Nearly 50% of Africa's total area is comprised of sedimentary basins. These basins number more than 80 and contain an estimated proven hydrocarbon reserve of 89 billion bbl (oil equivalent), about 8% of the world's resources. Of these reserves, 68% occur in North Africa, 22% in Nigeria, and 7% in the Aptian Salt basin, which encompasses the coastal parts of Cameroon, Gabon, Congo, Zaire, and Angola. The first discovery of hydrocarbons in Africa was in Egypt in 1886, and the most recent discoveries are in the Gulf of Guinea and the interior rift basins of central Africa.

Africa's basins can be classified into six types. However, each type has modifiers and most basins have evolved through a polycyclic history from one type to another.

Giant hydrocarbon accumulations are related to marine source strata and large, non-giant pools to nonmarine source strata. All sizes of fields occur in areas with marine source rocks, but giant fields very rarely occur in areas where nonmarine source rocks are thought to predominate.

Estimates of future potential reserves for each basin have been established by conventional basin assessment, play assessment, and volumetric yield methods, where data were sufficient. The most intensely explored basins are those containing giant fields. However, basins such as the Taoudenni, Zaire, Okawango, and Kalahari are each as large as Texas or the North Sea, yet the number of wildcats in each can be counted on one hand. Furthermore, about 80% of Africa's sedimentary area is virtually unexplored.

Giant accumulations will be found in the future in Tunisia and Egypt, in east Africa (if a deeper Karroo-play is pursued), and in the interior sag basins of central Africa, which are remote and unexplored. Some chance of finding one or two giant fields exists in Algeria and Libya, the Aptian Salt basin, the Gulf of Guinea, and the interior rift basins of central Africa, but generally only large accumulations will be found. Also, northwest Africa may yield oil in commercial quantities.

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