Imaging dipping sediments at a salt dome flank ‐ VSP seismic interferometry and reverse‐time migration

Abstract

We present results of applying seismic interferometry to image dipping sediments abutting a salt dome. We create a set of synthetic traces representing a multi‐level, walk away Vertical Seismic Profile (VSP) for a model composed of a simplified Gulf of Mexico vertical‐velocity gradient and an embedded overhanging salt dome. The sediment reflectors in the model dip up towards the salt dome flank. To process these data, we create a set of redatummed traces using seismic interferometry. This is done without having to perform any velocity analysis or moveout corrections. Each of these redatummed traces mimics the output of a down‐hole source and down‐hole receiver pair. The linear v(z) gradient enables the redattumed data set to illuminate and capture reflections from both the salt‐dome flank and the upward turning sediments. We then apply pre‐stack depth migration to these traces to produce the final image of the beds and the salt dome flank. The final migrated results demonstrate that the reflected turning ray energy from both the salt flank and sediments are adequate to create structurally correct images using the combination of seismic interferometry and prestack depth migration.