FRASER, ALASTAIR J., DAVID G. ROBERTS and CINDY A.YEILDING, BP Exploration, Houston,Texas

Abstract: The Deepwater Gulf of Mexico: A Continuing Success Story

A recent record flow rate of over 30,000bbls/day from a single production well in the Troika field underscores the continuing success of exploration and production in the deep-water (>2500') Gulf of Mexico.

The northern Gulf of Mexico can be divided into two parts of approximately equal area on the basis of present day water depth. The shelf is a mature but prolific hydrocarbon province. Roughly 40 billion barrels of oil equivalent have been discovered over a 50 year history contained in over 1000 fields. The province has sustained production levels of over 3mmboe/day since the 1970's, with no sign of imminent decline. In contrast, the deepwater GoM is an immature frontier province. Roughly 6 billion boe have been discovered since 1985 in some 20 fields. Geologically, we assert that there is every reason to expect that the deep-water will ultimately be as prolific as the shelf. Like the shelf it will not give up its riches easily. The deepwater is a geologically complex basin. However, our geological understanding of the deepwater Gulf of Mexico is evolving rapidly, largely as a result of the availability of high quality regional 3D data and the drilling of key wells in the ultra deep water.

The northern Gulf of Mexico comprises a passive continental margin which formed in response to Triassic-Early Jurassic rifting, followed by Mid-to Late Jurassic oceanic spreading. Since the Mid to Late Jurassic oceanic spreading, the evolution of the western part of the Gulf of Mexico, (north of the present day Sigsbee escarpment) is related to the post Cretaceous mobilisation of Upper Jurassic Louann Salt and the related Tertiary deepwater clastic fill. The key source rocks in the deepwater are basinal equivalents of the extensive Jurassic and Cretaceous carbonate platforms which rimmed the Gulf of Mexico in the early post rift. During the overlying Tertiary, rapid deposition of turbidite sands and muds from the proto Mississippi (particularly post Miocene) provides both reservoirs and seals which have been structured by movement of both autochthonous and allochthonous salt.

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