CONTENTS
PREFACE .................................................. vii
1 BASIC FORMULAS ...................................... .1
Pressure Gradient 1. Hydrostatic Pressure 3. Converting Pressure into
Mud Weight 4. Specific Gravity 5. Equivalent Circulating Density 6.
Maximum Allowable Mud Weight 7. Pump Output 7. Annular
Velocity 9. Capacity Formulas 12. Control Drilling 19. Buoyancy
Factor 20. Hydrostatic Pressure Decrease When Pulling Pipe out of
the Hole 20. Loss of Overbalance Due to Falling Mud Level 22.
Formation Temperature 24. Hydraulic Horsepower 25. Drill Pipe/Drill
Collar Calculations 25. Pump Pressure/Pump Stroke Relationship 27.
Cost per Foot 28. Temperature Conversion Formulas 29.
2 BASIC CALCULATIONS ................................. .31
Volumes and Strokes 3 1. Slug Calculations 33. Accumulator
Capacity 37. Bulk Density of Cuttings 41. Drill String Design
(Limitations) 42. Ton-Mile Calculations 44. Cementing Calculations 47.
Weighted Cement Calculations 53. Calculations for the Number of
Sacks of Cement Required 54. Calculations for the Number of Feet to
Be Cemented 57. Setting a Balanced Cement Plug 61. Differential
Hydrostatic Pressure Between Cement in the Annulus and Mud Inside
the Casing 65. Hydraulicing Casing 66. Depth of a Washout 70. Lost
Returns-Loss of Overbalance 7 1. Stuck Pipe Calculations 72.
Calculations Required for Spotting Pills 75. Pressure Required to
Break Circulation 79.
3 DRILLING FLUIDS ....................................... 81
Increase Mud Density 81. Dilution 85. Mixing Fluids of Different
Densities 86. Oil-Based Mud Calculations 87. Solids Analysis 91. Solids
Fractions 95. Dilution of Mud System 96. Displacement-Barrels of
Water/Slurry Required 97. Evaluation of Hydrocyclone 97. Evaluation
of Centrifuge 99.
4 PRESSURE CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .lo3
Kill Sheets and Related Calculations 103. Prerecorded
Information 115. Kick Analysis 124. Pressure Analysis 137.
Stripping/Snubbing Calculations 139. Subsea Considerations 144.
Workover Operations 153. Controlling Gas Migration 157. Gas
Lubrication 159. Annular Stripping Procedures 161.
5 ENGINEERING CALCULATIONS . . . . . . . . . . . . . . . . . . . . . . . . . .165
Bit Nozzle Selection-Optimized Hydraulics 165. Hydraulics
Analysis 169. Critical Annular Velocity and Critical Flow Rate 173.
“d” Exponent 174. Cuttings Slip Velocity 175. Surge and Swab
Pressures 179. Equivalent Circulation Density 187. Fracture Gradient
Determination-Surface Application 190. Fracture Gradient
Determination-Subsea Application 194. Directional Drilling
Calculations 197. Miscellaneous Equations and Calculations 203.
APPENDIXA .............................................. 209
APPENDIX B .............................................. 217
INDEX .................................................... 221
vi
PREFACE
Over the last several years, hundreds of oilfield personnel have told me that
they have enjoyed this book. Some use it as a secondary reference source:
others use it as their primary source for formulas and calculations; still others
use it to reduce the volume of materials they must carry to the rig floor or
job site.
Regardless of the reason people use it, the primary purpose of the book
is to provide a convenient source of reference to those people who don’t use
formulas and calculations on a regular basis.
In the preface to the first edition, I made reference to a driller who carried
a briefcase full of books with him each time he went to the rig floor. I also
mentioned a drilling supervisor who carried two briefcases of books. This
book should reduce the number of books each of them needs to perform
his job.
This book is still intended to serve oilfield workers for the entirety of their
careers. I have added several formulas and calculations, some in English field
units and some in Metric units. I have also added the Volumetric Procedure,
the Lubricate and Bleed Procedure (both Volume and Pressure Method), and
stripping procedures (both the Strip and Bleed Procedure and the Combined
Stripping and Volumetric Procedure).
This book has been designed for convenience. It will occupy very little
space in anyone’s briefcase. It has a spiral binding so it will lay flat and stay
open on a desk. 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.
This book is dedicated to the thousands of oilfield hands worldwide who
have to use formulas and calculations, whether on a daily basis or once or
twice a year, and who have problems remembering them. This book should
make their jobs a little easier.