of samples

Liquid Limit


5.1.3 PLASTIC LIMIT OF THE BENTONITE CLAY

Fig 5.3 Plastic Limit (%) v/s No. of samples

Result: The plastic limit of the bentonite clay is 73.33%.

The plasticity index of the bentonite clay is 521.67%.

The toughness index of the bentonite clay is 1.43.

5.1.4 FREE SWELL VOLUME OF THE BENTONITE CLAY

Fig 5.4 Swelling Volume (%) v/s No. of samples

Result: From the experiment performed on free swell apparatus, the free swell

volume of the bentonite clay is 533.2%.

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

1 2

Pla

stic

Lim

it(%

)

No. of samples

Plastic Limit

0%

100%

200%

300%

400%

500%

600%

1 2

Swe

llin

g V

olu

me

(%)

No. of samples

Free Swell Volume


5.1.5 MUD WEIGHT OF THE BENTONITE SLURRY

Fig 5.5 Mud Weight (G) v/s No. of samples

Result: From the experiment performed on mud balance, the mud weight of the

bentonite slurry comes out to be 1.02.

5.1.6 MUD VISCOSITY OF THE BENTONITE SLURRY

1

Fig5.6 Mud Viscosity(s) v/s No. of samples

Result: From the experiment performed on marsh cone funnel, the mud viscosity of

the bentonite slurry obtained is 28.74 s.

0

0.2

0.4

0.6

0.8

1

1.2

1 2 3

Mu

d W

eig

ht(

G)

No. of samples

Mud Weight

0

5

10

15

20

25

30

35

1 2 3

Mu

d V

isco

sity

(s)

No. of samples

Mud Viscosity


5.1.7 PLASTIC VISCOSITY OF THE BENTONITE SLURRY

Fig 5.7 Plastic Viscosity (cp) v/s No. of samples

Result: From the experiment performed on fann viscometer, the plastic viscosity of

the bentonite slurry obtained is 10 centipoises which is as per the codal provinces

given in API 13A 11.1.

5.1.8 YIELD POINT OF THE BENTONITE SLURRY

Fig 5.8 Yield point(lb/100 ft^2) v/s No. of samples

Result: From the experiment performed on fann viscometer, the yield point of the

bentonite slurry obtained is 12 lb/100 ft2 which is as per the codal provinces given in

API 13A 11.1.

0

2

4

6

8

10

12

1 2 3

Pla

stic

Vis

cosi

ty(c

p)

No. of samples

Plastic Viscosity

0

2

4

6

8

10

12

14

16

1 2 3

Yie

ld P

oin

t(lb

/10

0 f

t^2

)

No. of samples

Yield Point


5.1.9 GEL STRENGTH OF THE BENTONITE SLURRY

Fig 5.9 No. of samples v/s Gel Strength

Result: From the experiment performed on fann viscometer, the gel strength of the

bentonite slurry is G0= 4 lb/100ft^2& G10 = 10 lb/100ft^2 which is as per the codal

provinces given in API 13A 11.1.

5.1.10 FILTRATION (WATER LOSS) OF THE BENTONITE

SLURRY

Fig 5.10 Filtration Loss (ml) v/s No of samples

Result: From the experiment performed on filtration apparatus, the filtration (water

loss) of the bentonite slurry is 8 ml. The maximum limit of filtration loss is 16ml as

per API 13 A.

0 2 4 6 8 10 12 14

1

2

3

Gel Strength(lb/100 ft^2)

No

. of

sam

ple

s

Gel Strength

G10

G0

0

2

4

6

8

10

1 2

Filt

rati

on

Lo

ss(m

l)

No. of samples

Filtration Losses


5.1.11 pH VALUE OF THE BENTONITE SLURRY

Fig 5.11 pH (-log (mol/lit)) v/s No. of samples

Result:-From the test of pHydrion paper the pH value obtained for raw bentonite

slurry is 9.

5.1.12 CEC VALUE OF BENTONITE SLURRY

Fig 5.11 CEC VALUE (meq/100g) v/s No. of observation

Result:-CEC value of bentonite is 39 meq/100g.

