Adsorbed methane is an important component of shale gas. Shale generally contains a certain amount of primary water, and isothermal adsorption experiments on wet samples show that water inhibits methane adsorption. Researches on methane adsorption mainly focus on the conditions of low pressure and water content. In this study, a hybrid GCMC-MD simulation method is proposed to study methane adsorption characteristics under high pressure and water content in pores of different sizes. This method can obtain the bulk pressure of the system while ensuring the simultaneous movement of methane and water molecules, and has high efficiency and reliability. It is found that the existence of water does not change the morphology of excess isotherm, and the relative decrease of adsorption capacity due to the existence of water is not sensitive to temperature. In ≤3 nm pores, water molecules form water clusters and partially occupy wall adsorption sites, and the adsorption amount decreases linearly with increasing water saturation. In the 5 nm wide pore with 40% water saturation, water films formed and methane adsorption is strongly suppressed. It is expected these findings could provide guidance for the evaluation of the amount of adsorbed methane with primary water.
National Natural Science Foundation of China (No. 41690132 and 41872163), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA14010304) and the Major National Science and Technology Special Program of China (No. 2017ZX05037-001).
Zhou J,江文滨；林缅；姬莉莉；曹高辉. Impact of water on methane adsorption in nanopores: A hybrid GCMC-MD simulation study[C]ICCS 2020 Conference Proceedings,2020:184-196.
; Jiang WB(江文滨); Lin M(林缅); Ji LL(姬莉莉); Cao GH(曹高辉)
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