1. Interferometric Multiple Migration of UPRC Data
Jianhua Yu
University of Utah

2. Outline
 Motivation and Objective  Interferometric Migration: Crosscorrelogram migration Autocorrelogram migration  Examples Synthetic Data UPRC data  Summary

3. Outline
Motivation and Objective  Interferometric Migration: Crosscorrelogram migration Autocorrelogram migration  Examples Synthetic Data UPRC data  Summary

4. IVSPWD Objective ?  Provide Look-ahead Image Below Drill Bit
 Reduce Uncertainty in Drilling ?

5. Problem Deviated Well  No Source Wavelet  No Source Initiation Time
 Not Easy to Get Pilot Signal in
Deviated Well

6. Solution Interferometric Migration No need to know source wavelet
No need to know source location
No need to know initial time
No limits to deviated well

7. Outline. Motivation and Objective. Interferometric Migration. Examples
Outline Motivation and Objective Interferometric Migration Examples Summary

8. . Crosscorrelogram migration . Autocorrelogram migration
Interferometric Migration
. Crosscorrelogram migration Autocorrelogram migration

9. Primary, Ghost and Direct Wave
Well
Receiver
Ghost
Direct Wave
Primary
Drill bit
Primary, Ghost and Direct Wave

10. Free-surface related Ghost Travel Timex

11. Ghost Imaging Condition After Correlation of Traces:x g s g’
Condition: recording data have to be dense !!

12. Crosscorrelogram Ghost Imaging Condition:x g s g’

13. Crosscorrelogram Migration
Migrated Image
Crosscorrelation Function

14. . Crosscorrelogram migration . Autocorrelogram migration
Interferometric Migration
. Crosscorrelogram migration Autocorrelogram migration

15. Free-surface related Ghost Travel time:x

16. Autocorrelogram Ghost Imaging Condition:x

17. Autocorrelogram Migration
Migrated Image
Autocorrelation Function

18. Outline. Motivation and Objective. Autocorrelogram Migration Method
Outline Motivation and Objective Autocorrelogram Migration Method Examples Summary

19. Geological Model
X (m) 4 V1 V2
Depth (m) V3 V4 V5 V6 3

20. Velocity Model X(km) X(km) 0 4 0 4 Depth(km) 3 3 Interval Velocity
3.5
3.5
Depth(km)
2.0
2.0 3 3
Interval Velocity
RMS Velocity

21. Shot Gather and Crosscorrelogram
Traces
Traces
Time (s)
Time (s) 4 4
CSG 10 and Master trace at 80

22. Shot Gather and Autocorrelogram
Traces
Traces
Time (s)
Time (s) 4 4
CSG 10

23. Crosscorrelogram Migration Results
X (km)
X (km)
Time (s)
2.2
With primary
Without primary

24. Autocorrelogram Migration Results
X (km)
X (km)
Time (s)
2.2
With primary
Without primary

25. Acquisition Survey East (kft) North (kft) 3C Receivers Depth (kft) 4.5
4.5
Drill bit
North (kft)
Well Rig
3C Receivers -5
Depth (kft) 10

26. Main Acquisition Parameters
Drill-bit Depth: ft
Offset Range: ft
Recording Length: 20 s
Sample Interval: ms
Station Number:

27. Drill-bit Data of CSG #96
Trace Number
Time (s) 7

28. Main Processing Steps Frequency panel analysis and noise elimination
Trace editing and static shift
Frequency panel analysis and noise elimination
Amplitude balance and energy normalization
Velocity analysis
Calculating cross- and autocorrelograms, vertical stacking
Cross- and Autocorelogram migration

29. Frequency Panel Analysis
Time (s)
Time (s) 7 7
5-15 Hz
< 5 Hz

30. Frequency Panel Analysis
Time (s)
Time (s) 7 7
25-40 Hz
15-25 Hz

31. Processed CSG 96 Part of CRG 6
0.5
Time (s)
Time (s) 7
4.5

32. Crosscorrelogram of CSG 96
Trace No.
Time (s) 4
8 s
12 s
16 s

33. Autocorrelogram of CSG 96
Time (s) 4
8 s
12 s
16 s

34. Autocorrlogram Migration Images
Traces
Traces 1 50 1 50
0.5
Time (s)
3.2
Window = 8 s
Window=12 s

35. Crosscorrlogram Migration Images
Traces
Traces 1 50 1 50
0.5
Time (s)
3.2
Window = 8 s
Window=12 s

36. Acquisition Survey Map
Well Rig
Line AC4
North (ft)
Drill bit
3C Receivers
-5000
1500
3000
4500
East (ft)

37. Autocorrelation Ghost Image(Corr. Window=8 s)SP
1255
1235
1215
1.0
Drilling hole
Time (s)
2.0
3.0
Autocorrelation Ghost Image(Corr. Window=8 s)

38. Crosscorrelation Ghost Image ( Corr. Window 12 s)SP
1255
1235
1215
1.0
Drilling hole
Time (s)
2.0
3.0
Crosscorrelation Ghost Image ( Corr. Window 12 s)

39. Outline . Objective . Autocorrelogram Migration . Examples . Summary

40. SUMMARY
Crosscorr. and autocorrelogram migration works for deviated well
All result are comparable to surface-CDP section
No source position is needed for crosscorrelogram migration
Dense recording data is necessary for crosscorrelation migration to get good quality image

41. SUMMARY
Difficulty of separating upgoing and downgoing wave can cause artifacts in migration image

42. What’s Next Improve the method’s efficiency for real-time purpose
Reduced the virtual multiple and other wave’s influence
Integrated migration image of both borehole data and CDP data

43. Acknowledgements
I greatly appreciate Union Pacific Resources for donating this data
I am grateful to the 2000 sponsors of the UTAM consortium for financial support
I also thank all of people who give me some suggestions and help for this work