Wave-equation tomography for anisotropic parameters

Abstract:

Anisotropic models are recognized as more realistic representations of the subsurface where complex geological environment exists. These models are widely needed by many anisotropic migration and interpretation schemes. However, anisotropic model building is still a challenging problem in the industry. In this paper, we propose an approach to build the anisotropic model using Wave-Equation Tomography (WETom) on surface seismic data in the image space. To reduce the null space of the inversion, we parametrize our model space using only vertical velocity ($V_V$ ) and the anellipticity parameter $\eta$ . Numerical tests show that anisotropic WETom is effective in resolving model perturbations; however, ambiguity exists between the vertical velocity and the anellipticity parameter. Auxiliary information is needed to further constrain the inversion.