computational methods for inverse problems in geophysics
play

Computational Methods for Inverse Problems in Geophysics Russell J. - PowerPoint PPT Presentation

Computational Methods for Inverse Problems in Geophysics Russell J. Hewett Mathematics & CMDA, Virginia Tech Theory and Experience in Solving Inverse Problems in Geophysics Workshop Uppsala University April 9, 2019 RJH (Virginia Tech)


  1. Exploration Seismic Data Acquisition: Receivers Land: Geophone http://web.mit.edu/12.000/www/finalpresentation/experiments/geology.html RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 14 / 55

  2. Exploration Seismic Data Acquisition: Receivers Land: Geophone http://web.mit.edu/12.000/www/finalpresentation/experiments/geology.html RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 14 / 55

  3. Exploration Seismic Data Acquisition: Receivers Marine: Hydrophone https://woodshole.er.usgs.gov/operations/sfmapping/hydrophone.htm RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 14 / 55

  4. Exploration Seismic Data Acquisition: Receivers 4-Component Sensors (4C) https://www.glossary.oilfield.slb.com/Terms/sym/4c seismic data.aspx RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 14 / 55

  5. Exploration Seismic Data Acquisition x=128 t=1024 100 500 200 1000 t t x 300 1500 400 2000 500 100 200 300 400 500 100 200 300 400 500 y y t=1024 RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 15 / 55

  6. Geophysical Inverse Problems I am considering only the seismic inverse problem. Regimes I have neglected: ◮ CSEM (Controlled Source Electromagnetic) ◮ Gravity ◮ LIDAR ◮ etc. RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 16 / 55

  7. Geophysical Inverse Problems I will discuss only the full-waveform inversion problem and I will stay in an “exploration” context. Seismic Data Response RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 17 / 55

  8. Geophysical Inverse Problems I will discuss only the full-waveform inversion problem and I will stay in an “exploration” context. Seismic Data Response RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 17 / 55

  9. Geophysical Inverse Problems I will discuss only the full-waveform inversion problem and I will stay in an “exploration” context. Seismic Data Response RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 17 / 55

  10. (Exploration) Seismic Inverse Problem max $ ( d, k, $) RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 18 / 55

  11. (Exploration) Seismic Inverse Problem max $ ( d, k, $) d : data RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 18 / 55

  12. (Exploration) Seismic Inverse Problem max $ ( d, k, $) d : data k : knowledge RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 18 / 55

  13. (Exploration) Seismic Inverse Problem max $ ( d, k, $) d : data k : knowledge $ : money RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 18 / 55

  14. (Exploration) Seismic Inverse Problem max $ ( d, k, $) d : data k : knowledge $ : money $ : more money RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 18 / 55

  15. (Exploration) Seismic Inverse Problem max $ ( d, k, $) Subproblems: RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 19 / 55

  16. (Exploration) Seismic Inverse Problem max $ ( d, k, $) Subproblems: ◮ arg max $ ( d, k, $) d ◮ Find better data ◮ Engineers and Analysts RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 19 / 55

  17. (Exploration) Seismic Inverse Problem max $ ( d, k, $) Subproblems: ◮ arg max $ ( d, k, $) d ◮ Find better data ◮ Engineers and Analysts ◮ arg max $ ( d, k, $) k ◮ Find better knowledge or use knowledge better ◮ Research Scientists RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 19 / 55

  18. (Exploration) Seismic Inverse Problem max $ ( d, k, $) Subproblems: ◮ arg max $ ( d, k, $) d ◮ Find better data ◮ Engineers and Analysts ◮ arg max $ ( d, k, $) k ◮ Find better knowledge or use knowledge better ◮ Research Scientists ◮ arg min max $ ( d, k, $) $ ◮ Do all this, but cheaper ◮ Managers RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 19 / 55

  19. (Exploration) Seismic Inverse Problem max $ ( d, k, $) Subproblems: ◮ arg max $ ( d, k, $) d ◮ Find better data ◮ Engineers and Analysts ◮ arg max $ ( d, k, $) k ◮ Find better knowledge or use knowledge better ◮ Research Scientists ◮ arg min max $ ( d, k, $) $ ◮ Do all this, but cheaper ◮ Managers RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 19 / 55

