强矿压矿井定向长孔分段压裂技术研究及应用

Research and application of directional long-borehole staged hydraulic fracturing technology for strong rock pressure in mine

为解决神东矿区布尔台矿4-2煤层顶板坚硬,完整性较好,回采过程中顶板悬顶面积大,强矿压显现明显等问题,以千米定向钻进为基础,结合双封单卡裸眼分段水力压裂成套装备,研发了定向长钻孔分段压裂技术装备。通过布尔台42107综采工作面的工业性试验,最高一次性实现了468m裸眼钻孔的9段压裂施工,压裂最高压力达到25.9 MPa,最低压力9.3 MPa,实现了3 MPa以上明显压降70余次。研究结果表明:通过定向钻孔、高压注水、分段压裂,可在指定层位、区段形成多点段三维立体裂隙网络,悬顶面积降为原来的1/7,周期来压步距由最高45 m降至25 m,来压强度明显降低,实现了顶板的有效弱化,为矿区安全高效生产提供了有效的技术和装备保障。

In order to solve the problem that the roof of No.4-2coal seam in Bu er tai Coal Mine of Shendong Mining Area could not collapse along with mining,resulting in.large area hanging arch and strong mine pressure,the long-borehole staged hydraulic fracturing technology was introduced.It was based on directional drilling and hydraulic dual-anchor retrievable packer technology.Through industrial test of No. 42107fully-mechanized working face,the 468m uncased hole with 9 staged fracturing for weakening roof was carried out. More than 70 times significant drop (above 3MPa)appeared,with the max fracturing pressure up to 25.9MPa,the lowest was 9.3MPa.The results showed that multi-point three-dimensional fracture network was formed by directional drilling,high pressure water injection and staged fracturing on designed layer.The overhang area reduced to one seventh,with periodic weighting interval decreasing from 45m to 25m,realizing effective degradation of mine pressure.It provided the effective technical and equipment support for mine safety production and high efficiency.