注CO2与煤中矿物反应渗透率变化规律

以晋城矿区寺河井田为研究对象，借助扫描电镜和X射线衍射仪得出煤中矿物成分和充填方式；基于煤储层几何模型结合渗流理论，构建了煤体原始渗透率和矿物溶解后渗透率变化的数学模型；在对寺河矿孔径分布、不同矿物溶解度测试基础上，探讨了注CO2后与煤中不同矿物反应渗透率的变化规律。研究结果表明：煤中矿物主要为黏土和碳酸盐矿物；煤中矿物主要以薄膜状附着和完全或半充填于煤层裂隙2种充填方式存在；不同矿物溶解、沉淀时间差异性导致注CO2后煤储层渗透率呈现先增加后减小趋势；在矿物含量相同条件下，在大孔径孔裂隙中附着或充填的矿物含量越高，矿物溶解后煤储层渗透率增加越多。煤层注CO2后煤层渗透率变化实验测试一定程度上验证了数学模型的可靠性。

Variation of coal permeability after injection carbon dioxide reactions with minerals in coal

Taking on Sihe Mine in Jincheng mining area as the research object，the mineral components and filling ways in coal were conducted by scanning electron microscopy and X-ray diffraction.According to the coal reservoir geometry model and percolation theory，the mathematical model about the initial permeability of coal and the permeability after reaction with mineral were established.Based on pore size distribution and the different mineral solubility of coal samples in Sihe Mine，the variation rules about permeability after injection carbon dioxide reactions with different minerals in coal were discussed.The results show that minerals in coal are mainly composed of clay and carbonate minerals；minerals in coal exists in two ways，namely some minerals adhere to fracture amd completely fill or half fill in the coal fracture.The differences about reaction time among different minerals lead that coal reservoir permeability is increased first then decreased after injection carbon dioxide.When the contents of the minerals are the same，the higher of filling mineral contents in the large hole and cracks，the more increase of coal reservoir permeability after the dissolution of mineral；the experimental results verify the reliability of the mathematical model.