  20. Seismic Inverse Problem Full Waveform Inversion Objective J ( m ) = � d ( t ) − F ( m ( x )) � 2 2 d ( t ) : Data m ( x ) : Unknown physical coefficients F : Modeling operator RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 20 / 55

  21. Seismic Inverse Problem FWI Objective: “Complete” Version � J ( m, f ) = {� g ( d s ) − g ( S s F s ( R s ( m ) , f s )) � + T f ( f s ) } + T m ( m ) s ∈S RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 21 / 55

  22. Seismic Inverse Problem Full Waveform Inversion Objective J ( m ) = � d ( t ) − F ( m ( x )) � 2 2 d ( t ) : Data m ( x ) : Unknown physical coefficients F : Modeling operator RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 22 / 55

  23. Seismic Inversion Full Waveform Inversion Objective J ( m ) = � d ( t ) − F ( m ( x )) � 2 2 d ( t ) : Data m ( x ) : Unknown physical coefficients F : Modeling operator RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 23 / 55

  24. Seismic Inversion Full Waveform Inversion Objective J ( m ) = � d ( t ) − F ( m ( x )) � 2 2 d ( t ) : Data m ( x ) : Unknown physical coefficients F : Modeling operator RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 24 / 55

  25. Seismic Inversion Full Waveform Inversion Problem J ( m ) = � d ( t ) − F ( m ( x )) � 2 arg min 2 m s.t. L [ m ] u = f for F ( m ) = u ◮ L [ m ] u = f is a wave equation ◮ F operator solves wave equations ◮ PDE constrained optimization! ◮ Time-domain, frequency-domain, Laplace-domain, etc. RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 25 / 55

  26. Modeling Operators Example: Second Order Isotropic Acoustics (w/ Constant Density) ◮ m ( x ) = 1 /c 2 ( x ) , where c ( x ) is p-wave velocity ◮ L is self adjoint ◮ For continuous at least. . . ◮ Up to BCs F ( m 0 ) = u 0 ⇔ ( m 0 ∂ tt − △ ) u 0 = f F m 0 δm = δu ⇔ ( m 0 ∂ tt − △ ) δu = − δm∂ tt u 0 � δm, − � q, ∂ tt u 0 � T � Ω F ∗ m 0 r = δm ⇔ s.t. ( m 0 ∂ tt − △ ) q = r � T δm = − � q, ∂ tt u 0 � T = − q ( x, t ) ∂ tt u 0 ( x, t ) dt 0 RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 27 / 55

  27. Optimization Setup J ( m ) = 1 2 || d − F ( m ) || 2 2 ◮ Objective function evaluation ◮ Computation: Solve wave equation ◮ Cost: ∼ 1 RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 28 / 55

  28. Optimization Setup J ( m ) = 1 2 || d − F ( m ) || 2 2 ◮ Objective function evaluation ◮ Computation: Solve wave equation ◮ Cost: ∼ 1 ∇ J ( m 0 ) = − F ∗ m 0 ( d − F ( m 0 )) ◮ Objective gradient evalutation ◮ Computation: Adjoint state method ◮ Cost: ∼ 2+ RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 28 / 55

  29. Optimization Setup J ( m ) = 1 2 || d − F ( m ) || 2 2 ◮ Objective function evaluation ◮ Computation: Solve wave equation ◮ Cost: ∼ 1 ∇ J ( m 0 ) = − F ∗ m 0 ( d − F ( m 0 )) ◮ Objective gradient evalutation ◮ Computation: Adjoint state method ◮ Cost: ∼ 2+ D 2 Jδm = F ∗ m 0 F m 0 δm − < D 2 F δm, d − F ( m 0 ) > ◮ Objective Hessian application ◮ Computation: 2 nd -order adjoint state method ◮ Cost: ∼ 4+ RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 28 / 55

  30. Modeling Operators F ( m 0 ) = u 0 ⇔ L [ m 0 ] u 0 = f ◮ Forward modeling ◮ Cost: 1 wave solve RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 29 / 55

  31. Modeling Operators F ( m 0 ) = u 0 ⇔ L [ m 0 ] u 0 = f ◮ Forward modeling ◮ Cost: 1 wave solve L [ m 0 ] δu = − δL F m 0 δm = δu ⇔ δm [ δm ] u 0 ◮ Linear forward modeling (Born) ◮ Cost: 2 wave solves ◮ Impossible to form as matrix! RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 29 / 55

