Paul J. Post¹, Peter F. Harrison¹, Gregory L. Whittle¹

(1) Minerals Management Service, New Orleans, LA

ABSTRACT: Petroleum System Analysis As A Tool To Define Geologic Risk Within The Mississippi Fan Fold Belt, U.S. Gulf Of Mexico

Petroleum system analysis during play evolution can aid in establishing, assessing, and identifying risk parameters, thereby assisting in delineating the most prospective areas in a play.

The Mississippi Fan Fold Belt (MFFB) is a structurally and stratigraphically complex play where exploration is high risk. Initial industry enthusiasm regarding the potential of the large structures in the MFFB subsided following a dry hole drilled in Atwater Valley (AT) during the late 1980's. However, since 1995 a series of major discoveries, all of which are adjacent to and/or under the Sigsbee Salt Canopy (SSC), have made the MFFB one of the most aggressively pursued plays in the deepwater U.S. Gulf of Mexico.

Geohistory models were constructed using BasinMod(r) in an area adjacent to and partially under the SSC (AT 574 pseudo-well - "Neptune Field") and basinward of the SSC (AT 471 pseudo-well). These models incorporate publicly available borehole information with regional, depth-converted structure maps to assess risk associated with petroleum system elements (source, reservoir, and seal), and to constrain the timing of petroleum system processes (trap formation, generation-migration-accumulation, and critical moment). The results suggest that the influence of petroleum system elements and processes is approximately the same for MFFB structures regardless of their location. Consequently, it appears that the presence of cross-stratal migration pathways associated with the emplacement and development of the SSC may be an important risk factor, a better understanding of which may increase prospect success.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado