Crossline migration of three-dimensional prestack data

Abstract

A new technique for imaging 3-D prestack seismic reflection data has been developed. This method approximates the Kirchhoff one-pass 3-D prestack depth migration and is based on directly splitting the complex one-pass process into a simpler 2-D x 2-D operation. The first step is 2-D migration in the crossline direction. This is performed as a prestack time migration and creates a "true" 2-D line, provided that the crossline structure is not very complex. The second step, inline migration, is used to determine the velocity function and to obtain the depth image. The kinematics and amplitude behavior of this new scheme closely approximate that of the one-pass process. It is a significantly faster process, and offers a practical alternative for adjusting migration velocities, and building a velocity model. When applied to a field data example, the image created by our new technique compares quite favorably to other available 3-D migration schemes.