基于松软煤层不提钻筛管下入技术的瓦斯抽采

摘要

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，分析了现有钻孔护壁方法存在的不足，提出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 筛管的孔隙结构进行优化设计。井下工业性试验验证了不提钻筛管下入技术在松软煤层瓦斯抽采钻孔护壁应用中的先进性和可靠性，并与提钻后裸孔下入筛管相比，该技术可以缩短钻孔下入筛管时间6~5 h，提高了钻孔筛管下入率28%~38%和抽采纯量50%。%According to gas drainage channel jammed problem caused by a borehole wall easily collapsed after borehole drilled in a soft seam,the paper analyzed the insufficient the available borehole wall protection methods.The paper provided a screen pipe placing in the borehole technology without drilling rod lifting applied to the borehole wall protection for the gas drainage in the soft seam.Related drilling bit,drilling rod,borehole bottom suspended device and other equipment were researched and developed.An optimized design was conducted on the pore structure of PVC screen pipe.An industrial trial in the underground showed that an advancement and reliability of the screen pipe placing in the borehole technology without drilling rod lifting was verified in the application of the borehole wall protection to the gas drainage borehole in the soft seam.In comparison with the screen pipe placing in an open borehole after the drilling rod lifted,the technolo-gy could reduce screen pipe placing time 6~ 5 h in the borehole and could improve the screen pipe placing rate 28% ~ 38% and gas drain-age scalar 50%.