Characteristics of Black Shale Reservoirs and Controlling Factors of Gas Adsorption in the Lower Cambrian Niutitang Formation in the Southern Yangtze Basin Margin, China

The pore structure and shale adsorption capacity have a great impact on the formation of shale gas field of yield industrial gas flow. This investigation focuses on the characteristics of the reservoir and adsorbed gas of the Lower Cambrian Niutitang Formation in the southern margin of the Yangtze basin. On the basis of geochemical analysis, low pressure nitrogen gas adsorption, X-ray diffraction, and isothermal adsorption experiments on core samples, the Niutitang Formation shows following characteristics: (1) The pore of the Niutitang shale can be divided into four categories: interparticles pores, intraparticles pores, organic matter pores, and microfractures. (2) The pores structure of shale shows three characteristics: the micropores frequency peaks are higher than that of mesopores in the dV(d) curve, and specific surface area frequency is greatest in micropores; these pore characteristics primarily appear in siliceous shale. Pore volume frequency is primarily dominant in mesopores, which mainly app...