The layer series of development in NP1-5 area of Nanpu sag is braided delta front deposits. It consists of a large number of layers with complex contact relationship. Based on the principle of reservoir hierarchical structure, the reservoir formation in the study area has been divided into 9 hierarchies. The 5th to 7th hierarchies are the focus of this study, which are single delta-front sand body,single genesis sand body, single channel sand body. According to the characteristic of the interbed, the deposition time unit (single sand bed) was subdivided based on analyses of layers; according to the characteristic of microfacies, single genesis sand body was identified; according to the characteristic of well log, altitude and thickness, the single channel sand body in the main single genesis sand (underwater distributary channel) was identified. Findings show the single-channel sand bodies in the study area are always lay banded with a thickness of 3-5 m and a maximum width of 400 m. The single-channel sands cut into each other and build up the wide range of underwater distributary channel; by reworking from wave action and later erosion of underwater distributary channel, the channel border sand presents a sheet-like distribution; the mouth bar sand is rare and remainremains only in the interchannel.