Oil/gas reserves is one of the important achievements got in petroleum exploration. Growth

change and distribution pattern of reserves comprehensively reflect the exploration history and future exploration potential of a basin. Exploration in Tarim basin has entered into a new development stage since the middle of 1980's

and oil and gas reserves have been increasing continuously.By the end of 2001

cumulative proved oil and gas reserves in place had reached 538 million tons and 613.195 billion m

8

respectively

in Tarim basin.Exploration degree of both oil and gas are low (4.65% and 5.39%

respectively)

indicating that there are still large petroleum exploration potentials.The discoveries in Tarim basin are mainly of medium oilfields and large gas fields

and the abundance of oilfields ranges from low to medium

while that of the gasfields ranges from medium to high.Distribution of reserves that have already been discovered is significantly uneven in various structural units and horizons.The proved oil reserves in place are mainly distributed in the Ordovician

Carboniferous

Triassic and Tertiary in Shaya and Katake uplifts

while the proved gas reserves in place are mainly distributed in the Cretaceous and Tertiary in Kuqa depression.