煤矿井下气动冲击回转钻进工艺参数试验

Experimental Study on the Process Parameters of Pneumatic Percussive Rotary Drilling in Coal Mine

冲击回转钻进方法是解决硬岩层钻进效率低问题的主要技术方法之一。为了对煤矿井下穿层钻孔硬岩钻进采用的气动冲击回转钻进工艺参数进行优化,通过采集试验地层岩芯,制样并进行单轴抗压强度测试,将试验岩层分为下层泥质砂岩、中层石英砂岩和上层泥质砂岩;讨论气动冲击回转钻进方法的工作原理和钻具组合特点,分析影响钻进效率的主要工艺参数,包括气体压力、钻机转速和给进压力,并给出了在正交试验设计时各参数水平的选择;采用“纵向机械钻速对比、横向工艺参数优化”的技术思路,运用正交试验设计方法进行了工艺参数优化研究,分析了各岩层机械钻速及差异性原因。结果表明:气体压力对机械钻速的影响具有显著性,钻机转速和给进压力不显著,但钻机转速对机械钻速的敏感性比给进压力明显。通过工艺参数研究,在试验设备和钻具条件下,得出最优工艺参数:气体压力为1 MPa,钻机转速为40 r/min,给进压力为3.0 MPa。通过对各层机械钻速的研究,得到下层泥质砂岩机械钻速最高、上层泥质砂岩次之和中层石英砂岩机械钻速最低,分析认为对于两种泥质含量较大的砂岩,泥质含量越高,岩石相对越软,相应塑性增大,对于以冲击为主碎岩的方法,塑性越大对机械钻速越不利,钻进效率相对更低;上层泥质砂岩处于试验钻孔的最深孔段,钻头磨损较多,对深孔处的钻进效率有不利影响。

The impact rotary drilling method is one of the main technical methods to solve the problem of low drilling efficiency of hard rock formations.In order to optimize the pneumatic percussive rotary drilling process parameters used for the drilling of hard rock through strata boreholes of coal mine underground,the test rock strata was divided into lower argillaceous sandstone,middle quartz sandstone and upper argillaceous sandstone by collecting the core of the test formation,preparing samples and conducting uniaxial compressive strength tests.The working principle of pneumatic percussive rotary drilling method and the characteristics of drilling tool combination were discussed.The main process parameters affecting drilling efficiency were analyzed,including gas pressure,drilling rig speed and feed pressure,and the level selections of each parameter in orthogonal test design were given.Using the technical idea of“longitudinal rate of penetration comparison and horizontal process parameter optimization”,the process parameter optimization study was carried out by using the orthogonal experimental design method,and the rate of penetration and difference of each rock formation were analyzed.The results show that the influence of gas pressure on rate of penetration is significant,and the drilling rig speed and feed pressure are not significant,but the sensitivity of the drilling rig speed to the rate of penetration is obvious than the feed pressure.Through the study of process parameters,under the conditions of test equipment and drilling tools,the optimal process parameters are obtained:gas pressure is 1 MPa,drilling rig speed is 40 r/min,and feed pressure is 3.0 MPa.Through the study of the rate of penetration of each strata,it is obtained that the rate of penetration of the lower argillaceous sandstone is highest,the upper argillaceous sandstone is followed and the rate of penetration of the middle quartz sandstone is the lowest.The analysis believes that for the two kinds of sandstone with large argillaceous content,the higher the argillaceous content,the softer the rock,and the corresponding plasticity increases.For the method of percussive-based crushing,the greater the plasticity,the more unfavorable for the rate of penetration,and the drilling efficiency is relatively lower.The upper argillaceous sandstone is in the deepest section of the test boreholes,and the drill bit wears more,which has an adverse impact on the drilling efficiency at the deep hole.