(1) ELF Exploration Production, Pau, France
(2) Lille 1 University, France
(3) IFREMER, Brest, France
Abstract: Congo deep-sea fan: Recent high resolution data bridges the gap between exploration plays and reservoir understanding
Over 20 000 km of 2D seismic (multibeam bathymetry, 3.5 KHz, 75/105cc inch air gun multichannel high resolution seismic) have been acquired over the last 2 years on the Congo fan together with more than 40 gravity piston cores and 12 heat flow measurements in a project co-sponsored by ELF and IFREMER. The main objectives of these campaigns were jointly determined with ELF Gulf of Guinea subsidiaries. They include the study of the recent fan morphology and sedimentary processes, the observation of reservoir scale architecture in variable depositional settings, the study of slope stability conditions and petroleum system characteristics (the latter two items are not presented here). The recent Congo fan (latitude 4° to 8°S) covers an area 2/3 the size of the Amazon but with sediments dating back to the Oligocene, the overall fan almost doubles its size. It is a typical river-fed passive margin deep-sea fan starting out with a narrow deep incision and spreading out in a 450 km wide stacked channel-levee complex. Along this complex, highly sinuous grading down slope to straight channels enable coarse sand to be transported 700 km to an active depositional lobe. Present day geometries (from the multibeam survey) are directly compared to seismic attribute maps of neighboring fields. High resolution data in incised channels and channel-levee complexes are currently being used in ELF Geocenter as references for 3D reservoir construction. The control of sediment pathways and geometry of depositional lobes by compaction and creeping of underlying sediments has yet to be ascertained.
AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana