The continuity of shale smear influences hydrocarbon migration across faults.In similar condition of lithology and stress,the shale thickness and fault distance are the main influencing factors of shale smear continuity.Methods: In this paper,by using core data,the distribution characteristics of shale smear in faults are observed and analyzed,and the effectiveness of shale smear is studied by means of 3D quantitative physical simulation experiment.Results: The following researching results are obtained. First,effective shale smear is the necessary condition of fault sealing,and the continuous thickness of shale smear is an important parameter of sealing evaluation.Second,the shale smear forming process in shear fault zone is proposed,which can be divided into three stages,i.e.the shale layer is not completely faulted,the shear shale smear is formed and the continuity of shale smear is destroyed,among the effective shale smear is the former two stages.Third, based on the non-continuous equal proportion model,a new fault sealing evaluation parameter is presented,and the non-equal proportion evaluation theory and mathematical model are established,and a new sealing system evaluation calculation method is further formed.Conclusions: The results show the non-equal proportion evaluation method considered the shale smear effectiveness coefficient can be applied to determine the effective fault block trap and improve the success rate of exploration,and yield good exploration efficiency in study area.