高瓦斯矿井采空区大直径高位钻孔瓦斯抽采技术研究

发布时间：2018-04-25 04:20

本文选题：大直径钻孔 + 瓦斯抽采　；参考：《太原理工大学》2013年硕士论文

【摘要】：大直径钻孔是瓦斯抽采的发展趋势,也是今后高瓦斯综放工作面瓦斯抽采技术的研究重点。基于此,本文以沙曲矿为背景,对高瓦斯矿井大直径扇形高位钻孔瓦斯抽采技术进行了分析研究。利用Flac3D软件对该矿24207工作面采空区顶板覆岩的移动进行数值模拟,通过对Z方向位移等值线进行分析,得知在采空区后方60m处覆岩移动即达到了平衡状态,并可清晰的判断主要关键层的位置分布在工作面上方18m及46m处。最终运用经验公式法计算出的冒落带及裂隙带最大高度分别为16.88m和46.3m,利用关键层组合分析法计算出的冒落带及裂隙带高度分别为17.56m和44.96m,利用数值模拟分析法得出的结果为18m和50m。为尽量减少误差,取三者的平均值作为最终结果,即冒落带、裂隙带的的最大高度分别为17m和47m。系统的研究了“U”型、“U+L”、“Y”型通风情况下,采空区泄压瓦斯的运移规律和其在采空区空间的浓度分布特征。分析得知,相同条件下使用“Y”型通风工作面后方10m以内的上隅角瓦斯浓度在0.26%～0.36%之间,仅为“U”型通风时的1/8,“U+L”型通风时的3/4。对试验工作面回采期间瓦斯涌出量进行预测,计算知仅依靠通风稀释瓦斯,回风流中的瓦斯浓度高达2.24%,进行瓦斯抽采势在必行。论述了钻孔抽采瓦斯的基本原理,推导了不稳定渗流及稳定渗流时钻孔周边压力分布公式。得出距离钻孔越远的点压力降越小,同一地点的压力降随着抽放时间的增加而减小的结论。并利用Fluent软件对影响钻孔抽放效果主要因素进行了详细分析,得知钻孔的抽放效果受抽放负压、钻孔孔径以及煤层的渗透率影响较大；钻孔的影响范围以及钻孔的抽采量随着抽放负压的降低而增大；随着钻孔孔径的增大而增大；随着煤层渗透率的降低而增大。该结论与推导的公式相吻合,证明了采空大直径钻孔治理瓦斯的可行性。基于采空区覆岩沉降特征及泄压瓦斯运移规律,提出了大直径高位钻孔瓦斯抽采技术,确定了高位钻孔仰角的最佳取值范围为210939。,钻场的合理间距应在40m-45m之间。通过对钻孔和倾向高位巷的实测抽采数据进行分析,整个钻场5个钻孔的平均抽采纯量12.2m3/min,有效抽放时间达63天；布置在同一侧的倾向高位巷的平均抽采纯量为10.05m3/min,有效抽放时间43天。证明大直径高位钻孔能够替代高位巷治理采空区瓦斯,对其它矿井瓦斯治理具有较大的参考价值。
[Abstract]:Large diameter borehole is the development trend of gas drainage, and it is also the focus of research on gas drainage technology in high gas fully mechanized caving face in the future. Based on this, this paper analyzes and studies the gas drainage technology of large diameter and high position borehole in high gas mine based on Shaqu mine. By using Flac3D software, the movement of roof overburden in goaf of 24207 face of this mine is numerically simulated. By analyzing the contour of displacement in Z direction, it is known that the movement of overburden is in equilibrium state at 60m behind the goaf. The location of the key layer can be clearly judged at 18m and 46m above the working face. The maximum height of caving zone and fracture zone calculated by empirical formula method is 16.88m and 46.3mrespectively, the height of caving zone and fissured zone calculated by combination analysis of critical layer is 17.56m and 44.96mrespectively, and the result obtained by numerical simulation analysis is 18m and 50m. In order to reduce the error as far as possible, the average value of the three is taken as the final result, that is, the falling zone, the maximum height of the fracture zone is 17 m and 47 m, respectively. Under the condition of "U" type, "U L", "Y" type ventilation, the law of gas migration in goaf and its concentration distribution in goaf space are studied systematically. The analysis shows that under the same conditions, the gas concentration in the upper corner of "Y" ventilation working face within 10 m behind is between 0.26% and 0.36%, which is only 1 / 8 of "U" type ventilation and 3 / 4 of "U L" type ventilation. The quantity of gas emission during the mining of test face is predicted. The calculation only depends on ventilation to dilute the gas and the gas concentration in the return air flow is as high as 2.24, so it is imperative to carry out gas extraction. This paper discusses the basic principle of gas extraction by drilling and deduces the distribution formula of pressure around the borehole under unstable seepage and steady seepage. It is concluded that the pressure drop at the same point decreases with the increase of pumping time as the point pressure drop is smaller when the hole is farther away from the borehole. The main factors influencing the drainage effect of borehole are analyzed in detail by using Fluent software. It is found that the drainage effect of borehole is affected by negative pressure of pumping hole diameter of borehole and permeability of coal seam. The influence range of borehole and the extraction amount of borehole increase with the decrease of suction negative pressure, increase with the increase of borehole diameter, and increase with the decrease of coal seam permeability. The conclusion is in agreement with the derived formula and proves the feasibility of gas control by large diameter boreholes. Based on the subsidence characteristics of overburden and the law of gas migration in goaf, the gas extraction technology of large diameter and high hole is put forward, and the optimum range of elevation angle of high hole is determined to be 210939. The reasonable spacing of drilling field should be between 40m-45m. Through the analysis of the measured extraction data of boreholes and inclined high roadways, the average extraction scalar of 12.2m3 / min and the effective pumping time of 63 days were obtained from 5 boreholes in the whole drilling field. The average extraction scalar of inclined high roadway on the same side is 10.05 m3 / min, and the effective pumping time is 43 days. It is proved that the large diameter and high hole can replace the high level roadway to control the gas in goaf, which is of great reference value to the gas control in other mines.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TD712.6

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