3D Multisource Full-Waveform Inversion using Quasi-Monte Carlo Phase Encoding

1. 3D Multisource Full-Waveform Inversion using Quasi-Monte Carlo Phase Encoding Chaiwoot Boonyasiriwat Jan. 7, 2010

2. Outline • Introduction to Multisource Technology • Phase Encoding • Multisource Full-Waveform Inversion • Quasi-Monte Carlo Phase Encoding • Numerical Results • 3D SEG/EAGE Overthrust Model • Summary • Future Work • Acknowledgment 1

3. Introduction: Multisource Tech. • Migration • Delayed-shot migration (Zhang et al., 2005) • Random phase encoding (Romero et al., 2000) • Plane-wave migration (Liu et al., 2006; Shan and Biondi, 2008; Shan et al., 2009) • Full-Waveform Inversion (FWI) • Plane-wave FWI (Vigh and Starr, 2008) • Random phase encoding (Krebs et al., 2009; Zhan et al., 2009) 2

4. Single-Source Method 3

5. Multisource Method Linear Phase Encoding—Planewave Decomposition 4

6. Multisource Method Random Phase Encoding 5

7. CSG vs SSG CSG SSG 6

8. Outline • Introduction to Multisource Technology • Phase Encoding • Multisource Full-Waveform Inversion • Quasi-Monte Carlo Phase Encoding • Numerical Results • 3D SEG/EAGE Overthrust Model • Summary • Future Work • Acknowledgment 7

9. Conventional FWI Model Observed Data Evaluate misfit function and compute gradient Perturb Model Evaluate misfit function No Search criterion Yes Yes No Convergence criterion Done 8

10. Multisource FWI Model Encoded Data Evaluate misfit function and compute gradient Perturb Model Evaluate misfit function No Search criterion Yes Yes No Convergence criterion Done 9

11. 2D Multisource FWI Krebs Method (ExxonMobil): one SSG, random source polarity, dynamic encoding 8

12. 2D Multisource FWI Zhan Method (UTAM): multiple SSGs, random time shift, static encoding, deblurring filter 9

13. 3D Multisource FWI Krebs Source Configuration 10

14. 3D Multisource FWI Closely Packed Source Configuration 11

15. 3D Multisource FWI Loosely Packed Source Configuration 12

16. 3D Multisource FWI Quasi-Monte Carlo Source Configuration 13

17. Static vs Dynamic Configuration Static Dynamic Iteration 1 2 14

18. Outline • Introduction to Multisource Technology • Phase Encoding • Multisource Full-Waveform Inversion • Quasi-Monte Carlo Phase Encoding • Numerical Results • 3D SEG/EAGE Overthrust Model • Summary • Future Work • Acknowledgment 15

19. 3D SEG/EAGE Overthrust Model 16

20. Numerical Results True Velocity Model 17

21. Numerical Results Initial Velocity Model 18

22. Numerical Results Velocity Model from Static QMC 19

23. Numerical Results Velocity Model from Dynamic QMC 20

24. Numerical Results Velocity Model from Krebs Method 21

25. Outline • Introduction to Multisource Technology • Multisource Full-Waveform Inversion • Numerical Results • 3D SEG/EAGE Overthrust Model • Summary • Future Work • Acknowledgment 22

26. Summary • 3D multisource FWI using multiple SSGs is compared with multisource FWI using one SSG. • Using multiple SSGs and a dynamic QMC phase encoding provides a better-quality velocity model than a static QMC phase encoding and Krebs method. • Theoretical speedups need to be verified. • More reliable timing results will be presented later. 23

27. Outline • Introduction to Multisource Technology • Multisource Full-Waveform Inversion • Numerical Results • 3D SEG/EAGE Overthrust Model • Summary • Future Work • Acknowledgment 24

28. Future Work • Compare various multisource configurations. • Compare random phase encoding with plane-wave encoding. • Apply random time shifts and deblurring filter. • Apply 3D multisource FWI to field data. 25

29. Acknowledgment • Sponsors of 2009 UTAM consortium • HPC: AronAhmadia and Mark Cheeseman • Shaheen: Iain Georgeson and Jonathan Anderson • Multisource: Ge Zhan and Wei Dai • Workstation: Benoit Marchand • KAUST: Jerry Schuster 26