Characteristics And Influencing Factors Of Pore Structures Of Longmaxi Shale In Chongqing Southeast

Shale pore is shale gas reservoir space and shale pore structure characteristics are important parameters to evaluate shale storage.The study of shale pore structure characteristics is of great significance to clarify the reservoir space and occurrence of shale gas.Presented a study on shale of the Longmaxi formation in Southeastern Chongqing,high pressure mercury-injection,N2 and CO2 gas adsorption methods and scanning electron microscope were used in the study of the shale pore structure characteristics.The following results were obtained.Shale is dominated by quartz and clay minerals,with an average of 48% and 27%,and contain a small amount of carbonate minerals.Abundance of organic matter is higher,and TOC is generally greater than 1%.Under the scanning electron microscope,the organic matter pores,the clay minerals inter-crystalline pores and the brittle mineral inter-granular pores are more developed,and the connectivity is better.Micropore,mesopore and macropore occupy total pore volume ratio of 9%,59%,32%,and pore volume between 0.3~0.5nm,2~5nm and 5~30?m contribute most of the volume.Micropore,mesopore and macropore occupy total surface area ratio of 41%,53%,6%.Pore surface area between 0.3~0.5nm,2~5nm and 5~30?m contribute most of the surface area.Pores in 0.5nm,1.3nm,and 50~100nm are most developed.The pore volume and surface area of shale are mainly influenced by organic matter.The surface area and pore volume of macropore are mainly influenced by clay minerals,and the second is the brittle mineral.The degree of thermal evolution of shale pores in the first promotion after inhibition,the node is about 3.5%.