Migration velocity analysis for anisotropic models

Anisotropic models are recognized as a more realistic representation of the subsurface where complex geological environment exists. These models are widely needed by all kinds of migration and interpretation schemes. However, anisotropic model building is still a challenging problem in the industry. In this paper, we propose an approach to building anisotropic models from surface seismic data based on the theory of WaveEquation Migration Velocity Analysis (WEMVA). Because of the ambiguity between depth and δ , we parametrize our model space using only NMO velocity (Vnmo) and the anellipticity parameter η . We present a synthetic data example of anisotropic WEMVA applied to the shallow part of the Hess anisotropic synthetic VTI model. The results show that anisotropic WEMVA is effective in resolving the anisotropic perturbation; however, a unique solution to the inversion requires additional constraining information.