大直径竖井钻机压气反循环洗井效率模型试验研究

Model test study on efficiency of pressure gas reverse circulation shaft washing in large diameter shaft boring machine

针对我国西部侏罗系地层钻井法凿井钻进与洗井效率低下问题,以西部可可盖煤矿中央回风立井钻井法凿井为研究背景,基于自主研发的压气反循环洗井试验装置,开展压气反循环洗井的相似模型试验研究,并采用正交试验和极差分析相结合的方法,探究钻头转速、风压和风管埋入系数等因素对压气反循环洗井效率的影响规律,最后提出了高效洗井的参数组合。研究结果表明:①通过正交试验和极差分析结果,得出洗井效率主要影响因素的敏感性排序为:钻头转速>风压>风管埋入系数;②基于模型试验结果,提出了洗井效率的评判指标清屑率和携岩率,二者均随钻头转速、风压的增大呈先大幅增长后小幅降低的趋势,且与风管埋入系数呈正相关关系;③洗井液排量与钻头转速呈负相关关系,钻屑排量随着钻头转速、风压的增大均呈现先增长后降低的趋势;④基于模型试验结果,提出了高效洗井参数:钻头转速为8.6 r/min;风压为1.44 MPa;风管埋入系数为0.837。研究结果可为提高西部侏罗系地层钻进与洗井效率低下问题提供有益参考。

Aiming at the problem of low efficiency of drilling and washing shaft of shaft drilling sinking in Jurassic strata in western China, taking the central return air shaft drilling sinking in the western China Kekegai Coal Mine as the research background, based on the self-developed pressure gas reverse circulation shaft washing test device, the similar model test of pressure gas reverse circulation shaft washing was carried out. The orthogonal test and range analysis were used to explore the influence of factors such as bit speed, air pressure and air duct embedding coefficient and other factors on the efficiency of pressure gas reverse circulation shaft washing, and the parameter combination of efficient shaft washing was put forward. The results show that:① Through the results of orthogonal test and range analysis, the sensitivity order of the main influencing factors of shaft washing efficiency is as follows: bit speed > air pressure > air duct embedding coefficient.② Based on the results of the model test, the evaluation indexes of shaft washing efficiency are put forward, which are the debris removal rate and the rock carrying rate. Both of them increase sharply first and then decrease slightly with the increase of bit speed and air pressure, and are positively correlated with the buried coefficient of air duct.③ The displacement of washing fluid is negatively correlated with the rotation speed of the drill bit. The displacement of drilling cuttings increases first and then decreases with the increase of the rotation speed of the drill bit and the air pressure.④ Based on the model test results, the high-efficiency shaft washing parameters are proposed : the bit speed is 8.6 r/min, the air pressure is 1.44 MPa, and the air duct embedding coefficient is 0.837. The research results can provide a useful reference for improving the low efficiency of drilling and shaft washing in Jurassic strata in western China.