预抽钻孔负压沿孔长变化特性及对瓦斯抽采效果影响研究

发布时间：2018-11-25 11:39

【摘要】：开展预抽瓦斯钻孔负压沿孔长变化特性及对瓦斯抽采效果影响的研究工作,对研究抽采条件下瓦斯渗流特性,确定合理的瓦斯抽采参数,提高瓦斯抽采效果,有效消除抽采空白带,保障煤矿安全高效开采具有重要的理论和现实意义。本论文以河南焦煤能源集团九里山矿和山西亚美大宁煤矿为研究背景和实验地点,通过理论分析、实验室测试、数值模拟及现场验证等手段,系统开展了预抽瓦斯钻孔负压沿孔长变化特性及其对瓦斯抽采参数、瓦斯抽采效果的影响等研究工作。论文在系统分析抽采钻孔孔口负压、钻孔直径、钻孔瓦斯流量等参数对钻孔孔内负压分布影响的基础上,得出了抽采钻孔孔内负压沿孔长的分布规律。抽采钻孔孔内负压不是传统上认为的一个恒定值,抽采负压沿钻孔长度方向逐渐减少,与钻孔长度服从负指数关系,其关系式为x xep×-×+=eba,ba)(+为抽采钻孔孔口负压、e为与抽采钻孔孔口负压、钻孔直径、钻孔瓦斯流量、钻孔长度等相关的拟合系数。研究得到抽采钻孔孔内瓦斯流量沿钻孔长度方向逐渐减小,两者符合负指数关系,其关系式为xd xec Q×-×=44。论文提出了在孔口抽采负压、钻孔直径、煤层透气性系数、抽采时间一定的条件下,和传统上认为抽采钻孔径向上瓦斯压力等值线呈“U”型分布不同,钻孔径向上的瓦斯压力等值线呈“V”型分布。通过数值模拟和现场测试得出了抽采钻孔孔内负压逐渐减少对瓦斯抽采参数的影响,提出了不同孔深位置的有效抽采影响半径,即:有效抽采影响半径不仅与抽采时间、钻孔直径、煤层透气性系数有关,还与钻孔深度密切相关,各参数之间符合)/(5.05.0LBAtp Rn×+×××=fl的关系。研究得到了九里山矿合理的抽采参数:合理抽采负压为26.7~39.9k Pa,合理抽采钻孔直径为94mm~113mm。经九里山矿的现场验证结果,随着钻孔深度的增加,抽采钻孔孔内负压与孔口相比,均出现明显的降低,百米钻孔负压损失为19.73~22.64%。抽采参数优化后,抽采钻孔初始瓦斯抽采量为0.0203m3/min,比优化前提高了37%。瓦斯流量衰减系数为0.0042,比优化前降低了24%。东风井泵站、西风井泵站和南风井泵站的抽采浓度、抽采量均得到了显著提升。经亚美大宁煤矿的现场验证结果,钻孔长度在810m以前,抽采量随钻孔长度的增加而增加,当钻孔长度达到810m时,钻孔抽采量基本不变,合理抽采钻孔长度为810m。
[Abstract]:The change characteristics of negative pressure along the hole length and the influence on the gas drainage effect are studied. The reasonable gas drainage parameters are determined to improve the gas drainage effect. It is of great theoretical and practical significance to effectively eliminate the gap zone and ensure the safe and efficient mining of coal mines. This paper takes Jiulishan Coal Mine of Henan Coking Coal Energy Group and Yameidanning Coal Mine of Shanxi Province as the research background and experimental site, through theoretical analysis, laboratory test, numerical simulation and field verification, etc. The change characteristics of negative pressure along the hole length and its influence on the gas extraction parameters and the effect of gas drainage were carried out systematically. On the basis of the systematic analysis of the influence of the parameters such as negative pressure, bore hole diameter and gas flow rate on the distribution of negative pressure in the borehole, the distribution of negative pressure along the hole length in the drainage borehole is obtained. The negative pressure in the borehole is not a constant value, and the negative pressure decreases gradually along the length of the borehole. The relation between the negative pressure and the length of the borehole is negative exponent. The relation is x xep 脳-脳 = eba,ba). E is the fitting coefficient related to the negative pressure of the hole opening, the diameter of the borehole, the gas flow rate of the borehole, the length of the borehole and so on. The results show that the gas discharge in the borehole decreases gradually along the length of the borehole, and the relationship between the gas discharge and the gas discharge is negative exponentially, and the relation is xd xec Q 脳-脳 = 44. Under the condition of negative pressure, diameter of borehole, permeability coefficient of coal seam and extraction time, the distribution of gas pressure isoline in radial direction of borehole is different from that of traditional method. The gas pressure isoline in the radial direction of borehole is "V" type distribution. Through numerical simulation and field test, the influence of negative pressure in borehole on gas extraction parameters is obtained, and the influence radius of effective extraction at different hole depth is put forward, that is, the influence radius of effective extraction is not only associated with extraction time. The diameter of borehole, the permeability coefficient of coal seam, and the relationship between the drilling depth and the parameters (5.05.0LBAtp Rn 脳脳脳 = fl) are closely related. The reasonable extraction parameters of Jiulishan Mine are obtained: the reasonable negative pressure of extraction is 26.7ng / 39.9k Pa, and the reasonable diameter of the extraction borehole is 94mm / 113mm. With the increase of borehole depth, the negative pressure in the borehole is obviously lower than that in the hole, and the loss of negative pressure in the 100-meter borehole is 19.730.64. After optimizing the extraction parameters, the initial gas extraction rate of the drainage borehole is 0.0203 m3 / min, which is 37% higher than that before optimization. The attenuation coefficient of gas discharge is 0.0042, which is 24% lower than that before optimization. The extraction concentration and extraction volume of Dongfeng well pumping station, west wind well pumping station and south air well pumping station have been improved significantly. The results of field verification in Yamedaning Coal Mine show that the extraction capacity increases with the increase of drilling length before 810m. When the borehole length reaches 810m, the amount of borehole extraction is basically unchanged, and the reasonable extraction drilling length is 810m.
【学位授予单位】：河南理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TD712.6

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