Separation of diffracted waves in transversely isotropic media

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• 作者：Yogesh Arora ; Ilya Tsvankin
• 刊名：Studia Geophysica et Geodaetica
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：60
• 期：3
• 页码：487-499
• 全文大小：595 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Earth sciences
  Geophysics and Geodesy
  Structural Geology
  Meteorology and Climatology
  
• 出版者：Springer Netherlands
• ISSN：1573-1626
• 卷排序：60

文摘

Imaging diffracted waves can provide useful information about complex subsurface geology and fracture networks. Separation of diffractions from typically more intensive reflected events can be done based on specularity, which measures deviation from Snell’s law. Here, we analyze two formulations of specularity and their applicability to diffraction processing in the presence of anisotropy. We show that the most common definition of specularity, originally introduced for pure modes in isotropic media, remains valid for both pure and converted waves in arbitrarily anisotropic models. The other formulation operates directly with the difference between the slowness projections onto the reflector for the incident and reflected waves. Testing on a VTI (transversely isotropic with a vertical symmetry axis) diffraction ramp model demonstrates that both formulations produce satisfactory results for anisotropic media with appropriate tapering of the specularity gathers. Then separation and imaging of diffractions is performed for the structurally complex VTI Marmousi model. We also analyze the sensitivity of diffractions in the specularity gathers to errors in the symmetry-direction velocity and anellipticity parameter η.Keywordsdiffractiontransverse anisotropyKirchhoff migrationspecularity