0

2

4

6

8

10

1 2 3

pH

(-Lo

g(m

ol/

lit)

No of samples

pH

0

10

20

30

40

50

60

1 2 3

Ce

c va

lue

(me

q/1

00

g)

No of observations

Cec value of Bentonite


Analysis & Discussion:-

The specific gravity, liquid limit, plastic limit and free swell volume of the bentonite

clay are 2.66, 595%, 73.33% and 533.2% respectively. From the above geotechnical

properties we conclude that bentonite has high swelling characteristics so it can be

used as a drilling fluid.

The mud weight, mud viscosity of the bentonite slurry are 1.02, 28.74s. From the

above physical properties, we conclude that bentonite slurry can be used as a drilling

fluid as per API 13A 11.1.1.

Plastic Viscosity, Yield Point, Gel Strength and Filtration of the bentonite slurry are

10 centipoise, 12 lb/100 ft2, 4 lb/100ft

2(G0) & 10 lb/100ft

2(G10) and 8 ml. From these

hydraulic properties, we conclude that given drilling mud has ability to lift the

borehole cuttings.

The pH value of the bentonite slurry is 9 which indicates that bentonite slurry can be

used as drilling fluid due to its high alkalinity.


5.2.1MUD WEIGHT OF THE POLYMER SLURRY

Fig 5.12 Mud Weight (G) v/s No. of samples

Result: From the experiment performed on mud balance, the mud weight of the

polymer slurry comes out to be 1.33.

5.2.2MUD VISCOSITY OF THE POLYMER SLURRY

Fig5.13Mud Viscosity(s) v/s No. of samples

Result: From the experiment performed on marsh cone funnel, the mud viscosity of

the polymer slurry obtained is 55 s.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1 2 3

Mu

d W

eig

ht(

G)

No of observations

Mud weight

0

10

20

30

40

50

60

1 2 3

Mu

d V

isco

sity

(s)

No of observations

Mud Viscosity


5.2.3PLASTIC VISCOSITY OF THE POLYMER SLURRY

Fig 5.14 Plastic Viscosity (cp) v/s No. of samples (with and without KCL)

Result: From the experiment performed on fann viscometer, the plastic viscosity of

the polymer slurry obtained are 20 and 12 centipoise respectively.

0

5

10

15

20

25

1 2 3

PV

(cP

)

No of observations

PV (without KCl)

0

2

4

6

8

10

12

14

16

1 2 3

PV

(cP

)

No of observations

PV (with KCl)


5.2.4YIELD POINT OF THE POLYMER SLURRY

Fig 5.15 Yield point(lb/100 ft^2) v/s No. of samples

Result:The experiment performed on fann viscometer, the yield point of the polymer

slurry obtained are 38 and 16 lb/100 ft2.

0

10

20

30

40

50

60

1 2 3

YP

(lb

/10

0ft

^2)

No of observations

YP(without KCl)

0

5

10

15

20

1 2 3

YP

(lb

/10

0ft

^2)

No of observations

YP (with KCl)


5.2.5GEL STRENGTH OF THE POLYMER SLURRY

Fig 5.16No.of samples v/s Gel Strength

Result: From the experiment performed on fann viscometer, the gel strength of the

polymer slurry is G0= 10 lb/100ft^2& G10 = 14 lb/100ft^2.

5.2.6FILTRATION (WATER LOSS) OF THE POLYMER SLURRY

Fig 5.17 Filtration Loss (ml) v/s No of samples

Result: From the experiment performed on filtration apparatus, the filtration (water

loss) of the polymer slurry is 6 ml.

0 5 10 15 20

1

2

3

1 2 3

G-10 12 14 16

G-0 8 10 12

Gel Strength

0

1

2

3

4

5

6

7

1 2

Filt

rati

on

Lo

ss (

ml)

No of observations

Filtration Loss


5.2.7 pH VALUE OF THE POLYMER SLURRY

Fig 5.18pH (-log(mol/lit)) v/s No. of samples

Result:From the test of pHydrion paper the pH value obtained for raw polymer slurry

is 9.

Analysis & discussion:-

The mud weight, mud viscosity, of the polymer slurry are 1.33, 55s. These physical

properties indicate that polymer water slurry can replace bentonite water system.

The plastic viscosity, yield strength of the polymer slurry with KCl and w/o KCl are

20 and 12 centipoise, 38 and 16 lb/100ft2 respectively. These hydraulic properties

indicate that polymer water slurry can replace bentonite water system.

