Oil exploration has become a journey into ever deeper water as increasing competition for a smaller prize in the accessible shelf or failed rift basins has encouraged oil companies to explore the continental slopes, where success has been episodic and predominantly associated with stratigraphic channel plays. As a safer and highly rewarding alternative, we propose the ultra-deep water basin floor fan in the deep water abyssal plains setting as the future oil play for this century.
An extensive dataset of modern long streamer 2D seismic in ultra-deep water along both sides of the South Atlantic margins has been employed to identify a regional source rock and kitchen areas, while depth domain seismic profiles have been utilized to reveal the true geometries of basin floor fans on either side. A model of an ultra-deep water basin floor fan play with its associated resource potential has been put together and indicates a huge trapping geometry in the depth domain where it becomes apparent that the basin floor fans deposited at the base of slope directly overlying the mature source rock are in fact not dipping out to sea, but dip landward, eliminating the up-dip seal trapping risk.
Basin floor fan examples observed in Mauritania, Senegal and Sergipe have all been calibrated with seismic attributes associated with major recent discoveries. These have also been integrated with results from source rock maturity modelling and analysis of satellite seep clusters, both of which provide strong evidence of an oil generative system.
An identical geometric relationship can be seen on PreSDM data from other basins, for instance the Pelotas Basin in Brazil/Uruguay, Gabon, Namibia/South Africa and even Somalia on the eastern side of Africa. In addition, settings in South East Asia with similar potential but subtly different play types have been reviewed, to indicate how these systems might work in ultra-deep water outboard of broadly destructive margins.
The surprising result is that, significant areas around the globe below 3,000 metre of water, in the lower slope and abyssal plain setting, appear to have potential for a working hydrocarbon system.
