水力压裂技术具备安全性好、施工工艺简单的优点,被广泛应用于煤层坚硬顶板灾害治理.但由于岩体的不均质性,压裂孔周围裂隙网络扩展规律复杂,水力压裂裂纹监测精度低,压裂效果评估难度大.针对上述问题,通过对比分析常见水力压裂监测方法及监测方案的差异,揭示微震监测技术的优越性,并对水力压裂效果评估技术进行了讨论.研究表明,微震监测技术具有监测范围广、灵敏度高、连续性好的优点;地面监测、井下监测、联合监测等微震监测方法适用工况不同,监测精度相差较大,应根据现场工程布置与实际岩层条件选取合适的监测方法.坚硬顶板水力压裂效果评估多采用裂缝发育长度、来压步距等间接指标,基于微震参变量直接指标的效果评估相对较少.在此基础上,提出了水力压裂效果评估精细化的发展建议.研究成果对开展坚硬顶板水力压裂现场监测、优化坚硬顶板水力压裂工程设计具有重要指导意义.
Hydraulic fracturing technology has the advantages of good safety and simple construction process,and is widely used in the management of hard roof disasters in coal seams.However,due to the heterogeneity of the rock mass,the expansion pattern of the fracture network around the fracturing hole is complex,and the accuracy of hydraulic fracturing crack monitoring is low,making it difficult to evaluate the fracturing effect.Based on this,by comparing and analyzing the differences between common hydraulic fracturing monitoring methods and monitoring schemes,the superiority of microseismic monitoring technology is revealed,and the evaluation technology of hydraulic fracturing effect is discussed.The research shows that:Microseismic monitoring technology has wide monitoring range,high sensitivity,and good continuity;The microseismic monitoring methods such as ground monitoring,underground monitoring,and joint monitoring are suitable for different working conditions and have significant differences in monitoring accuracy;Therefore,appropriate monitoring methods should be selected based on the on-site engineering layout and actual rock conditions.The evaluation of hydraulic fracturing effect on hard roof often uses indirect indicators such as crack development length and weighting interval,while the evaluation based on direct indicators of microseismic parameters is inadequate.On this basis,development suggestions for the refinement of hydraulic fracturing effect evaluation are proposed.