Adsorbed gas is one of the crucial occurrences in shale gas reservoirs; thus, it is of great significance to ascertain the adsorption capacity of shale and the adsorption characteristics of CH₄. In this investigation, the Taiyuan–Shanxi Formations’ coal-measure shale gas reservoir of the Carboniferous–Permian era in the Hedong Coalfield was treated as the research target. Our results exhibit that the shale samples were characterized by a high total organic carbon (TOC) and over to high-over maturity, with an average TOC of 2.45% and average R_o of 2.59%. The mineral composition was dominated by clay (62% on average) and quartz (22.45% on average), and clay was mainly composed of kaolinite and illite. The Langmuir model showed a perfect fitting degree to the experimental data: V_L was in the range of 0.01 cm³/g to 0.77 cm³/g and P_L was in the range of 0.23–8.58 MPa. In addition, the fitting degree depicted a linear negative correlation versus TOC, while mineral composition did not exhibit a significant effect on the fitting degree, which was caused by the complex pore structure of organic matter, and the applicability of the monolayer adsorption theory was lower than that of CH₄ adsorption on the mineral’s pore surface. An apparent linear positive correlation of V_L versus the TOC value was recorded; furthermore, the normalized V_L increased with the growth of the total content of clay mineral (TCCM), decreased with the growth of the total content of brittle mineral (TCBM), while there was no obvious correlation of normalized V_L versus kaolinite, illite and quartz content. The huge amount of micropores and complex internal structure led to organic matter possessing a strong adsorption capacity for CH₄, and clay minerals also promoted adsorption due to the development of interlayer pores and intergranular pores.

中文翻译：

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河东煤田煤系页岩中CH4的吸附特征及控制因素

页岩气藏中的关键事件之一就是吸附气体。因此，确定页岩的吸附能力和CH ₄的吸附特性具有重要意义。本研究以河东煤田石炭系—二叠纪太原—山西组煤系页岩气储集层为研究对象。我们的结果表明，页岩样品的特征是总有机碳含量高且成熟度高，平均TOC为2.45％，平均R _o为2.59％。矿物成分以粘土（平均62％）和石英（平均22.45％）为主，粘土主要由高岭石和伊利石组成。Langmuir模型显示出与实验数据的最佳拟合度：V _L在0.01 cm ³ / g至0.77 cm ³ / g的范围内，而P _L在0.23至8.58 MPa的范围内。另外，拟合度与TOC呈线性负相关，而矿物组成对拟合度没有显着影响，这是有机物复杂的孔隙结构引起的，单层吸附理论的适用性较低。比CH ₄吸附在矿物的孔隙表面上。记录了V _L与TOC值之间的线性正相关关系。此外，归一化V _L随粘土矿物（TCCM）总含量的增加而增加，随脆性矿物（TCBM）总含量的增加而降低，而归一化V _L与高岭石，伊利石没有明显的相关性。和石英含量。大量的微孔和复杂的内部结构导致有机物对CH _4的吸附能力强，并且由于层间孔和粒间孔的发展，粘土矿物也促进了吸附。