1 / 32

CROSSWELL IMAGING BY 2-D PRESTACK WAVEPATH MIGRATION

CROSSWELL IMAGING BY 2-D PRESTACK WAVEPATH MIGRATION. H. Sun. Geology and Geophysics Department University of Utah. SEG 2-D Overthrust Data. KM Image. Model. WM Image. 4. Offset (km). 10. 4. Offset (km). 10. 4. Offset (km). 10. 0.5. Depth (km). 2.5.

marvel
Télécharger la présentation

CROSSWELL IMAGING BY 2-D PRESTACK WAVEPATH MIGRATION

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CROSSWELL IMAGING BY 2-D PRESTACK WAVEPATH MIGRATION H. Sun Geology and Geophysics Department University of Utah

  2. SEG 2-D Overthrust Data KM Image Model WM Image 4 Offset (km) 10 4 Offset (km) 10 4 Offset (km) 10 0.5 Depth (km) 2.5

  3. KM Image (Zoom A) WM Image (Zoom A) 2-D Husky Field Data 2.5 Offset (km) 5.5 2.5 Offset (km) 5.5 2.5 2.5 Depth (km) Depth (km) 5.0 5.0

  4. SEG 3-D Salt Data KM WM CPU: 1 CPU: 1/33 Sub WM Model CPU: 1/170 Horizontal Slice (Depth=1.4 km)

  5. A B C 2-D KM of a Single Trace C B A R S

  6. A B C 2-D WM of a Single Trace C B A R S

  7. True Reflection point Small Migration Aperture Fewer Artifacts Less Expensive Wavepath Migration Traveltime + Ray Direction

  8. Outline • WM Crosswell Imaging • Synthetic Crosswell Data • McElroy Crosswell Data • Synthetic Single Well Data • Conclusions

  9. Interface 2 KM Crosswell Imaging Source Well Receiver Well Down-going Interface 1 Up-going

  10. Interface 2 KM Crosswell Imaging Source Well Receiver Well Interface 1 Up-going

  11. Interface 2 KM Crosswell Imaging Source Well Receiver Well Down-going Interface 1

  12. Interface 2 KM Crosswell Imaging Source Well Receiver Well Down-going Interface 1 Up-going

  13. Problems in KM Crosswell Imaging • Insufficient Stacking Leads to Artifacts • Complex Data Cause Difficulty in • Up-going and Down-going Separation • Slow Computation

  14. Interface 2 WM Crosswell Imaging Source Well Receiver Well Down-going Interface 1 Up-going

  15. Advantages of WM Crosswell Imaging • Avoid Artifacts by Migrating to the • Primary Reflection Point • Handle Complex Data by Migrating • Up-going and Down-going together • No Constraints Needed • Fast Computation

  16. Shortcomings of WM • Weaker Events • Worse Interface Continuity

  17. Outline • WM Crosswell Imaging • Synthetic Crosswell Data • McElroy Crosswell Data • Synthetic Single Well Data • Conclusions

  18. Fault Model A Common Shot Gather Offset (m) 0 Geophone Depth (m) 0 90 210 0 0 Time (s) Depth (m) 210 0.2

  19. Better Image Better Resolution Crosswell Imaging of Synthetic Fault Data KM Model WM WM (no separation) Offset: 0~90 m, Depth: 0~210 m

  20. Outline • WM Crosswell Imaging • Synthetic Crosswell Data • McElroy Crosswell Data • Synthetic Single Well Data • Conclusions

  21. Traveltime Tomogram A Common Shot Gather Offset (m) 811 Hydrophone Depth (m) 0 56 963 811 0 6.7 Time (s) Depth (m) (km /s) 4.7 0.05 963

  22. KM Image ? ? 0 Offset (m) 56 Source Well Receiver Well 811 Up-going Depth (m) Separation Down-going 963 Synthetic Synthetic

  23. WM Image 0 Offset (m) 56 Source Well Receiver Well 811 Up-going Depth (m) Separation Down-going 963 Synthetic Synthetic

  24. WM Image Source Well Receiver Well 811 Up-going Depth (m) NO Separation Down-going 963 Synthetic 0 Offset (m) 56 Synthetic

  25. Receiver Well Source Well Synthetic Synthetic KM(CPU=2.5) WM (up+down) WM(CPU=1) Offset: 0~56 m, Depth: 811~963 m

  26. Outline • WM Crosswell Imaging • Synthetic Crosswell Data • McElroy Crosswell Data • Synthetic Single Well Data • Conclusions

  27. OYO Salt Model Offset (km) 0 9 0 Well ? ? ? ? Depth (km) Salt ? ? ? ? 6 4.5 2.8 Velocity (km/s)

  28. ? ? ? ? OYO Salt Model Velocity Model WM image KM image 2 Depth (km) Well ????? 5 Offset (km) Offset (km) Offset (km) 2.5 6.5 2.5 6.5 2.5 6.5

  29. Conclusions • Crosswell Synthetic Data • Fewer migration artifacts • Slightly better image resolution • Better for dipping fault boundary • No up- and down-going separation

  30. Conclusions • Crosswell McElroy Data • Similar image quality • No up- and down-going separation • 2.5 times faster than KM • Worse image continuity • Structure details? Artificial events?

  31. Conclusions • Single Well Synthetic Data • Similar image quality • Fewer migration artifacts

  32. Acknowledgements I thank UTAM sponsors for their financial support

More Related