摘要
页岩孔隙结构特征直接影响气体在其中的吸附和运移。以长宁示范区下志留统龙马溪组下部富有机质页岩样品为例,利用场发射扫描电镜(FE-SEM)、低压CO2气体吸附及低压Ar气体吸附等实验,对长宁示范区开发主体层段富有机质页岩的孔隙结构进行定性描述和定量表征。结果表明:长宁示范区富有机质页岩主要发育有机质孔隙,页岩孔隙结构非均质性强,平均比表面积为42.19m2/g,平均孔体积为0.059 1cm3/g,孔径小于2nm的微孔提供页岩60%以上的比表面积,是页岩气主要的吸附场所;孔径大于10nm的介孔和宏孔提供页岩70%以上的孔体积,是页岩气主要的储存场所。改进的气体吸附法可实现对页岩纳米级孔径分布的连续定量表征,研究结果对了解富有机质页岩纳米级孔隙结构特征、评价页岩含气性具有指导意义。
The pore structure of shales has a significant impact on gas adsorption and migration. This study combined field emission scanning electron microscopy( FE-SEM),low-pressure CO2 and Ar adsorption to investigate the pore structure of lower Silurian Longmaxi organic-rich shale samples in Changning demonstration zone,southern Sichuan basin. The result shows that the Longmaxi organic-rich shales are dominated by organic matter pores along with fewer intraparticle pores and interparticle pores. The pore structure of the shales is heterogeneous.The average specific surface area of the shale samples is 42. 19 m2/g,with the average pore volume of 0. 059 1 cm3/g. The micropores less than 2 nm account for above 60% of the total specific surface area,which provide most of adsorption sites for shale gas. The mesopores and macropores more than 10 nm accounts for above 70%of the total pore volume,which provide most of storage space for shale gas. The experiment used in this paper realized the quantitative characterization of nano-pore distribution in shales,and the findings have great significance in understanding the characteristics of nano-pore structure and evaluating gas-containing property of organic-rich shales.
出处
《东北石油大学学报》
CAS
北大核心
2017年第6期36-45,65,共11页
Journal of Northeast Petroleum University
基金
国家科技重大专项(2017ZX05037-002)
