基于页岩无机孔隙和有机孔隙润湿性和孔径的差异,考虑甲烷、氦气、水在页岩无机孔隙和有机孔隙中储集位置的不同,通过3种流体饱和实验建立了储层温度和压力条件下页岩气藏各赋存状态气体体积的实验测量和计算方法,得到页岩的无机孔隙度和有机孔隙度,并分析了页岩气储层含气量的影响因素.研究表明:对于所选岩样,无机孔隙和有机孔隙分别占总孔隙体积的65，和35，,无机孔隙中的游离气、有机孔隙中的游离气和吸附气分别平均占总含气量的51，、22，和27，,川南下志留统龙马溪组页岩具有较高的热演化程度,随总有机碳含量的增加,纳米级有机孔隙大量发育,为甲烷提供了吸附空间.明确了总有机碳含量主要影响吸附气含量,指出在页岩气资源量评价、产能预测和后期开发过程中,需要考虑有机质及其内部吸附气的影响.

Shale gas has enormous resources and potential, and has gradually become an important growth point of natural gas industry in China. Shale gas reservoirs are characterized by complex mineral compositions, multi-scale pore, various gas storage spaces and modes of occurrence, and strong heterogeneity. Shale pores can be divided into inorganic pores and organic pores. Inorganic pores are mainly composed of intergranular or intragranular pores of mineral particles such as quartz, feldspar and other minerals. The pore size is mainly micrometer scale, and the pore surface has water-wet characteristics. Organic pores are mainly nanoscale and exist in the organic matter of shale, with high specific surface area and oil-wet pore surfaces. Methane in shale gas reservoir has three occurrence states: free gas in inorganic pores, free gas and adsorbed gas in organic pores. Accurate volume measurement of gas with different occurrence state can provide important basic data for resource evaluation of shale gas reservoir. Based on the differences of wettability and pore size between shale inorganic pores and organic pores, and considering the different storage locations of methane, helium and water in shale inorganic pores and organic pores, experimental measurement and calculation methods are presented to test gas volume of different occurrence states under reservoir temperature and pressure conditions, and shale inorganic porosity and organic porosity are also obtained. On this basis, the influencing factors of gas content in shale gas reservoir are analyzed. The results show that for the selected rock samples, inorganic pores and organic pores account for 65， and35， of the total pore volume respectively, and the free gas in inorganic pores, free gas in organic pores and adsorbed gas account for 51，, 22， and 27， of the total gas content on average respectively. The shale of the Lower Silurian Longmaxi Formation in southern Sichuan has a high degree of thermal evolution. With the increase of the total organic carbon content, a large number of nanoscale organic pores are developed, providing adsorption space for methane. It is clarified that the total organic carbon content mainly affects the content of adsorbed gas. It is pointed out that in the evaluation of shale gas resource quantity, production capacity prediction, and later development process, the influence of organic matter and its internal adsorbed gas needs to be considered.