Carter / Lyons / Lapeyrouse Formulas and Calculations for Drilling, Production, and Workover

All the Formulas You Need to Solve Drilling and Production Problems
3. Auflage 2011
ISBN: 978-1-85617-930-0
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 304 Seiten

Formulas and Calculations for Drilling, Production, and Workover: All the Formulas You Need to Solve Drilling and Production Problems, Third Edition, provides a convenient source of reference for oil field workers who do not use formulas and calculations on a regular basis. This book is still intended for the entirety of their careers. It also aims to help reduce the volume of materials they must carry to the rig floor or job site. Starting with review of basic equations and basic calculations, the remaining chapters offer in-depth discussions of topics such as drilling fluids, pressure control, engineering calculations, and air and gas calculations. The formulas and calculations are provided in either English field units or in metric units. This edition includes the Volumetric Procedure, the Lubricate and Bleed Procedure (both Volume and Pressure Methods), and stripping procedures (both the Strip and Bleed Procedure and the Combined Stripping and Volumetric Procedure). The Table of Contents and the Index make looking up formulas and calculations quick and easy. Examples are used throughout to make the formulas as easy as possible to understand and work, and often exact words are used rather than symbols. - Back-of-the envelope calculations that save time and money - Easily evaluate the performance of your well - Confidently design or redesign operations that will improve production - Handle special production projects with ease

Mr. Carter has over fifty five years' experience in domestic and international engineering and management positions in the area of drilling, completion and E&P waste management with Conoco, Baroid, and several other drilling contractors. He has conducted seminars and schools on fluids, rig equipment, and drilling engineering related subjects associated with drilling optimization, cost reduction, and well control. Tom has served as Chairman of the API standardization committee (SC 13) on Drilling and Completion Fluid Materials. He was a SPE Distinguished Lecturer in 1993 and served as the Editor of the SPE reprint series book on drilling fluids. Currently, he is a member of the Chevron Clear Leader Center serving as a Technical Learning Advisor in Houston. He coordinates and has teaching participation in several subject areas such as Coiled Tubing Operations, Directional Drilling, Drilling Fluids, Drilling Practices, Fundamentals for Drilling and Completion, HPHT Drilling and Completions, and Solids Control and Waste Management. He is still active in several industry organizations and was President of the Houston chapter of the American Association of Drilling Engineers, Coordinator for the SPE North American Forum Series, Membership Chairman of the editorial committee for the Journal of Petroleum Technology and on the Board of Directors for the Ocean Energy Center Society (Ocean Star rig museum in Galveston). He has published 20 technical publications and holds five U.S. patents. He graduated with a BS in Geology from Centenary College in Shreveport, Louisiana in 1963.

Zielgruppe

Academic/professional/technical: Research and professional

Autoren/Hrsg.

Carter, Thomas

Lyons, William C.

Lapeyrouse, Norton J.

