Study On The Occurrence And Potential Exploration Of Shale Oil And Gas In Nanpu Depression

The research on accumulation of shale oil and gas is in its infancy in Nanpu Depression. Its occurrence and exploration potential are still unclear. Based on previous study and related geological data, this thesis focused on the distribution of oil and gas, the characteristics of reservoir and the hydrocarbon occurrence. Therefore, this thesis clarified the exploration potential and predicted the favorable areas in Paleogene shale of Nanpu Depression.The situation of shale oil and gas was discussed statistically, comprehensively using logging, drilling, well testing data and so on. The strata of Ed3, Es1 and Es3 were the main objective intervals with good showings in Paleogene shale of Nanpu Depression. Shale and limy mud stone were the main lithology of rock which generated condensate gas, associated gas and crude oil in the normal maturity. This showed that the hydrocarbon had great exploration potential in Paleogene shale of Nanpu Depression.According to single well and test data, the research on geological characteristics of Paleogene shale showed that it had wide distribution, favorable hydrocarbon generation conditions, high brittle mineral content and extremely low porosity and permeability. The nano-pores, secondary dissolved pores and micro-cracks were mainly developed as the reservoir spaces in the study area. These illustrated the Paleogene shale had excellent conditions on generation and accumulation of oil and gas.On the basis of these results and previous studies, the occurrence of oil and gas in Paleogene shale could be divided into three types through nano-CT and Langmuir adsorption models. The adsorbed type existed in the surface of organic matter and clay minerals particles; the dissociated type occurred in the pores and cracks; and the dissolved type with low content was negligible. In addition, the content of hydrocarbon mainly with the adsorbed and the dissociated was affected by the brittle mineral content, pressure, temperature and so on.Through volume method and genetic method, the shale gas resources should be calculated to 3.575 billion cubic meters while the shale oil resources could be about 508.3 million tons. In the light of the evaluation criteria in Nanpu Depression, the shale which was located near Nanpu 105x6 well was preferentially selected as the exploration zone of Es1; and the shale which were situated around Gao 80-12 well, Nanpu 280 well and Pugu 2 well were optimized as the favorable areas of Es3.