1. Center for Wave Phenomena Department of Geophysics Colorado School of Mines Golden, Colorado

2. CWP Faculty Ilya Tsvankin “We are committed to quality education.” Roel Snieder Dave Hale Ilya Tsvankin Paul Sava Norm Bleistein Ken Larner

3. What do we offer? Full financial support Diverse and enthusiastic faculty State-of-the-art research Industry contacts and internships

4. Need more Information? Prof. Ilya Tsvankin ilya@dix.mines.edu Prof. Roel Snieder rsnieder@mines.edu www.cwp.mines.edu Center for Wave Phenomena Colorado School of Mines Golden, CO 80401

5. Seismic interferometry: Who needs a seismic source? Roel Snieder email rsnieder@mines.edursnieder@mines.edu

6. Problem with sub-salt imaging reservoir salt

7. What if we had virtual sources below the salt? reservoir salt

8. Response to random sources

9. Correlation:

10. Very Long Baseline Interferometry http://www.lupus.gsfc.nasa.gov/brochure/bintro.html

11. Distance between USA and Germany http://www.lupus.gsfc.nasa.gov/brochure/btoday2.html

12. 1D example

13. Cross-correlation sum of causal and acausal response uncorrelated left- and rightgoing waves

14. Need to extend this to include: - heterogeneous media - more space dimensions

15. Derivation based on normal-modes (Lobkis and Weaver, JASA, 110, 3011-3017, 2001)

16. Displacement response Heaviside function

17. Velocity response

18. Uncorrelated excitation

19. Correlation

20. Correlation as sum over modes

21. For uncorrelated modes

23. Correlation Green’s function

24. Correlation and Green’s function - sum of causal and acausal Green’s function - holds for arbitrary heterogeneity

25. (Weaver and Lobkis, Ultrasonics, 40, 435-439, 2002)

27. Raindrop model Sources can be: - real sources - secondary sources (scatterers)

28. Extract response by correlation Correlation:

29. Non-stationary source point

31. Stationary source point

33. Stationary phase regions “anti-Fresnel zones”

34. Stationary phase integration (Snieder, Phys. Rev. E, 69, 046610, 2004)

35. Four types of averaging

36. Computing synthetic seismograms (Van Manen et al., Phys. Rev. Lett., 94, 164301,2005)

39. Field example of virtual sources (Bakulin and Calvert, SEG expanded abstracts, 2477-2480, 2004) reservoir complicated overburden

40. Peace River 4D VSP Component used, along-the-well (45 0 )

41. Image from virtual sources top bottom

42. Virtual sourceSurface

43. Surface waves (Campillo and Paul, Science, 299, 547-549, 2003)

44. correlation Green’s tensor Z/Z Z/R Z/T

45. Surface wave Green’s function (Snieder, Phys. Rev. E, 69, 046610, 2004)

46. Seismic interferometry in Millikan Library (Snieder and Safak, Bull. Seismol. Soc. Am., 96, 586-598, 2006)

47. Deconvolution with top floor

48. Deconvolution with bottom floor

49. traveling waves normal modes

53. Four new wave states (Snieder, Sheiman, and Calvert, Phys. Rev. E., 73, 066620, 2006)

54. building borehole

55. Advantage (1), virtual sources at new locations reservoir salt

56. Advantage (1), virtual sources at new locations

57. Advantage (2), virtual sources at “all” times

58. Advantage (3), use other type of data (Shapiro et al., Science, 307, 1615-1618, 2005) earthquake correlation (1 year) correlation (1 month)

59. 5-10 sec. 10 10.1 0.01 Frequency (Hz)

61. More information www.mines.edu/~rsnieder email rsnieder@mines.edu www.mines.edu/~rsnieder/SPICE06_Snieder.ppt