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页岩孔隙类型与结构对其含气性具有决定性的控制作用。通过扫描电镜二次电子成像、氩离子抛光技术和高分辨率扫描电镜,对渝东南地区下寒武统牛蹄塘组页岩中的孔隙体系进行分类描述,并初步探讨了孔隙特征与含气性的关系。渝东南地区下寒武统牛蹄塘组页岩主要发育了4个大类9个亚类的基质孔隙和3个大类4个亚类的天然裂缝。其中粒内孔、溶蚀孔、高角度剪切裂缝和低角度滑脱缝4类优势孔隙类型共同构成了牛蹄塘组的孔隙体系,具有孔隙类型多样、孔径规模小、连通性差、渗透率低等特点。孔隙体积主要由纳米级的微孔和中孔提供。有机质孔隙相对不发育、孔隙连通性差及滑脱裂缝呈区域性发育等是牛蹄塘组含气性不理想的可能原因。
Shale pore types and structures have a decisive control over their gas content. The pore system in Niutitang shale of the Lower Cambrian in the southeastern part of Chongqing was classified and described by means of SEM secondary electron imaging, argon ion polishing and high-resolution scanning electron microscopy. The characteristics of the pores and gas Sexual relations. In the Lower Cambrian Niutitang Formation shale in the southeastern part of Chongqing, there are mainly four types of matrix pores in 9 sub-categories and three types of natural fractures in 3 sub-categories. Among them, the four types of dominant pore types such as intragranular pores, dissolution pores, high-angle shear fractures and low-angle slip seam constitute the pore system of Niutitang Formation with various pore types, small pore size, poor connectivity and low permeability Features. The pore volume is mainly provided by nano-sized pores and mesopores. The relatively undeveloped pores of organic matter, the poor connectivity of pores and the regional development of slippage cracks are all the possible reasons for the poor gas-bearing properties of Niutitang Formation.