煤矿井下大直径定向钻进技术在水力压裂中的应用  

Application of large diameter directional drilling in hydraulic fracturing of underground coal mine

作　　者：刘徐三 LIU Xu-san(CCTEG Xi’an Research Institute,Xi’an 710077,China)

机构地区：[1]中煤科工集团西安研究院有限公司,陕西西安710077

出　　处：《煤炭工程》2020年第5期58-62,共5页Coal Engineering

摘　　要：为了解决碎软、低透气性煤层水力压裂非定向顺层钻孔成孔率低、成孔后易塌孔导致钻孔堵塞和非定向穿层钻孔有效孔段短的问题,提出了将煤矿井下底板穿层梳状定向钻进技术与水力射流冲孔技术相结合的增透方案,形成一套适应煤矿井下水力压裂的大直径定向钻进技术。现场应用结果表明:该技术既解决了成孔率低和成孔后塌孔导致的钻孔堵塞的问题,又解决了钻孔有效距离短、压裂后影响范围小造成的瓦斯抽采效果差问题;抽采最大浓度平均为5. 22%,抽采流量平均为4. 60m^3/min,日均瓦斯抽采量平均值334. 81m^3/d,与普通穿层钻孔抽采数据对比,压裂增透后钻孔瓦斯抽采流量提高约5. 23倍。对该矿区碎软煤层条件下的瓦斯强化抽采具有较强的指导意义。Aiming at the low hole forming rate of non-directional drilling in fractured soft and low permeability coal seam,frequent hole collapsing after hole forming, and short effective hole section, a set of large diameter directional drilling technology is proposed for hydraulic fracturing in coal mine. The field application results show that the technology solves not only the problems of low hole forming rate and hole collapse after hole forming,but also solves the poor gas drainage effect caused by short effective drilling distance and small influence range after fracturing,the average maximum concentration of gas extraction is 5. 22%;the average flow of gas extraction is 4. 60 m^3/min;the average daily gas extraction is 334. 81 m^3/d.Compared with the data of drilling and drainage in common seam-crossing drilling,the gas drainage flow of drilling hole after fracturing and permeability enhancement is increased by about 5. 23 times. It has a strong guiding significance for the gas intensified extraction under the condition of the broken soft coal seam in the mining area.

关 键 词：煤矿井下 大直径 定向钻进 水力压裂 水力射流 

分 类 号：TD713.3[矿业工程—矿井通风与安全]