Inhaltsverzeichnis

1;Front Cover;1
2;Formulas and Calculations for Drilling, Production, and Workover: All the Formulas You Need to Solve Drilling and Production Problems;4
3;Copyright;5
4;Contents;6
5;Preface;10
6;Chapter 1: Basic Equations;12
6.1;1.0. Terminology;12
6.2;1.1. Mud Weight MW (lb/ft3), Mud Weight MW (ppg), and Specific Gravity (SG) [USCS/British];12
6.3;1.2. Density . (kg/m3 or kg/liter), Mud Weight MW (N/m3 or N/liter), and Specific Gravity (SG) [SI-Metric];13
6.4;1.3. Hydrostatic Pressure (P) and (p) [USCS/British];15
6.5;1.4. Hydrostatic Pressure (P) and (p) [SI-Metric];16
6.6;1.5. Pressure Gradient (psi/ft), G (ppg) [USCS/British];18
6.7;1.6. Pressure Gradient G (SG) [SI-Metric];19
6.8;1.7. Equivalent Circulating "Density" ECD (ppg) [USCS/British];20
6.9;1.8. Equivalent Circulating "Density" ECD (N/liter) and ECD (SG) [SI-Metric];20
6.10;1.9. Mud Pump Output Q (bbl/stk) and q (gpm) [USCS/British];21
6.10.1;1.9.1. Triplex Pump;21
6.10.2;1.9.2. Duplex Pump;22
6.10.3;1.9.3. Hydraulic Horsepower;23
6.11;1.10. Capacity Formulas;24
6.11.1;1.10.1. Annular Capacity between Casing or Hole and Drill Pipe, Tubing, or Casing;24
6.11.2;1.10.2. Annular Capacity between Casing and Multiple Strings of Tubing;26
6.11.3;1.10.3. Capacity of Tubulars and Open Hole: Drill Pipe, Drill Collars, Tubing, Casing, Hole, and Any Cylindrical Object;29
6.11.4;1.10.4. Amount of Cuttings Drilled per Foot of Hole Drilled;30
6.12;1.11. Annular Velocity Van (ft/min);32
6.12.1;Metric Calculations;33
6.12.2;SI Unit Calculations;33
6.13;1.12. Strokes per Minute (SPM) Required for a Given Annular Velocity;34
6.14;1.13. Control Drilling;35
6.15;1.14. Buoyancy Factor (BF);35
6.16;1.15. Decrease When Pulling Pipe Out of the Hole;36
6.16.1;1.15.1. When Pulling DRY Pipe;36
6.16.2;1.15.2. When Pulling WET Pipe;37
6.17;1.16. Loss of Overbalance Due to Falling Mud Level;38
6.17.1;1.16.1. Feet of Pipe Pulled DRY to Lost Overbalance;38
6.17.2;1.16.2. Feet of Pipe Pulled WET to Lose Overbalance;38
6.17.2.1;Metric Calculations;39
6.17.2.2;SI Unit Calculations;40
6.17.2.3;Formation Temperature (Tf);40
6.18;1.17. Circulating Hydraulic Horsepower (HHP);40
6.18.1;1.17.1. Rule of Thumb Formulas;42
6.19;1.18. Pump Pressure/Pump Stroke Relationship (the Roughneck's Formula);42
6.19.1;Metric Calculation;44
6.19.2;SI Unit Calculation;44
6.20;1.19. Cost per Foot;44
6.21;1.20. Temperature Conversion Formulas;44
6.21.1;Convert Temperature, Fahrenheit (F) to Centigrade or Celsius (C);44
6.21.2;Convert Temperature, Centigrade or Celsius (C) to Fahrenheit;45
6.21.3;Convert Temperature, Centigrade, Celsius (C) to Kelvin (K);45
6.21.4;Convert Temperature, Fahrenheit (F) to Rankine (R);45
6.21.5;Rule of Thumb Formulas for Temperature Conversion;45
7;Chapter 2: Basic Calculations;48
7.1;2.0. Capacity, Volumes, and Strokes;53
7.1.1;2.0.1. Capacity of Drill Pipe, HWDP, Casing, or Open Hole in bbl/ft;53
