Petroleum Reservoir Evaluation and Development >
2022 , Vol. 12 >Issue 3: 455 - 461
DOI: https://doi.org/10.13809/j.cnki.cn32-1825/te.2022.03.007
Molecular simulation of adsorption law for shale kerogen
Received date: 2021-09-06
Online published: 2022-06-24
Shale gas is unconventional natural gas, mainly CH4, occurring in organic shale. The adsorbed gas is the main source for later production of shale gas. Therefore, studying the adsorption mechanism of shale plays an important role in shale gas development. By using type Ⅱ kerogen molecules, a type Ⅱ kerogen model is established. Then, Monte Carlo method and molecular simulation method are used to study the micro adsorption behavior and mechanism of CH4 in type Ⅱ kerogen. Experimental data are used to verify this model, and the effects of pore size, temperature and pressure on the adsorption behavior are investigated. The findings are as follows: ① The higher the pore size, the greater the excess adsorption capacity of CH4. The higher the temperature, the lower the excess adsorption capacity of CH4. With the increase of pressure, the absolute adsorption amount of CH4 increases rapidly at first and then gently, and the excess adsorption amount of CH4 increases first and then decreases. ② The adsorption heat of CH4 decreases with the increase of pore size. The adsorption of CH4 in kerogen is physical adsorption. ③ When the pore size is smaller than 1 nm, CH4 is the adsorption phase in kerogen; when the pore size is larger than one nanometer（1 nm）, CH4 is the coexistence of adsorption phase and free phase in kerogen.
Key words： molecular simulation; shale gas; kerogen; adsorption; adsorption mechanism
Jinghui LI , Xin HAN , Sijing HUANG , Yangyang YU , Xianyu QIANG , Kangfu GU , Dali HOU . Molecular simulation of adsorption law for shale kerogen[J]. Petroleum Reservoir Evaluation and Development, 2022 , 12(3) : 455 -461 . DOI: 10.13809/j.cnki.cn32-1825/te.2022.03.007
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