老虎台矿泥浆环境煤的瓦斯解吸机制研究

为了研究老虎台矿泥浆环境煤的瓦斯解吸机制,探讨了泥浆钻孔取心过程煤的瓦斯解吸状态,按照煤心管内的煤的瓦斯压力与管壁泥浆压力大小关系得出瓦斯解吸的四个阶段,并系统研究了相应阶段煤的瓦斯解吸特征;在此基础上研究了影响老虎台矿泥浆环境煤的瓦斯解吸控制因素,从提钻速率、瓦斯压力和粒径等因子深入分析了对泥浆环境煤的瓦斯解吸的影响,得出提钻速率愈小,泥浆环境下瓦斯逸散量愈大;在相同瓦斯压力条件下,煤样瓦斯解吸Q-t曲线呈“S”形态,一定时间后,瓦斯解吸量将不再增加,且瓦斯逸散量与瓦斯压力具有同步增大的趋势;煤样粒径在增加的同时,煤样瓦斯解吸初速度呈现不断减小的趋势,且粒径达到某一数值后,曲线收敛,煤样瓦斯解吸初速度趋于稳定。最后对老虎台矿煤样,在泥浆压力6.00MPa,瓦斯压力2.00MPa,提钻速率0.2m/s条件下开展瓦斯解吸实验,得出煤层瓦斯解吸规律曲线呈“S”形态展布,经多项式拟合得出瓦斯解吸规律Q-t模型。研究结果为地勘时期煤的瓦斯解吸测试,分析瓦斯逸散提供指导。

Study on Gas Desorption Mechanism of Coal under Slurry Environment in Laohutai Coalmine

To study gas desorption mechanism of coal under slurry environment in the Laohutai coalmine has discussed coal gas desorption status in mud drilling coring process.According to coal in core barrel relationship between gas pressure of coal and tube wall slurry pressure magnitudes have worked out gas desorption 4 stages,and systematically studied corresponding stage coal gas desorption features.On this basis studied gas desorption controlling factors of coal under slurry environment in the Laohutai coalmine.From factors of drilling tool lifting speed,gas pressure and grain size etc analyzed gas desorption impact of coal in slurry in detail,considered that the smaller the drilling tool lifting speed,the larger the gas fugitive emission.Under a same gas pressure,coal sample gas desorption Q-t curve presents“S”form,after a certain time,desorbed gas quantity increase no more,and gas fugitive emission and gas pressure have synchronous increase trend.At the coal grain size increase same time,coal sample gas desorption initial speed presents constant decrease trend,until grain size to a certain,curve constricted,coal sample desorption initial speed stabilized.Finally,to coal sample from Laohutai coalmine,under the conditions of slurry pressure 6.00MPa,gas pressure 2.00MPa,drilling tool lifting speed 0.2m/s carried out gas desorption test,worked out coal seam gas desorption pattern curve presents“S”form,through polynomial fitting worked out gas desorption pattern Q-t model.The studied result can provide guidance for gas desorption test,gas fugitive emission analysis during geological exploration process.