7.1.2;2.0.2. Capacity of Casing or Open Hole between Drill Pipe, HWDP, or Casing in bbl/ft;53
7.1.3;2.0.3. Capacity of Drill Pipe, HWDP, Casing, or Open Hole in ft/bbl;53
7.1.4;2.0.4. Capacity of Casing or Open Hole between Drill Pipe, HWDP, or Casing in ft/bbl;54
7.1.5;2.0.5. Volume of Drill Pipe, HWDP, Drill Collar, or Casing in bbl;54
7.1.6;2.0.6. Volume between Drill Pipe, HWDP, or Casing, and the Casing or Open Hole in bbl;54
7.1.7;2.0.7. Strokes to Displace the Drill String, Annulus, and Total Circulation from the Rotary Table to the Flowline;57
7.2;2.1. Slug Calculations;60
7.2.1;2.1.1. Barrels of Slug Required for a Desired Length of Dry Pipe;60
7.2.2;2.1.2. Weight of Slug Required for a Desired Length of Dry Pipe with a Set Volume of Slug;61
7.2.3;2.1.3. Volume, Height, and Pressure Gained Because of Placement of Slug in Drill Pipe;62
7.2.4;2.1.4. English Units Calculation;64
7.2.5;2.1.5. SI Calculation;65
7.3;2.2. Accumulator Capacity;65
7.3.1;2.2.1. Useable Volume per Bottle;65
7.3.2;2.2.2. Surface Application;65
7.3.3;2.2.3. English Units;66
7.3.4;2.2.4. Deepwater Applications;67
7.3.5;2.2.5. Accumulator Precharge Pressure;68
7.4;2.3. Bulk Density of Cuttings (Using Mud Balance);68
7.5;2.4. Drill String Design (Limitations);69
7.5.1;2.4.1. Calculate the Length of BHA Necessary for a Desired Weight on the Bit;69
7.5.2;2.4.2. Calculate the Feet of Drill Pipe That Can Be Used with a Specific Bottomhole Assembly (BHA);70
7.6;2.5. Ton-Mile (TM) Calculations;72
7.6.1;2.5.1. Round Trip Ton-Miles (RTTM);72
7.6.2;2.5.2. Drilling or "Connection" Ton-Miles;73
7.6.3;2.5.3. Ton-Miles during Coring Operations;74
7.6.4;2.5.4. Ton-Miles Setting Casing;75
7.6.5;2.5.5. Ton-Miles While Making Short Trips;75
7.6.6;2.5.6. Cutoff Practices for Rotary Drilling Line;75
7.6.7;2.5.7. Calculate the Length of Drill Line Cutoff;76
7.7;2.6. Cementing Calculations;77
7.7.1;2.6.1. Cement Additive Calculations;77
7.7.2;2.6.2. Water Requirements;79
7.7.3;2.6.3. Field Cement Additive Calculations;80
7.7.4;2.6.4. Weighted Cement Calculations;83
7.7.5;2.6.5. Calculations for the Number of Sacks of Cement Required;84
7.7.6;2.6.6. Calculations for the Number of Feet to Be Cemented;87
7.7.7;2.6.7. Setting a Balanced Cement Plug;90
7.7.8;2.6.8. Differential Hydrostatic Pressure between Cement in the Annulus and Mud inside the Casing;95
7.7.9;2.6.9. Hydraulicing Casing;97
7.8;2.7. Depth of a Washout;100
7.9;2.8. Lost Returns-Loss of Overbalance;102
7.10;2.9. Stuck Pipe Calculations;103
7.10.1;2.9.1. Determine the Length of Free Pipe in Feet and the Free Point Constant;103
7.11;2.10. Calculations Required for Placing Spotting Pills in an Open Hole Annulus;107
7.11.1;2.10.1. Calculate the Amount of Spotting Fluid Pill in Barrels Required to Cover the Stuck Point of the Drill String or Casin;107
7.11.2;2.10.2. Determine the Length of an Unweighted Spotting Fluid Pill That Will Balance Formation Pressure in the Annulus in Feet;111
