--> Abstract: Structural Control and Stratigraphic Architecture of Recent Discoveries and Producing Fields in the Central Northern Gulf of Mexico, by Joseph C. Fiduk and Andrew J. Pulham; #90082 (2008)

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Structural Control and Stratigraphic Architecture of Recent Discoveries and Producing Fields in the Central Northern Gulf of Mexico

Joseph C. Fiduk1 and Andrew J. Pulham2
1CGGVeritas, Houston, TX
2Earth Science Assoc. C&T, Boulder, CO

Hydrocarbon exploration beneath the shallow allochthonous salt canopy of the ultra-deepwater central Gulf of Mexico has encountered three thick, sand-rich, submarine fan successions that punctuate an otherwise relatively condensed and fine-grained basin center Cenozoic stratigraphy. These sand-rich fans are Late Paleocene, Early Miocene, and Middle Miocene in age and each coincide with periods of very high sediment flux combined with basin margin instability. They are the primary exploration target in most ultra-deepwater fields and recent discoveries.

The underlying basement configuration contains the horsts and grabens of a rift basin setting. The deep parts of the rift became salt basins filled with the Jurassic Louann salt. During the Cretaceous, kilometers-thick salt nappes extruded from these basins onto the earlier Mesozoic basin margins. The nappes may have coalesced to form a regional allochthonous salt nappe around the margin of the salt basins, similar to the modern Sigsbee Escarpment. Later clastic sedimentation caused deflation of the nappe leaving remnant salt structures behind. The remnant salt bodies form the core structures over which younger sand-rich fans are folded and draped.

Regional 2D time data and 3D depth data show that remnant salt bodies from the now deflated Cretaceous nappe form the core structure in fields at Chinook and Cascade and in recent discoveries at Stones, Das Bump, St. Malo, and Jack. Both seismic and well data show that the sand-rich outer fan of all three fan systems overlies the zone of salt nappe remnants indicating a very advantageous confluence of structure and stratigraphy in this region. Mapping of the basement and overlying Mesozoic and Cenozoic mega-sequences strongly suggests that deep structural control has repeatedly influenced sedimentation leading to a super sweet spot in the regional petroleum system.

AAPG International Conference and Exhibition, Cape Town, South Africa 2008 © AAPG Search and Discovery