下行瓦斯抽采穿层钻孔排水技术及装置研究与应用

Research and application of water drainage technology of downward gas extraction crossing hole

针对下行瓦斯抽采钻孔“排水难度大、易沉渣、封孔质量差、抽采浓度低”的问题,采用理论分析和现场试验的方式,研究下行瓦斯抽采穿层钻孔排水技术及装置。把下行穿层瓦斯抽采钻孔排水分为3个阶段:在施工过程中,通过理论计算,优化供水参数、供水管径,减少打钻过程中的沉渣量;在封孔前,采用潜入式排水装置,排水效率达到20L/min以上,钻孔注浆量提高40%;在抽采过程中,采用正压排水装置,排出抽采空间内的积水,排水效率达到10L/min以上,排水后瓦斯抽采浓度达到30%以上,保证了下行穿层瓦斯抽采钻孔的瓦斯抽采效果。

Aiming at the problems of difficult water drainage,sludge sediment,poor hole sealing quality and low gas extraction concentration of downward gas extraction crossing hole,theoretical analysis and field test were used to study the water drainage technology and device of downward gas extraction crossing hole.The water drainage had three stages:during the construction process,water supply parameters and pipe diameter were optimized by theoretical analysis to decrease the sludge sediment when drilling;before hole sealing,the application of submersible water drainage device made the drainage efficiency over 20 L/min,the hole grouting amount was increased by 40%;during gas extraction process,the positive-pressure water drainage device was used to drain the water in gas extraction space and the water drainage efficiency reached 10 L/min and the gas extraction concentration could reach 30%,which ensured the gas extraction effects of downward gas extraction crossing hole.