1. Overview of Utah Tomography and Modeling/Migration (UTAM) Chaiwoot B., T. Crosby, G. Jiang, R. He, G. Schuster, Chaiwoot B., T. Crosby, G. Jiang, R. He, G. Schuster, J. Sheng, J. Yu, M. Zhou and Xiang Xiao

2. 2004 UTAM Consortium AramcoBP-AmocoBGPGeotomoChevron-TexacoConoco-Phillips IMPINCOSisimageUnocalVeritasWestern-Geco ($24 K/year)

3. Started 1988 Started 1988 10-18 sponsors/year10-18 sponsors/year $24,000/year membership$24,000/year membership Benefits : Yearly meeting: Feb. 3-4Benefits : Yearly meeting: Feb. 3-4 Annual+midyr Report Software Goal: Innovative Imaging/Modeling Goal: Innovative Imaging/Modeling UTAM

4. Jianhua Yu, Min Zhou Gerard T. Schuster University of Utah Interferometric Imaging below Salt And Overburden

5. Outline Motivation Interferometric Imaging Synthetic Data Conclusions

6. Outline Motivation Interferometric Imaging Synthetic & Field Data Conclusions

7. Problems with VSP or CDP Salt Imaging Quality? Salt v(x,y,z) not known Static errors ?

8. Outline Motivation Interferometric Imaging Synthetic & Field Data Conclusions

9. Uninteresting Part of Medium How do you remove kinematic effects of propagating through unintersting parts of medium?

10. Pick Direct Arrival Time T and shift all Traces by T M M {M T M

11. M {MT Shifting Traces Removes Kinematic Effects Of Propagating through Uninteresting Parts of Medium

12. M Shifting Traces Removes Kinematic Effects Of Propagating through Uninteresting Parts of Medium

13. M Shifting Traces Removes Kinematic Effects Of Propagating through Uninteresting Parts of Medium.. M M m(x) = (g, t + t ) gx g MxMxMxMxgx Kirchhoff Migrate psuedo-shot gathers Kirchhoff Migrate psuedo-shot gathers Source Moved to Depth Can replace time-shifted traces by crosscorrelograms

14. M M M m(x) = (g, t + t ) gx g MxMxMxMxgx Kirchhoff Migrate psuedo-shot gathers Kirchhoff Migrate psuedo-shot gathers Can replace time-shifted traces by crosscorrelograms

15. M M M m(x) = (g, t + t ) gx g MxMxMxMxgx Kirchhoff Migrate psuedo-shot gathers Kirchhoff Migrate psuedo-shot gathers Can replace time-shifted traces by crosscorrelograms

16. M M M m(x) = (g, t + t ) gx g MxMxMxMxgx Kirchhoff Migrate psuedo-shot gathers Kirchhoff Migrate psuedo-shot gathers Can replace time-shifted traces by crosscorrelograms

17. M M M m(x) = (g, t + t ) gx g MxMxMxMxgx Kirchhoff Migrate psuedo-shot gathers Kirchhoff Migrate psuedo-shot gathers Can replace time-shifted traces by crosscorrelograms

18. M M M m(x) = (g, t + t ) gx g MxMxMxMxgx Kirchhoff Migrate psuedo-shot gathers Kirchhoff Migrate psuedo-shot gathers Can replace time-shifted traces by crosscorrelograms

19. M M M m(x) = (g, t + t ) gx g MxMxMxMxgx Kirchhoff Migrate psuedo-shot gathers Kirchhoff Migrate psuedo-shot gathers Can replace time-shifted traces by crosscorrelograms

20. Interferometric Summary Eliminates source statics and uninteresting parts of the medium. Lower source to be near target.

21. Interferometric Summary Eliminates source+rec statics and uninteresting parts of the medium. Reference layer Lower source+rec. to be near target.

22. Outline Motivation Interferometric Imaging Synthetic CDP Data & Field Data Conclusions

23. Shots: 280 Shot interval: 10 m Receivers: 300 Receiver interval: 10 m Temporal interval:1ms X (km) 0 3 0 1.8 Depth (km) Salt model

24. X (km) 0 3 0 1.8 Depth (km) True velocity model

25. X (km) 0 3 0 3 Time (s) CSG 100 Pick Traveltime Subsalt Reference Reflection

26. X (km) 0 3 0 1.8 Depth (km) Kirmig with inaccurate salt dome boundary

27. X (km) 0 3 0 1.8 Depth (km) RT migration with inaccurate salt dome boundary

28. X (km) 0 3 0 1.8 Depth (km) Standard mig Correct velocity X (km) 0 3 0 3 Standard mig Incorrect velocity RT mig

29. Outline Motivation Interferometric Imaging Synthetic HSP Data & Field Data Conclusions

30. 0 km 5 km 0 km 5 km Mig. Image+Corr. Vel. 0 km 1.2 s 0 km 1.2 km 0 km 1.2 km 0 km 1.2 km 0 km 1.2 km 0 km 1.2 km HSP Shot Gather Salt Model HSP Interferometric Imaging

