Abstract:

Tarim Basin,covering a range of 56×10⁴ km²,is a Meso-Cenozoic inland basin of composite-superposed type formed on a stable landmass.The Meso-Cenozoic sediments are mainly coal-bearing clastic rocks that are distributed within an area of 38×10⁴ km² with the thickness of 1600m-5000m.Triassic-Jurassic source rocks are dark argillaceous rocksand coal measures intercalated with gray carbonate rocks and oil shales of 700-1200mthick.Organic matter is primarily Ⅰ_B-Ⅲ type and partly Ⅰ-Ⅱ_A type,vitrinite re-flectance R_o is generally 0.6%—1.2%,suggesting good hydrocarbon generating potential.As for hydrocarbon preservation condition,sandbodies of fluvial,deltiac and lacustrine facies are well developed in Mesozoic,which might form favourable preservation sedimen-tary facies in time and space;many drape structures,compression anticlines,lithologic and stratigraphic traps developed there,which prepared fine conditions for the formation of hydrocarbon pools.Thus the Mesozoic stratum in Tarim Basin has shown bright prospects in hydrocarbon exploration.This has been proved by the discovery of a number of high-productive wells such as Sha-5(K₁),Sha-4(J)and Lunnan-2(T)wells.