4 research outputs found
μκ° μμ νλ μ ν λͺ¨λΈλ§μ μ΄μ©ν λΌνλΌμ€-νΈλ¦¬μ μμ νμ±ν μμ νν μμ°
νμλ
Όλ¬Έ (μμ¬)-- μμΈλνκ΅ λνμ : μλμ§μμ€ν
곡νλΆ, 2014. 2. μ μ°½μ.μ‘μ νμ±ν νμ¬ μλ£λ₯Ό ν΅ν΄ μν₯ν μμ νν μμ°μ μ΄μ©νμ¬ μ§ν ꡬ쑰μ λν μ 보λ₯Ό μ»κΈ° μν΄μλ κ·ΈλΌμ΄λ λ‘€κ³Ό λͺ¨λ λ³ν νλ€κ³Ό κ°μ νμ±νμ μν₯μ μ΅μ ν΄μΌ νλ€. λ§μ μ μ²λ¦¬λ₯Ό ν΅ν΄ νμ±νμ μν₯μ μ΅μ νλ κ³Όμ μ€μ μν₯νμ λν λ³ν λν νΌν μ μλ€. κ²λ€κ° μ€μ²΄νμ νλ©΄νλ₯Ό μμ ν λΆλ¦¬ ν΄λ΄λ κ²μ κ±°μ λΆκ°λ₯μ κ°κΉλ€. μ΄λ¬ν μ΄μ λ‘ μ€μ ννκ³Ό λ μ μ¬ν νλ₯Ό λ§λ€μ΄ λ΄κΈ° μν΄ λͺ¨λΈλ§ λ¨κ³μμ λ μ’
λ₯μ νλ₯Ό λͺ¨λ λ§λ€μ΄λΌ νμκ° μλ€. λ°λΌμ μ νν μμ νν μμ°μ μν΄μλ νμ±νλλ°©μ μμ μ΄μ©ν νμ±ν μμ νν μμ°μ΄ νμμ μ΄λ€. λν νμ±ν μμ νν μμ°μ Pν μλλΏλ§ μλλΌ Sν μλμ λ°λ μ 보λ ν¨κ» μμ° ν μ μμ΄μ μν₯ν μμ νν μμ°λ³΄λ€ λ λ§μ μ§μ§νμ μΈ μ 보λ₯Ό μ κ³΅ν΄ μ€ μ μλ€. μκ° μμ λͺ¨λΈλ§μ μ΄μ©ν λΌνλΌμ€-νΈλ¦¬μ μμ μμ νν μμ°μ μκ° μμ νλ μ ν λͺ¨λΈλ§κ³Ό λΌνλΌμ€-νΈλ¦¬μ μμ μμ νν μμ°μ κ²°ν©ν μκ³ λ¦¬μ¦μ΄λ€. μ μ ν νλμ₯κ³Ό μ μ ν νλμ₯μ μκ° μμμμ μ»κΈ° μνμ¬ μ격μ μ ν μ°¨λΆλ²μ΄ μ¬μ©λμλ€. νμ¬ μλ£μ λͺ¨λΈλ§ μλ£κ°μ μμ°¨, κ°μ μ‘μ μ, ν€μμ κ·Έλ¦¬κ³ κ΅¬λ°°λλ λΌνλΌμ€-νΈλ¦¬μ μμμμ κ³μ° λμλ€. μ°λ¦¬λ μκ° μμ νλ μ ν λͺ¨λΈλ§μΌλ‘ μ μ ν λ° μ μ ν νλμ₯μ ꡬνμλλ° μ΄λ μκ° μμμ νλμ₯μ λΌνλΌμ€-νΈλ¦¬μ μμ νλμ₯μ λΉν΄ λ μ§κ΄μ μΌλ‘ λ€λ£° μ μμ΄μμΌ λΏ μλλΌ νλ ¬ μλ²λ₯Ό μ΄μ©νμ§ μκ³ ν¨μ¨μ μΈ λͺ¨λΈλ§μ ν μ μμ΄μ μ΄λ€. μ΅μ ν κ³Όμ μ λΌνλΌμ€-νΈλ¦¬μ μμμμ μ§νλμλλ° μλνλ©΄ λΌνλΌμ€-νΈλ¦¬μ μμ μμ νν μμ°μ μ μ£Όν μ±λΆμ΄ λΆμ‘±ν μ€μ νμ₯ μλ£μ μ μ©μ΄ κ°λ₯νκΈ° λλ¬Έμ΄λ€. μ΄ μ°κ΅¬λ₯Ό ν΅ν΄ μ μλ μκ³ λ¦¬μ¦μ κ²μ¦νκΈ° μν΄μ μΈκ³΅ ν©μ±μλ£μ μ€μ νμ¬ μλ£μ λν΄ μμΉ μ€νμ μ§ννμλ€. μΈκ³΅ ν©μ±μλ£λ‘λ λͺ¨λΈ 94 μ‘μ μλ£λ₯Ό μ¬μ© νμκ³ μ€μ μλ£λ‘λ λ²€μλ―Ό ν¬λ¦ μ‘μ νμ¬ μλ£λ₯Ό μ¬μ© νμλ€.To obtain subsurface information from onshore seismic exploration data using full waveform inversion (FWI) based on the acoustic wave equation, elastic waves, such as ground rolls and mode-converted waves, should be suppressed through heavy preprocessing. However, the preprocessing deforms not only the elastic waves but also the acoustic waves. Moreover, it is not easy to separate body waves and surface waves in seismic traces. For these reasons, in