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Seismic Interferometry : Instead of using just primary

Seismic Interferometry : Instead of using just primary arrivals, you also use the multiples for a wider view. Overview of Seismic Interferometry and Applications in Exploration. Gerard Schuster KAUST & University of Utah. What is Seismic Interferometry ?. Outline. Applications.

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Seismic Interferometry : Instead of using just primary

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  1. Seismic Interferometry:Instead of using just primary arrivals, you also use the multiples for a wider view

  2. Overview of Seismic Interferometry and Applications in Exploration Gerard Schuster KAUST & University of Utah

  3. What is Seismic Interferometry? Outline • Applications • VSP->SSP (surface seismic profile) • VSP->SWP (single well profile) • SSP->SSP • Conclusions

  4. 1968 1970s Claerbout V(z)+passive Berryhill model-based redatum Cole+Claerbout V(x,y,z)+passive? 1980s Scherbaum earthquake V(z)+passive 1990s 1999 Rickett+Claerbout V(z) Helioseismology , passive Daylight Imaging Utah: Stationary Phase Theory, SSP, and VSP 2001 Seismic Interferometric imaging, deterministic Wapenaar Recip. Thm. Correlation Type 2002-04 Gerstoft + others Surface Wave Interferometry Snieder Stationary Phase Redatuming SELECTIVE HISTORY SEISMIC INTERFEROMETRY ! redatum Shell Virtual Sources:Calvert+Bakulin

  5. SELECTIVE HISTORY SEISMIC INTERFEROMETRY ! redatum Earthquakes Passive Reservoir Nowack, Sheng, Curtis etc Shell, Draganov, Wapenaar, Snieder, Polleto Miranda, etc Engineering Xwell Minato, Onishi, Matsuoka etc Surface waves Volcanoes+Coda Snieder, Scales, Gret et al Shapiro, Derode, Larose, Dong, Xue, Halliday, Curtis, Van Mannen, Robertsson, Gerstoft,Sabra, Kepler, Roux, He, Ritzwoller, Campillo etc Model Tank Scales, Malcolm etc Interpolation Sheng, Curry, Berkhout, Wang, Dong, Hanafy, Cao, etc VSP Yu, Calvert, Bakulin, He, Jiang, Hornby, Xiao, Willis, Lu, Toksoz, Campman etc Extrapolation Dong, Hanafy, Cao, etc EM Slob, Wapenaar, Snieder Theory: Acoustic, EM, Elastic, Potential Refractions Exploration Curry, Guitton, Shragg, Yu, Artman Boise State Univ, Dong Fink, Wapenaar, Snieder, Papanicolaou, Blomgren, Slob, Thorbeck, van derNeut etc

  6. Point Source Response with src at B and rec at B G(B|x) G(B|x) = iwt xB e B virtual primary iw(t ) F.S. multiple direct xB e iw( ) t + t + t + t e Bz zB Bz zB z x Answer: Redatums data bycorrelationof trace pairs and stacking the result for different shot positions correlation stacking What is Seismic Interferometry? s * = G(B|B) VSP => SSP B virtual source z A z Assume a VSP experiment • No need to know src. location Phase of Common Raypath Cancels • No need to know src excitation time • Redatum source closer to target

  7. What is Seismic Interferometry? Point Source Response with src at B and rec at B = x iwt xB e iw(t ) xB e iw( ) t + t + t + t e Bz zB Bz zB z x Answer: Redatums data bycorrelationof trace pairs and stacking the result for different shot positions correlation stacking * G(B|x) G(B|x) = G(B|B) ~ ~ z A z • No need to know src. location x Phase of Common Raypath Cancels • No need to know src excitation time • Redatum source closer to target

  8. G(x|B)* G(x|A) = G(A|B) x SSP VSP VSP A A B B A x Old Multiples Become New Primaries! x Reciprocity Correlation Equation 2D Reflection Data k ~ ~ • No need to know VSP rec location at x Phase of Common Raypath Cancels • No need to know receiver statics

  9. n G(x|B)* G(x|A) = G(A|B) S x well 2 d x Reciprocity Correlation Equation 2D Reflection Data k (Wapenaar, 2004) Finite aperture leads to incomplete G(B|A) B A A A B x x Old Multiples Become New Primaries! Problems: Finitesource aperture Muting, Least squares or MDD Atten. Compensation No attenuation Deghostfilt.,U & D separation 1-way+ far-field approx. { } * * * - G(A|x) = G(A|B) - G(B|A) G(B|x) G(A|x) G(B|x)

