下行瓦斯抽采钻孔施工工艺优化

Optimazation of Construction Technology for Downward Gas Extration Boreholes

针对顾北矿4煤围岩、层间砂岩裂隙水丰富,高抽巷施工下行穿层钻孔积水多,瓦斯抽采困难等问题,分析了影响抽采效果的因素。基于封堵压气排水的原理,提出了封堵注浆、护孔、两堵一注的封孔方式及排水技术,实现了下行孔高效抽采效果。工程实践中对比了采取相关技术措施的钻孔和未采取技术措施的钻孔抽采瓦斯效果,结果表明采取相关技术措施的钻孔平均单孔浓度是未采取措施的钻孔的4倍,平均单孔流量是其2倍,大大提高了抽采效果。

Surrounding rock cracks of 4^# coal seam and sandstone contain plenty of water,which results in lots of water remained in downward drillings bottom and low rate of gas extraction. We analyze factors that affect gas extraction effect. Based on the principle of sealing compressor drainage,we propose blocking grouting,protecting holes,two plugging and one injection hole sealing method and drainage technology to implement the efficient extraction of down hole. Comparing gas extraction effect of drilling with related technical measures and drilling without technical measures in engineering practice,the results show that average one- hole concentration in measured drilling field is 4 times higher than that without taking measures. Also,average one- hole flow in measured drilling field is 2times greater than that without taking measures. The construction techniques can enhance the effect of gas extraction largely.