Migration with arbitrarily wide-angle wave equations

Abstract

We develop a new scalar migration technique that is highly accurate for imaging steep dips in heterogeneous media. This method is based on arbitrarily wide-angle wave equations (AWWEs) that are highly accurate space-domain one-way wave equations and have a form similar to the 15° equation. The accuracy of the proposed method is increased by introducing auxiliary variables, as well as adjusting the parameters of the approximation. Poststack migration is carried out by downward continuation using the AWWE, for which we have developed a stable, explicit, double-marching scheme. Up to 80° accuracy is achieved by second-order AWWE migration with only 2.3 times the computational effort of the 15° equation and requiring almost the same storage. We illustrate the performance of AWWE migration using impulse-response graphs, a single-dipping reflector, and a slice of the SEG/EAGE salt model.