Abstract: In order to make clear the distribution characteristics of the residual oil in Tangjiahe oilfield, by taking Ed_3 reservoir in fault block 3 as an example, on the basis of data analysis on core, logging, seismic and dynamic information, the internal configuration model of the single sand body in the mouth bar was established, the identification marks and spatial distribution characteristics of the internal structural units of reservoirs in the mouth bar were discussed, and the threedimensional configuration model of the sand body was established. The results show that the sand body of Ed_3 reservoir in fault block 3 in Tangjiahe oilfield is in the shape of flowers or bands, with an average thickness of4.5～6.7 m and an average width of 400～1 000 m. Mud interlayers are developed inside the mouth bar, with the interlayer thickness generally less than 2 m. Vertically,the dam body is mostly separated by relatively stable mud interlayers, and the configuration interface of the single sand body controls the distribution of oil and gas. In the lateral direction, the sand bodies of a single dam are unconnected mudstone interlayer, weakly connected dam edge contact and connected main dam superposition.