Origin and Prediction of Abnormal Formation Pressures (eBook)

Front Cover 1
ORIGIN AND PREDICTION OF ABNORMAL FORMATION PRESSURES 4
Copyright Page 5
CONTENTS 12
Preface 8
List of Contributors 10
CHAPTER 1. INTRODUCTION TO ABNORMALLY PRESSURED FORMATIONS 18
Introduction 18
Abnormal pressures 19
Origin of vertical barriers resulting in abnormal formation pressures 20
Reservoir engineering concepts in abnormal pressure environments 30
Economics in overpressure environments 31
Summary 33
Bibliography 34
CHAPTER 2. ORIGIN OF ABNORMAL FORMATION PRESSURES 38
Introduction 38
Compaction process 41
State of stress in compacting shales 46
Compaction models 60
Creation and maintenance of abnormal pressures 68
Mechanisms generating abnormal formation pressures 72
Conclusions 81
Bibliography 81
CHAPTER 3. ORIGIN OF FORMATION FLUID PRESSURE DISTRIBUTIONS 86
Introduction 86
Factors causing fluid flow and pressure distributions 87
Presentation of pressure as the additive sum of two components 92
Some major factors of underground fluid forced convection and characteristics for correlation 95
Definitions of terms as used in this chapter 110
Conclusions 110
Bibliography 111
CHAPTER 4. SMECTITE–ILLITE TRANSFORMATIONS DURING DIAGENESIS AND CATAGENESIS AS RELATED TO OVERPRESSURES 114
Introduction 114
Burst's compaction model 116
Origin of abnormally high formation pressure 117
Clay-mineral transformation 122
Effect of thermobaric conditions 127
Effect of hydrochemical factors 130
Discussion 133
Summary 137
Conclusions 138
Bibliography 138
CHAPTER 5. METHODS OF ESTIMATING AND PREDICTING ABNORMAL FORMATION PRESSURES 140
Introduction 140
Prediction of abnormally high pressure in regions with nonequilibrium compaction 143
Abnormal pressure due to temperature variations 147
Estimation and prediction of abnormally low pressures in basins in permafrost regions 147
Formation pressure in regions with upthrown and downthrown blocks (uplift and subsidence of sedimentary rocks) 148
Calculation of abnormal pore pressure during drilling 151
Radioactivity study of zones with abnormally high formation pressure 157
Pulsed neutron capture logs 158
Shale water influx — driving mechanism 163
Various geophysical well logging methods — a summary 164
Conclusions 165
Bibliography 165
CHAPTER 6. DRILLING PARAMETERS 168
Drilling rate (penetration) 168
Drilling rate equations 173
Porosity and formation pressure logs 174
Logging while drilling 176
Torque 176
Drag 177
Drilling mud parameters 177
Shale cuttings parameters 180
Other pressure indicator methods 182
Drilling concepts in overpressured environments 182
Bibliography 182
CHAPTER 7. SEISMIC METHODS OF PRESSURE PREDICTION 186
Introduction 186
Prediction of abnormal pressure from geophysical data 186
Empirical relationships 187
Practical applications 190
Bibliography 205
CHAPTER 8. TECTONICS AND OVERPRESSURED FORMATIONS 208
Introduction 208
Faulting as a cause of overpressured formations 208
Shale diapirism (mud lumps, mud volcanoes) 215
Prediction of tectonically caused overpressures by using resistivity and density measurements of associated shales 217
Origin and distribution of overpressures in carbonate reservoirs 217
Conclusions 222
Bibliography 223
CHAPTER 9. PREDICTION OF ABNORMALLY HIGH PRESSURES IN PETROLIFEROUS SALT-BEARING SECTIONS 226
Introduction 226
Indicators of approaching the overpressured zones 228
Locating the areal positions of AHFP zones 230
Quantitative AHFP forecast 234
Conclusions 237
Bibliography 237
CHAPTER 10. PORE WATER COMPACTION CHEMISTRY AS RELATED TO OVERPRESSURES 240
Introduction 240
Overview and constraints 241
Chemical composition of subsurface brines 252
Laboratory experiments 268
Fluid chemistry compaction models 289
Isotope studies of interstitial fluids 299
Summary and conclusions 302
Bibliography 305
CHAPTER 11. ABNORMALLY LOW FORMATION PRESSURES 312
Introduction 312
Origin of abnormal pressures 313
Estimation of the effects of temperature change and erosion on pore pressure 317
Summary 325
Bibliography 325
CHAPTER 12. MATHEMATICAL MODELING OF ABNORMALLY HIGH FORMATION PRESSURES 328
Introduction 328
Methodology of simulation of dynamic systems 329
Analytical approach 329
Analytical models 331
Numerical models 335
Tectonic and lithological modeling 339
Numerical criterion and sensitivity analysis for time-dependent formation pressure in a sealed layer 344
Formation pressure in the case of constant fluid flow through the lower boundary of the formation 348
Identification of conductivity function for petroleum reservoirs 356
Conclusions 365
Nomenclature used in this chapter 365
Bibliography 366
CHAPTER 13. INTERRELATIONSHIP AMONG FLUID PRODUCTION, SUBSIDENCE AND RESERVOIR PRESSURE 370
Introduction 370
Compaction of rocks 370
Conclusions 375
Bibliography 375
Author Index 378
Subject Index 386