Currently, low-pressure gas (carbon dioxide and nitrogen) adsorption experiments have been widely applied to describe pore structure features of shales. However, there are no standard models in calculations of pore structure parameters from low-pressure gas adsorption experiments, which limits comparison between various studies. To evaluate the applicability of calculating methods, 9 Chang 7 shale samples were performed gas adsorption experiments and pore structure parameters are obtained using Monte Carlo simulation (MC), Density Functional Theory (DFT) and Barrett-Joyner-Halenda (BJH) methods. The results show that MC and DFT can accurately characterize micropore structures, but MC model provides a wider pore size range than DFT. Therefore, we recommend that MC method should be used to get micropore parameters from CO₂ adsorption data. Under the influence of tensile strength effect (TSE), a fake peak located at ~3.8 nm in pore size distribution (PSD) lines obtained from N₂ desorption curves with BJH model, and an overestimation for pore structure parameters in meso-to macropore dimension based on this method was found. This phenomenon implied that the parameters from N₂ desorption using BJH model are not applicable for the calculation of parameters for pore structure. What's more, compared with DFT method, BJH model based on adsorption curve ignores the effect of adsorption potential on location of pore condensation transition, which may lead to an underestimation of the shale pore structure parameters in narrow mesopore range (<10 nm). Therefore, DFT method was recommended to characterize the meso- and macroporous pore structure of shales based on N₂ adsorption data.

目前，低压气体（二氧化碳和氮气）吸附实验已广泛应用于描述页岩孔隙结构特征。然而，低压气体吸附实验的孔隙结构参数计算没有标准模型，这限制了各种研究之间的比较。为评价计算方法的适用性，利用蒙特卡罗模拟（MC）、密度泛函理论（DFT）和Barrett-Joyner-Halenda（BJH）方法对9长7页岩样品进行了气体吸附实验，获得了孔隙结构参数。结果表明，MC 和 DFT 可以准确表征微孔结构，但 MC 模型提供的孔径范围比 DFT 更宽。因此，我们建议使用 MC 方法从 CO _{2 中}获取微孔参数吸附数据。在拉伸强度效应 (TSE) 的影响下，从使用 BJH 模型的N ₂解吸曲线获得的孔径分布 (PSD) 线中位于~3.8 nm 处的假峰，以及对细孔到大孔尺寸的孔结构参数的高估基于这种方法被发现。这种现象意味着来自 N ₂的参数BJH 模型解吸不适用于孔结构参数的计算。此外，与DFT方法相比，基于吸附曲线的BJH模型忽略了吸附势对孔隙凝结转变位置的影响，这可能导致对窄介孔范围（<10 nm）页岩孔隙结构参数的低估。因此，推荐采用DFT方法基于N ₂吸附数据表征页岩的中孔和大孔结构。