Abstract: By taking the 4 th member of Quantou formation in Zhongtan 25 block of Fuyu oilfield, Songliao basin as an example, through genetic analysis and stratification of single sand body, combined with the superposition mode of single sand body of composite channel, single sand body identification of composite channel plane was carried out, and the distribution and connectivity of single sand body were studied. The results show that the vertical superposition styles of single sand body in the whole region mainly include isolated style and cut superposition style. The spatial contact styles of single sand body include multi-layer, multilateral, unilateral,superposition, butt joint and isolated styles. Interval layer division standard for natural gamma ray is greater than 84.5 API, the microelectrode separation value is less than 0.2 Ω·m. The classification standard for the layer within the interlayers is that the degree of natural gamma ray return is greater than 16% and that of deep lateral return is greater than 17%.