31. 0 km 5 km 0 km 5 km Mig. Image+Corr. Vel. HSP Interferometric Imaging 0 km 1.2 s 0 km 1.2 km 0 km 1.2 km 0 km 1.2 km 0 km 1.2 km 0 km 1.2 km HSP Shot Gather Salt Model HSP Interferometric Imaging

32. 0 km 5 km 0 km 5 km Mig. Image+Corr. Vel. 0 km 1.2 s 0 km 1.2 km 0 km 1.2 km 0 km 1.2 km 0 km 1.2 km 0 km 1.2 km Salt Model HSP Shot Gather HSP Image HSP Interferometric Imaging

33. 0 km 5 km 0 km 5 km Mig. Image+Corr. Vel. 0 km 1.2 s 0 km 1.2 km 0 km 1.2 km 0 km 1.2 km 0 km 1.2 km 0 km 1.2 km Salt Model HSP Shot Gather HSP Image SWI-HSP Image Garbage HSP Interferometric Imaging

34. 0 km 5 km 0 km 5 km Mig. Image+Corr. Vel. 0 km 1.2 s 0 km 1.2 km 0 km 1.2 km 0 km 1.2 km 0 km 1.2 km 0 km 1.2 km Salt Model HSP Shot Gather HSP Image SWI-HSP Image Garbage No Need for V HSP Interferometric Imaging

35. Outline Motivation Interferometric Imaging Synthetic VSP Data & Field Data Conclusions

36. VSP Data 0 km 2 km 0 km 3 km Image Below Salt Without Knowing Salt Velocity

37. X (m) 14001000 950 1950 Depth (m) Interferometric Image

38. Well 2 0 Depth (km) 0 3X (km) SEG/EAGE Model 256 Sources V = 1.5 - 3.0 km/s

39. Time (s) 3 0 02.4 X (km) 1.42.4 X (km) Xcross 60 CRG 60

40. 2.0 0.5 Depth (km) 0.52.5 X (km) Kirchh Mig (45) Xcorr Mig (45) Xcorr. Mig ( 15’) 2.5 0.5

41. Outline Motivation Interferometric Imaging Synthetic VSP Data & Field Data Conclusions

42. Time (s) 0.3 0 30 900 Depth (ft) Raw Data(CRG15)

43. Time (s) 0.3 0 30 900 Depth (ft) Ghosts

44. Depth (ft) 1300 200 0400 X (ft) 0400 X (ft) Standard migXcorr. mig

45. SUMMARY Interferometric Imaging: Kinematically equivalent to sources-receivers below datumInterferometric Imaging: Kinematically equivalent to sources-receivers below datum Interferometric TomographyInterferometric Tomography True wave equation statics w/o V(x,y,z)True wave equation statics w/o V(x,y,z) HSP, VSP and CDP dataHSP, VSP and CDP data Salt + Overburden

46. SUMMARY Interferometric Imaging: Kinematically equivalent to sources-receivers below datumInterferometric Imaging: Kinematically equivalent to sources-receivers below datum Interferometric TomographyInterferometric Tomography True wave equation statics w/o V(x,y,z)True wave equation statics w/o V(x,y,z) HSP, VSP and CDP dataHSP, VSP and CDP data Salt + Overburden

47. Crosscorrelogram Migration Conclusions Eliminate the static errors in the well No need to know source (RVSP) or receiver location (VSP) Half sensitivity to velocity migration errors than mult. migration by “mirrors”. Increased illumination coverage in the VSP image. VSP ->CDP

48. Conclusions Loss of some lateral resolution? Be careful about virtual multiple Xcorr Narrow Angle Kirchhoff Wide Angle vs Ghost is weaker than primary Extra summation compared to KM

49. Outline Motivation Crosscorrelation Migration SEG/EAGE Model 2-D RVSP Field Data Conclusions

50. Well 2 0 Depth (km) 0 3X (km) SEG/EAGE Model 256 Sources V = 1.5 - 3.0 km/s

51. Well 2 0 Depth (km) 03X (km) Receiver interval: 10 m Receiver depth range: 0.1 -1 km Receiver number: 91 Sample interval: 1 ms Recording length: 3 s Well location: (1.5 km, 0 km) Source interval: 10 m Source number: 256 Acquisition Parameters: 1 km

52. Time (s) 3 0 0.2 0.9 Depth (km) CSG 160

53. Time (s) 3 0 0.2 0.9 Depth (km) Ghosts (CSG 160)

54. Time (s) 3 0 02.4 X (km) 1.42.4 X (km) Xcross 60 CRG 60

55. 2.0 0.5 Depth (km) 0.52.5 X (km) Kirchh Mig (45) Xcorr Mig (45) Xcorr. Mig ( 15’) 2.5 0.5

