综采工作面水力压裂初次放顶技术研究

Study on hydraulic fracturing technology in initial caving of fully-mechanized coal mining face

针对柠条塔煤综采工作面顶板稳定难以垮落,工作面大面积悬顶带来的安全隐患问题,在综采工作面开切眼实施水力压裂初次放顶技术,通过监测水力裂缝扩展、水压变化及顶板垮落效果,分析水力压裂技术在初采期间的控顶效果。结果表明:针对厚而稳定的砂岩顶板,在开切眼处沿工作面推进方向实施水力压裂钻孔,可有效弱化顶板岩层,有利于综采工作面初采期间顶板岩层顺利、安全垮落。根据柠条塔煤矿顶板岩层条件,确定了合理的压裂参数,包括钻孔间距、长度、倾角以及压裂所需压裂,可保证工作面顶板在初采期间分层、分次逐步垮落,未形成强烈冲击,确保了工作面安全初采。

The roof of fully-mechanized coal mining face in Ningtiaota coal mine is stable and difficult to cave. The impending roof with a large area has become a potential accident. In this paper,hydraulic fracturing technology was applied in the open-off cut of fully-mechanized working face in Ningtiaota coal mine to cut the roof.The fracture propagation process,pressure variation and roof caving state were monitored to illustrate the effect of this technology. This results showed that hydraulic fracturing could effectively weaken the roof strata and ensured roof caving safety during initial mining period. The fracturing parameters,such as interval,depth,angle and required fracturing pressure of boreholes,for working face were determined based on the roof conditions of this coal mine.This program was able to guarantee a sequential caving process,reduced mine earthquakes and ensured production safety during initial mining period.