煤矿井下筛管完孔技术在穿层孔中的应用

Application of screen pipe completion for trans-seam borehole in underground coal mine

针对煤矿井下筛管完孔技术在穿层孔完孔中应用时存在的悬挂可靠性差、全孔下入筛管成本高等问题,研究了穿层孔筛管悬挂装置的最优卡爪长度,优选了配套钻头,并在淮北芦岭煤矿进行了现场应用。应用结果表明:当悬挂装置卡爪长度95mm时,在常用?103mm孔径的大倾角穿层孔中悬挂可靠,三翼开闭式钻头岩层钻进效率高,中心翼片打开可靠。在相同抽采条件下,施工的70个筛管完孔穿层钻孔比同样数量的裸眼完孔穿层孔瓦斯抽采浓度提高26%,抽采流量提高78%,在9个月的抽采效果考察周期的后期,抽采流量平均增幅还提高了25%,提出了穿层孔煤孔段筛管下入方法,设计了可脱式定位接头,完善了煤矿井下穿层孔筛管完孔技术,为穿层孔煤孔段定位筛管完孔提供了技术思路。

Aiming at the problems in the trans-seam borehole completion,such as poor reliability of fixaton,high cost of full-hole screen pipe,the optimal jaw length of the suspension device was studied and the drill bit was optimized. The application results in Huaibei Coal Mine show that,when the jaw length was 95 mm,it was reliable in the commonly used 103 mm large-dip trans-seam borehole,the drill bit has high drilling efficiency and the bit opening is reliable. Under the same extraction conditions,compared with the same number of open holes,the gas extraction concentration and extraction flow rate of the 70 screen pipe completion hole increased 26% and 78% respectively. In the late period of the nine-month extraction period,the average increase of extraction flow rate increased by 20%. The method of screen pipe running in the coal hole section was also proposed,the detachable positioning device was designed,and the technology of screen pipe completion for trans-seam borehole in underground coal mine was improved.