Application of TRA to the Pre- and Post-Stack Imaging of a Salt Dome Flank

Abstract

We present results of applying Time-Reversed Acoustics (TRA) to seismic imaging of a salt dome flank. We create a set of synthetic traces representing a multi-level, walk away VSP for a model composed of a simplified Gulf of Mexico vertical-velocity gradient and an embedded overhanging salt dome. To process these data, we first apply source-receiver reciprocity and the concepts of TRA to the synthetic traces. This creates a set of redatummed traces without having to perform any velocity analysis, moveout corrections or other processing. Each of these redatummed traces is equivalent to the output of a down-hole source and down-hole receiver pair. For quick turn around analyses, we can select from these redatummed traces only the zero-offset, or collocated, down-hole source/receiver pairs. For a more thorough analysis we utilize all the redatummed traces. We then apply conventional post- or pre-stack depth migration, respectively, to these traces to produce the final image of the salt dome flank. The migrated results show that the redatummed turning ray energy reflected from the salt dome flank is handled correctly by this method and produces effective images of the salt.