On the basis of the field sections’data and results of core observation，we established the identification standards of interlayers in the vertical direction for underwater distributary channel sandbodies and the division standards of the single sandbodies in the lateral direction with logging and performance data in the study area. Further，we identified the single sandbodies in underwater distributary channels in Chang812 of L158 Block，Huanjiang Oilfield，Ordos Basin，analyzed the spatial superposition types of the single sandbodies and calculated their proportions. At last，we studied the influence of these superposition relationship modes on the connectivity among the sandbodies and expounded the distribution characteristics of the remaining oil. The results show that the widths of single river channels of Chang812 in L158 Block，Huanjiang Oilfield are 230-450 m，and the thicknesses of the single sandbodies are 4-10 m. Seven superposition types are found from the single sandbodies, i.e.，three in the vertical direction (separated type，vertical contact type，and vertical cutting type) and four in the lateral direction (interdistributary contact type，embankment contact type，butt contact type，and side cutting contact type). There are 10 spatial combination modes，dominated by separated-side cutting and vertical contact-side cutting combinations. The remaining oil is enriched in the flanks of the upper single sandbodies and the tops of the lower single sandbodies of the two-way weakly connected sandbodies，and the flanks of the upper single sandbodies of the weakly connected sandbodies in the lateral direction，but it is not enriched in the lower single sandbodies of the weakly connected sandbodies in the lateral direction and the strongly connected sandbodies.