1. College of Earth Sciences��Jilin University��Changchun 130061��China; 2. Institute of Northeast Petroleum Bureau��SINOPEC��Changchun 130062��China

A comprehensive study of sedimentary filling characteristics and basin evolution in Zhangwu Basin is presented in this paper by comparing the sedimentary sequences of Well ZW3 and Well ZW10 analyzing and a balanced geological section of I1 seismic profile�� There are three varied superimposed stratal relationship styles be- tween Jiufotang Formation and Shahai Formation��including back- stepping (fading)��still- standing and over- step- ping styles��which are caused by the right lateral wrench during the basin development�� A large amount of mud and oil shale developed in the lower member of the Jiufutang Formation during the stage of extension��reflecting the in- creased accommodation space and the shortage of sediment supply�� The potential capacity of oil and gas is good in this member�� The filling of the upper member of Jiufotang Formation had formed during the stage of transtension�� Well ZW10��representing the filling of the eastern region of the basin��is a set of mudstones and Well ZW3��repre- senting the western region��is a set of coarse clastic deposits��reflecting the occurrence of slip- wrench of this basin�� The uplift in the fault depression resulted from slipping and wrenching of the faults��had separated the hydrocarbon- generative depressions and the lower reservoir system started to develop�� The large- scale of tectonic inversion oc- curred at the ending of Jiufotang Formation and a serious erosion on the eastern edge of the basin made the upper member of the Jiufotang Formation partly lost�� The filling of the lower member of the Shahai Formation developed during the stage of extension- transtension�� The dark shale with good potential capacity of oil and gas developed in the lower part and the content of sandstones in both Well ZW3��and Well ZW10 had an obvious increase in the up- per part��reflecting adequate supply and rapid progradation of sediments�� The slipping and wrenching had made the uplift develop again and form the upper reservoir system�� The filling of the upper member of Shahai Formation oc- curred during the stage of basin fade with a strong sand progradation�� A big scale of tectonic inversion occurred again at the ending of the Shahai Formation and the upper member of the Shahai Formation was largely lost��