Prestack Depth Migration Analysis Using A High Precision Hybrid Method And Its Parallel Implementation

Abstract

Prestack depth migration is an important imaging method for complex geological structures. A generalizsed system for wavefield continuation based on wavefield splitting theory is presented in this paper. The system is coupled by downgoing and upgoing waves, and the commonly used equation for wavefield continuation is a special case of this coupled system. Based on an approximation of the square root operator, a new hybrid migration method with high precision is derived. The method can be implemented numerically through the splitting technique. Two examples of numerical migration are given: one is a poststack depth migration for a model with large lateral velocity contrasts; the other is a prestack depth migration for the Marmousi model with complex strucdtures. Both numerical results demonstrate the effectiveness and high precision of the hybrid method. The MPI parallel computation is adopted in order to increase computational efficiency.