摘要
利用煤岩力学-渗流试验系统TAWD-2000,对平顶山矿、长治矿和金佳矿的三类原煤试样开展了温度、气压和围压耦合下的CO_2渗流行为试验研究,系统分析了三类原煤试样的渗透率随温度、气压和围压的演化规律及影响因素.结果表明:原煤渗透率随气压的增大呈指数增大趋势,低围压下,指数增长趋势明显,高围压下,增长趋于线性;原煤渗透率随围压的增大呈指数减小趋势,当围压较低时,煤样渗透率对围压变化非常敏感,渗透率随着围压的增大迅速减小,随后趋于稳定;原煤的渗透率随温度的升高大多呈减小趋势,但也可能出现先减小后增大的趋势,这是原煤热膨胀、CO_2解吸和裂隙残余水分蒸发耦合作用的结果.
Experimental studies of the seepage behavior of CO_2 in raw coal samples from Pingdingshan, Changzhi and Jinjia mine under variable temperature, confining pressure and gas pressure were performed on rock mechanics testing system TAWD-2000. Evolutions of coal permeability with coal temperature, gas pressure and confining pressure were explored. The results show that:the permeability of raw coal increases exponentially with increasing gas pressure. When confining pressure is lower, the exponential function pattern of coal permeability evolution is obvious, whereas the evolution pattern trends to be linear-like when confining pressure is higher. The permeability of raw coal decreases exponentially with increasing confining pressure. Coal permeability is more sensitive to changes of confining pressure when it is lower. Moreover, coal permeability decreases promptly firstly with the increasing of confining pressure, and then tends to be stable. The permeability of most raw coal samples decreases with the increasing of temperature, whereas it decreases firstly and then increases sometimes. It is a competitive result of thermal expansion, CO_2 desorption and the evaporation of residual water from fracture channels.
引文
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