抽采钻孔漏气对瓦斯抽采浓度影响因素研究

Study on influence factors of gas extraction concentration caused by gas leakage

为提高瓦斯抽采率,降低抽采浓度衰减速度,利用自主研发抽采钻孔卸压漏气物理模拟实验平台,采用理论分析与实验研究相结合的方法,研究抽采负压、煤层初始压力、煤层透气性系数不同条件下抽采钻孔漏气对瓦斯抽采浓度影响规律.结果表明:随抽采负压的升高,抽采浓度呈先升高后降低的趋势,最佳抽采负压为30 kPa到40 kPa之间,35 kPa时抽采浓度最高;随煤层透气性系数与煤层初始压力的升高,抽采浓度下降速率变缓且稳定时抽采浓度较高;抽采浓度随抽采时间的变化曲线均符合指数衰减拟合方程。

In order to improve the gas extraction rate and reduce the attenuation speed of extraction concentration,the influence of pumping hole leakage on gas extraction concentration under different conditions of pumping negative pressure,different coal seam initial pressure and different coal seam permeability coefficient is studied by using the pressure relief and gas leakage experimental platform and the method of combining theoretical analysis with experimental research.The results show that the extraction concentration first increases and then decreases with the increase of negative extraction pressure.The optimal negative extraction pressure is between 30 KPa and 40 kPa,and the highest extraction concentration is at 35 kPa.With the increase of permeability coefficient of coal seam and initial pressure of coal seam,the decline rate of mining concentration slows down and is stable at a higher gas extraction concentration.The variation curve of extraction concentration with extraction time accords with the exponential decay fitting equation.