Factorization Synthesized‐Shot Prestack Depth Migration in Helical Coordinate System

Abstract

AbstractBased on the synthesized‐shot prestack depth migration, a new highly efficient method for the synthesized‐shot prestack depth migration is proposed. It is a hybrid method which implements wavefield extrapolation with factorization in the helical coordinate system. The wavefield extrapolation is divided into two explicit solving processes: one is a causal process, and the other is an anticausal process. Such explicit solving processes in the helical coordinate system can enhance the wavefield extrapolation efficiency. Moreover, based on the phase encoding principle, the synthesized‐wavefield corresponding to multiple ray parameters is encoded and stacked. Then calculations are implemented with the MPI parallel algorithm based on ray parameters. Thus the calculation efficiency is improved further. After deriving the relevant formulae and analyzing the computation cost quantitatively, numerical calculations for the Marmousi complex model are presented, including the comparisons between them. The imaging results show that the method presented in this paper has advantages of high precision and good efficiency. So it can be applied to field data processing.