1887
Volume 63, Issue 2
  • E-ISSN: 1365-2478

Abstract

ABSTRACT

Reverse‐time migration can accurately image complex geologic structures in anisotropic media. Extended images at selected locations in the Earth, i.e., at common‐image‐point gathers, carry rich information to characterize the angle‐dependent illumination and to provide measurements for migration velocity analysis. However, characterizing the anisotropy influence on such extended images is a challenge. Extended common‐image‐point gathers are cheap to evaluate since they sample the image at sparse locations indicated by the presence of strong reflectors. Such gathers are also sensitive to velocity error that manifests itself through moveout as a function of space and time lags. Furthermore, inaccurate anisotropy leaves a distinctive signature in common‐image‐point gathers, which can be used to evaluate anisotropy through techniques similar to the ones used in conventional wavefield tomography. It specifically admits a V‐shaped residual moveout with the slope of the “V” flanks depending on the anisotropic parameter η regardless of the complexity of the velocity model. It reflects the fourth‐order nature of the anisotropy influence on moveout as it manifests itself in this distinct signature in extended images after handling the velocity properly in the imaging process. Synthetic and real data observations support this assertion.

Loading

Article metrics loading...

/content/journals/10.1111/1365-2478.12189
2014-11-04
2024-03-29
Loading full text...

Full text loading...

References

  1. AlkhalifahT.2000. An acoustic wave equation for anisotropic media. Geophysics65, 1239–1250.
    [Google Scholar]
  2. AlkhalifahT. and FomelS.2011. The basic components of residual migration in VTI media using anisotropy continuation. Journal of Petroleum Exploration and Production Technology1, 17–22.
    [Google Scholar]
  3. AlkhalifahT., FomelS. and BiondiB.2001. The space‐time domain: theory and modelling for anisotropic media. Geophysical Journal International144, 105–113.
    [Google Scholar]
  4. BaysalE., KosloffD. D. and SherwoodJ. W. C.1983. Reverse time migration. Geophysics48, 1514–1524.
    [Google Scholar]
  5. BerkhoutA. J.1982. Imaging of Acouting Energy by Wave Field Extrapolation. Elsevier.
    [Google Scholar]
  6. ClærboutJ. F.1985. Imaging the Earth's Interior. Blackwell Scientific Publications.
    [Google Scholar]
  7. CullisonT. and SavaP.2011. An image‐guided method for automatically picking common‐image‐point gathers. 81st SEG annual international meeting, San Antonio,USA, Expanded Abstracts.
  8. DuveneckE. and BakkerP. M.2011. Stable P‐wave modeling for reverse‐time migration in tilted TI media. Geophysics76, S65–S75.
    [Google Scholar]
  9. FletcherR. P., DuX. and FowlerP.J.2009. Reverse time migration in tilted transversely isotropic (TTI) media. Geophysics74, WCA179–WCA187.
    [Google Scholar]
  10. FowlerP. J., DuX. and FletcherR. P.2010. Coupled equations for reverse time migration in transversely isotropic media. Geophysics75, S11–S22.
    [Google Scholar]
  11. GrayS. H., EtgenJ., DellingerJ. and WhitmoreD.2001. Seismic migration problems and solutions. Geophysics66, 1622–1640.
    [Google Scholar]
  12. McMechanG. A.1983. Migration by extrapolation of time‐dependent boundary values. Geophysical Prospecting31, 413–420.
    [Google Scholar]
  13. RickettJ. and SavaP.2002. Offset and angle‐domain common image‐point gathers for shot‐profile migration. Geophysics67, 883–889.
    [Google Scholar]
  14. SavaP. and AlkhalifahT.2012. Wide‐azimuth angle gathers for anisotropic wave‐equation migration. Geophysical Prospecting61, 75–91.
    [Google Scholar]
  15. SavaP. and FomelS.2003. Angle‐domain common image gathers by wavefield continuation methods. Geophysics68, 1065–1074.
    [Google Scholar]
  16. SavaP. and FomelS.2005. Coordinate‐independent angle‐gathers for wave equation migration. 75th SEG annual international meeting, Houston, USA Expanded Abstracts, 2052–2055.
  17. SavaP. and FomelS.2006. Time‐shift imaging condition in seismic migration. Geophysics71, S209–S217.
    [Google Scholar]
  18. Sava, P. and VasconcelosI.2011. Extended imaging condition for wave‐equation migration. Geophysical Prospecting59, 35–55.
    [Google Scholar]
  19. SavaP. and VladI.2011. Wide‐azimuth angle gathers for wave‐equation migration. Geophysics76S131–S141.
    [Google Scholar]
  20. ShenP. and SymesW. W.2008. Automatic velocity analysis via shot profile migration. Geophysics73, VE49–VE59.
    [Google Scholar]
  21. SymesW.2009. Migration velocity analysis and waveform inversion. Geophysical Prospecting56, 765–790.
    [Google Scholar]
  22. ThomsenL.2001. Seismic anisotropy. Geophysics66, 40–41.
    [Google Scholar]
  23. YangT. and SavaP.2010, Wave‐equation migration velocity analysis with extended common image‐point gathers. 80th SEG annual international meeting, Denver, USA, Expanded Abstracts.
  24. YangT. and SavaP.2011. Image‐domain waveform tomography with two‐way wave‐equation. 81st SEG annual international meeting, San Antonio, USA, Expanded Abstracts.
  25. ZhangY., ZhangH. and ZhangG.2011. A stable TTI reverse time migration and its implementation. Geophysics76, WA3–WA11.
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journals/10.1111/1365-2478.12189
Loading
/content/journals/10.1111/1365-2478.12189
Loading

Data & Media loading...

  • Article Type: Research Article

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error