A developed dual-site Langmuir model to represent the high-pressure methane adsorption and thermodynamic parameters in shale
Ke Hu1
Qian Zhang2
Yufei Liu1
Muhammad Abdurrahman Thaika1
1.School of Mining and Petroleum Engineering,University of Alberta,Edmonton T6G1H9,Canada2.Institute of Energy,School of Earth and Space Science,Peking University,Beijing 100871,China
摘要：Comprehending the mechanism of methane adsorption in shales is a crucial step towards optimizing the development of deep-buried shale gas.This is because the methane adsorbed in shale represents a significant proportion of the subsurface shale gas resource.To properly characterize the methane adsorption on shale,which exhibits diverse mineral compositions and multi-scale pore sizes,it is crucial to capture the energy heterogeneity of the adsorption sites.In this paper,a dual-site Langmuir model is proposed,which accounts for the temperature and pressure dependence of the density of the adsorbed phase.The model is applied to the isothermals of methane adsorption on shale,at pressures of up to 30 MPa and temperatures ranging from 40 to 100 ℃.The results show that the proposed model can describe the adsorption behavior of methane on shale more accurately than conventional models,which assume a constant value for the density of adsorbed phase.Furthermore,the proposed model can be extrapolated to higher temperatures and pressures.Thermodynamic parameters were analyzed using correctly derived equations.The results indicate that the widely used,but incorrect,equation would underestimate the isosteric heat of adsorption.Neglecting the real gas behavior,volume of the adsorbed phase,and energy heterogeneity of the adsorption sites can lead to overestimation of the isosteric heat of adsorption.Furthermore,the isosteric heat evalu-ated from excess adsorption data can only be used to make a rough estimate of the real isosteric heat at very low pressure.
机标关键词：langmuirshalemodeladsorptiondevelopeddual-sitehigh-pressuremethane
论文发表日期：2023-10-28
在线出版日期：2025-08-15（本平台首次上网日期，不代表文献的发表时间）
页数：17( 21-37 )
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