煤层顶板大直径定向钻孔用双级双速PDC钻头设计及应用  

Design and application of PDC bit for large diameter directional drilling of coal seam roof with double stage and double speed

作　　者：高晓亮 居培 赵建国 GAO Xiaoliang;JU Pei;ZHAO Jianguo(Xi’an Research Institute Co.Ltd.,China Coal Technology and Engineering Group Corp.,Xi’an 710077,China)

机构地区：[1]中煤科工集团西安研究院有限公司,陕西西安710077

出　　处：《煤田地质与勘探》2021年第5期272-277,285,共7页Coal Geology & Exploration

基　　金：中煤科工集团西安研究院有限公司科技创新基金项目(2018XAYZD01)。

摘　　要：大直径定向钻进成孔技术的发展,为"以孔代巷"技术抽采采空区上隅角瓦斯提供了技术支持。受限于井下设备条件,常规大直径钻孔主要采用逐级扩孔工艺。然而,逐级扩孔钻进需要多次提钻、下钻,辅助时间长、工人劳动强度大。为提高煤层顶板大直径钻孔成孔效率,开发了双级双速钻进工艺,该工艺采用螺杆马达与钻机分别驱动一级、二级钻头进行单次双级扩孔钻进,可大大提高成孔效率。通过分析双级双速钻进工艺特点、拟钻地层岩性等,从剖面形状、切削齿排布、水路设计以及导向器设计等方面设计了双级双速钻头,该钻头采用球头螺旋形导向器,更容易沿既有钻孔轨迹钻进;采用等切削布齿,提高破岩效率、降低切削齿不均匀磨损,进而提高钻头寿命与钻进效率。设计的双级双速钻头进行了现场试验,试验表明双级双速钻头能够沿先导孔钻进,较常规逐级扩孔钻头综合效率提高25%以上,使用后钻头磨损均匀,满足了双级双速工艺要求,大大提高了煤层顶板大直径钻孔施工效率。The development of large diameter directional drilling technology has provided technical support for the extraction of gas in the upper corner of the goaf by "replacing roadway with borehole". At present, conventional large-diameter drilling mainly adopts the step-by-step hole-forming method, which solves the problem of insufficient power of large-diameter drilling equipment in underground coal mines. However, step-by-step reaming requires multiple times of lifting and lowering, long auxiliary time and intensive labor of the workers. In order to improve the drilling efficiency of large-diameter holes in the coal roof, a double stage drilling process with two speeds was developed. The process uses a screw motor and a drill to drive the first and second drill bits for reaming construction, which can greatly improve the efficiency of hole formation. For the implementation of such technology, a double stage and double speed drill bit was designed from the aspects of section shape, cutting tooth arrangement, waterway design and guide design by analyzing the characteristics of the drilling process and the lithology of the formation to be drilled. The drill bit adopts a ball head spiral guide, which makes it easier to drill along the existing drilling trajectory. The use of equal cutting teeth can improve the efficiency of rock breaking and reduce the uneven wear of the cutting teeth, thereby increasing the life of the bit and the efficiency of drilling. The designed drill bit was tested in the field. The results show that the double stage drill bit with two speeds has high rock breaking efficiency, uniform drill bit wear, and can drill along the pilot hole. It meets the requirements of the double stage and double speed process and greatly improves the efficiency of large-diameter drilling in the coal roof.

关 键 词：定向钻进 大直径钻孔 双级双速 钻头设计 PDC钻头 

分 类 号：TD41[矿业工程—矿山机电]