封孔器在有残留煤渣钻孔中移动的试验研究

Experimental study on borehole packer movement in borehole with residual coal dregs

为揭示钻孔内残留煤渣阻碍封孔器移动的作用机制,寻求最佳的降阻方法,首先,设计封孔器在煤层钻孔内移动的试验方案及装置,并开展7种不同端头锥面角度的封孔器在模拟钻孔内的移动试验;然后,分析封孔器前方的煤渣堆积状态及其移动阻力参数;最后,基于试验结果,解释炸药和封孔器在煤层钻孔内的堵塞现象,改进钻孔瓦斯涌出初速度测定装备的封孔器。结果表明,随着封孔器向前移动,封孔器前方的煤渣堆积长度和高度逐步增加,封孔器所受的阻力几乎呈指数规律增加;如果封孔器的端头锥面角度较大,就会被堆积的煤渣完全堵塞;随着封孔器端头锥面角度的减小,封孔器所受阻力逐步降低,并趋于稳定;改进型封孔器(前端安装锥面角度为20°的空心罩)的送入阻力小、推进速度快,送入钻孔深度大。

Residual coal dregs may block borehole packer movement in the hole. The paper was aimed at working out an effective method to reduce the drag. Firstly, experimental equipment and plan were designed about the borehole packer movement in coal hole, and seven borehole packers of having different terminal conical surface angle were designed and manufactured, and experiments were carried out about seven borehole packers moving in a simulation borehole.Accumulation states of coal dregs in front of borehole packer and drag on borehole packer were analyzed.The blocking phenomenon was explained the pack of dynamite and the borehole packer moving in the coal hole. The borehole packer of an equipment for measuring gas emission initial velocity from borehole was improved. The results show that with the borehole packer moving forward, both length and height of coal dregs accumulation increase gradually, and the drag increases exponentially, that the borehole packer will be blocked completely if the conical surface angle of front end is bigger, that with conical surface angle decreasing, the drag decreases gradually until reaching a stable value,and that the improved borehole packer whose conical surface angle is 20 degrees is much smaller than that on the existent borehole packers.