Practical implementation of three-dimensional poststack depth migration

This work deals with the practical aspects of three-dimensional (3-D) poststack depth migration. A method, based on depth extrapolation in the frequency domain, is used for the migration. This method is suitable for structures with arbitrary velocity variation, and the number of computations required can be directly related to the complexity of the given velocity function. We demonstrate the superior computational efficiency of this method for 3-D depth migration relative to the reverse-time migration method. The computational algorithm used for the migration is designed for a multi-processor machine (Cray-XMP/48) and takes advantage of advanced disk technologies to overcome the input/output (I/O) problem. The method is demonstrated with both synthetic and field data. The migration of a typical 3-D data volume can be accomplished in only a few hours. -Authors