Abstract Evidence is presented from the interpretation of seismic data for the compressional deformation of intra-plate oceanic crust in the eastern Gulf of Guinea, a region occupied by the Douala-Rio Muni Basin and the Cameroon Volcanic Line. The deformation has taken the form of the reactivation of syn-kinematic structures in the fabric of the oceanic crust. The origin of the Cameroon Volcanic Line is usually attributed to a mantle hotspot, but interpretation of the seismic data indicates that strike-slip and/or compressional tectonics and reactivation of the fabric of the oceanic crust have all played an important role in its evolution. A regional tectonic model is presented that associates deformation in the eastern Gulf of Guinea with regional alpine-related far-field compressive stress. In this way, a causal link is invoked between deformation of the oceanic crust and strike-slip movement on the Central African Shear Zone, establishing a continent–ocean tectonic link. The evolution of the Cameroon Volcanic Line and the continent–ocean tectonic link has imparted a unique tectonostratigraphic history to the Douala-Rio Muni Basin and has influenced its petroleum endowment. The structural and combination trapping potential has been greatly enhanced in this environment and the structural architecture of the basin has influenced the depositional patterns of the deep water reservoir sands.

Abstract Two major Cretaceous transgressive-regressive sedimentation cycles occur from Zaire to the Douala basin, Cameroon. These two major cycles are separated by a major interregional unconformity of late middle-late Turonian age. The major middle Cretaceous cycle is divided into three major cycles: a late Albian, an early-middle Cenomanian, and a late Cenomanian – early middle Turonian cycle. The major Late Cretaceous cycle is also divided into three minor cycles: a Coniacian-Santonian, a Campanian, and a Maestrichtian cycle. All major and minor cycles are well defined in Zaire and Cabinda, but the minor cycles are not as well defined in Gabon and in the Douala basin. With a few differences, the middle and Late Cretaceous cycles of central West Africa correlate with those of the eastern Arabian Peninsula, northern Europe, north central Asia, and the Western Interior of North America. The fact that the central West African cycles correspond in time with those of other areas of the world suggests that the effects of the local salt tectonics and the rate of sedimentation were not strong enough to change the time in which these cycles occurred.

ABSTRACT The Sanaga Sud field is located 10 km northwest of the coastal town of Kribi in the central portion of the Douala basin. The Sanaga Sud A-1 discovery well was drilled in 1979 to test an eroded, paleotopographic high block composed of Lower Cretaceous sands and shales and overlain by Upper Cretaceous shales. The structure contained a prominent near-horizontal seismic amplitude event. Drilling results showed that the amplitude event was a gas-water contact. Two appraisal wells, Sanaga Sud A-2 and A-3, were drilled in 1981. All three wells tested gas and condensate. Gross pay thickness averages 250 m, with an average porosity of 23% and an average permeability of 142 md. Total recoverable hydrocarbons for the field are estimated to be 900 bcf of gas and 4.5 million of bbl of condensate.