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Neocomian-Barremian Tectonostratigraphy and Trapping Mechanisms in the Pre-Salt Synrift Interval of the Gabon South Basin
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, First EAGE West Africa Workshop 2013 - Subsurface Challenges in West Africa, Nov 2013, cp-364-00018
- ISBN: 978-90-73834-58-3
Abstract
Hydrocarbon exploration in the pre-salt synrift interval of the Gabon South Basin inboard of the Dentale Trough has been largely dormant since the discovery of the Lucina and M’Bya fields in the 1980s. Exploration has focused on the Gamba (Aptian) sand overlying the Dentale Trough, with some notable successes in the Etame and Dussafu Permits. Gamba Fields have been on production since 2004 in Etame, and recent Gamba and Dentale discoveries have been made in Dussafu. Hydrocarbons trapped in various Dentale reservoirs in the Etame Permit have not yet been placed on production. Renewed interest in testing remaining Exploration opportunities in Etame Permit led Partners to look for alternative targets that had not been recently evaluated via the drill bit. The pre-Gamba syn-rift interval was the focus of this evaluation. Six trapping styles are attributed to the above tectonostratigraphic evolution: (1) four-way closed rollover anticlines; (2) up thrown tilted fault-blocks; (3) downthrown blocks of basin margin faults; (4) four-way closed structures resulting from transpressional strike-slip deformation; (5) depositional pinch-out; and (6) onlap onto unconformities. Draping over synrift structures form the traditional Gamba Formation traps.