In order to solve the oil and gas development problems of the coastal sandbar in Z block of the Indus Basin, such as thin reservoir, rapid lateral change and strong heterogeneity, based on core, logging, seismic and production test data, the microfacies division, favorable sandbody distribution and deposition model are detailed analyzed, which can provide a basis for fine characterization of the internal structure of sand bar reservoir. The results are shown as follows: According to the sedimentary facies markers, the sandbar reservoir microfacies can be divided into center bar, bar edge and inter bar. By means of seismic attributes and reservoir inversion, the internal structure and contact relationship of sandbar reservoir can be predicted effectively. The center bar is in the core part of sandbar, with the shape of point or strip on the plane. The sandstone thickness is thick (>3m), and reservoir physical property is the best, which constitutes the dominant reservoir. The bar edge is located in the flank of the center bar, which is flat sheet or strip on the plane, the lithology is thin sand and mud interbedded, single sand thickness is thin (<2m), and the reservoir physical property is medium. The inter bar is between the main sandbar, mainly fine sediment with poor reservoir physical property. The sandbar microfacies changes rapidly, and different microfacies types overlap each other, especially the inter bar interspersed between the center bar and bar edge, which intensifies the heterogeneity within the sandbar reservoir.