煤层坚硬顶板定向长孔水力压裂技术研究及应用

Research and application of directional long-hole hydraulic fracturing technology of coal seam hard roof

针对煤层顶板坚硬采空区大面积悬顶后突然垮落易引发强矿压动力灾害等问题,采用定向长钻孔分段水力压裂技术弱化煤层顶板,并在布尔台煤矿42108工作面进行现场应用,分别从压裂层位选择、压裂钻孔布置、定向钻孔施工、分段水力压力施工等方面论述了定向长钻孔水力压裂技术,现场结果表明,超前治理工作面中部坚硬顶板面积230.1万m^(2),压裂后顶板来压步距降低了20.83%~27.27%,动载系数较未压裂段降低了5.03%~10.32%,同时利用音频电透视方法对压裂效果检测,判识单个压裂段的弱化影响范围30 m左右,单个压裂钻场弱化影响范围为走向300 m,倾向230 m,实现了对整个工作面坚硬顶板区域性有效弱化治理。

In view of the dynamic disaster of strong mine pressure in Buertai Coal Mine which is initiated by large area hanging roof and sudden roof caving of in goaf of hard roof coal seam,directional drilling and segmented hydraulic fracturing were used to weaken the roof in 42108 working face of Buertai Coal Mine.The technology is discussed from the fracturing horizon selection,fracturing borehole layout,directional drilling construction,segmented hydraulic fraction construction.The results show that,using the technology,a large area of 2.301 million m^(2) hard roof was treated in advance;after fracturing,the roof weighting interval decreased by 20.83%~27.27%;the dynamic load coefficient decreased by 5.03%~10.32%compared with the non-fractured section.According to the fracturing effect monitoring with audio-frequency electrical penetration,the weakening influence range of a single fracturing section is about 30m,and the weakening influence range of a single fracturing drilling field is 300m along the strike and 230 m along the dip.The hard roof of the whole working face was effectively weakened.