56. Static errors (ms) -50 50 0 900 Well Depth (m) Raw Data Static Errors at Well

57. 2.0 0.5 Depth (km) 0.5 Kirchhoff Migration Static Error: 0 X (km) Static Error: 25 ms 2.5 Static Error: 50ms 2.5 0.5

58. 2.0 0.5 Depth (km) 0.5 Crosscorrelation Migration Static Error: 0 X (km) Static Error: 25ms 2.5 Static Error: 50 ms 2.5 0.5

59. Velocity Model Primary vs Multiple Image 0 11 0 16 0 16 X (km) Depth (km)

60. Contents Motivation Crosscorrelation Imaging Condition SEG/EAGE Model 2-D RVSP Field Data Conclusions

61. Time (s) 0.3 0 30 900 Depth (ft) Raw Data(CRG15)

62. Time (s) 0.3 0 30 900 Depth (ft) Ghosts

63. 524 Trace No. Time (s) 1.2 0.2 xcorr data (muted) Time (s) 1.4 0.5 524 Trace No. Field Data ( CSG 25 ) Raw data (muted) Master trace

64. Depth (ft) 1300 200 0400 X (ft) 0400 X (ft) Standard migXcorr. mig

65. Depth (ft) 1100 0 Standard Well data Xcorr. Exxon Data

66. Outline Motivation Crosscorrelation Migration SEG/EAGE Model 2-D RVSP Field Data Conclusions

67. Crosscorrelogram Migration Conclusions Eliminate the static errors in the well No need to know source (RVSP) or receiver location (VSP) Half sensitivity to velocity migration errors than mult. migration by “mirrors”. Increased illumination coverage in the VSP image. VSP ->CDP

68. Conclusions Loss of some lateral resolution? Be careful about virtual multiple Xcorr Narrow Angle Kirchhoff Wide Angle vs Ghost is weaker than primary Extra summation compared to KM

69. Acknowledgments UTAM sponsors Exxon for 2-D field data J. Claerbout + J. Rickett II evolved from daylight imaging

70. Depth (ft) 1300 200 0400 X (ft) 0400 X (ft) Standard migXcorr. mig

71. Geological Model 0 4 0 3 Depth(km) X(km) (2001)

72. Migration Result Using Crosscorrelation Imaging 1.6 0 2.2 Time (s) 2.1 X (km) Too simple? Widen illumination? If there are static errors in well?

73. Why Use Crosscorrelation Migration? Widen the illumination coverage in the VSP image VSP geometry Equivalent surface geometry Xcorr

74. Seismic Ghost Reflection Direct Ghost ? Find R(x,z) but not know source location

75. Direct Ghost 12Directx Directx Master Seismic Ghost Reflection Seismic Interferogram: Correlate Traces t }M m(x) = (g, t + t ) gx g MxMxMxMxgx M Kirchhoff Migrate psuedo-shot gathers Kirchhoff Migrate psuedo-shot gathers Ghost Direct has kinematics of primary reflection x M

76. Well Source Receiver Primary Direct Wave Ghost RVSP

77. x g s Ghost Reflection Imaging Condition Ghost Reflection Imaging Condition:

78. x g s After Crosscorrelation of Two Traces at Locations g & g’

79. x g s

80. x g s

81. Recall Green’s Theorem Every Surface Point = Source Point

82. Why is there insensitivity to static errors in the well? s g’g x Static errors

83. Crosscorrelogram Migration Migrated Image Crosscorrelograms Crosscorrelation Imaging Condition

84. Depth (ft) 1100 0 Well dataXcorr. Migration Field Data

85. Depth (ft) 1100 0 Well dataStandard Migration Exxon Data

86. Above Source Imaging{ Wider Coverage VSP Interferometric Summary Wider, taller coverage. Eliminates well statics and uninteresting parts of the medium. M M m(x) = (g, t + t ) gx g MxMxMxMxgx Kirchhoff Migrate psuedo-shot gathers Kirchhoff Migrate psuedo-shot gathers

87. Shifting Traces Removes Kinematic Effects Of Propagating through Uninteresting Parts of Medium.. M M M m(x) = (g, t + t ) gx g MxMxMxMxgx Kirchhoff Migrate psuedo-shot gathers Kirchhoff Migrate psuedo-shot gathersg Source Moved to Depth Can replace time-shifted traces by crosscorrelograms

88. m Distance (km) 010 CDP Interferometric Imaging Depth (km) 10 Distance (km) 010 0 010 Model KM image with Incorrect velocity km/s Datuming with Reflections sg 3.2 3.0 2.8

89. m Distance (km) 010 CDP Interferometric Imaging Depth (km) 10 Distance (km) 010 0 010 Model KM image with Incorrect velocity km/s Datuming with Reflections sg 3.2 3.0 2.8

90. m Distance (km) 010 CDP Interferometric Imaging Depth (km) 10 Distance (km) 010 0 010 Model KM image with Incorrect velocity km/s Datuming with Reflections sg 3.2 3.0 2.8