下扬子地区大隆组页岩孔隙发育特征及主控因素  

The development characteristics and main control factors of shale pores in the Dalong Formation of Lower Yangtze region

作　　者：曹磊 郭英海[2,4] 赵恒[1,3] 朱士飞[1,3] CAO Lei;GUO Ying-hai;ZHAO Heng;ZHU Shi-fei(Jiangsu Institute of Geology and Mineral Design,Xuzhou 221006,China;School of Resources and Earth Sciences,China University of Mining and Technology,Xuzhou 221116,China;Key Laboratory of Coal Resources and Mineral Resources,China Coal Geology Bureau,Xuzhou 221006,China;Coal Seam Key Laboratory of Gas Resources and Accumulation Process,Ministry of Education,Xuzhou 221008,China)

机构地区：[1]江苏地质矿产设计研究院,江苏徐州221006 [2]中国矿业大学资源与地球科学学院,江苏徐州221116 [3]中国煤炭地质总局煤系矿产资源重点实验室,江苏徐州221006 [4]煤层气资源与成藏过程教育部重点实验室,江苏徐州221008

出　　处：《岩石矿物学杂志》2023年第5期652-662,共11页Acta Petrologica et Mineralogica

基　　金：江苏省自然科学基金青年基金项目(BK20200171)。

摘　　要：为了研究下扬子地区二叠系大隆组页岩孔隙结构特征,联合扫描电镜、高压压汞、N_(2)/CO_(2)气体吸附实验手段对页岩储层孔隙结构进行了研究。结果表明,研究区二叠系大隆组页岩孔隙类型以有机质孔、粒间孔、粒内孔、溶蚀孔和微裂缝为主;孔隙结构为多峰态-多尺度孔隙并存,微孔-介孔-宏孔都有发育,各个尺度的孔隙对孔容都有所贡献,其中以0.75~1.5 nm的微孔、10~35 nm的介孔及大于100 nm的宏孔为主。通过拟合孔体积、比表面积与埋深、有机碳(TOC)、成熟度(R_(O))以及矿物含量的相关性发现,微孔表面积与埋深、TOC呈正相关;微介孔体积和表面积均与R_(O)呈负相关;宏孔体积与埋深、TOC、黏土矿物含量呈负相关,与R_(O)呈较正相关;宏孔表面积与埋深成正比,与R_(O)成反比。研究结果说明下扬子地区大隆组页岩孔隙发育主要受控于埋深、TOC、R_(O)、黏土矿物含量等因素。In order to study the pore structure characteristics of the Permian Dalong Formation shale in the Lower Yangtze area,the pore structure of the shale reservoir was studied by means of scanning electron microscopy,high-pressure mercury injection and N_(2)/CO_(2)gas adsorption experiments.The results show that the pore types of the Permian Dalong Formation shale in the study area are mainly organic pores,intergranular pores,intragranular pores,dissolution pores and microfractures.The pore structure is multi-modal and multi-scale,and micropores,mesoporous and macropores are developed.The pores of all sizes contributed to the pore volume,and the micropores of 0.75~1.5 nm,mesoporous pores of 10~35 nm and macropores larger than 100 nm were the main ones.By fitting the correlation between pore volume,specific surface area and buried depth,TOC,maturity(R_(O))and mineral content,it was found that the surface area of micropore was positively correlated with burial depth and TOC.The volume and surface area of micro-mesoporous pore were negatively correlated with R_(O).Macropore volume is negatively correlated with burial depth,TOC,and Clay mineral content,while it is positively correlated with R_(O).Macropore surface area is proportional to buried depth and inversely proportional to R_(O).The research results show that the development of shale pore in the Dalong Formation of the Lower Yangtze area is mainly controlled by factors such as burial depth,TOC,R_(O)and clay mineral content.

关 键 词：下扬子地区 大隆组 孔隙结构 发育特征 主控因素 

分 类 号：P618.13[天文地球—矿床学] P588.2[天文地球—地质学]