Abstract: Wave-Equation Migration: Two Approaches
K. Larner, L. Hatton
A conventional stacked seismic section displays data only as a passing wave field recorded at selected points on the earth's surface. In regions of complex geology, this display may bear little resemblance to a cross section of subsurface reflectors. Migration is the technique used to transform the wave field of a seismic section into a reflectivity display. Thus it should be possible to relate any seismic-migration method to a solution of the scalar-wave equation--the assumed mathematical description of wave propagation in the earth's subsurface. Such solutions can be derived from either an integral or differential form of this equation. For example, a refinement of the conventional method of summing along diffraction hyperbolas is founded on the integral solution. In re ent years, integral solutions have been complemented by solutions of differential forms of the wave equation, following the pioneering work by Jon F. Claerbout.
Comparison migrations of both synthetic data and of marine and land profiles, for good data of modest dip, produce results which are remarkably similar despite their very different conceptual bases and realizations. This outcome is very encouraging, as it increases confidence in the rationale behind migration. For poorer data of modest dip, the solutions based on differential forms of the scalar-wave equation have noticeably superior S/N compared with their integral-form counterparts. The seismic-trace spacing (receiver group interval) plays different, but fundamental, roles in governing the accuracy and quality of both types of migration.
AAPG Search and Discovery Article #90976©1976 AAPG-SEPM-SEG Pacific Section Meeting, San Francisco, California