顶板定向梳状长钻孔分段水力压裂抽采技术研究

Study on segmented hydraulic fracturing extraction technology of roof directional comb long drilling holes

由于顶板定向长钻孔水力压裂产生的裂隙无法控制,裂隙无法沟通厚煤层中下部,效果达不到预期。因此,提出在煤层顶板施工主孔,每间隔一段,施工分支钻孔穿入煤层中进行分段压裂。现场实际施工压裂钻孔1个,主孔终孔孔深486m,施工分支孔5个,总进尺921m。现场泵注压力12.6~18.5MPa,压裂液单段用量121~786m^(3),总用量1586m^(3),通过瞬变电磁测试得出水力压裂半径达35m以上,瓦斯抽采浓度21.1%~68.8%(平均浓度48.5%),平均抽采纯量1.6m^(3)/min,抽采效果较顶板定向长钻孔水力压裂技术提高1.7倍。

Because the fractures produced by hydraulic fracturing of long directional drilling holes in the roof can not be controlled,and the fractures can not communicate with the middle and lower parts of thick coal seam,the effect can not reach the expectation.Therefore,it is proposed to construct the main hole in the roof of coal seam,and each interval,the construction branch drilling holes penetrate into the coal seam,and then conduct segmented fracturing.One fracturing drilling hole is actually constructed on site,the final hole depth of the main hole is 486 m,and five branch holes are constructed,with a total footage of 921 m.The on-site pumping pressure is 12.6~18.5 MPa,the consumption of fracturing fluid in a single section is 121〜786 m^(3),and the total consumption is 1586 m^(3);The transient electromagnetic test shows that the hydraulic fracturing radius is more than 35 m;The gas extraction concentration is 21.1%~68.8%(average concentration is 48.5%),and the average net extraction volume is 1.6 m^(3)/min.The extraction effect is 1.7 times higher than that of roof directional long drilling hydraulic fracturing technology.