基于垮落充填的坚硬顶板分段压裂弱化解危技术

Collapse filling-based technology of weakening and danger-solving by staged fracturing in hard roof

坚硬顶板条件下采煤工作面容易诱发冲击地压、煤与瓦斯突出、矿震及采空区飓风等动力灾害,严重威胁矿井的安全生产。基于裸眼分段压裂超前弱化模式,结合"压裂垮落体+煤柱+承重岩层"协同支撑理念,提出坚硬顶板分段压裂超前弱化解危技术。综合采用理论分析、技术研发、工程应用等方法,探索顶板分段压裂超前弱化解危机理,研究形成稳定协同支撑系统的定量判定公式,并在河东煤田保德煤矿开展工程应用。结果表明:根据判定公式可优选压裂目标层位,顶板分段水力压裂弱化技术实施过程中,最高压力22.43MPa,破裂压降最大达6.17MPa,单个钻场3个钻孔累计出现3.0MPa以上压力降167次;根据压裂前后工作面来压情况可知,压裂后顶板来压步距、动载系数、来压均值分别降低35.02%、14.29%、13.87%,巷道变形得到有效控制,验证分段压裂能够形成人造协同支撑系统,实现坚硬顶板动力灾害的弱化解危。研究实践可为同类地质条件下顶板强矿压灾害防治提供技术借鉴。

The working face is easy to induce dynamic disasters such as rock burst, coal and gas outburst, mine earthquake and hurricane in goaf under the condition of hard roof, which seriously threatens the safety of mine production. the pre-weakening and risk-solving technology of staged fracturing in hard roof is proposed based on the mode of advanced weakening by staged fracturing through open holes, combined with the synergetic support concept with "fracturing collapse body+coal pillar+load-bearing rock layer". By using the methods of theoretical analysis, technical research and development and engineering application, the crisis mechanism of advanced weakening of the staged fracturing in roof was explored, and the quantitative judgment formula for the formation of stable collaborative support system was developed, and the engineering application was carried out in Baode Coal Mine in Hedong Coalfield. The results show that the maximum hydraulic fracturing pressure is 22.43 MPa, the maximum fracture pressure drop is 6.17 MPa, and the pressure drop above 3.0 MPa is more than 167 times in three boreholes by implementing the hydraulic fracturing weakening technology of roof section according to the selected of fracturing target layer by determination formula. Through the analysis of the working face pressure before and after fracturing, the roof weighting step distance, dynamic load coefficient and average pressure after fracturing are reduced by 35.02%, 14.29% and 13.87% respectively, and the deformation along the roadways is effectively controlled. It is verified that staged fracturing can form artificial cooperative support system, realize the weakening and solution of dynamic disasters of hard roof, and provide technical and equipment support for the prevention and control of strong mine pressure disasters of roof under similar geological conditions.