  10. G(x|B)* G(x|A) Im[G(A|B)] x • Seismic Interferometry: imaginary Summary ~ ~ x x k AB AB G(B|x) G(A|x) G(A|B) • Merits: Eliminates need for src location, excitation time, some statics. Moves rec./srcs closer to target , no velocity model needed (unlike Berryhill). • Challenges: Finite aperture and noise, attenuation, acoustic & farfield approximations

  11. What is Seismic Interferometry? Outline • Applications • VSP->SSP (surface seismic profile) • VSP->SWP (single well profile) • SSP->SSP • Conclusions

  12. VSP VSP SSP 1. FK Filter up and downgoing waves x x k G(A|x)* G(B|x) G(A|x)* = Im[G(A|B)] G(B|x) 2. Correlation: f(A,B,x) = f(A,B,x) 3. Summation: k = Im[G(A|B)] M(x) = Mig(G(A|B)) 4. Migration: A B A B A B x x x Implementation Challenge: Finite Receiver Aperture = Partial Reconstruction

  13. 3D SEG Salt Model Test (He, 2006)

  14. VSP Multiples Migration Stack of 6 receiver gathers ( Courtesy of P/GSI: ~¼ million traces, ~3 GB memory, ~4 hours on a PC ) (He, 2006)

  15. Marine 3D VSP Field Data Application

  16. BP 3D VSP Survey Geometry (36 recs) ~ 11 km 1.6 km 4.0 km (He et al., 2007) 3 km

  17. VSP->SSP Summary x k G(A|x)* G(B|x) = Im[G(A|B)] A B A B A B x x x VSP VSP SSP ! Key Point #1: Every Bounce Pt on Surface Acts a New Virtual Source Key Point #2: Kills Receiver Statics Key Point #3: Redatuming = Huge Increase Illumination area Key Point #4: Liabilities: Finite Aperture noise, attenuation, loss amplitudes fidelity

  18. What is Seismic Interferometry? Outline • Applications • VSP->SSP (surface seismic profile) • VSP->SWP (single well profile) • SSP->SSP • Conclusions

  19. Motivation Problem: Overburden+statics defocus VSP migration Solution: VSP -> SWP Transform (Calvert, Bakulin) VSP VSP SWP Redatum sources below overburden Local VSP migration

  20. 0 Reflection wavefield Time (s) 3 VSP Geometry 1500 Depth (m) 3500 Offset (m) 1000 0 (He , 2006)

  21. 0 Reflection wavefield Time (s) 3 VSP Geometry 1500 Depth (m) superresolution 3500 Offset (m) 1000 0 China (He , 2006)

  22. 120 shots ? 98 geophones Poor image of flank by standard migration VSP Salt Flank Imaging (Hornby & Yu, 2006) Overburden

  23. Interferometric Migration Result 0 2000 ft

  24. VSP->SWP Summary ! 1. Redatum sources below overburden 2. Local VSP migration 3. Kills Source Statics and no need to know src location or excitation time 4. Super-resolution 5. Instead of redatuming receivers to surface, we redatum sources to depth.

  25. What is Seismic Interferometry? Outline • Applications • VSP->SSP (surface seismic profile) • VSP->SWP (single well profile) • SSP->SSP • Conclusions

  26. Surface Wave Interferometry G(A|x)* G(B|x) G(B|A) A B x A B x

  27. Surface Wave Interferometry G(A|x)* G(B|x) = G(B|A) x A B

  28. Surface Wave Interferometry x S-velocity distribution, surface wave predic.+elimination G(A|x)* G(B|x) = G(B|A) x A B Shear velocity Yao (2009)

  29. 3x3 Classification Matrix SSP VSP SWP out in SSP SSP SSP SSP VSP SSP SWP VSP VSP SSP VSP VSP VSP SWP SWP SWP SSP SWP VSP SWP SWP

  30. G(x|B)* G(x|A) Im[G(A|B)] x • Seismic Interferometry: Summary ~ ~ x x k AB AB • Merits: Eliminates need for src location, excitation time, some statics. Moves rec./srcs closer to target , no velocity model needed (unlike Berryhill). G(B|x) G(A|x) G(A|B) • Challenges: Finite aperture and noise, attenuation, acoustic & farfield approximations , amplitude fidelity • Killer Apps in Earthquake: Surface wave interferometry • Killer Apps in Exploration: Passive reservoir monitoring? OBS? EM? VSP

  31. UTAM sponsors Thanks • Min Zhou, ChaiwootBoonyasiriwat, Ge Zhan

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