Development of a Computer Program for Solids Control.
ABSTRACT
Computer software is used extensively to increase productivity and reduce man‟s hours of labour.
This work presents the development of a solids control software (SOLCON) which is designed for real time mud system management and quick performance of routine rig computations:
determination of total solids and low gravity solids content;
mud property and density control requiring optimal ejection rate into the mixing pit; volume of mud and amount of barite,
bentonite and additives to be added during the upgrading process of the mud.
This software has the ability to evaluate the need for dilution depending on the maximum allowable drilled solids, viscosity and recommended total solids in the drilling fluid.
Finally, this software provides the atmosphere to control drilled solids as quickly as possible with all the necessary parameters.
TABLE OF CONTENTS
DECLEARATION I
ABSTRACT II
DEDICATION III
ACKNOWLEDGEMENT IV
TABLE OF CONTENTS V
LIST OF FIGURES VI
LIST OF TABLES VII
CHAPTER ONE
1.0 Formulation Of The Problem 1
1.1Introduction 1
1.2 Literature Review 2
1.3 Research Methodology 6
1.4 Objectives 6
1.5 Organization of Thesis 7
CHAPTER TWO
2.0Review of Drilling Fluid Technology 8
2.1water Based Fluids 9
2.1.1 Fresh Water Mud 9
2.1.2 Inhibited Water-Based Fluid 10
2.1.3 Dispersed Mud 11
2.1.4 Non-Dispersed Mud 11
2.1.5 Flocculated Mud 12
2.1.6 Brines 12
2.1.7 Criteria For Selecting Water-Based Muds 12
2.2 Oil Based Fluids 13
2.2.1 Criteria for Selecting Oil-Based Muds 14
2.3 Aerated Fluids 14
2.3.1 Criteria for Selecting Aerated Fluids 15
2.4 Unweighted Muds 15
2.5 Weighted Muds 20
2.6 Importance of Solids Control 23
2.6.1 Stuck Pipe 23
2.6.2 Transport of Cuttings 24
2.6.3 Lost Circulation 24
2.6.4 Torque and Drag 24
2.6.5 Low Drilling Rate 25
CHAPTER THREE
3.0 Solids Control of Drilling Fluids 26
3.1 Drilling Fluid Testing 26
3.1.1 The Mud Balance 26
3.1.2 The Marsh Funnel 27
3.1.3 The API Filter Press 28
3.1.4 Sand Content Test 29
3.1.5 The Mud Retort 30
3.1.6 Cation Exchange 31
3.1.7 pH Determination 31
3.1.8 Water Hardness 32
3.1.9 Alkalinity 33
3.1.10 Chloride Concentration 34
3.1.11 Chemical Analysis 34
3.1.12 Gel Strength 34
3.1.13 Resistivity 35
3.2. Treatment of Drilling Fluid 35
3.2.1 Removal of Solids 36
3.2.2 Addition of Solids 36
3.2.3 Chemical Treatment of Solids 36
3.2.4 Dilution of Mud 37
3.3 Solids Removal Equipment 37
3.3.1 Shale Shakers 38
3.3.2 Degasser 40
3.3.3 Hydrocyclones 41
3.3.3.1 Desanders 42
3.3.3.2 Desilters 42
3.3.3.3 Mud Cleaners 43
3.3.4 Centrifuge 43
CHAPTER FOUR
4.0 Development of a for Solids Control 45
4.1 Solids Control 45
4.2 Program Development 45
4.2.1 Solids Control for Unweighted Mud 46
4.2.1.1 Hydrocyclone Analysis 47
4.2.1.2 Ejection Calculation 47
4.2.1.3 Dilution Based on Volume of Solids Drilled 48
4.2.2 Solids Control for Weighted Muds 51
4.2.2.1 Flowrates Involving the Centrifuge 51
4.2.2.2 Mass Rate of Clay and Additives 52
4.2.2.3 Flowrates into the Mixing Pit 52
4.2.2.4 Solids Content Determination 53
4.2.2.5 Quality of Low Gravity Solids in Drilling Fluid 54
4.2.3 Basis for Dilution 57
4.2.3.1 Dilution Based on Fraction of Drilled Solids and Recommended Solids 57
4.2.3.2 Chemical Upgrading 59
4.2.3.3 Dilution Based on Viscosity 61
4.2.4 Density Control 62
4.2.4.1 Addition of Barite 62
4.2.4.2 Addition of Barite with Water 62
4.2.4.3 Efficiency Calculation 63
4.3 Results and Discussion 64
4.3.1 Sensitivity Analysis
4.3.2 Analysis of Entrained Drilled Solids after Routine Solids Control 69
4.3.3 Economic 72
CHAPTER FIVE
5.0 Summary, Conclusion and Recommendation 73
5.1 Summary 74
5.2 Conclusion 74
5.3 Recommendation 75
NOMENCLATURE 76
REFERENCES 80
INTRODUCTION
Drilling fluid was introduced into the rotary drilling technology as means of transporting the drilled solids to the surface. Other function of the drilling fluids are controlling subsurface pressure, lubricating the drill string, cleaning the bottom of the hole, aiding in formation evaluation protecting formation productivity and aiding formation stability (Moore, 1986).
