Abstract: Kulongshan overthrust nappe is located in west of nothern margin of Qilíanshan mountain. It is a faulted basin in Mesozoicand a foreland in Cenozoic. In its Qingxi depression is found fractured reservoirs, In order to make elear the oil-gas enrichment , this paperdiscusses the effect of tearing faults in overthrust nappe on oil-gas accumulation by means of the analysis of structural faults and theirdistinct oil-gas distribution. ht is pointed out thal il is N-E tearing fault that controls the distribution of open frachral bel, which could behigh-yielding block.

Key words: Jiuquan basin, foreland basin, overthrust fault, tearing fault, fracture, petroleum reservoir