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Regional Controls from Temporal and Spatial Distribution of Continental Slope and Abyssal Plain Reservoir Systems of the Gulf of Mexico Basin

Galloway, William 1; Whiteaker, Timothy L.1; Ganey-Curry, Patricia 1
1 Institute for Geophysics, Univ. Texas at Austin, Austin, TX.

By the beginning of Cenozoic time, the Gulf of Mexico had assumed its general configuration as a small ocean basin, created in the late Jurassic and early Cretaceous as a part of the greater Atlantic spreading history. Thus clastic sediment entered a basin with a continental slope and extensive abyssal plain. In the late 20th Century, deep-water exploration began to test the hydrocarbon potential of these continental slope and subjacent abyssal plain depositional systems. A succession of major plays ensued, beginning with the “Flex Trend” discoveries in Plio-Pleistocene slope apron turbidite reservoirs, and culminating most recently in giant-field discoveries in Paleocene abyssal submarine fan systems. Regional mapping of the deep Gulf basin reveals several key attributes of the known and potential reservoir systems. 1. Approximately two-thirds of the sediment entering the Gulf Basin was ultimately deposited in continental slope and abyssal plain settings. 2. The principal accumulation phases of deep-water strata, particularly sand-rich intervals, correspond closely with major phases of sediment influx into the basin from tectonically uplifted and/or erosionally rejuvenated sources on the North American continent. 3. The geographic location of slope and basin depocenters was determined by the sites where major fluvial systems draining those sources entered the Gulf. 4. Reservoir systems deposited by various gravity mass transport processes accumulated widely within major offlapping continental slope aprons and as large submarine fan systems on the paleo-abyssal plain. 5. Contemporaneous gravity tectonic domains further accentuated partitioning of sediment among shelf margin, continental slope, and basinal systems. 6. Regional seismic lines show that basin-scale, sand-rich deep slope and abyssal systems remain untested by drilling, particularly in the western Gulf. 7. Both seismic facies mapping and ODP drilling of the Quaternary Mississippi fan demonstrate that fan systems are quite capable of and have repeatedly distributed sand hundreds of kilometers beyond the contemporaneous shelf margin.


AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009