Paper Summary

Seismic anisotropy refers to seismic waves traveling with different velocity at different propagation angle, usually in consolidated, shale-prone areas such as in Gulf of Mexico and West Africa. Conventional isotropic (velocity independent of angle) pre-stack depth migration often produces mis-positioned and distorted images in these areas. Instead of using a single migration velocity parameter as in the isotropic depth migration, the anisotropic pre-stack depth migration uses the vertical (or normal) velocity and the anisotropic parameters (often referred to as delta and epsilon) estimated from seismic data with well controls. The anisotropic migration with the anisotropic velocity models significantly improves the accuracy of positioning and the interpretability of subsalt events around and below the salt bodies.