HYDROCARBON ACCUMULATIONS IN THE TARIM BASIN, CHINA

The Tarim basin is the largest and least explored inland basin in Chin a. The areal extent of the basin reaches 560,000 km(2). The interior o f the basin is mostly covered by the Takla Makan Desert, which is abou t 330,000 km(2) in areal extent. The basin has become the object of sp ecial attention since China set aside first- and third-round onshore b idding blocks in the Tarim basin for foreign oil firms to explore. The Tarim basin is a polyhistory superimposed basin that has experienced seven evolutionary stages: (1) Sinian-Cambrian-Ordovician aulacogen st age, (2) Silurian-Devonian intracratonic depression stage, (3) Carboni ferous marginal sea stage, (4) Permian rift basin stage, (5) Triassic- Jurassic foreland basin stage, (6) Cretaceous-Paleogene NeoTethys bay stage, and (7) Neogene-Pleistocene foreland and inland basin stage. Bo th the basin's Paleozoic marine platform sequences and the Mesozoic-Ce nozoic terrestrial fills are believed to contain substantial volumes o f hydrocarbons. After recent years of exploration, nine oil and gas fi elds have been proven and 23 discoveries have been made in the Tabei, Tazhong, and Southwest areas. Kekeya, Lunnan, Sangtamu, Jiefangqudong, Donghetang, and Tazhong 4 oil fields have been put into production. O utput of crude oil was 2.6 million t (metric tons) (52,000 BOPD) in 19 95. The production will increase to 5 million t (100,000 BOPD) in 1997 . Giant oil and gas traps probably will be discovered in the Tarim bas in. The prospect is promising.