--> Delineation of Gravity-Flow Depositional Elements within the Miocene Succession in the Toe-Thrusted Domain of the Niger Delta Deep-Offshore, by Claudio Nini, Lorenzo Lipparini, Babatunde Ogunshote, and Michel Vivier; #90037 (2005)

Datapages, Inc.Print this page

Delineation of Gravity-Flow Depositional Elements within the Miocene Succession in the Toe-Thrusted Domain of the Niger Delta Deep-Offshore

Claudio Nini1, Lorenzo Lipparini1, Babatunde Ogunshote2, and Michel Vivier2
1 ENI S.p.A. - Exploration & Production Division, San Donato Milanese (Milan), Italy
2 Nae Ltd, Port Harcourt, Nigeria

A 3D PSTM seismic data set, from a block in the Niger Delta deep offshore, has been analysed in order to delineate the occurrence and the architecture of gravity-flow depositional elements within the lower slope - basin plain Miocene succession. The area under investigation is part of the outermost thrust zone, whose deformation is triggered by gravity gliding due to the deltaic sediment loading on the shelf. Investigations have been concentrated on the NW-SE trending belt of narrow fault-bounded anticlines, which constitutes the main prospective sector of the block. The first major deformation phase occurred in the latest Miocene. The extensive application of 3D multi-volumes interpretative tools from preliminary to advanced phases of the explorative process strongly contributed to outline the stacking pattern and the internal architecture of the slope depositional elements. Moderate to high sinuosity channels with slightly erosive bases have been observed, ranging from isolated events to vertical stacked complexes. Sinuous channels vary from prevailing vertical aggrading to high laterally migrating systems, showing successive avulsion phases. Crevasse splays have been locally recognised at external channel bends. More lateral continuous seismic features associated with slope channels have been referred to thin bedded levee sands in the overbank area. Small frontal lobes have been recognised at the end of some channelised features where turbidite flows pass from confined to unconfined conditions. Identified Miocene slope channel-lobe systems show a dominant NE-SW trend. Minor topographic constraints along the slope profile locally conditioned the morphology of channel complexes and produced isolated ponding effects.