the modeling step, we need to generate both types of waves to obtain more similar seismic waves to the real seismic waves. Therefore, elastic full waveform inversion using elastic wave equation is necessary for more accurate full waveform inversion. In addition, elastic full waveform inversion can give better geological information than acoustic full waveform inversion because it inverts P-wave velocity, S-wave velocity and density. Laplace-Fourier domain FWI using time-domain modeling combines time-domain wave propagation modeling and Laplace-Fourier-domain FWI. To obtain forward wavefield and adjoint wavefield in the time domain, we implemented staggered grid finite difference method. The residuals between the recorded and modeled data, virtual sources, hessian matrices and gradient directions were calculated in the Laplace-Fourier domain. We used time domain wave propagation modeling for the forward and adjoint wavefield because it is more intuitive to treat the wavefield in the time domain than in the Laplace-Fourier domain. Moreover, time domain wave propagation modeling using staggered grid finite difference method does not need matrix solver which is necessary for the conventional Laplace-Fourier domain FWI. The optimization procedure is conducted in the Laplace-Fourier domain because Laplace-Fourier-domain FWI can be applied to real seismic data, which lacks low-frequency components. To validate our proposed algorithm, we performed numerical tests with synthetic data and real exploration data. We applied the algorithm to Model 94 synthetic onshore data and Benjamin Creek real onshore data.Abstract..........................................................................................................1
Chapter 1 Introduction .............................................................................1
Chapter 2 Theory.......................................................................................7
2.1 Time domain wave propagation modeling....................................7
2.2 Wavefield in the Laplace-Fourier domain.....................................9
2.3 Full waveform inversion in the Laplace-Fourier domain............10
2.4 The construction of the virtual source vectors ............................13
2.5 Update model parameters with the pseudo-Hessian ...................15
2.6 Algorithm of the Laplace-Fourier domain FWI using time domain modeling...................................................................................17
Chapter 3 Numerical Examples .............................................................19
3.1 Comparison of the memory and time..........................................19
3.2 Synthetic data FWI Example ......................................................23
3.2.1 Model 94 synthetic onshore data.............................................23
3.2.2 Laplace-Fourier domain FWI ..................................................25
3.3 Field data FWI Example .............................................................36
3.3.1 Benjamin Creek field onshore data .........................................36
3.3.2 Laplace-Fourier domain FWI ..................................................38
Chapter 4 Conclusions ............................................................................48
Chapter 5 References ..............................................................................50Maste
source-independent frequency-domain acoustic full waveform inversion using time-domain modeling
νμλ
Όλ¬Έ (λ°μ¬)-- μμΈλνκ΅ λνμ : μλμ§μμ€ν
곡νλΆ, 2017. 2. μ μ°½μ.μμ νν μμ°μ μ§ν 맀μ§μ λ¬Όμ± κ°μ κ³μ°νλ λ°©λ²μΌλ‘ κ΄μΈ‘ νλμ₯κ³Ό μμΉ νλμ₯ μ¬μ΄μ μ°¨μ΄λ₯Ό μ€μ¬λκ°λ λ°©ν₯μΌλ‘ μ§ν 맀μ§μ λ¬Όμ± κ°μ μ
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립 μμ νν μμ° κΈ°λ²μ μ μνλ€. μ‘μ νν λ
립 μμ νν μμ°μ ν¬κ² λμ½λ³Όλ£¨μ
κΈ°λ°κ³Ό μ½λ³Όλ£¨μ
κΈ°λ°μΌλ‘ λλ μ μμΌλ©° λ³Έ μ°κ΅¬μμλ κ° μ‘μ νν λ
립 μμ νν μμ°μ νΉμ±μ λΉκ΅νμλ€. μ‘μ νν λ
립 μμ νν μμ°μμ κ°μ₯ μ€μν κ²μ μ°Έμ‘° νΈλ μ΄μ€μ μ ν λ°©λ²μ΄λ―λ‘ μ°Έμ‘° νΈλ μ΄μ€ μ ν λ°©λ²μ λ³κ²½μμΌκ°λ©° μ΄λ ν μ°Έμ‘° νΈλ μ΄μ€ μ ν λ°©λ²μ΄ κ°μ₯ μ μ ν λ°©λ²μΈμ§ μ μνμλ€. λν κΈ°μ‘΄μ μ‘μ νν λ
