Tarim Basin

covering a range of 56×10

4

km

2

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 38×10

4

km

2

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(K

1

)

Sha-4(J)and Lunnan-2(T)wells.