Abstract: The study of 3D prestack time migration profile of Well Xidi?2 indicates that the time domain profile of the Wutonggou formation as a target zone in drilled well with hither structural position has bigger t0 compared with well logging data. Such a log?seismic discrepancy occurs from the bottom of Paleogene in this area. The analysis suggests that the reason for it mainly results from the lateral velocity changes of the Cenozoic here. Prestack depth migration processing technique is an effective approach for precise imaging of complex structures.This paper uses Kirchhoff ingegral method to make prestack depth migration processing, and gets the south?north reducing velocity model for the space variation in this area. Finally, the morphology of formation has been corrected, the relative relationship between wells has been recovered, and the problem of the log?seismic data discrepancy has been resolved