基于COMSOL Multiphysics的煤层透气性系数计算方法优化

Optimized Methods for Calculating Permeability Coefficient of Coal Seam Based on COMSOL Multiphysics

基于COMSOL Multiphysics的数值分析功能与相似理论,计算了未经简化处理后的煤层瓦斯径向不稳定流动偏微分方程,利用Boltzmann函数对导出的lg Y与lg F0关系曲线进行了拟合并导出了拟合方程。在拟合方程的基础之上通过变量代换导出了含有煤层透气性系数的理论方程,解决了钻孔径向流量法中煤层透气性系数计算无法找到合适计算公式或存在2个互相矛盾计算公式的问题,简化了计算步骤。

Based on the numerical analysis of COMSOL Multiphysics and similarity theory, we calculated the partial differential equations of gas radial instability of coal seam gas without un-simplified processing, and fitted the relation curve of lg Y and lg F0 derived by using Boltzmann function and derived a fitting equation. On the basis of the fitting equation, we derived the theoretical equation of permeability coefficient of coal seam through the variable substitution to solve problems that the permeability coefficient of coal seam can not find the proper calculation formula or there are two contradictory formulas in borehole radial flow method, and simplify the calculation procedure.