Abstract：The oil/gas in Qian northwest area of Jilin Province is mainly concentrated on thin sand body with delta front facies. The trap types are mainly lithologic trap and lithologic-structural composite trap. On a basis of 3-D high-resolution seismic data acquisition and processing and through integrative use of coherent volume with optimum frequency band,integrative detection of dips and fault edges，analysis of sedimentary microfacies and seismic inversion etc.，the paper gained the following major results:the rule of spatial distribution of faults is known，total 135 faults are interpreted(only 29 faults in 2-D data);the corresponding relation between sedimentary fades and logging response is built up，the characters of sedimentary microfacies such as underwater distributary channel，river mouth bar,distant sand bar and sheet sand on natural potential logging and resistivity logging are given separately; the scopes of distribution of reservoirs and oil/gas are defined. The good results are obtained by drilling, played a good role in improvement of exploration effects in Jilin prospectmg area.
