WELL LOGGING AND FORMATION EVALUATION free download pdf

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INTRODUCTION

The purpose of this book is to provide a series of techniques which will
be of real practical value to petrophysicists in their day-to-day jobs. These
are based on my experience from many years working in oil companies.
To this end I have concentrated wherever possible on providing one recommended
technique, rather than offer the reader a choice of different
options.
The primary functions of a petrophysicist are to ensure that the right
operational decisions are made during the course of drilling and testing a
well—from data gathering, completion and testing—and thereafter to
provide the necessary parameters to enable an accurate static and dynamic
model of the reservoir to be constructed. Lying somewhere between
Operations, Production Geology, Seismology, Production Technology and
Reservoir Engineering, the petrophysicist has a key role in ensuring the
success of a well, and the characterization of a reservoir.
The target audience for this book are operational petrophysicists in their
first few years within the discipline. It is expected that they have some
knowledge of petroleum engineering and basic petrophysics, but lack
experience in operational petrophysics and advanced logging techniques.
The book also may be useful for those in sister disciplines (particularly
production geology and reservoir engineering) who are using the interpretations
supplied by petrophysicists.

CONTENTS
Introduction ix
1 Basics 1
1.1 Terminology 1
1.2 Basic Log Types 3
1.3 Logging Contracts 9
1.4 Preparing a Logging Programme 11
1.5 Operational Decisions 14
1.6 Coring 16
1.7 Wellsite Mud Logging 21
1.8 Testing/Production Issues 24
2 Quicklook Log Interpretation 29
2.1 Basic Quality Control 29
2.2 Identifying the Reservoir 30
2.3 Identifying the Fluid Type and Contacts 32
2.4 Calculating the Porosity 34
2.5 Calculating Hydrocarbon Saturation 37
2.6 Presenting the Results 40
2.7 Pressure/Sampling 42
2.8 Permeability Determination 45
3 Full Interpretation 49
3.1 Net Sand Definition 49
3.2 Porosity Calculation 51
3.3 Archie Saturation 53
3.4 Permeability 54
4 Saturation/Height Analysis 59
4.1 Core Capillary Pressure Analysis 60
4.2 Log-Derived Functions 64
5 Advanced Log Interpretation Techniques 67
5.1 Shaly Sand Analysis 67
5.2 Carbonates 73
5.3 Multi-Mineral/Statistical Models 74
5.4 NMR Logging 76
5.5 Fuzzy Logic 85
5.6 Thin Beds 87
5.7 Thermal Decay Neutron Interpretation 93
5.8 Error Analyses 96
5.9 Borehole Corrections 101
6 Integration with Seismic 103
6.1 Synthetic Seismograms 103
6.2 Fluid Replacement Modelling 108
6.3 Acoustic/Elastic Impedance Modelling 110
7 Rock Mechanics Issues 115
8 Value Of Information 119
9 Equity Determinations 125
9.1 Basis for Equity Determination 126
9.2 Procedures/Timing for Equity Determination 127
9.3 The Role of the Petrophysicist 129
10 Production Geology Issues 137
10.1 Understanding Geological Maps 140
10.2 Basic Geological Concepts 147
11 Reservoir Engineering Issues 155
11.1 Behavior of Gases 155
11.2 Behavior of Oil/Wet Gas Reservoirs 159
11.3 Material Balance 162
11.4 Darcy’s Law 163
11.5 Well Testing 166
12 Homing-in Techniques 171
12.1 Magnetostatic Homing-in 171
12.2 Electromagnetic Homing-in 185
13 Well Deviation, Surveying, and Geosteering 193
13.1 Well Deviation 193
13.2 Surveying 195
13.3 Geosteering 197
13.4 Horizontal Wells Drilled above a Contact 203
13.5 Estimating the Productivity Index for Long
Horizontal Wells 205
Appendix 1 Test Well 1 Data Sheet 207
Appendix 2 Additional Data for Full Evaluation 215
Appendix 3 Solutions to Exercises 218
Appendix 4 Additional Mathematics Theory 251
Appendix 5 Abbreviations and Acronyms 264
Appendix 6 Useful Conversion Units and Constants 268
Appendix 7 Contractor Tool Mnemonics 271
Bibliography 309
About the Author 313
Acknowledgments 314
Index 315