煤矿瓦斯抽放孔跟管钻进用偏心PDC钻头的研制

为解决松软突出煤层钻进难、成孔难这一问题,我们研制了一种偏心跟管PDC钻头,并研究了施工过程中的参数对钻进效率和钻头寿命的影响。结果显示:PDC偏心钻头能够比较快速的破碎岩石,适用于煤系地层的瓦斯抽采孔钻进。但对于松软煤层钻进过程,其需要较大的水路以充分冷却钻头及排除岩粉。对现场施工的研究表明,合理的切削角和侧转角,以及相应的空间参数,能够保证PDC钻头快速破碎岩石,并提高钻头寿命。

Development of excentric PDC bit drilling with casing used for gas drainage drilling in coal mine

To slove the problem of drilling in soft and outburst coal seam , an excentric bit that drills with casing is developed, and the drilling parameters are studied to enhance the efficiency and lifetime of the bit. Results show that the PDC excentric bit could break rocks quickly, thus suitable for the drilling of gas drainage hole in coal-bearing strata. But for the soft coal strata it requires more water to cool the bit and wash away rock powders. Results show that the PDC bit could cut rocks quicker and last longer when drilling at reasonable cutting angle, side angle and related spatial parameters.