--> Abstract: Evolution of Distributary Channel-Lobe Complexes in the Development of a Deepwater Turbidite Fan as Revealed By Ultrahigh-Resolution 3d Seismic Data, East Breaks, Gulf of Mexico, by Chris Edwards, David C. Hoyal, Benjamin Sheets, and Roger Bloch; #90082 (2008)

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Evolution of Distributary Channel-Lobe Complexes in the Development of a Deepwater Turbidite Fan as Revealed By Ultrahigh-Resolution 3d Seismic Data, East Breaks, Gulf of Mexico

Chris Edwards, David C. Hoyal, Benjamin Sheets, and Roger Bloch
Upstream Research Company, ExxonMobil Corporation, Houston, TX

An ultra-high resolution seismic volume reveals the internal stratigraphic architecture associated with the progradation of a deepwater fan within a Pleistocene intraslope basin (Basin IV) of the Brazos-Trinity system, Gulf of Mexico. Fan progradation occurred by sequential deposition and avulsion of 12 temporally-distinct channel-lobe complexes. Complexes at the base of the fan are characterized by an overlapping stacking pattern with limited lateral offset. As the fan evolves, complexes increasingly show compensatory stacking patterns and decreasing overlap. The transition reflects a physiographic control of the bowl-shaped basin such that as the basin fills, confinement decreases resulting in a greater area available for lateral deposition.

Channel patterns associated with channel-lobe complexes also evolve during fan progradation. In the early stages, channelization is poorly developed and occurs as numerous, radially-arranged, short-length segments. At upper levels in the fan, channels lengthen and become defined by single-thread trunk channels feeding bifurcating distributaries on terminal lobes. As a result, basal bounding surfaces of the uppermost complexes are more extensive and incise deeper into underlying deposits. Tank experiments confirm that the process of channel formation is more efficient under lower gradients. Thus the evolution from disorganized to organized channel patterns with longer run-out distances probably reflects a reduction in gradient associated with progradation. These high-resolution datasets reveal the complexity of architectural elements in turbidite fan reservoirs, an appreciation of which is essential to address and predict production performance issues in hydrocarbon-bearing systems elsewhere.

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