Understanding subsalt illumination through ray-trace modeling, Part 3: Salt ridges and furrows, and the impact of acquisition orientation

Abstract

The complex structure and high velocity of salt in the Gulf of Mexico create seismic imaging difficulties. 3-D prestack depth migration (PreSDM) of seismic data allows imaging of reflectors under the salt sheets and of detached bodies of irregular shape. But 3-D PreSDM cannot fill in shadow zones below salt where little data were recorded. Additionally, amplitude variations caused by salt structures focusing or dispersing seismic energy are usually poorly handled by 3-D PreSDM. Ray-trace modeling can clarify subsalt imaging problems, and the modeling results should be incorporated into exploration and development plans.