Equatorial Guinea territory overlies parts of two world-class petroliferous sedimentary basins. Both are highly prospective for hydrocarbons with proven petroleum systems including marine oil-prone source rocks and high quality sandstone reservoirs.
In the north of the country around Bioko, the offshore sector overlies the distal parts of the Niger Delta-Rio del Rey basin system. The Niger Delta is one of the world’s largest petroleum provinces with estimated proven oil reserves of 48 billion bbls. The Equatorial Guinea part of the basin has established oil and gas production from the Zafiro and Alba fields plus a number of other discoveries.
The southern part of Equatorial Guinea’s offshore sector overlies the Rio Muni Basin. This is contiguous with the Kribi-Campo (Douala) Basin of Cameroon to the north (which hosts the Sanaga Sud - Kribi oil and gas fields) and with the North Gabon Basin to the south which contains numerous oil and gas discoveries. The excellent potential of the Rio Muni Basin has been demonstrated by the discovery of commercial oil at the Ceiba Field and the Okume Complex fields, and with a number of other discoveries under appraisal.
The 2007 Belinda discovery in Block I (now renamed Aseng Field) and other discoveries in Blocks O and I and across the border in Cameroon have demonstrated the prospectivity of the Douala Basin.
The sedimentary section beneath both the Bioko and Rio Muni areas extends oceanward to the territorial limit of Equatorial Guinea. The sediments of the distal Niger Delta Basin and those of the deep water Douala and Rio Muni basins merge in the region south of Bioko, giving significant petroleum potential to the whole of Equatorial Guinea’s offshore areas.
Industry attention is now extending to the ultra-deepwater Gulf of Guinea around the islands of the Cameroon volcanic trend which include the Equatorial Guinean island of Annobon. Here it is postulated that the extensive offshore economic zone could contain a thick sedimentary section with petroleum potential, as evidenced by oil seeps on the neighbouring volcanic islands of Sao Tome and Principe.