Abstract：The Mesozoic of Jiuquan basin was in developed stage of extensional fault basin,forming a series of NNE Early Cretaceous secondary sags characterized by fault in east and overlap in west and having the feature of east fault lake basin and geologic background of tectonic-stratigraphic (lithologic)reservoir.The targets of former oil/gas exploration were structural reservoirs,which was not ideal in recent exploration,although achieved some important results.In view of such technical difficulties as strong heterogeneity of reservoirs and poor quality of seismic data,the paper fully used drilling data and adopted such techniques as analysis of seismic attributes,horizontal slices,inclination logging and imaging logging,and sequence-stratigraphy in exploration and study of tectonic-stratigraphic reservoirs of two sags: Qingxi and Ying'er,which discovered a lot of tectonic-stratigraphic traps by fine interpretation of fault-block structures and prediction of sedimentary facies and reservoirs,where two regional prospecting wells,YX1 and C3,were optimally settled in Qingxi sag and Ying'er sag respectively and commercial oil flow was gained after drilling.The breakthrough has been made in tectonic-stratigraphic reservoir prospecting of Jiuquan basin.
