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sep:research:theses:sep154 [2014/08/07 22:01]
myfusan
sep:research:theses:sep154 [2015/05/27 02:06] (current)
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  * Appendix B: [[http://sepwww.stanford.edu/data/media/public/docs/sep154/append2.pdf|Rock physics modeling]]   * Appendix B: [[http://sepwww.stanford.edu/data/media/public/docs/sep154/append2.pdf|Rock physics modeling]]
  * Appendix C: [[http://sepwww.stanford.edu/data/media/public/docs/sep154/append3.pdf|RTM-based WEMVA for VTI models]]   * Appendix C: [[http://sepwww.stanford.edu/data/media/public/docs/sep154/append3.pdf|RTM-based WEMVA for VTI models]]
-  * [[http://sepwww.stanford.edu/data/media/public/docs/sep151/bibli.pdf|Bibliography]]\\+  * [[http://sepwww.stanford.edu/data/media/public/docs/sep154/bibli.pdf|Bibliography]]\\ 
**Abstract** **Abstract**
 +
Wave-equation migration velocity analysis (WEMVA) is a powerful technique for robust velocity model building when the subsurface is complex and the starting model is far from true. However, this traditional isotropic WEMVA technique cannot explain anisotropic wave phenomenon, which has significant effects when the reflectors are steeply dipping and/or the waves are traveling at large angles. Furthermore, errors in Wave-equation migration velocity analysis (WEMVA) is a powerful technique for robust velocity model building when the subsurface is complex and the starting model is far from true. However, this traditional isotropic WEMVA technique cannot explain anisotropic wave phenomenon, which has significant effects when the reflectors are steeply dipping and/or the waves are traveling at large angles. Furthermore, errors in
the anisotropic parameters cause similar defocusing as errors in isotropic velocity. Any defocusing caused by anisotropy may be translated to false updates in the isotropic velocity, which lead to further mispositioning and misinterpretations. However, simple extension of the isotropic WEMVA to the anisotropic medium cannot provide an unique and reliable solution due to the nonlinear and underdetermined nature of the anisotropic model building problem. Many anisotropic models with vastly different geological interpretations may explain the surface seismic data equally well. the anisotropic parameters cause similar defocusing as errors in isotropic velocity. Any defocusing caused by anisotropy may be translated to false updates in the isotropic velocity, which lead to further mispositioning and misinterpretations. However, simple extension of the isotropic WEMVA to the anisotropic medium cannot provide an unique and reliable solution due to the nonlinear and underdetermined nature of the anisotropic model building problem. Many anisotropic models with vastly different geological interpretations may explain the surface seismic data equally well.
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The migration image based on the inverted models shows better-resolved The migration image based on the inverted models shows better-resolved
faulting discontinuities and better imaged salt flanks. faulting discontinuities and better imaged salt flanks.
 +
 +**Reproducibility and source codes**\\
 +This thesis has been tested for [[sep:research:reproducible|reproducibility]]. The source codes are made available for [[http://sepwww.stanford.edu/data/media/private/docs/sep154/src.tgz|download]]. The scripts are available for [[http://sepwww.stanford.edu/data/media/private/docs/sep154/chap3.tgz|chapter 3]] and
 +[[http://sepwww.stanford.edu/data/media/private/docs/sep154/chap4.tgz|chapter 4]].\\
**Defense**\\ **Defense**\\
[[http://sepwww.stanford.edu/data/media/public/docs/sep154/elita-defense.pptx|Defense presentation]]\\ [[http://sepwww.stanford.edu/data/media/public/docs/sep154/elita-defense.pptx|Defense presentation]]\\
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