One major function of the rig circulation system is the removal of drilled solids from the drilling mud before recirculation because of the adverse effects the drilled solids have on the drilling rate. One way of reducing drilling cost is the maximization of drilled solids removal from the drilling fluid (Field, 1972).
For sometimes now the industry has battled with various unsatisfactory solutions to the problem of solids control. These included the following:
A piecemeal, temporary and very expensive way to reduce solids content is by discarding part of the system and rebuilding volume with added solids, water and chemical
The use of „inhibitors‟ such as lime and polymers to reduce the contribution of drilled solids to mud. Generally, these materials only delays the time when a mud must be.
A benefit more apparent than real way is the use „thinners‟. Thinners can reduce the gel strength and the yield point of the mud (Nelson, 1970).
There are direct and indirect costs associated with drilled solids. The direct cost involves dilution and discarding of the excess volume of mud. The indirect cost is connected to the increase mud weight resulting from the presence of drilled solids in the drilling fluid.
This may results in pressure differential between the drilling fluid and the formation fluid and hence reduction in rate of penetration.
A reduction in hole cleaning ability as result of an increase in plastic viscosity may also lead to reduction in rate of penetration and generation of finer cuttings (Wells, 1976). Low rate of penetration increases rig time and in tend increase the cost of drilling.
In order to maintain a low specific gravity of solids in the drilling fluid, about one- quarter of the volume of the drilling fluid containing the drilled solids is removed.
REFERENCES
Becker T.E., Azar J.J., “mud-Weight and Hole-Geometry Effects on Cuttings Transport While Drilling Directionally”, SPE journal, 1985
Billy Pete Huddleston, William. Strange, “The Future of Aerated Fluid in the Drilling Industry”, presented at AIME Regional meeting in Austin Texas, February 1957
Bourgoyne et al. “Drilling Fluids”, Applied Drilling Engineering Copyrite by Society of Petroleum Engineers, 1986, pp 57-77
Conyers J.C.,”A Practical Approach To Solids Control Through Economic Evaluation Of Mechanical Equipment”, presented at Offshore South East Asia Conference, SPE session, February 1980
Dahi B., Saasen A., Omland T.H., “Successful Drilling Of Oil And Gas Wells By Optimal Drilling-Fluid/Solids Control-A Practical And Theoretical Evaluation”, presented at IADC/SPE Asia Pacific Drilling Technology Conference, Bangkok, Thailand, November 2008
Dearing H.L.,”Material Balance Concepts Aid in Solids Control and Mud System Evaluation”, presented at IADC/SPE Drilling Conference held in Houston, Texas, February 1990
Dicorp, Diversity Technologies Corporation 2002, www.di-corp.com/
Field L.J., Anderson, D. B.: “An Analytical Approach to Removing Mud Solids”, JPT, June 1972
Global Trade http//www.alibaba.com
Horage W. Hindry, “Characteristics and Application of an Oil-base Mud”, presented at Los Angeles Meeting, October 1940
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