  32. Modeling Operators F ( m 0 ) = u 0 ⇔ L [ m 0 ] u 0 = f F ∈ R m × n ◮ Forward modeling ◮ Cost: 1 wave solve L [ m 0 ] δu = − δL F m 0 δm = δu ⇔ δm [ δm ] u 0 ◮ Linear forward modeling (Born) ◮ Cost: 2 wave solves ◮ Impossible to form as matrix! RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 29 / 55

  33. Modeling Operators F ( m 0 ) = u 0 ⇔ L [ m 0 ] u 0 = f F ∈ R m × n ◮ Forward modeling 3D Survey ◮ Cost: 1 wave solve ◮ 10 × 1000 rcv (small) ◮ 8s recording (short) L [ m 0 ] δu = − δL ◮ 8ms sampling (long) F m 0 δm = δu ⇔ δm [ δm ] u 0 ◮ m = 10,000,000 samples ◮ Linear forward modeling (Born) ◮ Cost: 2 wave solves ◮ Impossible to form as matrix! RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 29 / 55

  34. Modeling Operators F ( m 0 ) = u 0 ⇔ L [ m 0 ] u 0 = f F ∈ R m × n ◮ Forward modeling 3D Survey ◮ Cost: 1 wave solve ◮ 10 × 1000 rcv (small) ◮ 8s recording (short) L [ m 0 ] δu = − δL ◮ 8ms sampling (long) F m 0 δm = δu ⇔ δm [ δm ] u 0 ◮ m = 10,000,000 samples ◮ Linear forward modeling (Born) 3D Modeling ◮ Cost: 2 wave solves ◮ 876 × 1001 × 750 dof ◮ Impossible to form as matrix! ◮ n = 657,657,000 dof RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 29 / 55

  35. Modeling Operators F ( m 0 ) = u 0 ⇔ L [ m 0 ] u 0 = f F ∈ R m × n ◮ Forward modeling 3D Survey ◮ Cost: 1 wave solve ◮ 10 × 1000 rcv (small) ◮ 8s recording (short) L [ m 0 ] δu = − δL ◮ 8ms sampling (long) F m 0 δm = δu ⇔ δm [ δm ] u 0 ◮ m = 10,000,000 samples ◮ Linear forward modeling (Born) 3D Modeling ◮ Cost: 2 wave solves ◮ 876 × 1001 × 750 dof ◮ Impossible to form as matrix! ◮ n = 657,657,000 dof Matrix Size ◮ IEEE single precision. . . ◮ ∼ 23.4PB Storage ◮ n wave solves ◮ ∼ 18 years @ 100k/day RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 29 / 55

  36. Modeling Operators F ( m 0 ) = u 0 ⇔ L [ m 0 ] u 0 = f F ∈ R m × n ◮ Forward modeling 3D Survey ◮ Cost: 1 wave solve ◮ 10 × 1000 rcv (small) ◮ 8s recording (short) L [ m 0 ] δu = − δL ◮ 8ms sampling (long) F m 0 δm = δu ⇔ δm [ δm ] u 0 ◮ m = 10,000,000 samples ◮ Linear forward modeling (Born) 3D Modeling ◮ Cost: 2 wave solves ◮ 876 × 1001 × 750 dof ◮ Impossible to form as matrix! ◮ n = 657,657,000 dof Matrix Size q, − δL � � δm [ δm ] u 0 F ∗ Ω × T ◮ IEEE single precision. . . m 0 r = δm ⇔ s.t. L ∗ [ m 0 ] q = r ◮ ∼ 23.4PB Storage ◮ n wave solves ◮ Adjoint modeling ◮ ∼ 18 years ◮ “Migration” or imaging operator @ 100k/day ◮ Cost: 1+ wave solves RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 29 / 55

  37. Solving FWI ◮ Solve with gradient-based optimization Generalized Gradient Scheme 1. Given m 0 . 2. While i < MaxIter 2.1 g i = ∇ J ( m i ) 2.2 s i = h ( m i , g i ) 2.3 α = LineSearch ( m i , g i , s i ) 2.4 m i +1 = m i + αs i ◮ Gradient descent? ◮ L-BFGS? ◮ Hessian/Quasi-Newton schemes? RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 30 / 55

  38. Solving FWI (a) True (b) Initial (c) Final ◮ 50 L-BFGS iterations w/ Locally 1D Time Solver (L. Zepeda, RJH, M. Rao, L. Demanet (SEG 2013)) RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 31 / 55

