页岩超临界态吸附气量计算模型

页岩吸附气量是决定页岩气井开发价值和开发寿命的关键性参数，也是能否成功进行开发的重要参考因素。由于现有的适用于亚临界态的单分子层吸附的兰格缪尔等温吸附模型不适用于中国页岩气的储层条件，为此，通过不同温度下的等温吸附实验，拟合等温吸附曲线并分析影响页岩吸附能力的因素，发现影响页岩吸附能力的主要因素为地层温度和压力、孔隙度、有机质含量及成熟度、矿物组成及含量（其中以黏土矿物为直接影响因素）。以波拉尼吸附理论为基础，构建了考虑温度、压力、孔隙度、有机质含量及成熟度、矿物组成及含量的页岩吸附气定量计算模型。对比该模型的计算结果在整体趋势上与现场岩芯取样分析含气量结果基本一致。新模型考虑了超临界吸附，弥补了目前普遍采用的单层吸附模型的不足，对页岩吸附气量定量计算具有重要的现实意义。

Calculation Model of Shale Gas Adsorption Capacity Under Supercritical Conditions

Shale gas adsorption capacity is a key parameter in determining the development value and life of shale gas wells. The existing Langmuir isotherm adsorption model for the adsorption of monolayers is not suitable for the reservoir conditions of shale gas in China. Therefore, the main factors affecting shale gas adsorption capacity were studied by isothermal adsorption experiments at different temperatures and fitting of the isothermal adsorption curves. The analysis shows that the main factors are formation temperature and pressure, porosity, organic matter content and maturity, and mineral composition and content (including clay minerals as direct factors). Based on the Polanyi adsorption theory, a quantitative calculation model of shale gas adsorption that considers temperature, pressure, porosity, organic matter content and maturity, and mineral composition and content was constructed. The calculation results are consistent with the results of the analysis of gas content from on-site core sampling. The new model considers supercritical adsorption, which compensates for the shortcomings of the monolayer adsorption model that is currently in use, and has important practical significance for shale gas adsorption capacity calculation.