Abstract：Surface layer wave field correction taking wave theory as basis and prestack depth migration are effective means for improving imaging precision of piedmont complex structures. The paper introduced the prestack depth migration from relief surface based on implicit wide-angle finite-difference one-way propagation operator and used SEG piedmont nappe structure model for test. The result showed that the illuminated weighting imaging results by wave equation prestack depth migration from relief surface very coincide with the structural configuration of model. On that basis, using this method for synthetic data volume of Kulongshan model in Yumen Oilfield and carrying out the correlation among the following processed results: static correction and wave equation datuming continuation, poststack depth migration and prestack depth migration, Kirchhoff migration and wave equation migration, which concluded as follows: in the area of strong relief surface, large lateral variation of surface velocities and directly emerging high-velocity beds, the error of common time-shift static correction is far greater than that of wave equation datuming correction;2.on the basis of wave equation datuming correction, the precision of wave equation prestack depth migration is distinctively higher than that of Kirchhoff migration; ③one-step method of wave equation prestack depth migration from relief surface can also reasonably describe the configuration of reflectors near surface.
