Offshore petroleum frontiers

Of the world's relatively unexplored areas with hydrocarbon potential, the continental margins are the most important. Petroleum consultant, Michel Halbouty, in 1981 estimated the area of the world's prospective offshore petroleum-containing sedimentary basins at nearly 23 million km², about 31 per cent of the world's total petroliferus basins. ¹ Estimates of the offshore basins' recoverable reserves vary. In 1982 one investigator, Karl Hinz, cited estimates for the offshore of between 874,000 million and 2.149 million million bbl of crude oil (45 per cent of the world's estimated total) and 170 and 175 million million m³ of the world's exploitable gas supply, a proportion similar to that of crude oil. ² When Hinz made these estimates, drillers had completed only six boreholes in Norway's waters north of 62°N., ³ and Alaska's offshore was only beginning to be explored, as were several areas in Africa and south-east Asia. Hinz stressed that our ‘present knowledge of the geological structure and development of the continental margins is still too full of gaps for realistic assessment of their hydrocarbon potential’. ⁴ Hinz's statement remains true today.