Duncan S Macgregor¹, Julian Robinson², Gerrard Spear²

(1) PGS Reservoir Consultants, Maidenhead, United Kingdom
(2) PGS Reservoir

ABSTRACT: Play Types Of The Deepwater Northern Gulf of Guinea Margin

The northern Gulf of Guinea margin, from Côte D'Ivoire to the Niger Delta, is a region with a similar structural history, that is reflected by commonalities in the stratigraphic response and consequently in the play fairways identified across the region. While there has been significant exploration on the narrow shelf characterising the margin, resulting in a series of modest oil and gas discoveries, the deep water prospectivity, which is shown in this paper to be considerably more favourable than the shelf, is almost completely unexplored. This paper attempts an integrated play fairway review of the deepwater area along this transform margin, based on the integration of existing publications with more detailed studies based on 3D seismic in a number of areas.

Play fairways are classified by reservoir and trap type, with an analysis of each undertaken. The most attractive deepwater play types are a) anticlinal traps on late syn-rift (Apto-Albian) and early post-rift (Late Cretaceous) reservoirs and b) stratigraphic traps associated with large Late Cretaceous submarine fan complexes. The anticlinal play occurs along the extensions into continental crust of the St Paul and Romanche oceanic fracture zones, with the largest and most recent structuring generally associated with the latter trend. These key plays are best defined in areas of 3D coverage, particularly the Late Cretaceous stratigraphic play, which relies on imaging on seismic amplitudes. Active kitchens are evidenced involving Early and Late Cretaceous source rocks, particularly in the Côte D'Ivoire and Ghana to Nigeria segments of the region, the latter kitchen being thought to be the source of a large onshore tar belt. Considerable volumetric potential is indicated that promises to make the region one of significant new exploration activity in coming years.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado