组合煤岩渗透规律试验研究

Experimental study on permeability law of combined coal and rock

为探究煤岩中CH4的渗透规律,以试验研究为主要手段,结合敏感性分析,利用自主研发的试验系统,对煤、砂岩以及不同煤岩比的组合煤岩体试件,开展了考虑体积应力和孔隙压力影响的渗透规律试验研究.研究结果表明:当孔隙压力恒定时,随着体积应力的递增,无论是煤、砂岩还是组合煤岩,渗透率都会呈现出递减的趋势;通过进行敏感性分析发现试件的渗透率变化率和孔隙压力敏感系数均与煤岩比有关.在低体积应力条件下,试件煤含量越高,孔隙压力对渗透率影响越明显,并且对孔隙压力变化越敏感;煤岩比对组合煤岩中CH4的渗透率有较大影响,对含煤量高的煤岩试件增加孔隙压力可有效提高CH4渗透率.

In order to investigate the infiltration law of CH4 in coal rock,the self-developed testing system is used to study the permeability law of coal,sandstone and different coal-rock ratio combined coal and rock specimens considering the effects of volume stress and pore pressure.This study uses experimental research as the primary means combining with sensitivity analysis.The results show that the permeability will show a decreasing trend whether it is coal,sandstone or combined coal with the increase of volume stress when the pore pressure is constant.Through sensitivity analysis,it is found that the permeability change rate and pore pressure sensitivity coefficient of the specimen are related to the coal-rock ratio.Under low volume stress conditions,the higher the coal content of the specimen,the more obvious the influence of pore pressure on the permeability and the more sensitive it is to the change of pore pressure.According to the above findings,the coal-rock ratio has a great influence on the permeability of CH4 in the combined coal,increasing the pore pressure on coal rock samples with high coal content can improve the permeability of CH4 effectively.