含水率对含瓦斯煤的渗流特性影响试验研究

Experimental study of moisture content influences on permeability of coal containing gas

利用自主研发的三轴煤岩瓦斯渗流试验系统,测定煤样在含水率、围压和瓦斯压力的不同组合情况下的渗流量,得到含水率与含瓦斯煤渗透特性之间的关系表达式,揭示了受水分影响的含瓦斯煤渗透特性的一些新的认识:①不同含水率煤样,固定瓦斯压力条件下,含瓦斯煤渗透率随围压的增大而减小,且呈指数函数关系;②不同含水率条件下的含瓦斯煤,随着瓦斯压力的增大,含瓦斯煤渗透率的先减小后增大,呈现出"V"字型变化趋势,具有明显的Klinkenberg效应;③瓦斯压力对含瓦斯煤渗透性的影响大于围压的影响;④恒定温度环境条件下,含水率对含瓦斯煤的渗透性有很明显的影响,随着煤样中含水率的增加,含瓦斯煤的渗透率逐渐减小,整体呈负指数关系。

The relational expression between the moisture content and the permeability of coal containing gas was obtained through measuring the gas seepage flux under the combination of moisture, confining pressure and gas pressure by using a self-developed triaxial gas seepage testing system. Based on the experimental data of coal containing gas,some novel interaction results of seepage property influenced by moisture are obtained as follows：① For coal samples of different moisture content, the permeability of coal containing gas decreases with increasing of confining pressure un-der the fixed gas pressure condition;and the decreasing rule obeys an exponential law. ② With the increasing in gas pressure, the permeability of coal samples decreases first and then increases, presenting a ＂V＂ style change trend and obvious Klinkenberg effect. ③ The influence of gas pressure on the permeability of coal containing gas is greater than the effect of confining pressure. ④ Moisture content has a significant effect on the permeability of coal containing gas under the constant temperature condition;and the permeability of coal containing gas slowly decreases with the in-crease in moisture content, following a negative exponential function law.