MULTIPLE WEIGHTS IN DIFFRACTION STACK MIGRATION

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