  39. Real-world Utility ◮ Interpreters don’t actually use inverted material parameters ◮ They still want to look at seismic “images” ◮ Found by “migration” or imaging algorithms ◮ Kirchoff migration ◮ (One-way) wave equation migration ◮ Reverse-time migration ◮ Linearized inversion RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 32 / 55

  40. Real-world Utility ◮ Interpreters don’t actually use inverted material parameters ◮ They still want to look at seismic “images” ◮ Found by “migration” or imaging algorithms ◮ Kirchoff migration ◮ (One-way) wave equation migration ◮ Reverse-time migration ◮ Linearized inversion ◮ Migration is essentially back-propagation ◮ Or, we can consider it as a gradient calculation in FWI RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 32 / 55

  41. Real-world Utility ◮ Interpreters don’t actually use inverted material parameters ◮ They still want to look at seismic “images” ◮ Found by “migration” or imaging algorithms ◮ Kirchoff migration ◮ (One-way) wave equation migration ◮ Reverse-time migration ◮ Linearized inversion ◮ Migration is essentially back-propagation ◮ Or, we can consider it as a gradient calculation in FWI ◮ In any case, it is computed at much higher-frequency ◮ Looking at reflectivity, not material parameters RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 32 / 55

  42. Seismic Image Netherlands Block F3 - Crossline 900 https://ghassanalregibdotcom.files.wordpress.com/2018/05/amir aapg2018 slides.pdf RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 33 / 55

  43. Real World Results “An offshore Gabon full-waveform inversion case study,” Xiao, et al., Interpretation , November 2016. Data from CGG. RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 34 / 55

  44. Real World Results “An offshore Gabon full-waveform inversion case study,” Xiao, et al., Interpretation , November 2016. Data from CGG. RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 34 / 55

  45. Real World Results “An offshore Gabon full-waveform inversion case study,” Xiao, et al., Interpretation , November 2016. Data from CGG. RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 34 / 55

  46. Real World Results “An offshore Gabon full-waveform inversion case study,” Xiao, et al., Interpretation , November 2016. Data from CGG. RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 34 / 55

  47. Challenges for FWI ◮ Due to the physical formulation ◮ Due to mathematical formulation ◮ Due to computational requirements ◮ Due to business decisions RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 35 / 55

  48. Cycle Skipping Jean Virieux ◮ Due to the physical and mathematical formulations ◮ Manifests as global nonconvexity ◮ Partially resolved by working in frequency domain (or in Laplace domain) ◮ Time-domain wave equation becomes Helmholtz equation RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 36 / 55

  49. FWI In Frequency Domain 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 ◮ max. 512 wavelengths in domain ◮ PML width: 2.5 wavelengths ◮ 64 × 64 domain decomposition RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 37 / 55

  50. FWI In Frequency Domain 0 20 40 60 80 100 120 140 0 100 200 300 400 500 0 20 40 60 80 100 120 140 0 100 200 300 400 500 0 20 40 60 80 100 120 140 0 100 200 300 400 500 ◮ Frequency continuation RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 38 / 55

  51. Realistic and Practical Physics ◮ I have shown the idea behind FWI using constant density acoustic physics ◮ Of course, the earth is not constant density, nor acoustic ◮ Massive increase in computational – and software – costs ◮ Does better physics drive the need for more compute? ◮ Or is more compute driving the availability of better physics? RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 39 / 55

  52. Realistic and Practical Physics Physical Models ∂ tt u = a △ u + f Physics Solutions Parameters Computation Iso-Aco (const. ρ ) (2nd) 1 1 – RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 40 / 55

  53. Realistic and Practical Physics Physical Models � p � � p � g � � � � − c ∇· ∂ t = + a ∇ v v h Physics Solutions Parameters Computation Iso-Aco (const. ρ ) (2nd) 1 1 – Iso-Aco (1st) 4 2 1x-2x RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 40 / 55

  54. Realistic and Practical Physics Physical Models � ˜ � � ˜ � g − A T D ∗ R � � � � σ σ ∂ t = + a R T DA v v h Physics Solutions Parameters Computation Iso-Aco (const. ρ ) (2nd) 1 1 – Iso-Aco (1st) 4 2 1x-2x TTI-Aco (1st) 5 (+?) 4 3x RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 40 / 55

