页岩气在矿物孔隙中的微观吸附机理差异性研究

Microscopic Adsorption Mechanism Difference in the Mineral Pore of Shale Gas Reservoir

针对页岩气在不同矿物孔隙中的吸附机理差异性,采用巨正则蒙特卡洛分子模拟方法(GCMC),利用Material Studio软件模拟页岩气体在3种矿物(干酪根、黏土矿物、石英)孔隙模型中的赋存状态,研究页岩气在不同矿物孔隙中的吸附机理。结果表明:不同类型矿物的吸附能力按大小依次为干酪根、黏土矿物、石英;有机质、黏土矿物和碎屑矿物吸附能力产生巨大差异的主要原因是气体在不同矿物表面的吸附位特征(吸附质气体分布密度和吸附强度)显著不同;深入理解页岩气在不同矿物孔隙中的吸附机理差异对客观评价吸附气含量至关重要。该研究可为今后预测不同地区页岩气吸附能力提供理论基础。

The giant regular Monte Carlo molecular simulation method(GCMC)was used to study the microscopic adsorption mechanism difference for the shale gas in different mineral pores.Material Studio software was adopted to simulate the occurrences of shale gas in three mineral pore categories(kerogen,clay mineral,quartz)and explore the adsorption mechanism of shale gas in different mineral pore categories.Research indicates that the mineral adsorption capacity from high to low is kerogen,clay mineral and quartz.The great differences in adsorption capacity for organic matter,clay mineral and clastic mineral mainly result from the change of adsorption site(distribution density and adsorption intensity of adsorbate gas)on various mineral surfaces.An integral understanding of the adsorption mechanism differences for the shale gas in various mineral pore categories is favorable to the adsorbed gas content evaluation.This research could provide certain theoretical reference for the prediction of shale gas adsorption capacity in different regions.