Norman Bleistein recently proposed a modification of the back-projection method used by Gregory Beylkin in his velocity inversion algorithm. Bleistein's modification provides an algorithm for imaging reflection coefficients and incident angles of specular reflectors within the earth. One particular version of the algorithm can be used to image data for a single source-receiver offset. The images for several offsets can then be used in a multiparameter inversion scheme to give images of changes in subsurface mechanical properties. This development solves the problems in applying multiparameter inversion in areas where reflector structure is complicated and effects of raypath curvature are important.
I derive the Beylkin-Bleistein back-projection kernel for constant offset data and depth-dependent reference velocities. An imaging algorithm using the kernel is applied to seismic data shot over two reservoirs with different gas saturations. The results show that the multiparameter inversion method is more useful than single parameter methods for determining reservoir gas saturation.
AAPG Search and Discovery Article #91038©1987 AAPG Annual Convention, Los Angeles, California, June 7-10, 1987.