Acknowledgments xv
Introduction xix
I. Waves: The Foundation of Seismology 1
1 General Properties of Waves 3
1.1 Mechanical waves 3
1.2 Particle motion 4
1.3 Polarization 5
1.4 Elastic properties 6
1.5 Wavespeed 7
1.6 Display of wavefield data 8
1.7 Waveform 9
1.8 Impulse response 15
1.9 Reciprocity 17
1.10 Source and receiver directivity 17
1.11 Wavefront and rays 18
1.12 Huygens' principle 20
1.13 Fermat's principle 22
1.14 Snell's law 23
1.15 Critical angle 26
1.16 Dimensional effects 26
1.16.1 Waveform 26
1.16.2 Energy density and geometric spreading 27
2 Waves in Fluids 33
2.1 Why fluids? 33
2.2 Parameters 34
2.3 Equation of motion 36
2.4 The big picture 41
2.5 Velocity variation 42
2.6 What about density? 45
2.7 Fine layering 45
3 Understanding Seismic Events 51
3.1 Half space 51
3.1.1 Uncertainty analysis applied to direct waves 54
3.2 Reflection 56
3.2.1 Traveltime 56
3.2.2 Reflection coefficient 62
3.2.3 Normal incidence 63
3.2.4 Angular reflection coefficient 68
3.2.5 Postcritical reflection 69
3.2.6 Fresnel zone 71
3.3 Head wave 78
3.4 The point source: Tying it all together 81
3.5 Diffraction 84
3.6 Ghost 89
3.7 Velocity layering 92
3.7.1 More events 92
3.7.2 Multiples 93
3.8 Classification 96
4 Reservoir Fluid Properties 99
4.1 Pressure and temperature range 99
4.2 Gas 100
4.2.1 Gas density 100
4.2.2 Gas modules and velocity 101
4.3 Oil 102
4.3.1 Oil density 104
4.3.2 Oil modules and velocity 104
4.4 Brine 106
4.4.1 Brine density 107
4.4.2 Brine modules and velocity 108
4.5 Fluid mixture 108
4.5.1 Fluid density 109
4.5.2 Fluid modules and velocity 110
5 Waves in Solids 113
5.1 Strain 113
5.2 Stress 115
5.3 Hooke's law and elastic parameters 116
5.4 Equations of motion 118
5.5 Wave types and speeds 120
5.6 Mode conversion 123
5.7 Snell's law and critical angles 125
5.8 Velocity layering 127
5.9 Elastic reflection coefficient 127
5.10 Reflection coefficient approximations 130
5.11 Anisotropy 131
6 Waves in Porous Solids 135
6.1 Rock as a porous solid 135
6.2 Empirical relationships 136
6.3 Parameters 138
6.4 Equation of motion 139
6.5 Wave types 140
6.6 Rock density 140
6.7 Gassmann theory and wavespeeds 141
6.8 Attenuation and dispersion 144
6.9 Rock velocity ranges 150
II. Acquisition: Gathering Seismic Data 153
7 2D Land Acquisition 155
7.1 Historical summary 155
7.2 Hardware 156
7.2.1 Source 156
7.2.2 Receiver 160
7.2.3 Recording system 163
7.3 Field procedure 163
7.3.1 Vertical stack 164
7.3.2 Roll and cabling 164
7.4 SEGY headers and sorting 168
8 Financial Aspects of 3D Seismic 171
8.1 The big picture: stock price 171
8.2 Economics 173
8.3 The exploration process 173
8.4 A savings/gain model 174
8.4.1 Savings 175
8.4.2 Gains 176
8.4.3 Net value, profit, and rate of return 176
8.5 Some industry trends 180
9 Survey Predesign 185
9.1 Acquisition parameters 185
9.2 Time sample rate 187
9.3 Offset range 188
9.4 Listen time 189
9.5 Spatial sampling and aliasing 191
9.6 Total signal-to-noise improvement 196
10 Land Shooting Geometry 201
10.1 Coordinates and related quantities 201
10.2 Cross spread method 204
10.3 Swath method 208
10.4 Fringe 210
10.5 Perimeter or loop method 212
10.6 Cabling, template shooting, and fold 215
10.7 Crooked line 2D 219
11 Land 3D Design Optimization 223
11.1 Optimization and inversion 223
11.2 Assumptions, target variables, and constraints 226
11.3 A direct method 228
11.4 Method 2 229
11.5 Examples 230
12 Marine Acquisition Methods 235
12.1 Towed receiver systems 235
12.1.1 Receiver cable 235
12.1.2 Source array 239
12.1.3 Acquisition geometry 242
12.1.4 Flip-flop shooting 245
12.1.5 Positioning 245
12.1.6 Cable feathering 247
12.2 Fixed receiver systems 248
12.3 Marine acquisition and the environment 251
13 Data Dimensionality and Components 253
III. Data Processing: Creating the Seismic Image 259
14 Processing and Binning Overview 261
14.1 Why do we need to process seismic data? 261
14.2 Filtering and noise removal 264
14.3 Processing flow 266
14.4 Bins 270
14.4.1 Bin size calculation 272
