特厚坚硬煤层深浅交替钻孔水力压裂弱化顶煤技术研究  

Top coal weakening in extra-thick hard coal seam using hydraulic fracturing with alternated drilling of deep and shallow holes

作　　者：康晓峰 KANG Xiaofeng(Shanxi Xinzhou Shenda Energy Group Co.,Ltd.,Xinzhou 034000,China)

机构地区：[1]山西忻州神达能源集团有限公司,山西忻州034000

出　　处：《煤炭工程》2023年第3期19-24,共6页Coal Engineering

摘　　要：为有效解决特厚煤层大采高放顶煤开采设计时,因顶煤坚硬并且工作面上方为采空区,导致矿压显现较小,放煤过程中煤块较大、冒放性差、回采率低等技术难题,在特厚坚硬煤层中采用深浅交替钻孔水力压裂弱化顶煤技术,并在金山煤业13101工作面进行工业性试验,通过FLAC^(3D)数值模拟以及现场监测等多种手段对水力压裂效果进行综合分析。结果表明:在特厚坚硬煤层中采用深浅交替钻孔水力压裂技术,钻孔孔壁四周出现大量微小裂缝以及多条贯穿大裂缝,可有效破坏坚硬顶煤层的完整性,使顶煤能够充分垮落和回收,并且缩短周期来压步距,减小压裂范围支架工作阻力,压裂后顶煤煤块大块最大粒度从800 mm左右下降到300 mm以下,放顶煤回采率提高11.3%,实现了工作面安全高效生产和资源的充分回收。水力压裂弱化特厚坚硬顶煤技术为相似工程设计提供了技术途径和方向。In order to solve the technical problems in the mining design of large mining height top coal caving in extra-thick coal seam,it is considered that,the hard top coal and the working face is above the goaf,so the mining pressure is mild,leading to over-large coal blocks,poor cavability,low recovery rate in the top coal caving,a hydraulic fracturing technology with deep and shallow alternating borehole is adopted to weaken the top coal,and the industrial test is conducted in 13101 working face of Jinshan Coal Mine.The fracturing effect is analyzed through FLAC^(3D)numerical simulation and field monitoring,and the results show that the technology can effectively break the integrity of the hard top coal seam,as a large number of tiny cracks and multiple large cracks running through the borehole wall appeared,which enables the top coal to fully collapse thus to be recovered,and shortens the periodical weighting interval,reduces the working resistance of support in the fracturing range.After fracturing,the maximum size of the top coal block has dropped from about 800 mm to less than 300 mm,and the recovery rate of the top coal caving has increased by 11.3%,the safe and efficient production of the working face and full recovery of resources is achieved.

关 键 词：特厚煤层 水力压裂 坚硬顶煤 弱化顶煤 

分 类 号：TD325[矿业工程—矿井建设]