Abstract: Wang-43 block of Wangjiagang oilfield is a typical complex fault block oil reservoir.At present it is of high water cut,prominent development contradiction and weak geological foundation.The development adjustment and EOR in the next step urgently need reliable fine geological model.Aiming at the reservoir geological characteristics of complex fracture system,with the integrated application of a number of key technologies,fine geologic research has been carried out and the fine 3D geological model of complex fault block reservoir has been established.In complex fault block oil reservoir,affected by the contemporaneous faults,the stratigraphic loss is serious and lack of correlation marker stratigraphic correlation technology,low-grade fault identification technology,fine reservoir classification and fine 3D geological modeling technology.The research results can not only provide reliable geological guidance for subsequent development adjustment of Wang-43 block but also provide reference for similar reservoir development study.