CASE HISTORY 1: Seismic Modeling Beneath a Salt Flow
A high relief structure was noted on seismic data beneath a salt overhang. The prospective nature of this subsalt feature hinged upon the ability to discriminate between a structural anticline in depth and the illusion of an anticline in time. Imaging distortion brought about by: (1) velocity pull up due to the high velocity of salt; and (2) raypath bending associated with salt boundaries, complicates structural interpretation. A depth model was created from an interpreted time-migrated line to confirm the presence of a true anticline in depth. The resulting two-dimensional (2-D) synthetic seismic section compared well with the original seismic line. Finally, depth migration was performed on the original seismic data, with a result similar to that of the modeling. This result demonstrated the use of a simple modeling technique to validate a prospective exploration target.