有效应力对保德区块煤储层渗透率影响研究

通过有效应力单因素影响保德区块煤岩气体渗流实验,分析了煤岩渗透率应力敏感性以及割理压缩系数变化特征.结果表明:保德区块煤储层渗透率与有效应力呈负指数函数关系;煤层埋深越深,煤岩渗透率变化幅度越小,渗透率应力敏感性下降。渗透率损害系数的线性函数拟合相关系数较低,应力敏感系数的负指数函数拟合相关系数较高,应力敏感系数比渗透率损害系数更具规律性。在高有效应力阶段,煤岩割理压缩系数更趋近于常数,低有效应力阶段,割理压缩系数应视为变量。

Study on influence of effective stress on coal reservoir permeability in the Baode block

This study is based on the gas seepage experiments of coal in the Baode Block under the influence of the single factor of effective stress. The purpose is to analyze the stress sensitivity of permeability and the change features of cleat compressibility. The results show that the coal permeability in the Baode Block decreases according to a negative exponential function with the increase of effective stress. The deeper the buried depth of coal seam, the smaller the change in coal permeability, meanwhile permeability stress sensitivity decreases. The correlation coefficient of linear function fitting of permeability damage coefficient is low. The correlation coefficient of negative exponential function fitting of the stress sensitivity coefficient is high. The stress sensitivity is more regular than permeability damage coefficient. In the high effective stress stage, cleat compressibility is close to a constant. In the low effective stress stage, cleat compressibility can be regarded as a variable.