Global deep- and ultra-deep-water oil and gas exploration: review and outlook

Global deep- and ultra-deep-water oil and gas exploration has experienced three stages: deep-water discovery (1959-1983), deep-water rapid development and ultra-deep-water discovery (1984-2009), and deep- and ultra-deep-water stable development (2010-present). Deep-water mature exploration areas distributed mainly in the Gulf of Mexico, eastern Brazil, and West Africa, and new discoveries of ultra-deep-water fields are in the northeast Latin America, East Africa, and the eastern Mediterranean. In the past decade, the global deep-water and ultra-deep-water exploration investment showed a two-staged characteristic. In the first four years from 2011 to 2014 the investment and the number of wells were relatively large. As the oil price fell in 2014, the investment decreased sharply, and investment projects were mostly concentrated in the key areas in Latin America, North America, and Africa. In terms of reserves, the "multi-field breakthroughs and centralized distribution" is the typical characteristic. New field breakthroughs in natural gas were in the East Africa, the eastern Mediterranean, and the Black Sea basin, and those in oil were in Guyana. The discovery time was concentrated in the years from 2011 to 2015, and the water depth was mainly in 1 500～2 400 m. The potential of oil and gas resources in the deep-water and ultra-deep-water field is huge. Technological progress has enhanced the competitiveness of exploration. With the gradual recovery of oil price, investment into deep-water has been increasing. In the future, the reserve growth will sustain in the mature fields and multiple breakthroughs are expected to be made in deep-water frontiers including East Africa, eastern Mediterranean, Black Sea, and Suriname, which will lead the direction of global deep-water and ultra-deep-water oil and gas exploration and promote deep-water exploration into a new era of reserve growth.