Exploration Practices of Lithologic Reservoir of Palaeogene Dongying Formation in Gaonan Slope of Nanpu Sag

This paper analyzes the accumulation conditions of the lithological reservoir of Dongying Formation in Gaonan Slope of Nanpu sag,such as the structural setting,resource base and hydrocarbon migration pathways,so as to deeply develop the given reservoirs. Three typical accumulation models of the lithologic reservoirs are determined in the study area,i. e. updip-pinchout lithologic reservoir,lenticular sandstone reservoir and discordant-screened reservoir,in the distributary channel sandstone of the downthrow fan delta in the synsedimentary fault. The study suggests that the formation and distribution of Dongying distributary channel sandstone reservoir are mainly controlled by three factors involving the hydrocarbon resources,structure and lithology. In the past two years,the commercial oil flow was seen in six wells( including G129x1 and G183x1) drilled in the lower-generation and upper-preservation lithologic reservoir of Dongying Formation in the Gaonan area. It is of guiding significance for future exploration of lithologic reservoir in the similar areas.