Abstract: The Miyang depression is a fault-depression lake basin holding continental deposits of Tertiary age. Though covering an area of only 1,000 square kilometers, the basin is rich in oil. The updip lithologic pinch-out pool formed of Shuanghe subaqueous alluvial fan is well-developed in the 3rd member of Hetaoyuan formation in the southern part of the depression. This alluvial fan is characterized by: (1) predominance of coarse clastics of poor sorting, with frequent occurrence of massive and graded bedding; (2) predominance of composite rhythmic sedimentation of flood turbidity flow, with grain sizes typical of the flow; (3) a fanlike planar distribution of deposits, posing as a wedge in the section; (4) a subdivision of three subfacies zones in the top, middle and bottom parts of the fan; (5) the occurrence of subaqueous channel turbidites at the top of the fan and (6) apparent reflection of the fan on the seismic profiles. The pool is mainly reservoired in the top and middle parts of the fan.