7.12;2.11. Pressure Required to Break Circulation;112
7.12.1;2.11.1. Pressure Required to Break the Mud's Gel Strength inside the Drill String in psi;112
7.12.2;2.11.2. Calculate the Effective Gel Strength Based on the Actual Pressure Required to Break the Circulation;114
7.13;References;114
8;Chapter 3: Drilling Fluids;116
8.1;3.0. Mud Density Increase and Volume Change;118
8.1.1;3.0.1. Increase Mud Density with No Base Liquid Added and No Volume Limit;118
8.1.2;3.0.2. Increase Mud Weight with No Base Liquid Added but Limit Final Volume;120
8.1.3;3.0.3. Increase the Mud Density with Base Liquid Added and No Volume Limit;121
8.1.4;3.0.4. Increase Mud Weight with Base Liquid Added but Limit Final Volume;123
8.1.5;3.0.5. Increase Mud Weight with Base Liquid Added but Limit Final Volume and Limited Weight Material Inventory;124
8.1.6;3.0.6. Increase Mud Weight to a Maximum Mud Weight with Base Liquid Added but with Limited Weight Material Inventory;126
8.1.7;3.0.7. SI Unit Calculation;127
8.2;3.1. Mud Weight Reduction with Base Liquid Dilution;127
8.2.1;3.1.1. Mud Weight Reduction with Base Liquid;127
8.3;3.2. Mixing Fluids of Different Densities;129
8.3.1;3.2.1. The Material Balance Formula;129
8.4;3.3. Oil-Based Mud Calculations;130
8.4.1;3.3.1. Calculate the Starting Volume of Liquid (Base Oil plus Water) Required to Prepare a Desired Final Volume of Mud;130
8.4.2;3.3.2. Oil/Water Ratio from Retort Data;131
8.4.3;3.3.3. Change the OWR;132
8.5;3.4. Solids Analysis;134
8.6;3.5. Solids Fractions (Barite-Treated Muds);139
8.6.1;3.5.1. Calculate the Maximum Recommended Solids Fraction in Percent (%) Based on the Mud Weight;139
8.6.2;3.5.2. Calculate the Maximum Recommended Low Gravity Solids (LGS) Fraction in Percent (%) Based on the Mud Weight;139
8.7;3.6. Dilution of Mud System;140
8.7.1;3.6.1. Calculate the Volume of Dilution in bbls Required to Reduce the Solids Content in the Mud System;140
8.7.2;3.6.2. Displacement-Barrels of Water/Slurry Required;141
8.8;3.7. Evaluation of Hydrocyclones;142
8.8.1;3.7.1. Calculate the Mass of Solids (for an Unweighted Mud) and the Volume of Water Discarded by One Cone of a Hydrocyclone (;142
8.8.2;3.7.2. Calculate the Mass Rate of Solids in gal/hr;142
8.8.3;3.7.3. Calculate the Volume of Liquid Ejected by One Cone of a Hydrocyclone in gal/hr;142
8.9;3.8. Evaluation of Centrifuge;143
8.9.1;3.8.1. Evaluate the Centrifuge Underflow;143
8.10;References;147
9;Chapter 4: Pressure Control...;148
9.1;4.0. Normal Kill Sheet;148
9.1.1;Prerecorded Data;148
9.1.2;Drill String Volume;148
9.1.3;Annular Volume;148
9.1.4;Pump Data;149
9.1.5;Kick Data;149
9.2;4.1. Calculations;149
9.2.1;Kill Weight Mud (KWM);149
9.2.2;Initial Circulating Pressure (ICP);149
9.2.3;Final Circulating Pressure (FCP);150
9.2.4;Psi/Stroke;150
9.2.5;Drill String Volume;151
9.2.6;Annular Volume;151
