The isotopic characteristics of noble gases have been long used in the study of the genesis and origin of natural gases.A systematic analysis of the abundance and isotopic composition of noble gases in natural gases from different structural units shows that the majority of samples is low in the ratio of

3

He/

4

He

with the R/R

a

values generally less than 0.1

indicating a crustal radiogenic genesis of the noble gases and a significant "cold" feature of the basin.No simple correlation exists between the

3

He/

4

He ratios and both of heat flow and paleo-geothermal gradient

revealing little heat sourcing from mantle.The lower level of

21

Ne/

22

Ne ratios influenced by the relatively late hydrocarbon generation and accumulation period

mostly during the Himalaya movement

shows an inconspicuous proportion of mantle-derived gas in natural gases from Kuqa Depression.The relative depletion of

129

Xe shows that the mixing of mantle-derived volatile constituents is insignificant.Furthermore

compared with the natural gases from Tabei Uplift and Tazhong Uplift

the Xe in natural gases from Kuqa Depression was more likely derived from the crust due to the influences of lithology and structural features.