Seismic Amplitude Inversion in Reflection Tomography (eBook)

Yanghua Wang (Autor)

eBook Download: PDF

2003 | 1. Auflage
270 Seiten
Elsevier Science (Verlag)
978-0-08-054087-0 (ISBN)

Infos

This is the first book of its kind on seismic amplitude inversion in the context of reflection tomography. The aim of the monograph is to advocate the use of ray-amplitude data, separately or jointly with traveltime data, in reflection seismic tomography.

The emphasis of seismic exploration is on imaging techniques, so that seismic section can be interpreted directly as a geological section. In contrast it is perhaps ironic that, in decades of industrial seismology, one major aspect of waveform data that potentially is easier to measure and analyse has generally been ignored. That is, the information content of seismic amplitudes. Perhaps the potential complexity has deterred most researchers from a more thorough investigation of the practical use of seismic amplitude data. The author of this volume presents an authoritative and detailed study of amplitude data, as used in conjunction with traveltime data, to provide better constraints on the variation of seismic wave speed in the subsurface.

One of the fundamental problems in conventional reflection seismic tomography using only traveltime data is the possible ambiguity between the velocity variation and the reflector depth. The inclusion of amplitude data in the inversion may help to resolve this problem because the amplitudes and traveltimes are sensitive to different features of the subsurface model, and thereby provide more accurate information about the subsurface structure and the velocity distribution. An essential goal of this monograph is to make the amplitude inversion method work with real reflection seismic data.

Inhalt

Cover 1
Contents 14
Preface 8
Introduction 10
Chapter 1. Introduction to amplitude inversion 18
1.1 Introduction 18
1.2 Velocity-depth ambiguity in traveltime inversion 20
1.3 Resolving ambiguity by using amplitude information 21
1.4 Overview of amplitude inversion 24
1.5 Analytical expression for the geometrical spreading function for layered structures 28
Chapter 2. Traveltime and ray-amplitude in heterogeneous media 32
2.1 Introduction 32
2.2 Bending ray tracing method 34
2.3 Traveltime and its perturbations 37
2.4 Propagator of paraxial rays and geometrical spreading 40
2.5 Ray perturbations due to model perturbations 44
2.6 Ray amplitude 49
Chapter 3. Amplitude coefficients and approximations 52
3.1 Introduction 52
3.2 The Zöppritz equations 53
3.3 The pseudo-p 2 expressions 55
3.4 Quadratic expressions in terms of elastic contrasts 56
3.5 Accuracy of the quadratic approximations 58
3.6 Amplitude coefficients represented as a function of three elastic parameters 61
3.7 Three elastic parameters from amplitude inversion 62
3.8 Implication for fluid substitution modelling 65
Chapter 4. Amplitude inversion for interface geometry 68
4.1 Introduction 68
4.2 Parameterization and forward modelling 69
4.3 Subspace gradient inversion method 71
4.4 A simple example of reflection amplitude inversion 74
4.5 Inversion for an interface represented as a sum of harmonic functions 81
4.6 Stability of the amplitude inversion 87
4.7 Strategy for the choice of Ak and M 89
4.8 Discussion 93
Chapter 5. Amplitude inversion for velocity variation 96
5.1 Introduction 96
5.2 Amplitude dependence on slowness perturbation 97
5.3 Inversion algorithm 100
5.4 Inversion example of 1-D slowness distribution 104
5.5 Constraining higher wavenumber components 106
5.6 Robustness of the inversion in the presence of model error or data noise 110
5.7 Inversion of arbitrary smooth velocity anomalies 112
5.8 Discussion 118
Chapter 6. Sensitivities of traveltimes and amplitudes in joint inversion 120
6.1 Introduction 120
6.2 The Hessian and the norm in model space 122
6.3 Sensitivities to interface geometry 128
6.4 Sensitivities to 2-D slowness variation 142
6.5 Inversion formula 148
6.6 Joint inversion for an interface 152
6.7 Joint inversion for slowness 153
6.8 Discussion 157
Chapter 7. Amplitude inversion of a multi-layered structure 160
7.1 Introduction 160
7.2 Forward calculation and inverse method 161
7.3 Preliminary inversion test 165
7.4 Damped subspace method 169
7.5 Multi-scale scheme 172
7.6 Multi-stage damped subspace method 174
Chapter 8. Practical approach to application 180
8.1 Introduction 180
8.2 Amplitudes estimated from migrated gathers 182
8.3 Demigration of reflection amplitudes 186
8.4 Winnowing amplitudes by LOESS 189
8.5 Inversion procedure 191
8.6 Inversion results 194
Chapter 9. Simultaneous inversion for model geometry and elastic parameters 200
9.1 Introduction 200
9.2 Ray-amplitude and its approximation 201
9.3 Inversion method 202
9.4 Inversion example 207
9.5 Measurements for lithological interpretation 212
9.6 Structural effects on amplitude variation 215
Chapter 10. Decomposition of structural effect and AVO attributes 218
10.1 Introduction 218
10.2 Decomposition of ray-amplitude 219
10.3 The inverse problem 221
10.4 Sample dataset of gas-water contact 223
10.5 Inversion results 226
10.6 The Chebyshev spectra of the AVO attributes 229
Chapter 11. Amplitude tomography in practice 234
11.1 Introduction 234
11.2 Estimate of amplitudes, traveltimes and data uncertainties 236
11.3 Tomographic inversion incorporating more information and using an improved forward calculation 238
11.4 Consideration of factors influencing amplitudes 239
11.5 Turning-ray tomography for near-surface velocity structure and attenuation 243
11.6 Prestack seismic trace inversion for ray elastic impedance 244
Appendices 252
A.1 Derivation of the geometrical spreading function 252
A.2 Derivation of reflection amplitude demigration 256
References 260
Author Index 268
Topic Index 270

Produkt-Details

• Erscheint lt. Verlag: 25.2.2003
• Sprache: englisch
• Themenwelt: Sachbuch/Ratgeber
• Themenwelt: Naturwissenschaften ► Geowissenschaften ► Geologie
• Themenwelt: Naturwissenschaften ► Geowissenschaften ► Geophysik
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Angewandte Physik
• Themenwelt: Technik
• ISBN-10: 0-08-054087-2 / 0080540872
• ISBN-13: 978-0-08-054087-0 / 9780080540870