9.2.7;Strokes to Bit;151
9.2.8;Bit-to-Casing Strokes;152
9.2.9;Bit-to-Surface Strokes;152
9.2.10;Kill Weight Mud (KWM);152
9.2.11;Initial Circulating Pressure (ICP);152
9.2.12;Final Circulating Pressure (FCP);152
9.2.13;Pressure Chart;152
9.2.14;Pressure;153
9.2.15;Trip Margin (TM);153
9.2.16;Determine psi/stk;153
9.3;4.2. Kill Sheet with a Tapered String;155
9.3.1;Data from Kill Sheet;156
9.4;4.3. Kill Sheet for a Highly Deviated Well;157
9.5;4.4. Prerecorded Information;161
9.5.1;Maximum Anticipated Surface Pressure;161
9.5.2;Sizing Diverter Lines;163
9.5.3;Formation Pressure Tests;163
9.5.4;Maximum Allowable Mud Weight from Leak-Off Test Data;166
9.5.5;Maximum Allowable Shut-In Casing Pressure (MASICP), Also Called Maximum Allowable Shut-In Annular Pressure (MASP);166
9.5.6;Kick Tolerance Factor (KTF);166
9.5.7;Maximum Surface Pressure from Kick Tolerance Data;167
9.5.8;Maximum Formation Pressure (FP) That Can Be Controlled when Shutting in a Well;167
9.5.9;Maximum Influx Height Possible to Equal Maximum Allowable Shut-In Casing Pressure (MASICP);168
9.5.10;Maximum Influx, Barrels to Equal Maximum Allowable Shut-In Casing Pressure (MASICP);168
9.5.11;Adjusting Maximum Allowable Shut-In Casing Pressure for an Increase in Mud Weight;169
9.6;4.5. Kick Analysis;170
9.6.1;Formation Pressure (FP) with the Well Shut-In on a Kick;170
9.6.2;Bottomhole Pressure (BHP) with the Well Shut-In on a Kick;170
9.6.3;Shut-In Drill Pipe Pressure (SIDPP);170
9.6.4;Shut-In Casing Pressure (SICP);171
9.6.5;Height, ft, of Influx;171
9.6.6;Estimated Type of Influx;173
9.6.7;Gas Migration in a Shut-In Well;173
9.6.8;Metric Calculation;174
9.6.9;SI Units Calculation;174
9.6.10;Hydrostatic Pressure Decrease at TD Caused by Gas-Cut Mud Method 1;175
9.6.11;Maximum Surface Pressure from a Gas Kick in a Water-Base Mud;175
9.6.12;Maximum Pit Gain from Gas Kick in a Water-Base Mud;176
9.6.13;Maximum Pressures when Circulating Out a Kick (Moore Equations);177
9.6.14;Gas Flow into the Wellbore;183
9.7;4.6. Pressure Analysis;183
9.7.1;Gas Expansion Equations;183
9.7.2;Hydrostatic Pressure Exerted by Each Barrel of Mud in the Casing;184
9.7.3;Surface Pressure during Drill Stem Tests;185
9.8;4.7. Stripping/Snubbing Calculations;186
9.8.1;Breakover Point between Stripping and Snubbing;186
9.8.2;Minimum Surface Pressure before Stripping Is Possible;187
9.8.3;Height Gain from Stripping into Influx;187
9.8.4;Casing Pressure Increase from Stripping into Influx;188
9.8.5;Volume of Mud That Must Be Bled to Maintain Constant Bottomhole Pressure with a Gas Bubble Rising;188
9.8.6;Maximum Allowable Surface Pressure (MASP) Governed by the Formation from Equation (4.22);189
9.8.7;Maximum Allowable Surface Pressure (MASP) Governed by Casing Burst Pressure;190
9.9;4.8. Subsea Considerations;190
9.9.1;Casing Pressure Decrease When Bringing Well on Choke;190
9.9.2;Pressure Chart for Bringing Well on Choke;191