14.4.2 Effects of fold and offset variation 275
14.4.3 Anatomy of a bin 276
15 Computing 283
15.1 RAM and disk storage 283
15.2 The 2D survey size 286
15.3 The 3D survey size 286
15.4 Processing speed 286
15.5 Speed and 3D migration 289
16 Creating the CMP Stack 291
16.1 Gain 291
16.2 Deconvolution 292
16.3 Sorting 298
16.4 Normal moveout 301
16.5 Dip moveout 309
16.6 Common midpoint stacking 312
16.7 Statics 316
17 Migration I: Concepts 321
17.1 Constant velocity migration and modeling pairs 322
17.2 Dip from seismic slope 326
17.3 Migration distance 327
17.4 Variable velocity migration and modeling pairs 327
17.5 3D migration 327
17.6 Lateral resolution in 2D and 3D data 333
17.7 Survey design for linear u(z) 337
18 Migration II: Classification and Velocity Analysis 343
18.1 Kinds of migration 343
18.2 Stolt migration theory 348
18.3 Overview of algorithms 349
18.4 Kirchhoff depth migration methodology 351
18.5 Migration velocity analysis 356
19 Historical Perspective 361
19.1 Progress in seismic processing 361
19.1.1 Dip moveout 361
19.1.2 Anisotropy 362
19.1.3 3D processes 363
19.1.4 Depth migration 364
19.2 A brief account of dip moveout 365
19.2.1 Dip moveout just isn't normal 365
19.2.2 Velocity variation 372
19.2.3 Anisotropy 374
IV. Color Plates 377
V. Interpretation: Extracting Geologic 401
Information from Seismic Data
20 Synthetic Seismogram, Tuning, and Resolution 403
20.1 Creating the synthetic seismogram 403
20.1.1 Earth model 404
20.1.2 Traveltimes 406
20.1.3 Reflection coefficients 407
20.1.4 Wavelet 408
20.1.5 Convolutional model 411
20.1.6 Examples 412
20.1.7 Transmission loss 419
20.2 Tuning 423
20.3 Resolution 427
21 Introduction to Interpretation 433
21.1 What does it mean to interpret seismic data? 433
21.2 Background information 433
21.3 Interactive interpretation systems 438
21.4 Interactive interpretation project components 439
22 Data Volume 443
22.1 Data 2D subsets 444
22.2 Display of seismic data 447
22.3 Interpretation products 448
23 Structure 451
23.1 Fault detection and mapping 452
23.2 Time structure and horizon tracking 456
23.3 Time-to-depth conversion methods 459
23.4 A vertical ray case history 462
23.5 Structural uncertainty 464
23.6 Extreme velocity variation 467
24 Stratigraphy 469
24.1 Stratigraphy and 2D seismic data 469
24.2 Stratigraphy and 3D seismic data 473
24.3 Case history: Stacked sand channel systems 478
24.4 Stratigraphy and structure: A case history 481
24.5 Carbonates 482
25 Seismic attributes 485
25.1 Definition and history 485
25.2 Classification schemes 486
25.2.1 General and special 486
25.2.2 Dimensional 487
25.2.3 Reflection characteristic 488
25.2.4 Procedural 489
25.3 Prediction of reservoir properties 489
25.3.1 Procedure 489
25.3.2 Case history 491
25.3.3 Multiattribute analysis 492
25.4 Selected general attributes 494
25.4.1 Complex trace 494
25.4.2 Dip, azimuth, curvature, and gradient 495
25.4.3 Coherence 495
25.4.4 Spectral decomposition 497
25.4.5 Impedance 501
25.4.6 Spice 502
26 Amplitude in Space, Time, and Offset 505
26.1 Prestack amplitude factors 505
26.2 Stack amplitude and R0 506
26.3 Predictive rock model 508
26.4 Calibrated rock model for Glenn sandstone 510
26.5 Lateral and time-lapse effects 511
26.5.1 Gas 511
26.5.2 Porosity 513
26.5.3 Oil saturation 513
26.5.4 Lithology: Sandstone-limestone 513
26.5.5 Temperature (steamflood) 514
26.5.6 Lithology: Sandstone-clay 514
26.5.7 Permeability 516
26.5.8 Summary and discussion 516
26.6 Time-lapse 3D seismic 517
26.7 Offset effects (AVO) 522
Appendix A Fourier Transform 527
A.1 Definitions 527
A.2 Frequency domain 529
A.3 Spike input 533
A.4 Properties of the Fourier transform 534
A.5 Two spikes 538
A.6 The discrete case 539
A.7 Detection of periodic signals 540
A.8 2D Fourier transform 541
Appendix B Glossary of Terms 545
Appendix C Conversion Factors 557
Appendix D Bibliography 559
Index 577



Library of Congress Subject Headings for this publication: Seismic reflection method