Petroleum Systems of Deep-Water Basins - Gulf Coast Section SEPM

The Rio Muni Basin of Equatorial Guinea:
A New Hydrocarbon Province
Paul Dailly
Kenny Goh
Phil Lowry
Gene Monson
Triton Energy
6688 North Central Expressway
Dallas, Texas 75206
e-mail: daillyp@tritonenergy.com
Abstract
The Rio Muni basin underlies the continental shelf of the west African republic of Equatorial Guinea, located
between Gabon and Cameroon. The basin is situated above a section dominated by a northeast-southwest trending
oceanic fracture zone and its continental extension. This fracture zone constitutes the boundary between the Equatorial
Atlantic margin and the West African salt basin.
Despite its location between the prolific hydrocarbon provinces of the Niger delta to the north and the Gabon
coastal basin to the south, the Rio Muni basin has been overlooked by the industry for much of the last decade. Previous
wells have proved a viable source rock, but no accumulations. Triton Energy licensed Blocks F & G in 1997 and
drilled the Ceiba 1 discovery well in 1999, proving a new hydrocarbon system in the deep water, Late Cretaceous post
rift sequence. Deformation by Santonian-Coniacian transpression caused uplift of the shelfal area and deposition of a
thick, slope fan sequence. Contemporaneous salt deformation of rafted deposits and the development of a base of
slope compressional belt are also evident. The resultant turbidite sequences form the reservoirs in the Ceiba discovery,
which has been tested at 12,400 BOPD. Both Late Cretaceous and Tertiary turbidite reservoirs form exploration targets
in the basin; these may be charged by a deep water source kitchen from which earlier, shelfal wells were
shadowed.
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