3D PSTM Using Weighted Multipath Summation for Imaging Shallow Subsurface

A new method for imaging shallow subsurface using 3D prestack time migration is proposed. The method is implemented as a very fast, fully automatic, macromodel-independent procedure. The migration algorithm is based on a multipath summation of seismic traces. Contrary to the conventional techniques requiring information on migration parameter (velocity or radius of wavefront curvature) which is usually estimated by a time-consuming optimization procedure, the proposed multipath approach does not require exact values of the parameter since applies spatial summation over a wide range of the parameter values. Furthermore, performing the multipath summation with image-dependent weighting can significantly improve the resulting images. The method was tested on synthetic and real data. The results of the testing show that the obtained time migration images are usually similar to those obtained using the conventional Kirchhoff migration. In cases of varying velocities the results of the weighted multipath migration may be even superior to those of the conventional migration.