富有机质页岩中不同矿物的解吸规律

四川盆地龙马溪组页岩气开发已由地质勘探转变为开发建产阶段，研究页岩中甲烷的解吸规律对于把握页岩气产出规律、正确评价页岩气可采储量有着重要意义。为了研究页岩中不同矿物的解吸特征及其对页岩气解吸的贡献，对龙马溪组页岩、蒙脱石、高岭石、伊利石、绿泥石、Ⅱ型干酪根及石英样品开展了60℃下高压甲烷等温吸附/解吸实验。在此基础上，定量分析了页岩、黏土矿物、石英及Ⅱ型干酪根的解吸迟滞现象，并计算了黏土矿物、Ⅱ型干酪根及石英中甲烷解吸效率曲线，研究了不同矿物之间解吸规律的差异性。研究结果表明，甲烷在干酪根、黏土矿物样品中的解吸过程表现出明显的解吸滞后现象，且不同黏土矿物样品的解吸滞后程度存在较明显的差异；干酪根的解吸迟滞系数最大，达到43.67%，不同类型黏土矿物的解吸迟滞系数不同，其大小顺序为蒙脱石>高岭石>绿泥石>伊利石；随着压力降低，页岩岩样、黏土矿物、干酪根和石英的解吸效率都呈增大的趋势，且干酪根、黏土矿物、页岩的甲烷解吸效率曲线都呈现出明显的阶段性。

The desorption laws of different minerals in the organic-rich shale

In China, the research stage of the Longmaxi Formation shale gas reservoirs has changed from geological exploration to development and production. These is a great significance to research the law of desorption of methane in shale for grasping the law of shale gas production and correctly evaluating the recoverable reserves of shale gas. In order to research the desorption characteristics of different minerals in shale and their contribution to shale gas desorption. High pressure methane isotherm adsorption/desorption experiments at 60℃ were carried out on samples of shale, montmorillonite, kaolinite, illite, chlorite, type Ⅱkerogen and quartz. On this basis, the desorption hysteresis of shale, clay minerals, quartz and type Ⅱ kerogen was quantitatively analyzed, and the methane desorption efficiency curve in clay minerals, type Ⅱ kerogen and quartz was calculated, and the difference in desorption law between different minerals was studied. The results show that the desorption process of methane in kerogen, shale and clay mineral samples shows obvious desorption hysteresis, and the degree of desorption hysteresis of different types of samples are different. Kerogen has the largest desorption hysteresis coefficient, reaching 43.67%. The desorption hysteresis coefficients of different types of clay minerals are different, and the order of magnitude is montmorillonite>kaolinite> chlorite>illite. As the pressure decreases, the desorption efficiency of shale rock samples, clay minerals, kerogen and quartz all show an increasing trend, and the methane desorption efficiency curves of kerogen, clay minerals, and shale all show obvious stage characteristics.