Connectivity Issues in Slope Mound-Contourite Systems

Jean-Pierre Henriet, David Van Rooij, Anneleen Foubert, Hans Pirlet, and Pieter Van Rensbergen
Renard Centre of Marine Geology, Ghent University, Gent, Belgium

Carbonate mound provinces are increasingly reported on continental margins, in water depths ranging between 500 and 1000m. Their potential should not be overlooked. In Porcupine Seabight, W of Ireland, 4 major provinces yield a total estimate of some 4000 mounds.

The analysis of both 3D seismic data sets and dense grids of very-high resolution 2D data, groundtruthed by coring and IODP drilling (Exp. 307), suggests that carbonate mounds should not systematically be regarded as isolated reservoirs once buried, but that their sole layer, when consisting of high-energy contouritic deposits, may play a significant role in the connectivity issue. In the midslope ‘Belgica’ and ‘Viking’ mound provinces, mounds indeed are frequently rooted on high-energy contouritic layers with clinoform deposits, which might provide the pathway for fluid migration.

In addition to these ‘coupled mound-sole’ reservoir systems of hybrid biogenic/terrigenic nature, one might pay attention to the spatially associated reservoirs of turbiditic nature. Canyon breaks control the accumulation of perched turbidite deposits, while downslope plunge pools collect turbiditic sediments from the inter-mound drainage systems.

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