Semblance-based anisotropy parameter estimation using isotropic depth-migrated common image gathers
Fan Xia · 2016
Semblance-based residual moveout (RMO) analysis of P-wave data provides a robust and efficient means to estimate the anisotropy parameter in vertical transverse isotropy (VTI) media. In this paper, a semblance-based approach is developed to estimate the anellipticity parameter η in depth domain using the common image gathers (CIG) generated by an isotropic depth migration with a preferred isotropic velocity inverted from an isotropic migration velocity analysis. An analytical RMO function is derived to measure depth residuals of the isotropic depth-migrated CIG without weak anisotropy assumption. The semblance analysis can be applied to the RMO to directly search for effective values of the anellipticity parameter, which can be then converted into an interval anellipticity model in depth domain. A workflow is also proposed to build the anisotropy model in depth domain that maintains the simplicity of the traditional normal moveout (NMO) velocity analysis. The capability of this method is demonstrated for estimating anisotropy parameter with two synthetic examples of heterogeneous VTI model. Presentation Date: Monday, October 17, 2016 Start Time: 1:00:00 PM Location: 166 Presentation Type: ORAL