松软煤层瓦斯抽采钻孔不提钻下入筛管技术

Application of technology of placing screen pipe in gas drainage boreholes without lifting rod in soft coal seam

针对在松软煤层中成孔后孔壁易坍塌,造成瓦斯抽采通道堵塞的问题,通过分析钻孔的护壁方法,提出将不提钻筛管下入技术应用于松软煤层瓦斯抽采钻孔护壁中,并研制出配套的钻头、钻杆、孔底悬挂装置等设备,对PVC筛管的结构进行了设计,最后通过井下工业性试验,证明在松软煤层瓦斯抽采钻孔护壁中应用不提钻筛管下入技术工艺先进和技术可靠,与提钻后裸孔下筛管相比,该技术可以缩短钻孔下筛管时间,提高钻孔筛管下入率和抽采效果.

According to the blockage in channels of gas drainage caused by collapsing after completion of drilling in soft seam, through analyzing the technology of boreholes wall protection, this paper proposed and designed a method of without raising the rod that applied to gas drainage boreholes wall protection in soft coal seam. Matching bits, drill rod, and downhole suspension device, etc. were researched and developed, and the structure of PVC screen pipe was designed. Testing result shows that the technique is advanced in process and reliable technically in the application of gas drainage borehole wall protection in soft coal seam by industrial experiment in mine. Compared with putting into screen pipe after lifting the drill pipe in bare hole, this technology can shorten the time of placing screen pipe in borehole and improve the rate of placing in boreholes and improve the efficiency of gas drainage.