9.9.3;Maximum Allowable Mud Weight, ppg, Subsea Stack as Derived from Leak-Off Test Data;192
9.9.4;Maximum Allowable Shut-In Casing (Annulus) Pressure from Equation (4.22);192
9.9.5;Casing Burst Pressure-Subsea Stack;193
9.9.6;Velocity, ft/min, through the Choke Line;195
9.9.7;Adjusting Choke Line Pressure Loss for a Higher Mud Weight;195
9.9.8;Minimum Conductor Casing Setting Depth;196
9.9.9;Maximum Mud Weight with Returns Back to Rig Floor;197
9.9.10;Reduction in Bottomhole Pressure if Riser Is Disconnected;197
9.9.11;Bottomhole Pressure When Circulating Out a Kick;198
9.10;4.9. Workover Operations;199
9.10.1;Bullheading;199
9.10.2;Lubricate and Bleed;202
9.11;4.10. Controlling Gas Migration;204
9.11.1;Drill Pipe Pressure Method;205
9.11.1.1;SI Units;205
9.11.1.2;Metric Units;205
9.11.2;Volumetric Method of Gas Migration;206
9.11.2.1;SI Units;206
9.11.2.2;Metric Units;206
9.12;4.11. Gas Lubrication;207
9.12.1;Gas Lubrication-Volume Method;207
9.12.1.1;SI Units;207
9.12.1.2;Metric Units;208
9.12.2;Gas Lubrication-Pressure Method;208
9.13;4.12. Annular Stripping Procedures;209
9.13.1;Strip and Bleed Procedure;209
9.13.2;Combined Stripping/Volumetric Procedure;210
9.14;4.13. Worksheet;210
9.15;References;211
10;Chapter 5: Engineering Calculations;214
10.1;5.0. Bit Nozzle Selection-Optimized Hydraulics;214
10.2;5.1. Hydraulics Analysis;220
10.3;5.2. Critical Annular Velocity and Critical Flow Rate;223
10.4;5.3. The "d" Exponent;225
10.5;5.4. Cuttings Slip Velocity;226
10.6;5.5. Surge and Swab Pressures;231
10.7;5.6. Equivalent Circulation Density (ECD);240
10.8;5.7. Fracture Gradient Determination-Surface Applications;244
10.9;5.8. Fracture Gradient Determination-Subsea Applications;248
10.10;5.9. Directional Drilling Calculations;251
10.10.1;5.9.1. Directional Survey Calculations;251
10.10.2;5.9.2. Deviation/Departure Calculation;254
10.10.3;5.9.3. Dogleg Severity Calculation;255
10.10.4;5.9.4. Available Weight on the Bit in Directional Wells;256
10.10.5;5.9.5. Determining True Vertical Depth;257
10.11;5.10. Miscellaneous Equations and Calculations;258
10.11.1;5.10.1. Surface Equipment Pressure Losses;258
10.11.2;5.10.2. Drill Stem Bore Pressure Losses;258
10.11.3;5.10.3. Annular Pressure Losses;259
10.11.4;5.10.4. Pressure Loss through Common Pipe Fittings;260
10.11.5;5.10.5. Minimum Flow Rate for PDC Bits;261
10.11.6;5.10.6. Critical RPM: RPM to Avoid Due to Excessive Vibration (Accurate to Approximately 15%);261
10.12;References;262
11;Chapter 6: Air and Gas Calculations;264
12;Appendix A;278
12.1;Tank Capacity Determinations;279
12.1.1;Rectangular Tanks with Flat Bottoms;279
12.1.2;Rectangular Tanks with Sloping Sides;280
12.1.3;Circular Cylindrical Tanks;283
12.1.4;Tapered Cylindrical Tanks;283
12.1.5;Horizontal Cylindrical Tank;284
13;Appendix B;286
14;Appendix C: Average Annual Atmospheric Conditions;290
15;Index;296