Gel Strength of the polymer slurry is 10 and 14 lb/100ft2 for G0 and G10, which

indicates the ability of drilling mud to suspend the drill solids.

Filtration of the polymer slurry is 6ml getting from filtration apparatus, which

indicates less filtration loss. Thus the drilling fluid will be able to form tough mud

cakes on the walls of bore hole, hence providing the required formation stability.

The pH value of the polymer slurry is 9 which indicates that polymer slurry can be

used as drilling fluid due to its high alkalinity.

0

2

4

6

8

10

1 2 3

pH

No of observations

pH


5.3.1 CEC value of Shale

Fig 5.19 CEC VALUE(meq/100g) v/s No. of observation

Result:-CEC value of shale is 20 meq/100g.

Analysis & Discussion:- The given CEC value of shale indicates that it is of

moderately reactive type.

0

5

10

15

20

25

1 2 3

Ce

c va

lue

(m

eq

/10

0g)

No of observations

CEC Value of shale


5.3.2 SHALE DISPERSION TEST

Polymer slurry with full

dispersion of shale after 24 hrs of

shale dispersion test

Polymer slurry including shale

particles w/o KCL and PHPA At

the beginning of shale dispersion

test

Polymer slurry including shale

particles with KCL and PHPA At the

beginning of shale dispersion test

Polymer slurry with undispersed

shale after 24 hrs of shale

dispersion test


Fig 5.20 Percentage Recovery% v/s No of observations

Result: The percentage recovery of shale in case of polymer slurry w/o KCL is 25% and in

case of polymer slurry with KCL and PHPA is 85%.

5.3.3 SOIL FLUID INTERACTION

We tested the reactive shale with 2 samples according to the procedure of shale dispersion

test. The first sample was formed using 3 polymers Pac LV, Pac RG &XC polymer in their

respective proportions & the second sample was prepared with the polymers as above but

including KCl & PHPA.

From the above results it can be clearly stated that the percentage recovery of the shale with

the polymer including the KCl & PHPA is quite high.

This is due to encapsulation of PHPA and KCL (fluid) over the shale (soil) which decreases

the dispersivity of shale and results in more borehole stability.

0

10

20

30

40

50

60

70

80

90

100

1 2

Pe

rce

nta

ge R

eco

very

(%)

No of observations

Shale dispersion test

Without KCl With KCl and PHPA


COMPARATIVE PLOTS OF BENTONITE MUD

PROPERTIES

Fig 5.21

0

25

50

75

100

125

150

175

200

225

250

275

300

325

350

375

400

425

450

475

500

525

550

575

600

625

650

675

700

Bentonite Mud Properties


COMPARATIVE PLOTS OF POLYMER MUD PROPERTIES

Fig 5.21

0

5

10

15

20

25

30

35

40

45

50

55

60

Polymer Mud Properties


Analysis & Discussion:-

From the above comparative plot of graphs following results are drawn:-

As the depth of drilling increases the probability of borehole instability increases

which leads to collapse of the hole so it becomes inevitable to increase the mud

weight of slurry to withstand the formation pressure. The percentage increase in the

value of mud weight for polymer based mud is 30.39%.

The mud viscosity is determined to get the idea of the lifting (the cuttings) capacity of

drilling fluid. The percentage increase in the value of mud viscosity for polymer mud

is 91.36%.

Plastic viscosity is determined to control equivalent circulating density, surge and

swab pressure, differential sticking, rate of penetration etc. while drilling. The

percentage increase in the value of plastic viscosity for polymer mud with KCL and

w/o KCl is 20% and 100% respectively.

Yield point indicates the ability of the drilling mud to carry the cuttings to the surface.

Also frictional pressure loss is directly related to the yield point. If you have higher

Yield point, you will have high pressure loss while the drilling mud is being

circulated.The percentage increase in the value of yield point for polymer mud with

KCL and w/o KCl is 216%and 33% respectively.

The gel strength of the drilling fluid is determined because it demonstrates the ability

of the drilling mud to suspend drill solid and weighting material when circulation is

ceased. The percentage increase in the value G0 is 150% and in the value of G10 is

40%.

Thus the objective of measuring the filtration properties is to design the fluid in such a

way that the tough filter cake is deposited on the walls of the hole which will prevent

the loss of the drilling fluid. The decrease in filtration loss is 25%.

