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. Outline What is Seismic Interferometry?What is Seismic Interferometry? ApplicationsApplications ConclusionsConclusions VSP->SSP (surface seismic profile)VSP->SSP (surface seismic profile) VSP->SWP (single well profile)VSP->SWP (single well profile) SSP->SSPSSP->SSP

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

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

6. What is Seismic Interferometry? Answer: Redatums data by correlation of trace pairs and stacking the result for different shot positions stacking the result for different shot positions A G(B|x) * = G(B|B) Point Source Response with src at B and rec at B Assume a VSP experiment VSP experiment direct F.S. multiple i  e xBxBxBxB +  BzBzBzBz zBzBzBzB i  e xBxBxBxB i  e  BzBzBzBz zBzBzBzB = VSP => SSP B z z Phase of Common Raypath Cancels Raypath Cancels virtual primary B x z virtual sourcecorrelation No need to know src. location No need to know src. location No need to know src excitation time No need to know src excitation time stacking Redatum source closer to target Redatum source closer to target s

7. A G(B|x) * = G(B|B) Point Source Response with src at B and rec at B i  e xBxBxBxB +  BzBzBzBz zBzBzBzB i  e xBxBxBxB i  e  BzBzBzBz zBzBzBzB = z z Phase of Common Raypath Cancels Raypath Cancels x z x x ~~ No need to know src. location No need to know src. location No need to know src excitation time No need to know src excitation time Redatum source closer to target Redatum source closer to target Answer: Redatums data by correlation of trace pairs and stacking the result for different shot positions stacking the result for different shot positions correlation stacking What is Seismic Interferometry?

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

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

10. Instead of using just primary arrivals, you also use the multiples for a wider/partial vision Small vs Huge Illumination Primary reflections Multiple reflections Standard VSP Imaging Interferometric VSP Imaging Standard VSP vs Interferometric VSP Imaging

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

12. Outline What is Seismic Interferometry?What is Seismic Interferometry? ApplicationsApplications ConclusionsConclusions VSP->SSP (surface seismic profile)VSP->SSP (surface seismic profile) VSP->SWP (single well profile)VSP->SWP (single well profile) SSP->SSPSSP->SSP

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

14. 3D SEG Salt Model Test (He, 2006)

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

16. Marine 3D VSP Field Data Application

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

18. VSP->SSP Summary ! 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 x = Im[G(A|B)] G(A|x)* G(B|x) k A x B A x B A x B VSP VSP SSP Key Point #4: Liabilities: Finite Aperture noise, attenuation, loss amplitudes fidelity

19. Outline What is Seismic Interferometry?What is Seismic Interferometry? ApplicationsApplications ConclusionsConclusions VSP->SSP (surface seismic profile)VSP->SSP (surface seismic profile) VSP->SWP (single well profile)VSP->SWP (single well profile) SSP->SSPSSP->SSP

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

21. VSP Geometry Offset (m) 0 1000 Depth (m) (m) 1500 3500 Time (s) 0 3 Reflectionwavefield (He, 2006)

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

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

24. 0 2000 ft Interferometric Migration Result

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

26. Outline What is Seismic Interferometry?What is Seismic Interferometry? ApplicationsApplications ConclusionsConclusions VSP->SSP (surface seismic profile)VSP->SSP (surface seismic profile) VSP->SWP (single well profile)VSP->SWP (single well profile) SSP->SSPSSP->SSP

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

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

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

30. 3x3 Classification Matrix SSPVSPSWP VSP SSP SWP SSPSSPSSPSSPVSPSWP VSPVSPVSP SWPSWPSWP VSP SWP SWP VSP SSP SSP in out

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

32. Thanks UTAM sponsorsUTAM sponsors Min Zhou, Chaiwoot Boonyasiriwat, Ge ZhanMin Zhou, Chaiwoot Boonyasiriwat, Ge Zhan