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국회도서관 홈으로 정보검색 소장정보 검색

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동의어 포함

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Title Page

Abstract

Contents

1. Introduction 16

1.1. Full-waveform inversion 17

1.2. Scattering theory and inverse scattering problem 20

1.3. The Lippmann-Schwinger equation 22

1.4. Outline 24

2. Theory 26

2.1. Lippmann-Schwinger equation of seismic scattering 27

2.2. Waveform inversion based on the Lippmann-Schwinger equation 31

2.3. Waveform inversion procedure 35

2.3.1. Forward modeling of the acoustic wave equation 36

2.3.2. The virtual scattering source 43

2.3.3. The scattered wavefield and total wavefield 47

2.3.4. The sloth perturbation 48

2.3.5. Updating of the velocity model 51

3. Numerical examples 54

3.1. Synthetic data example for the Marmousi model 55

3.1.1. Sensitivity to the presence of noise in data 76

3.1.2. Sensitivity to the lack of low frequencies in data 84

3.1.3. Sensitivity to the accuracy of the initial models 87

3.2. Field data example with the Gulf of Mexico data set 97

3.3. Field data example with the TOTAL data set 111

4. Discussion 118

4.1. The presence of noise in data 120

4.2. The lack of low frequencies in data 122

4.3. The accuracy of the initial models 124

4.4. Green's function and the assumption of acoustic media 127

5. Conclusions 128

References 132

초록 140

List of Figures

Figure 2.1. A diagram of the data residual, virtual scattering source and scattered... 34

Figure 2.2. The workflow of Lippmann-Schwinger waveform inversion (LSWI). 52

Figure 3.1. The Marmousi P-wave velocity model. 57

Figure 3.2. (a) A common-shot gather seismogram and (b) a frequency spectrum... 58

Figure 3.3. The initial velocity model for the waveform inversion of the synthetic... 59

Figure 3.4. The frequency-domain reference wavefields propagated in the refer-... 60

Figure 3.5. The frequency-domain data residuals for the 100th shot (located at... 61

Figure 3.6. The frequency-domain virtual scattering sources for the 100th shot... 64

Figure 3.7. The frequency-domain scattered wavefields reconstructed for the... 65

Figure 3.8. The frequency-domain total wavefields reconstructed for the 100th... 66

Figure 3.9. The frequency-domain actual wavefields propagated in the true Mar-... 67

Figure 3.10. The sloth perturbations computed with respect to a frequency of (a)... 68

Figure 3.11. The velocity model updated by the waveform inversion of the syn-... 69

Figure 3.12. The frequency-domain data residuals for the 100th shot (located at... 71

Figure 3.13. The common-shot gather seismograms for the 50th shot (located at a distance of 2.4 km) 72

Figure 3.14. The common-shot gather seismograms for the 100th shot (located at a distance of 4.8 km) 73

Figure 3.15. The common-shot gather seismograms for the 150th shot (located at a distance of 7.2 km) 74

Figure 3.16. The common-shot gather seismograms of the noise-contaminated... 77

Figure 3.17. The inverted velocity models for the noise-contaminated Marmousi... 78

Figure 3.18. The common-shot gather seismograms of noise-contaminated Marmousi data set with Gaussian random ... 79

Figure 3.19. The synthetic common-shot gather seismograms recovered by the waveform inversion of noise-... 80

Figure 3.20. The common-shot gather seismograms of noise-contaminated Marmousi data set with Gaussian random... 81

Figure 3.21. The synthetic common-shot gather seismograms recovered by the waveform inversion of noise-... 82

Figure 3.22. The inverted velocity models with frequency components starting... 86

Figure 3.23. The initial velocity models for the waveform inversion 89

Figure 3.24. The inverted velocity models started with the initial velocity models 90

Figure 3.25. The common-shot gather seismograms of 100th shot 91

Figure 3.26. The comparison of traces from the common-shot gather seismograms of 100th shot for the inverted... 92

Figure 3.27. The migration images for the initial velocity models 95

Figure 3.28. The migration images for the inverted velocity models updated from... 96

Figure 3.29. (a) A common-shot gather seismogram and (b) a frequency spectrum... 98

Figure 3.30. The initial velocity model for the waveform inversion of the Gulf of Mexico data set. 99

Figure 3.31. The inverted velocity model for the waveform inversion of the Gulf of Mexico data set. 100

Figure 3.32. The common-shot gather seismograms of the 210th shot of the Gulf of Mexico data set 102

Figure 3.33. The common-shot gather seismograms of the 250th shot of the Gulf of Mexico data set 103

Figure 3.34. The common-shot gather seismograms of the 300th shot of the Gulf of Mexico data set 104

Figure 3.35. The common-shot gather seismograms of the 350th shot of the Gulf of Mexico data set 105

Figure 3.36. The frequency spectrums after the low-pass and high-pass filter is... 107

Figure 3.37. The inverted velocity model for the waveform inversion of the Gulf of Mexico data set 108

Figure 3.38. The inverted velocity model for the waveform inversion of the Gulf of Mexico data set 109

Figure 3.39. The inverted velocity model for the waveform inversion of the Gulf of Mexico data set 110

Figure 3.40. (a) A common-shot gather seismogram and (b) a frequency spectrum... 112

Figure 3.41. The initial velocity model for the waveform inversion of the TOTAL data set. 113

Figure 3.42. The inverted velocity model for the waveform inversion of the TOTAL data set. 114

Figure 3.43. The common-shot gather seismograms of the 200th shot of the TOTAL data set 115

Figure 3.44. The common-shot gather seismograms of the 600th shot of the TOTAL data set 116

Figure 3.45. The common-shot gather seismograms of the 1000th shot of the TOTAL data set 117