Adsorbed gas is a major component of shale gas, therefore, it is important to determine the mechanism of gas adsorption in shales and their associated gas adsorption capacity when evaluating shale gas resources. Given that the composition of shale gas is quite complex in some geological conditions, the competitive adsorption of multicomponent gases in shales needs to be unambiguously illustrated. Based on related and currently available literature, the present study investigates the mechanism involved in multicomponent gas adsorption in shales and provides a brief introduction to three mathematical models used to illustrate competitive adsorption: the extended Langmuir model, the ideal adsorbed solution theory (IAST), and the lattice density functional theory (Lattice DFT). Controlling factors, such as TOC content, shale composition, pore structure, maturity, gas composition, moisture content, and pressure, which influence the competitive adsorption of multicomponent gases in shales are discussed. In summary, this study provides some new insights into multicomponent gas adsorption mechanisms in shales, suggests potential problems related to multicomponent gas adsorption, and outlines future work required in overmature shale gas exploration.%吸附气是页岩气的重要组成部分, 页岩气吸附机理的研究及吸附量的计算是页岩气研究的重点内容.在某些地质条件下, 页岩气组成复杂, 不仅包含甲烷, 还有一定量的乙烷等湿气以及氮气和二氧化碳等非烃气体, 因此有必要针对页岩开展多元气体竞争吸附研究.本文在前人研究基础上, 分析页岩中多元气体竞争吸附的机理, 介绍扩展Langmuir方程、理想吸附溶液理论(IAST)和晶格密度泛函理论(Lattice DFT)等3种竞争吸附预测模型, 探讨有机质含量、页岩组成、孔隙结构、成熟度、气体组成、含水率和压力等影响页岩中多元气体竞争吸附的因素, 阐述页岩中多元气体竞争吸附的研究现状并指出其中存在的问题与难点, 并对页岩中多元气体竞争吸附研究的发展趋势和需要解决的问题进行探讨.
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