3D Pre-Stack Depth Migration for Complicated Structure by DSR Wave Equation and Its Application

There are rich oil and gas resources in marine carbonates, but the seismic imaging is difficult for such marine carbonate exploration areas because the reservoir structures are very complicated. Theoretically speaking, the effective method to solve the complicated structure imaging is 3D pre-stack depth migration method by the wave equations. 3D pre-stack depth migration can be realized by wave equations in Common Shot Point (CSP) field or in Common Middle Point (CMP) field. The two methods are suitable to different data conditions and use the different continuation operators. Based on the double square root (DSR) wave equation migration, the arithmetic is studied for 3D pre-stack depth migration method in CMP field, and the method and software of 3D pre-stack depth migration are developed in this paper. Aimed at the 3D seismic data collected from the narrow azimuth angle at present, the advantage of this method is to reduce the 5 dimensions in 3D DSR pre-stack depth migration method down to 4 dimensions, so as to realize 3D pre-stack depth migration for CMP gathers and also to improve the computing efficiency. Because the computing of 3D pre-stack depth migration is huge, the parallel arithmetic method is utilized to shorten the data processing period. The correctness and validity of the method are proved by the theoretical model and real data processing.