립 μμ νν μμ°μ νμ₯ μλ£μ μ μ©ν λ λ°μνμλ λ¬Έμ μ μ 극볡νκΈ° μν΄μ μκ° μ°½μ μ μ©ν μ‘μ νν λ
립 μμ νν μμ°μ μ μνμλ€. κΈ°μ‘΄ μ£Όνμ μμ μμ νν μμ°μλ μκ° μ°½μ μ μ©νκΈ°κ° μ½μ§ μκΈ° λλ¬Έμ μκ° μμ λͺ¨λΈλ§μ μ΄μ©ν μ£Όνμ μμ μμ νν μμ°μ μκ° μ°½μ μ μ©νμ¬ νμ₯ μλ£μ λν μ μ©μ±μ λμ΄κ³ μ νμλ€. μ μλ μκ³ λ¦¬μ¦μ κ²μ¦νκΈ° μν΄μ Marmousi μΈκ³΅ ν©μ± μλ£μ λν΄ μ‘μμ΄ μλ νκ²½κ³Ό μλ νκ²½μμ μν₯ν μμ νν μμ°μ μ΄μ©νμ¬ μμΉ μ€νμ μ§ννμλ€. λμ½λ³Όλ£¨μ
κΈ°λ°κ³Ό μ½λ³Όλ£¨μ
κΈ°λ°μ μ‘μ νν λ
립 μμ νν μμ°μ λν΄ κ°κ° μ€νμ μ§ννμκ³ μ°Έμ‘° νΈλ μ΄μ€μ μ ν λ°©λ²κ³Ό μκ° μ°½μ κΈΈμ΄λ₯Ό λ³κ²½νλ©΄μ κ²°κ³Όλ₯Ό λΉκ΅νμλ€. νμ₯ μλ£μ λν μ μ©μ±μ κ²μ¦νκΈ° μν΄μ λ©μμ½λ§(Gulf of Mexico) νμ₯ μλ£μ μ‘μ νν λ
립 μμ νν μμ°μ μ μ©νμκ³ μλ λͺ¨λΈμ μ±κ³΅μ μΌλ‘ λμΆνμλ€. μμ°λ μλ λͺ¨λΈμ ꡬ쑰보μ , κ³΅ν΅ μ΄λ―Έμ§ λͺ¨μ, κ³΅ν΅ μ‘μ μ λͺ¨μμ λΉκ΅λ₯Ό ν΅ν΄ κ²μ¦λμλ€. μμΉ μμ λ₯Ό ν΅ν΄ μ‘μ μ μ£Όλ³ μ μ μμ νΈλ μ΄μ€λ₯Ό μ΄μ©νμ¬ μ°Έμ‘° νΈλ μ΄μ€λ₯Ό ꡬμ±νκ³ μ§μ νλ§ ν¬ν¨ νλλ‘ μκ° μ°½μ μ μ©ν μ½λ³Όλ£¨μ
κΈ°λ°μ μ‘μ νν λ
립 μμ νν μμ°μ΄ μ€μ μλ£μ κ°μ₯ μ ν©ν λ°©λ²μμ 보μλ€.μ 1 μ₯ μ λ‘ 1
1.1 μ°κ΅¬μ λ°°κ²½ 1
1.2 μ°κ΅¬μ λͺ©μ 7
1.3 μ°κ΅¬μ κ΅¬μ± 9
μ 2 μ₯ μ£Όνμ μμ μμ νν μμ° 10
2.1 μ£Όνμ μμ μμ νν μμ° μκ³ λ¦¬μ¦ 10
2.2 μκ° μμ λͺ¨λΈλ§μ μ΄μ©ν μ£Όνμ μμ μμ νν μμ° 14
2.3 L-BFGSλ₯Ό μ΄μ©ν μ΅μ ν 18
2.4 λ°λ³΅μ μ‘μ νν μμ° 23
2.4.1 λ°λ³΅μ μ‘μ νν μμ° μ΄λ‘ 23
2.4.2 λ°λ³΅μ μ‘μ νν μμ°μ λ¬Έμ μ 26
μ 3 μ₯ μ‘μ νν λ
립 μμ νν μμ° 35
3.1 λμ½λ³Όλ£¨μ
λ°©λ² 35
3.1.1 λμ½λ³Όλ£¨μ
λ°©λ²μ μ΄μ©ν νλμ₯ 35
3.1.2 λμ½λ³Όλ£¨μ
λ°©λ²μ μ΄μ©ν μμ νν μμ° 41
3.2 μ½λ³Όλ£¨μ
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3.2.1 μ½λ³Όλ£¨μ
λ°©λ²μ μ΄μ©ν νλμ₯ 44
3.2.2 μ½λ³Όλ£¨μ
λ°©λ²μ μ΄μ©ν μμ νν μμ° 50
3.3 μ°Έμ‘° νΈλ μ΄μ€ μ ν 53
3.4 μκ° μ°½μ μ΄μ©ν μ°Έμ‘° νΈλ μ΄μ€ 67
μ 4 μ₯ μΈκ³΅ ν©μ± μλ£ μμΉ μμ 77
4.1 μμ νν μμ°μ μν μ€λΉ 77
4.2 Marmoursi μΈκ³΅ ν©μ± μλ£ 80
4.3 μ‘μμ ν¬ν¨ν Marmoursi μΈκ³΅ ν©μ± μλ£ 95
4.3.1 κ°μ°μ€ 무μμ μ‘μ 97
4.3.2 κ°μ°μ€ 무μμ μ‘μκ³Ό μ€νμ΄ν¬ μ‘μ 108
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μ 5 μ₯ νμ₯ μλ£ μμΉ μμ 131
5.1 μμ νν μμ°μ μν μ€λΉ 131
5.2 λ©μμ½λ§ νμ₯ μλ£ 136
μ 6 μ₯ κ²° λ‘ 165
μ°Έκ³ λ¬Έν 169Docto