Due to years of water-injection recovery，the distribution of oil and water is quite complex in the Sangonghe Formation in Block Cai9 of Cainan oilfield. To improve the development efficiency of oil field is very urgent. The key to the adjustment of well pattern in the current development stage of the study area is to make clear the overlapping relation of reservoir，which refers to the distribution characteristics of reservoir architecture of the second and the third layers of the second member in the Sangonghe Formation in the braided river delta front. Therefore，first of all it is required to analyze the rock electrical characteristics of sedimentary microfacies in order to establish the identification marks of sedimentary microfacies for the single well and lay a solid foundation for further fine contrast between the wells. Then，based on the identification results of sedimentary microfacies of the single well，these dimentary microfacies were anatomized in order to make clear the identification marks of different levels of reservoir architecture unit，according to the core，mud logging and well logging data. Being guided by the fluvial facies sedimentary patterns，the static distribution model of cross-well reservoir architecture unit was established to realize the quantitative characterization of different levels of reservoir architecture unit.Finally，the rationality and reliability of the static distribution model of reservoir architecture unit was verified by the dynamic data. The result shows that the established static distribution model of reservoir architecture unit is reasonable and reliable in the Sangonghe Formation in Block Cai9 of Cainan oilfield，and it is also in good agreement with the actual production situation of the research region，which has guiding function for the development of reservoir in the later stage.