Abstract：The subsurface geological conditions in central Sichuan area is so complicated that the severe lateral change in thickness of the high velocity salt formation causes the structural distortion for strata below. In order to solve the problem the 3D-PSDM (Pre-Stack Depth Migration) processing was conducted for the seismic data from this area. Method and principle of Kichhoff Pre-Stack Depth Migration and technique for how to build accurate depth-velocity model were introduced in this paper, the processing results from both PSDM (Pre-Stack Depth Migration) and PSTM (Pre-Stack Time Migration) were compared and analyzed. It is demonstrated in this paper that the successful application of 3D Kichhoff Pre-Stack Depth Migration technique in this area could remove the side effect of the high velocity salt formation which causes velocity anomaly, then build an accurate velocity model and at last obtain correct images for the subsurface structures.
