1. MD+AVO Inversion: Real Examples University of Utah Jianhua Yu

2. MD+AVO Outline Objective Examples Conclusions

3. MD+AVO Outline Objective Examples Conclusions

4. Strengths of MD Enhance the illumination of subsurface structureEnhance the illumination of subsurface structure Mitigate migration noise and artifactsMitigate migration noise and artifacts Improve the spatial resolutionImprove the spatial resolution

5. MD+AVO Outline Objective Examples Conclusions

6. Processing Steps: Preprocessing : Filtering, amplitude balancing, and demultiple Prestack migration to generate the migrated COG sections Velocity analysis and estimate RMS velocity model for migration in time domain

7. Apply MD to common offset sections Normal AVO parameter Inversion Apply MD to AVO section Processing Steps:

8. MD+AVO Outline Objective Examples Conclusions

9. MD+AVO Outline Objective Examples Conclusions 2-D North Sea Data

10. Time (s) 0.0 3.0 0.262.0 Offset (km) CDP Gather 1.53.5 Velocity Scan (km/s) Multiples

11. Time (s) 0.0 3.0 0.262.0 Offset (km) CDP 1764 0.262.0 Offset (km) 0.262.0 Offset (km) Raw data Demultiple Multiples AVO ? Before demultipleAfter demultiple

12. Time (s) 1.0 3.5 0.262.00.262.0 1.0 3.5 CDP 150 Offset (km) CDP 150 NMO raw data NMO demultiple

13. Time (s) 0 3.5 7 20 X (km) Time Migration Section

14. Time (s) 0 3.5 7 20 X (km) MD Result in Time Domain Mig+MDMig 12.1 13.6 X (km) - - 3.6 - +2.3 Before MD After MD Zone of interest

15. B -0.4 0.4 A Crossplot of A and B before MD Near Well A Time interval: 1900-2900 ms

16. B -0.4 0.4 A Crossplot of A and B after MD Near Well A Time interval: 1900-2900 ms

17. B -0.4 0.4 A Crossplot of A and B Based on Well log from Well 1 ( from C.-S. Yin, M.L. Batzle, and C. C. Mosher) Depth: 1900-3100 m

18. B -0.4 0.4 A Well Data -0.40.4 A -0.40.4 A After MDBefore MD

19. MD+AVO Outline Objective Examples Conclusions 2-D GOM Data

20. Two CSGs with AGC+MUTE 8 Time (s) 0 Shot Number 1350

21. Spectrum of Two Shot Gathes Shot 1Shot 2 120 1 Frequency (Hz) 0

22. Amplitude within Geometry Map 1 Receiver Number 177 Shot Number 1800 0.03 0.005

23. Velocity Scanning of CMP Gathers CDP 4600 CDP 4750 8 Time (s) 0 CDP 4850 CDP 5000CDP 5500CDP 6000 Zone of Interest CDP 4750CDP 4850 CDP 5000

24. Time (s) Offset (km) CRG before and After MD Before MD After MD 0.5 1.3 Before MDAfter MD Multiple

25. Time (s) 0 2 0 15 X (km) PSTM Image

26. Time (s) 0 2 0 15 X (km) Mig MD

27. Time (s) 0 2.0 015 X (km) AVO Parameter: A*B Before MD

28. Time (s) 0 2.0 015 X (km) AVO Parameter: A*B After MD

29. Crossplot of Parameters A and B Before MDAfter MD 1 B 1 1

30. Time (s) 0.32 1.6 010 X (km) AVO Parameter: A*B Before MD

31. Time (s) 0.32 1.6 010 X (km) AVO Parameter: A*B After MD

32. Time (s) X (km) AVO Parameter: A*B Before MDAfter MD

33. MD+AVO Outline Objective Examples Conclusions

34. Conclusions Improve resolution and mitigate some migration artifacts in AVO attribute sections Help identifying the AVO anomaly In the future, test on 3-D seismic attribute analysis

35. Acknowledgments Thank ChevronTxaco, ExxsonMobil, and WesternGeco for providing the data setsThank ChevronTxaco, ExxsonMobil, and WesternGeco for providing the data sets Thank 2002 UTAM sponsors for their financial supportThank 2002 UTAM sponsors for their financial support Thank Alan Leeds for his constructive comments and suggestions.Thank Alan Leeds for his constructive comments and suggestions.