Abstract: The coupling contact relationship between fault and sand reservoir determines the validity of the hydrocarbon migration and transportation system. It is a key problem in shallow oil and gas exploration and evaluation on the western slope of the Bozhong Sag. Based on the logging data from 6 evaluation wells and the 3-D seismic data from the Oilfield CFD A, the connectivity boundaries of reservoir sand bodies and the types of fault-sand coupling contact are studied in this paper. Three types of oil and gas migration systems, namely the forward, lateral and compositeare, classified. Using the quantitative description method for the fault-sand coupling system, it is clear that the relative efficiency of oil and gas forward migration in the shallow sand bodies in this area is about 1.7, compared to the efficiency of lateral migration. On this basis, the quantitative relationship between fault-sand contact area and oil column height is established. Practice has proved that this method is feasible for predicting the oil column height of shallow undrained sand body in similar blocks, and has important significance for reference of the exploration and evaluation of subsequent reservoirs.