Leseproben

Chapter One

Basic Equations

Publisher Summary

This chapter introduces the concept of density in oil field terminology, which refers to specific weight. Specific weight is in the units of lb/ft3 or lb/gallon (ppg). This chapter refers to the specific weight as mud weight. Density is used only when referring to the SI-metric values of kg/m3, kg/liter, and gram/cm3 (which are actual density values in that unit system) and for the term ECD. This chapter describes the mud weight, and specific gravity in USCS/British units and SI units. Following this, it provides an understanding of hydrostatic pressure using formulae and equations. It also explains pressure gradient in USCS/British units and SI units. Furthermore, it explains some capacity formulas for annular capacity between casing or hole and drill pipe, tubing, or casing. Finally, it illustrates some temperature and conversion formulas.

This chapter introduces the various units of weight that are used in the drilling profession. The use of the term in the book is explained as it pertains to the calculations presented in the book. Basic equations for mud weight and specific gravity are presented.

Key Words: Mud weight, density, specific gravity, SI units, hydrostatic pressure, Rankine

1.0 Terminology

The term density as used in USCS/British oil field terminology is a slang term for a value that is actually specific weight. Specific weight is in the units of lb/ft3 or lb/gallon (ppg). Actual density in the USCS/British would be the specific weight term divided by 32.2 ft/sec2 and would result in a USCS/British density of slug/ft3. Neither the density term nor the actual density term is used in this book. This book uses the term mud weight (MW) for specific weight (lb/ft3or ppg). Density is used only when referring to the SI-metric values of kg/m3, kg/liter, and gram/cm3 (which are actual density values in that unit system) and for the term ECD.

1.1 Mud Weight MW (lb/ft3), Mud Weight MW (ppg), and Specific Gravity (SG) [USCS/British]

Definition: Mud weight of fresh water MW (lb/ft3)

fw=62.4lb/ft3 (1.1)

(1.1)

Example: Mud weight of fresh water MW (ppg)

fw=62.4(12)3(231)MWfw=8.34ppg (1.2)

(1.2)

where: 1 gal = 231 in.3

1 ft = 12 in.

Example: Specific gravity of fresh water SG

fw=62.462.4=1.0 (1.3)

(1.3)

or

fw=8.348.34=1.0 (1.4)

(1.4)

Example: SG of a mud weight of 12.0 ppg

m=12.08.34=1.44 (1.5)

(1.5)

1.2 Density ? (kg/m3 or kg/liter), Mud Weight MW (N/m3 or N/liter), and Specific Gravity (SG) [SI-Metric]

Definition: Mud density of fresh water ? (kg/m3)

fw=1000.0kg/m3 (1.6)

(1.6)

Example: Mud density of fresh water ? (kg/liter)

fw=1000.0(10-3)?fw=1.0kg/liter

where: 1 liter = 10-3 m3

Example: Mud weight of fresh water MW (N/m3)

fw=1000.0g=1000.09.81MWfw=9810.0N/m3

where: g = 9.81 m/sec2

Example: Mud weight of fresh water MW (N/liter)

fw=1.0g=1.09.81MWfw=9.81N/liter

Example: Specific gravity of fresh water SG (using density)

fw=1000.01000.0=1.0

or

fw=1.01.0=1.0

Example: Specific gravity of fresh water SG (using mud weight)

fw=9810.09810.0=1.0

or

fw=9.819.81=1.0

Conversion: Mud weight of 12.0 ppg to mud weight MW (N/liter)

=12.0(1.175)=14.1N/liter (1.7)

(1.7)

where: 1 ppg = 1.175 N/liter

Example: Mud weight of 14.1 N/liter to density ? (kg/liter)

m=14.11g=1.44kg/liter

Example: SG of mud using density of 1.44 kg/liter

m=1.441.0=1.44

Example: SG of a mud with a specific weight of 14.1 N/liter

m=14.19.81=1.44

Table 1-1

Mud Weight and Density Conversion Factors Summary

lb/ft3

lb/gal

0.134

lb/ft3

SG

(1/62.4)

lb/gal

SG

(1/8.34)

kg/m3

N/m3

9.81

kg/liter

N/liter

9.81

kg/m3

N/liter

(9.81/1000)

N/liter

SG

(1/9.81)

N/m3

SG

(1/9810)

1.3 Hydrostatic Pressure (P) and (p) [USCS/British]

Definition: Hydrostatic pressure P (lb/ft3) at a depth H (ft) below surface is

(lb/ft2)=MW(lb/ft3)H(ft) (1.8)

(1.8)

where: H (ft) is true vertical depth (TVD)

