The Hydrocarbon Source Potential of Brazil and West Africa Marginal Basins

The rapid growth of exploration in the Brazilian and west African marginal basins in the last decade can be attributed to the recognition by oil companies that these basins constitute some of the last frontiers in the world for appropriation of large oil and gas reserves. In most Brazilian and West African basins, exploration is far from being mature, since deep water probes practically have not started. However, evidences have shown that similar oil types in the southern Brazilian Santos, Campos and Espirito Santo basins, are to be found in the West African Cuanza, Cabinda and Zaire basins. Such basins fit neatly in the gig-saw puzzle if the maps of the South America and Africa continents were to be brought together (Mello et al., 1993). A geochemical survey of the most productive Brazilian and West African sedimentary basins, using a wide selection of oils and source rocks ranging from Lower Cretaceous to Miocene in age, has been carried out. The aims were to identify and characterize the oil types, to assess the respective depositional paleoenvironments and the age of their putative source rocks, and to perform the oil-oil and oil-source rock correlations in order to compare and characterize oils derived from both sides of the Atlantic. This approach was based mainly on the distributions and concentrations of biological markers (Moldowan et al., 1985; . Mello et al., 1988, Mello and Maxwell, 1991).