From the above results we conclude that polymer drilling fluid is better than bentonite

drilling system for depth greater than 600 m.


CHAPTER 7

CONCLUSION

From the above results and analysis following conclusions are drawn for

Bentonite-water system (PHASE I):-

Geo technical properties

The specific gravity of the bentonite clay is 2.66.

The liquid limit of the bentonite clay is 595%.

The plastic limit of the bentonite clay is 73.33%.

The free swell volume of the bentonite clay is 533.2%

Physical properties

The mud weight of the bentonite slurry is 1.02.

The mud viscosity of the bentonite slurry is 28.74 s.

The plastic viscosity of the bentonite slurry is 10 centipoises.

The yield point of the bentonite slurry is 12 lb/100 ft2.

The gel strength of the bentonite slurry is g0= 4 & g10 = 10.

The filtration (water loss) of the bentonite slurry is 8 ml.

Chemical properties

The pH value of the bentonite slurry is 9.

The CEC value of bentonite slurry is 39 meq/100 gm.


Polymer-Water system (Phase II):-

Physical properties

The mud weight of the polymer slurry is 1.33.

The mud viscosity of the polymer slurry is 55 s.

The plastic viscosity of the polymer slurry obtained are 20 and 12 centipoise with

KCL and w/o KCL respectively.

The yield point of the polymer slurry obtained are 38 and 16 lb/100 ft2with KCL and

w/o KCL respectively.

The gel strength of the polymer slurry is G0= 10 lb/100ft^2& G10 = 14 lb/100ft^2.

Chemical properties

The filtration (water loss) of the polymer slurry is 6 ml.

The pH value of the polymer slurry is 9.

Shale (Phase III):-

Chemical properties

CEC value of shale is 20 meq/100g.

The percentage recovery of shale in case of polymer slurry w/o KCL is 25% and in

case of polymer slurry with KCL and PHPA is 85%.


The result indicates the deficiency of bentonite to act as a efficient drilling fluid when used in

oil wells, for depths greater than 600-800m. The present values obtained are valid only for

bentonite water system where dispersion of the fluid into the formation is not a major issue.

The dispersion criteria of drilling fluid given as per petroleum standards (API 13A 11.1.1)

suggest that present designed bentonite drilling fluid is suitable up to a depth of 600m only. It

is further observed that when shale formations are encountered bentonite as a drilling fluid

shows very less dispersion and therefore it is to be replaced by Polymer system, whose

laboratory investigation work will be carried out in phase II.

From the result of shale dispersion test it can be clearly stated that the percentage recovery of

the shale with the polymer including the KCl & PHPA is quite high as nearly as 240%

compared to bentonite drilling fluids. This is due to encapsulation of PHPA and KCL (fluid)

over the shale(soil) which decreases the dispersivity of shale and results in more borehole

stability.

Polymer drilling fluid provide inhibition against reactive formations by providing viscosity,

without the need for bentonite, when using inhibitors as KCL, PHPA. Bentonite will not

yield in the presence of the inhibition agents. Thus from the above research study it reveals

that if proper selection of polymer is done on the basis of soil polymer interaction & polymer

chemistry, a reproductive/efficient drliing fluid can be designed to substitute bentonite

drilling fluids and other costly imported polymer drilling fluids particularily where shale

dispersibility problems are very high at greater depths.


REFERENCES

The following literature has been studied to support the study:

Soil Mechanics & Foundation Engineering -K R ARORA

AMOCO drilling manual-ONGC

ISO 14001:2004 EMS

IS:2720 (PART 3/ SEC 1)1980 ( SPECIFIC GRAVITY OF BENTONITE)

IS:2720 (PART 5) 1985 ( LIQUID LIMIT OF BENTONITE)

IS:2720 (PART 5) 1985 (PLASTIC LIMIT OF BENTONITE)

IS:2720 (PART 40) 1977 ( FREE SWELL INDEX OF BENTONITE)

API (AMERICAN PETROLEUM INSTITUTE) 18th

Edition 2010

AADE 41

AADE-04-DF-HO-30

AADE-11-NTCE-39

Few research papers have also been studied to know the properties of water based

drilling fluids, shale stability, shale interaction etc

GOOGLE for few images.


NOTES

8th UDP FINAL Approved

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