PETROLEUM GEOLOGY OF THE TARIM BASIN, NW CHINA - RECENT ADVANCES

The Tarim Basin is located in the Xijiang Uygur Autonomous Region of N W China, and covers an area of about 560,000 sq. km. At dawn on Septem ber 22nd, 1984, Well Shashen-2 (drilled by a team from the Ministry of Geology and Mineral Resources) blew-out spectacularly when it penetra ted Ordovician dolomites at a depth of 5,392m. The blow-out marked the discovery of a highly-productive oil- and gasfield, from which daily output has reached 1,000 m(3) oil and 2 MM (million) m(3) gas. Over th e last decade or so, 560,000 km of gravimetric surveys (scale 1:10(6)) and 338,000 km of airborne magnetic surveys (1:200,000) have been com pleted. Some 200,000 line-km of 2-D seismic profiles and 10,000 km of 3-D surveys have also been carried out, and more than 200 wells have b een drilled. Twenty-two oilfields producing from ten stratigraphic int ervals, four of which have reserves of more than 100 million tons, hav e been discovered or explored, indicating that the future prospects fo r petroleum exploration in the basin are very favourable (Kang and Hua ng, 1992; Jia, 1991a; 1991b). Annual production in the Tarim Basin rea ched 2,300,000 t in 1995 (Kang et al., 1996).