Lessons from Mars on Exploring for Giants

Keith R. Woidneck, R. Keith, Jackie C. Mutschler, and Rob K. Kasten

Mars field, located in Mississippi Canyon blocks 763 and 807, stands out as the largest known field in the deep water Gulf of Mexico. Discovered in 1989, Mars is currently in the early stages of development. Understanding the geologic controls on this giant oil field provides insights which can be applied to exploration.

Characteristics that distinguish Mars as a giant oil field are the large number of high quality reservoirs within an effective trapping configuration, and the highly efficient hydrocarbon migration pathway. Reservoir deposition was strongly influenced by shallow salt sheets, which focused deep marine sediment gravity flows. Trapping is predominantly stratigraphic, with reservoir limits controlled by basin geometry during deposition. Surrounding salt canopies served to focus, rather than impede, hydrocarbon migration into the Mars basin.

Mars field geology typifies that of a broader play fairway, providing a framework for evaluating further prospectivity. The play fairway is characterized by Miocene to lower Pliocene deep marine reservoirs, primary salt withdrawal basins, thin salt canopies, and a low Pleistocene sedimentation rate. Experience at Mars demonstrates the importance of considering a range of possible reserve outcomes during prospect evaluation, and the value of high quality 3-D seismic data for reducing uncertainty.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California