低瓦斯赋存高强度开采煤层驱替促抽技术研究

Replacement and pumping technology for coal seams with low gas content and high intensity mining

针对低瓦斯煤层高产高效矿井瓦斯高强度涌出,常规抽采和煤层改性技术瓦斯抽采效果较差的问题,基于煤层瓦斯赋存特性及流动机理研究,提出煤层井下注气驱替促抽技术,并开展现场试验与应用。结果表明:低瓦斯赋存煤层常规抽采条件下,瓦斯抽采纯量低、流量衰减快,注气驱替促抽可快速、高效提升抽采效果;持续性注气促抽较间歇性驱替效果更佳;注气压力越大、注产间距有效影响范围越大,驱替促抽效果越好;试验条件范围内,实际驱替促抽瓦斯量相较于常规抽采预测瓦斯量增幅可达367.5%~487.6%;注气驱替促抽可实现煤层瓦斯含量的快速降低,保障上隅角瓦斯浓度维持低位水平,应用区段内煤层瓦斯含量月平均降低0.402~0.565 m^(3)/t,上隅角瓦斯浓度最大为0.31%。

For the effect of conventional gas extraction and coal seam modification technology is poor for the high intensity gas emission in high yield and efficiency mines in low gas coal seams,the technology of gas injection and displacement is proposed,and the field test and application are carried out based on the study of the occurrence characteristics and flow mechanism of coal seam gas.The results show that:under the condition of conventional extraction of low gas coal seams,the pure gas extraction is low,the flow attenuation is fast,and the effect of gas extraction can be improved efficiently after the implementation of gas injection;continuous gas injection is more effective than intermittent displacement;the effect of gas extraction is improved by increasing the gas injection pressure and effective influence range of the injection spacing;within the range of test conditions,actual gas production can be increased by 367.5%to 487.6%in comparison to the conventional extraction prediction;the gas injection can achieve the rapid reduction of coal seam gas content and ensure the gas concentration in the upper corner maintain at a low level,the monthly average reduction of coal seam gas in the application section is 0.402~0.565 m^(3)/t,and the maximum gas concentration in the upper corner is 0.31%.