钻杆直径及钻进速度对钻屑量影响试验研究

Experimental study on the influence of drill pipe diameter and drilling velocity on drilling cuttings

钻杆直径和钻进速度不统一造成钻屑量差异显著,使得现场钻屑量指标测定准确性无法保证。考虑深部开采条件下水平地应力作用不可忽略,建立了钻孔周围平面应变力学模型,引入有效应力推导得到单位长度钻屑量理论公式,经与现场钻屑量对比分析,验证了理论公式正确性,提出现场钻杆直径42 mm为宜。利用自主研制的三维应力煤体钻屑量检测试验装置,进行了不同钻杆直径及钻进速度钻屑量试验,得到钻杆直径及钻进速度与钻屑量间关系规律。结果表明:钻杆直径由12 mm增加至18 mm时,钻屑量均值和极大值均随钻杆直径增加而增大,均呈抛物线规律递增。对钻屑量均值与理论值进行对比分析,确定最优钻杆直径为16 mm。基于最优钻杆直径,钻进速度为2,2.5,3,3.5 mm/s时,钻屑量极大值为10.8,11.6,12.3,13.0 g,增加了7.4%,6.0%,5.7%,其增加幅度逐渐减小;同时钻屑量均值分别为9.34,10.14,10.8,11.20 g,增加了8.57%,6.51%和3.70%,呈幂函数递增规律。利用钻屑量指标法预测煤矿动力灾害时,应统一设定钻进速度及钻杆直径尺寸,提高预测准确性和可靠性。

Considering the effects of horizontal stress under deep mining conditions, the model of the plane strain around the drill hole was established, and the theoretical formula of the drill cuttings per unit length was deduced by introducing the effective stress. The theoretical formula is verified by comparative analysis with field drill cuttings, and it is suggested that the diameter of field drill pipe is 42 mm.The relationships among drilling velocity, the diameter of drill pipe and the amount of drilling cuttings were analyzed by using the self-developed three-dimensional stress coal body cuttings measurement test device. The results show when the diameter of the drill pipe increase from 12 mm to 18 mm, the mean and maximum value of drilling cuttings increase with the diameter of the drill pipe, which increases with the parabola law. Comparing and analyzing the average value of drill cuttings and the theoretical value,we determine the optimal diameter of the drill pipe is 16 mm. Based on the optimal 16 mm pipe diameter, when drilling velocity is 2, 2.5, 3 and 3.5 mm/s, the maximum drilling cuttings value is 10.8, 11.6, 12.3, 13.0 g. The weight increase by 7.4%, 6.0%, 5.7% and the increase range decreases. The mean drilling cuttings are 9.34, 10.14, 10.8, 11.20 g respectively,which increases by 8.57%, 6.51% and 3.70% with power function law. It is necessary to set the drilling velocity and diameter of drill pipe to enhance the accuracy and reliability When using the cuttings measurement method to predict coal mine power disaster.