  55. Realistic and Practical Physics Physical Models � σ � � σ � g − C D ∗ � � � � ∂ t = + a D v v h Physics Solutions Parameters Computation Iso-Aco (const. ρ ) (2nd) 1 1 – Iso-Aco (1st) 4 2 1x-2x TTI-Aco (1st) 5 (+?) 4 3x Iso-Ela (1st) 9 3 ∼ 40x RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 40 / 55

  56. Realistic and Practical Physics Physical Models � σ � � σ � g − C D ∗ � � � � ∂ t = + a D v v h Physics Solutions Parameters Computation Iso-Aco (const. ρ ) (2nd) 1 1 – Iso-Aco (1st) 4 2 1x-2x TTI-Aco (1st) 5 (+?) 4 3x Iso-Ela (1st) 9 3 ∼ 40x VTI-Ela (1st) 9 8 ∼ 40x RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 40 / 55

  57. Realistic and Practical Physics Physical Models � σ � � σ � g − C D ∗ � � � � ∂ t = + a D v v h Physics Solutions Parameters Computation Iso-Aco (const. ρ ) (2nd) 1 1 – Iso-Aco (1st) 4 2 1x-2x TTI-Aco (1st) 5 (+?) 4 3x Iso-Ela (1st) 9 3 ∼ 40x VTI-Ela (1st) 9 8 ∼ 40x TTI-Ela (1st) 9 36 > 100x RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 40 / 55

  58. Realistic and Practical Physics Physical Models � σ � � σ � g − C D ∗ � � � � ∂ t = + a D v v h Physics Solutions Parameters Computation Iso-Aco (const. ρ ) (2nd) 1 1 – Iso-Aco (1st) 4 2 1x-2x TTI-Aco (1st) 5 (+?) 4 3x Iso-Ela (1st) 9 3 ∼ 40x VTI-Ela (1st) 9 8 ∼ 40x TTI-Ela (1st) 9 36 > 100x Elastic (1st) 9 81 > 100x RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 40 / 55

  59. Software Considerations ◮ I have greatly simplified the problem ◮ Only considering one simple PDE and an “academic” objective function ◮ My personal results in this talk are only embarassingly parallel ◮ Essentially data parallel in shot record ◮ There is still model parallelism to exploit, which requires high-end HPC software ◮ In addition to. . . RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 41 / 55

  60. Software Considerations FWI Objective J ( m ) = � d − F ( m ) � 2 2 d ( t ) : Data m ( x ) : Unknown physical coefficients F : Modeling operator f s ( x, t ) : RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 42 / 55

  61. Software Considerations FWI Objective � � d s − F s ( m ) � 2 J ( m ) = 2 s ∈S d s ( t ) : Data for shot s m ( x ) : Unknown physical coefficients F s : Modeling operator for shot s f s ( x, t ) : RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 42 / 55

  62. Software Considerations FWI Objective � � d s − S s F s ( m ) � 2 J ( m ) = 2 s ∈S d s ( t ) : Data for shot s m ( x ) : Unknown physical coefficients F s : Modeling operator for shot s f s ( x, t ) : S s : Data sampling operator for shot s RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 42 / 55

  63. Software Considerations FWI Objective � J ( m ) = � d s − S s F s ( m ) � s ∈S d s ( t ) : Data for shot s m ( x ) : Unknown physical coefficients F s : Modeling operator for shot s f s ( x, t ) : S s : Data sampling operator for shot s �·� : (Arbitrary) residual norm RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 42 / 55

  64. Software Considerations FWI Objective � J ( m, f ) = � d s − S s F s ( m, f s ) � s ∈S d s ( t ) : Data for shot s m ( x ) : Unknown physical coefficients F s : Modeling operator for shot s f s ( x, t ) : S s : Data sampling operator for shot s �·� : (Arbitrary) residual norm f s ( x, t ) : Unknown seismic source function for shot s RJH (Virginia Tech) Computation & Geophysical Inversion Uppsala / April 9, 2019 42 / 55

Download Presentation
Download Policy: The content available on the website is offered to you 'AS IS' for your personal information and use only. It cannot be commercialized, licensed, or distributed on other websites without prior consent from the author. To download a presentation, simply click this link. If you encounter any difficulties during the download process, it's possible that the publisher has removed the file from their server.

Recommend


More recommend