Influencing Factors And Evaluation Of Mobile Oil Contents In Shahejie Formation Shale In Dongpu Depression

The lacustrine shale oil is rich in oil resources and has great exploration and development value.Although the predecessors have carried out a lot of research on lacustrine shale and have obtained many research results,the influencing factors of shale movable oil content are unclear at present,which restricts the further exploration and development of lacustrine shale oil.In this paper,a series of organic geochemical,inorganic rock deposits,pore structure and movable oil content analysis tests were carried out on the shale of Shahejie Formation in Dongpu Depression.The results show that the shale of the Shahejie Formation in the study area has higher organic matter abundance,with an average TOC of 1.7%.The organic matter type is mainly type?₁ kerogen,which is currently in a early maturity-peak mature stage.The mineral composition is mainly carbonate rock minerals and clay minerals,followed by felsic minerals.The pore morphology is mainly parallel plate slit type-unilateral slit type,and mainly develops macropores and mesopores,and smaller mesopores and macropores make the main contribution to the pore volume and specific surface area within their respective pore size ranges.According to the mineral composition and structural characteristics,the shale of Shahejie Formation is divided into8 types of lithofacies,among which the thin laminated clayey marl and thin laminated clayey mudstone are the most developed.By comparison,it is found that the organic matter abundance of the thin laminated clayey marl is the highest,the organic type of the laminated clayey mudstone is the best,and the movable oil content of the thin laminated clayey marl is the highest;The organic matter abundance of the massive clayey marl is the lowest,the organic matter type of the massive clayey mudstone is the worst,and the movable oil content of the laminated and the massive clayey mudstone is the lowest.Combining single factor analysis and SPSS multiple regression analysis,it is believed that the main controlling factors of movable oil content are organic matter abundance(TOC)and clay mineral content.An evaluation model of movable oil content was established,and the accuracy of the model was verified.The evaluation model can be used to evaluate the actual lacustrine shale mobile oil content.