Example: Pressure (lb/ft2) in fresh water at a depth of 1000 ft

=62.41000=62,400lb/ft2

Example: Pressure (lb/ft2) in 12.0 ppg at a depth of 1000 ft

=(89.9)(1000)=89,900lb/ft2

Definition: Hydrostatic pressure p (psi) at a depth H (ft) below surface is (using equation (1.8))

psi122=MWlb/ft3Hft

which reduces to

(psi)=MW(lb/ft3)1(12)2H(ft)

or

(psi)=0.00695MW(lb/ft3)H(ft) (1.9)

(1.9)

Example: Pressure (psi) in fresh water at a depth of 1000 ft

=0.00695(62.4)(1000)=434psi

Example: Pressure (psi) in 12.0 ppg at a depth of 1000 ft

=0.00695(89.9)(1000)=624psi

Definition: Hydrostatic pressure p (psi) at a depth H (ft) below surface is (using equation (1.8))

(psi)(12)2=MW(ppg)(12)3231H(ft)

which reduces to

(psi)=MW(ppg)12231H(ft)

or

(psi)=0.052MW(ppg)H(ft) (1.10)

(1.10)

Example: Pressure (psi) in fresh water at a depth of 1000 ft

=0.052(8.34)(1000)=434psi

Example: Pressure (psi) in 12.0 ppg mud at a depth of 1000 ft

=0.052(12.0)(1000)=624psi

1.4 Hydrostatic Pressure (P) and (p) [SI-Metric]

Definition: Hydrostatic pressure P (N/m2) at a depth H (m) below surface is (using N/m3)

(N/m2)=MW(N/m3)H(m) (1.11)

(1.11)

Example: Pressure (N/m2) in fresh water at a depth of 305 m (~ 1000 ft)

=(9810)(305)=2,992,050N/m2

Definition: Hydrostatic pressure P (N/m2) at a depth H (m) below surface is (using N/liter)

(N/m2)=1000MW(N/liter)H(m) (1.12)

(1.12)

Example: Pressure (N/m2) in fresh water at a depth of 305 m (~ 1000 ft)

=1000(9.81)(305)=2,992,050N/m2

Definition: Hydrostatic pressure P (N/m2) at a depth H (m) below surface is (using SG)

(N/m2)=SGMWfw(N/m3)H(m) (1.13)

(1.13)

or

(N/m2)=1000SGMWfw(N/liter)H(m) (1.14)

(1.14)

Example: Pressure (N/m2) in fresh water at a depth of 305 m (~ 1000 ft)

=1000(1.0)(9.81)(305)=2,992,050N/m2

Example: Pressure (N/m2) in mud with an SGm of 1.44 at a depth of 305 m (~ 1000 ft)

=1000(1.44)(9.81)(305)=4,308,552N/m2

Definition: Hydrostatic pressure p (N/cm2) at a depth H (m) below surface is (using SG)

(N/cm2)=10-4SGMWfw(N/m3)H(m) (1.15)

(1.15)

Example: Pressure (N/cm2) in fresh water at a depth of 305 m (~ 1000 ft)

=10-41.09810305=299N/cm2

Example: Pressure (N/cm2) in mud with an SG of 1.44 at a depth of 305 m (~ 1000 ft)

=10-41.449810305=431N/cm2

NOTE: The values of p (N/cm2) are 0.69 of the values of p (psi).

1.5 Pressure Gradient ? (psi/ft), G (ppg) [USCS/British]

Definition: Pressure gradient ? (psi/ft) is obtained from equation (1.10)

(psi/ft)=p(psi)H(ft)=0.052MW(ppg)?(psi/ft)=0.052MW(ppg) (1.16)

(1.16)

Example: Pressure gradient ?fw (psi/ft) for fresh water

fw=0.0528.34?fw=0.434psi/ft

Example: Pressure gradient ?m (psi/ft) for 12.0 ppg...