煤体吸附过程中的变形-渗透特性试验研究

Experimental study on the characteristics of deformation and permeation during coal-bed methane adsorption

采用自主研制的煤岩三轴变形—渗透试验台,针对取自山西沁水煤田3#煤层的试验煤样进行煤体吸附过程中的应力应变和渗透特性试验研究。结果表明:自由状态和外部压力加载状态下,煤体的变形均随吸附瓦斯压力的增加而分阶段地逐渐增加,直至较高压力时变形趋于平衡;煤体变形量随吸附量的增加而有规律地增加,表现为开始阶段增长趋势较慢,后期变化较快;在同等的瓦斯吸附压力状态下,吸附量及其对应的煤体渗透率随轴压和围压的上升而逐渐下降,下降规律接近线性;在相同的轴压和围压的组合下,吸附瓦斯的煤体渗透率随瓦斯压力的增加而逐渐增加,规律是线性的。

Coal triaxial deformation-permeation experimental system developed independent- ly had been implied to research the stress-strain and permeability characteristics of coal sample in process of coal-bed methane adsorption, and the coal sample was taken from No. 3 coal seam of Qinshui coalfield in Shanxi Province. The results showed that in a state of free or external pres- sure loading, coal transformation increased gradually by stages following the increase of absorbed gas pressure, the transformation tended to balance until the pressure became higher. Coal de- formation increased regularly following the increase of adsorbing capacity, it had slower growth trend in incipient stage and faster in later stage. Under the same absorbed gas pressure, coal ad- sorbing capacity and permeability decreased gradually following the increase of axle load and con- fining pressure, and the decline law was close to linear; if the axle load and confining pressure were invariable, the permeability of coal increased regularly following the increase of gas pres- sure, and the law was linear.