Elastic Plane Wave Response Migration

Any amplitude-based lithologic inversion method must compensate for all changes in the amplitudes that are not directly related to the properties to be estimated. Conventional methods for compensation of geometrical spreading and transmission/conversion losses are not applicable when the subsurface structures cannot be reasonably approximated by horizontal layers. Migrationbased methods have been recently proposed to improve the estimation of angle-dependent reflectivity in the presence of complex structures. An anisotropic prestack reverse-time migration is deveioped to estimate the reflectivity as a function of the local illumination angle. This migration method generates four simultaneous images which correspond to the in-depth (local) plane-wave response for PP, PS, SP, and SS reflections, and can be used in a Zoeppritz-based elastic inversion scheme.