陆相轻质页岩油赋存孔隙空间及孔隙连通性定量表征

轻质页岩油是我国“十四五”期间陆相页岩油气重点勘探对象，轻质油易于散失，如何定量表征轻质油所赋存的陆相页岩储层孔隙空间及含有轻质油的页岩储层孔隙连通性是亟待解决的重要问题。本项目以川东南地区涪陵区块凉高山组页岩为研究对象，在钻井现场将页岩岩心及时冷冻至-50℃，最大限度减少页岩中轻烃损失；从总有机碳含量、纹层发育、矿物组成三方面划分页岩岩相，对冷冻的不同岩相类型页岩开展密闭碎样、索氏抽提实验、抽提前、抽提后孔隙结构联合表征实验，定量精确表征易于散失的轻质页岩油所赋存孔隙空间；对冷冻的页岩进行切割、钻样，开展自发渗吸实验、核磁共振实验，定量精细表征页岩储层孔隙整体连通性和各孔径区间连通孔隙所占比例；结合离心实验，明确轻质页岩油可动性，进而查明孔隙结构和孔隙连通性对轻质页岩油可动性的影响。预期成果对完善轻质页岩油成藏理论和指导有利区优选均具有重要的理论和现实意义。

Light shale oil is the key exploration target of Lacustrine shale oil and gas during the "14th Five-Year Plan" period in my country. Since light shale oil is easy to disperse, how to quantitatively characterize the pore space and its connectivity of lacustrine shale containing light oil is an important problem to be solved urgently. In this project, Lianggaoshan Formation shale in the Fuling area in southeastern Sichuan will be taken as the research object. Shale samples containing light shale oil will be immediately frozen to -50℃ to minimize the loss of light hydrocarbons at the drilling site. Then, Shale lithofacies will be classified from three aspects: total organic carbon content, laminar and mineral composition and the frozen shale samples with different lithofacies will be crushed in a sealed way and Soxhlet extraction experiments will be carried out, as well as the characterization experiments of pore structure before and after the extraction, to quantitatively characterize the pore space storing light shale oil. The frozen samples on site will be cut, and spontaneous imbibition test, nuclear magnetic resonance test and mercury intrusion porosimetry test will be carried out to quantitatively characterize the overall connectivity of shale pores and the proportion of connected pores in each pore size section. Combined with centrifugal experiments, the mobility of light shale oil will be clarified, and then the influence of pore structure and connectivity on the mobility of light shale oil will be clarified. The expected results have important theoretical and practical significance for improving the theory of light shale oil accumulation and guiding the optimization of favorable areas for light shale oil.