基于Klinkenberg效应影响的煤体瓦斯渗流规律及其渗透率计算方法

针对气体渗流存在的Klinkenberg效应,利用自主研发的三轴瓦斯渗流实验系统,对煤层瓦斯的渗流特性进行了研究。通过实验数据分析和理论推导,提出了一种综合气体动力黏度和压缩因子影响及克氏效应的煤层瓦斯渗透率计算方法。通过比较传统的拟压力法计算结果,考虑克氏效应方法在理论上和数据处理结果上更合理、更准确。研究结果表明:1克氏效应对煤层瓦斯渗流影响明显,利用考虑克氏效应方法评估的渗透率结果正确,能充分反映出气体渗流的真实状态。2吸附解吸作用对煤层瓦斯渗透性有一定的影响,其影响结果是导致煤层绝对渗透率的降低。3处于标准状况附近的气体,可以忽略动力黏度和压缩因子对其渗透性的影响,离开标准状况较远的气体,需要考虑动力黏度和压缩因子对其渗透性的影响。研究结果对正确认识克氏效应和选择更精确的含瓦斯煤渗透率计算方法具有一定的指导价值。

Coalbed gas seepage law and permeability calculation-method based on Klinkenberg effect

Using a self-developed triaxial gas seepage experiment system，the seepage characteristics of coalbed gas has been investigated for the Klinkenberg effect of gas seepage.With experimental data analysis and theoretical derivation，a method considering Klinkenberg effect for evaluating the permeability of coalbed gas had been developed，synthesizing the influence of gas dynamic viscosity and gas compressibility factor.The method considering Klinkenberg effect is more reasonable and more precise than the tradition pseudo pressure method through comparing the calculation results.The results show that：① The Klinkenberg effect has an obvious effect on the seepage of coalbed gas.The permeability results assessed by the method considering Klinkenberg effect are valid and can fully reflect the true state of gas flow.② The effect of adsorption and desorption has a certain impact on the coal seam gas permeability and can lead to the reduction of absolute permeability in a coal seam.③ The effect of dynamic viscosity and compressibility factor on gas permeability can be ignored in a close vicinity of the standard state.However，the effect of dynamic viscosity and compressibility factor on gas permeability cannot be ignored far away from the standard state.Research results are useful for correctly understanding the Klinkenberg effect and selecting more accurate calculation method for the permeability assessment on coalbed gas.