MULTIPLE WEIGHTS IN DIFFRACTION STACK MIGRATION

Three-dimensional (3-D) prestack diffraction-stack migration methods (often called Kirchhoff migration/ inversion) play a fundamental role in seismic imaging. In addition to estimating the location of arbitrarily curved reflectors and the angle-dependent reflection coefficients upon them, they can also be used to provide useful kinematic and dynamic information about the specular reflection ray that connects the source and receiver via the unknown reflecting interface. This is achieved by performing a diffraction stack more than once upon the same seismic data set using identical stacking surfaces but different weights. Some of these weights can be applied simultaneously, i.e., as a weight-vector. The approach offers the possibility of determining various useful quantities that help to compute and interpret migrated reflections. The vector-weighted diffraction stack is principally intended to economize the amplitude-preserving migration that normally would require a large amount of dynamic ray tracing. A simple 2-D synthetic example shows how the method works in principle.58121820183