1887
PDF

Abstract

Summary

The application of reverse-time migration (RTM) on a large scale has become affordable and has led to significant advances in seismic depth imaging in complex areas, especially for sub-salt imaging. For imaging in anisotropic media with vertically transverse isotropy (VTI), RTM is usually based on an acoustic VTI approximation of the elastic wave equation by setting the vertical shear-wave velocity to zero. However, these equations generate artificial pseudo shear-waves that spoil any seismic imaging process. By studying the wave modes associated to that equation, we identify that a second mode exists for the anelliptic case, i.e., when the Thomsen parameters ∈ is different from δ. This mode generates the spurious pseudo shearwaves. We show that as long as the simulation of the P-wave propagation is consistent with the usual marine seismic wavelengths, the spurious pseudo-shear wave is not generated or very weak compared to the P-wave mode. We illustrate this fact, for the case of a homogeneous medium modelling and for the more realistic case of a 2D Salt body modelling.

Loading

Article metrics loading...

/content/papers/10.3997/2214-4609.201702259
2017-09-11
2024-03-29
Loading full text...

Full text loading...

/deliver/fulltext/2214-4609/2017/43848.html?itemId=/content/papers/10.3997/2214-4609.201702259&mimeType=html&fmt=ahah

References

  1. Alkhalifah, T.
    [2000] An acoustic wave equation for anisotropic media. Geophysics, 65(4), 1239–1250.
    [Google Scholar]
  2. Duveneck, E., P.Milcik, P. M.Bakker, and C.Perkins
    [2008] Acoustic VTI wave equations and their application for anisotropic reverse-time migration. 78th Annual International Meeting, SEG,Expanded Abstracts, 2186–2190.
    [Google Scholar]
  3. Thomsen, L.
    [1986] Weak elastic anisotropy. Geophysics, 51, 1954–1966.
    [Google Scholar]
  4. Zhou, H., Zhang, G. and Bloor, R.
    [2006] An Anisotropic Acoustic Wave Equation for VTI Media. 68th EAGE Conference and Exhibition incorporating SPE EUROPEC 2006.
    [Google Scholar]
  5. Alkhalifah, T.
    [2000] An acoustic wave equation for anisotropic media. Geophysics, 65(4), 1239–1250.
    [Google Scholar]
  6. Duveneck, E., P.Milcik, P. M.Bakker, and C.Perkins
    [2008] Acoustic VTI wave equations and their application for anisotropic reverse-time migration. 78th Annual International Meeting, SEG,Expanded Abstracts, 2186–2190.
    [Google Scholar]
  7. Thomsen, L.
    [1986] Weak elastic anisotropy. Geophysics, 51, 1954–1966.
    [Google Scholar]
  8. Zhou, H., Zhang, G. and Bloor, R.
    [2006] An Anisotropic Acoustic Wave Equation for VTI Media. 68th EAGE Conference and Exhibition incorporating SPE EUROPEC 2006.
    [Google Scholar]
http://instance.metastore.ingenta.com/content/papers/10.3997/2214-4609.201702259
Loading
/content/papers/10.3997/2214-4609.201702259
Loading

Data & Media loading...

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