Computational Strategies For Reverse-time Migration

The imaging condition used in reverse-time migration requires that the source wavefield (computed via a forward recursion) and the receiver wavefield (computed via a backwards recursion) must be made available at the same time in an implementation of the algorithm. Several strategies to organize the calculation can be employed, differing in balance between memory and computation. This paper describes and compares these different approaches, and argues that strategies favoring computational complexity over memory (to the point where disk i/o can be avoided) are attractive for 3D prestack migrations. An example of 3D reverse-time migration applied to wide-azimuth data from the Gulf of Mexico is presented to support the claim.