Petroleum: Reserves in Nigeria at the moment are estimated at over 23 billion barrels of crude oil and 260 trillion cubic feet of natural gas. The natu- ral gas reserve amounts to three times the total crude reserves. From a modest initial output of 5,000 barrels per day (bpd) in 1958 when production first began, Nigeria's production rose rapidly, to 2.4 million bpd in 1979. Nigeria's petroleum resources lie mostly in the Niger Delta, the central coastal plain of southern Nigeria; at the continental margin; and at the small offshore portion which extends into Equatorial Guinea and Carneroun, where the delta is known as the Rio del Rey Basin.

So far, 29.2 billion barrels of crude oil have been discovered in the delta, 23.3 billion barrels in the Nigerian sector, 937 million barrels in the Rio del Rey Basin, and 45 million barrels of condensate in Equatorial Guinea. Ancient delta front sands of Late Cenozoic age account for the bulk of the Niger Delta oil fields. (Whiteman, 1982). So far, about 870 oil fields have been discovered with over 4000 oil wells, the bulk of which are not yet producing. Among the giant fields is the Edop field, the largest offshore platform in Nigeria which can handle 180,000 barrels per day, but will increase production to 250,000 barrels per day.

Other large fields include Janes Creek, Imo River, Nembe, Meren, Delta south and Okan. A major boost to the Nigerian petroleum sector was the coming on stream recently of the Oso condensate project. With 500 million barrels of condensate and a production capacity of 100,000 bpd, the Oso field, which is offshore Akwa lbom State and is operated by the Nigerian National Petroleum Corporation/ Mobil joint venture, will generate eleven billion dollars to the Nigerian government, and allow the reinjection of all the associated gas produced by Mobil in the eastern offshore delta. Over 70 per cent of the associated gas in Nigerian oil fields is flared; and less than 30 per cent is used for power generation and by industries. Shell, Exxon, Mobil, Chevron, Agip, Elf, and Texaco are the main operators.

Since petroleum is a wasting asset, the NNPC has encouraged exploration in other Nigerian sedi- mentary basins, notably the Borno and Anambra Basins, and the deep water Niger Delta. With their sedimentary sequences, the Borno and Anambra Basins have been drilled, though without success so far. The deeper offshore Niger Delta is the most promising petroleum frontier province, where water depths between 200 and 1,500m have been allo- cated for prospecting, with encouraging recent discoveries.