KAPOOR, S. (JERRY), UWE ALBERTIN, WENFONG CHANG, Western Geophysical, Houston, TX, NIGEL PURNELL, BP Exploration, Houston, TX, and ALAN ANDERSON, BHP Petroleum, Houston,TX

Abstract: Subsalt Imaging in the Deepwater Gulf of Mexico

Recent discoveries in the deepwater Gulf of Mexico have led to the development of imaging technology to provide images of subsalt data that are structurally as interpretable as those outside of salt.

With the cost of acquiring lease blocks in the desirable areas of the deepwater Gulf of Mexico reaching $38m and the cost of drilling wells approaching $40m, the economics of performing 3-D prestack depth migration are quite favorable. The increased availability of computer power has allowed us to perform 3-D prestack depth migrations using algorithms and parameters that only a couple of years ago were unfeasible.

There are four key elements to successful subsalt imaging: 1) An accurate sediment velocity model; 2) Precise definition of salt geometry; 3) Application of migration algorithms with appropriate parameters; and 4) Teamwork.

We will explore these key elements and discuss factors where expense and effort provide the most benefit and those where increased effort provides little benefit. Although these techniques are illustrated with examples from an area of significant complexity in the Gulf of Mexico, we believe that this expertise is transferable to other areas of the world where the geology is similar, such as the deepwater areas of West Africa.

AAPG Search and Discovery Article #90923@1999 International Conference and Exhibition, Birmingham, England