以川西南地区寒武系筇竹寺组页岩为例,应用岩石薄片鉴定、矿物X射线衍射、压汞-吸附联合测定、氦气孔隙度测试、氩离子抛光-扫描电镜观察及页岩气储层测井定量表征等多种技术方法,开展页岩孔隙结构、类型及特征研究,探讨了有机-无机复合型连通孔隙系统的形成机制及其对页岩气富集的控制作用.研究结果表明:①研究区筇竹寺组富有机质页岩孔隙以介孔和微孔为主,其次为大孔;②页岩孔隙类型以粒(晶)间孔、黏土矿物层间孔为主,多呈三角形、多边形及狭缝形;其次为有机黏土复合体内的有机质孔,多呈不规则形;③富有机质页岩具备发育有机-无机复合型连通孔隙系统的条件,有机质孔和无机矿物孔的复合提高了页岩储集能力,控制了页岩气的富集.

Taking the shale of the Cambrian Qiongzhusi Formation of Southeastern Sichuan Basin as an example, a variety of technical methods including rock thin slice identification, mineral X ray diffraction, pressure mercury-adsorption joint determination, helium porosity measure, argon ion polishing-scanning electron microscope, and quantitative characterization of shale gas reservoir by logging are applied to analyze the types and structures of the shale of the Cambrian Qiongzhusi Formation, and to discuss the mechanism of organic-inorganic compound connected pore systems and the significance on shale gas enrichment. The results show that: (1) the pores in the organic shale are mainly micropores (< 2 nm) and mesopores (2~50 nm), followed by macropores (> 50 nm); (2) the pore types are mainly intergranular pores and clay mineral interlayer pores, mostly triangular, polygonal and slit, then are irregular organic pores in organic matter-clay complex; (3) the rich organic shale has favorable conditions for the development of organic-inorganic composite connected pore systems, which improves shale storage ability and controls the enrichment of shale gas.