Geology and Geochemistry of Oil and Gas (eBook)

Cover 1
Contents 18
Dedication 6
Foreword 8
Preface 10
Nomenclature 12
Abbreviations 16
Systems Approach in Science 22
Natural Systems and their Classification 22
Rocks, Water, Organic Matter and Gases as a Specific Natural System 28
Systems Approach in Petroleum Geology 29
Oil and Gas-Bearing Rocks 40
Composition of Oil- and Gas-Bearing Rocks 40
Reservoir Rocks 41
Porosity 42
Permeability 43
Caprocks 50
Oil and Gas Reservoirs 56
Temperature and Pressure in the Subsurface 60
Deformation of Rocks in Depth 60
Porosity and permeability versus depth of burial 60
Temperature 63
Paleotemperature 70
Abnormally-High Formation Pressure 72
Well-logging data 72
Seismic data 73
Drilling data 74
Effect of pressure and temperature 79
Effect of formation water chemistry 83
Secondary montmorillonite 85
Origin of Abnormal Formation Pressures 85
Water 92
Physical and Chemical Properties of Waters 92
Classifications of Oilfield Waters 96
Water Drive 100
Water drive systems 101
Crude Oils 108
Composition of Crude Oils¹º 108
Classification of Crude Oils 110
Natural Gases and Condensates 122
Composition of Natural Gases 122
Isotope Composition of Natural Gases 124
Carbon 124
Hydrogen 124
Sulfur 125
Nitrogen 125
Inert gases 126
Physical Properties of Natural Gases 127
Gas density 127
Combustion heating value 128
Compressibility of natural gases 128
Deviation of pressure at bottom of gas column 129
Gas viscosity 130
Hydrate formation 130
Solubility of gases in water 131
Solubility of hydrocarbon gases in crude oils 133
Phase Transformation and Condensates¹¹ 133
Dispersed Organic Matter 138
Organic Matter Insoluble in Organic Solvents: Kerogen 138
Insoluble Portion of Organic Matter 139
Organic Matter Soluble in Organic Solvents 146
Combined Studies of Soluble and Insoluble Portions of Organic Matter 150
Origin of Oil and Natural Gas 156
Initial Organic Matter and its Transformation 156
Stagewise Nature and Cyclic Transformation of Organic Matter 159
Role of Energy in the Oil Generation Process 162
Formation of Hydrocarbon Accumulations 168
Sedimentary Basins 168
Hydrocarbon Expulsion ("Primary Migration"), Heterogeneity of the Medium, Dissolution in Water and Gas, and Diffusion 172
Overburden Pressure 174
Pore Pressure 174
Rock Compaction 175
Temperature 175
Geochemical Non-Uniformity 175
Dissolution in Compressed Gases (See Retrograde Dissolution in Chapter 6) 178
Diffusion 178
Primary Accumulation and Free Phase Migration ("Secondary Migration") 179
Time of Formation of Hydrocarbon Accumulations 190
Paleogeologic Method 190
Mineralogic Technique 190
Helium– Argon Technique 191
Determination Based on the Composition of Oil Fractions with Boiling Point below 200°C 191
Volumetric Technique 191
Saturation Pressure Technique 192
Classifications of Oil and Gas Accumulations 194
Classification of Types of Oil and Gas Accumulations and Traps, Reserves, Fluid Quality, Production Rates 194
Classification of Hydrocarbon Accumulations Based on Phase Relationships 197
Gas accumulations 196
Oil accumulations 198
Classification of Oil and Gas Reservoirs Based on Drive Mechanism 204
Solution gas drive 205
Gas-cap drive 208
Water drive 209
Gravity drainage 212
Combination-drive reservoirs 212
Open combination-drive reservoirs 212
Closed combination-drive reservoirs 214
Classification of Hydrocarbon Accumulations Based on the Types of Traps 215
Vertical Zonation of Hydrocarbon Accumulations 219
Mathematical Modeling in Petroleum Geology 226
Principles of Mathematical Modeling of Geologic Systems 226
Models of Static Geologic Systems 230
Analytical approach 231
Entropy of geologic systems 231
Anisotropy of sedimentary rocks 236
Petrophyical relationships 238
Statistical approach 242
One-dimensional models 242
Rock properties 242
Crude oil properties 246
Two-dimensional models 248
Reservoir rocks 248
Crude oil 251
Natural gas 257
Formation water 258
Multidimensional models 261
Reservoir rocks 261
Crude oil 262
Models of Dynamic Geologic Systems 270
Analytical approach 271
Statistical approach 272
Combination of analytical and statistical approaches 277
Sediment compaction 277
Simulation of rock properties 278
Prediction of rock properties 286
Prediction of hydrocarbon reserves 286
Evolution of pore-fluid (formation) pressure 291
Simulation of oil/water mobility 292
Algorithm of Accelerated Exploration for Hydrocarbon Accumulations 294
Concluding Remarks 294
Wettability and Capillarity 296
Introduction 296
Wettability 296
Interfacial Tension and Contact Angle 299
Effect of Contact Angle and Interfacial Tension on Movement of Oil 302
Water block 305
Buoyancy 306
Sample problem 307
Gas Migration 307
Permeability 310
Glossary* 316
References and Bibliography 366
Author Index 382
Subject Index 386
Erratum to the Subject Index 392