水分对煤体瓦斯吸附及径向渗流影响试验研究

 为了解水力化钻孔周围煤体瓦斯径向渗流特性，利用自行研制的径向瓦斯渗流试验系统，对青东煤矿突出煤层试样，进行干燥煤样、液态水润湿煤样、吸附瓦斯后高压注水煤样的等温解吸及径向稳态渗流试验。结果表明：(1) 相同平衡压力下，高压注水煤样等温吸附量高于干燥煤样，均显著高于液态水润湿煤样的吸附量。(2) 随含水率增加液态水润湿煤样等温吸附量逐渐降低，呈对数函数关系，得出各系数随吸附压力变化的拟合函数。(3) 相同覆压下，高压注水煤样瓦斯渗透率显著高于干燥煤样渗透率，液态水润湿煤样渗透率略低于干燥煤样渗透率；且液态水润湿煤渗透率随含水率增加而降低，在低瓦斯压力阶段尤为显著。根据试验结果分析水分对径向瓦斯渗流特性的影响机制，并指出水力化钻孔径向瓦斯流动经过原始解吸渗流区、压力水抑制解吸渗流区、液态水自然润湿解吸渗流区3个区域。

EXPERIMENTAL STUDY OF EFFECT OF WATER ON SORPTION AND RADIAL GAS SEEPAGE OF COAL

For knowing the radial gas seepage characteristics in coal around hydraulic borehole，isothermal desorption experiment and radial gas seepage experiment of drying coal sample，liquid water wetting coal sample and high pressure water injection coal sample after methane adsorption，produced by the outburst coal from Qingdong mine，were carried out by a self-developed test system of radial gas seepage. The results show that：(1) At the same balanced gas pressure，the adsorption capacity of high pressure water injection coal sample is higher than that of drying coal sample，which are significantly higher than that of liquid water wetting coal sample. (2) Adsorption capacity of liquid water wetting coal sample decreases with the increase of moisture content；and the relationship between adsorption capacity and moisture content can be described as logarithmic function；the fitting function of the relationship between the coefficients and adsorption gas pressure is obtained. (3) At the same overburden pressure，the permeability of high pressure water injection coal sample is significantly higher than that of drying coal sample；the permeability of liquid water wetting coal sample is slightly lower than that of drying coal sample；the permeability of liquid water wetting coal sample decrease with the increase of moisture content；and the trend is particularly significant in low gas pressure stage. Based on the results of test，effect mechanism of water on the radial gas flow characteristics is analyzed；it is pointed out that the coal gas around the hydraulic drilling flows through the original desorption and seepage area，pressure water inhibitory desorption and seepage area and liquid water natural wetting coal desorption and seepage area.