不同温度条件下气体压力升降过程中瓦斯运移规律的试验研究

利用自主研发的含瓦斯煤热-流-固耦合三轴伺服渗流装置，对不同温度条件下型煤试件在气体压力升降过程的渗流特性进行了试验研究，以模拟随采深增加引起的地温升高条件下煤的渗透特性。同时，为探讨低渗储层的滑脱效应进行了相同条件下氦气的平行试验。研究结果表明：（1）升压阶段，轴向应变增大，径向应变减小，近似呈线性变化；降压阶段，随气体压力降低，应变呈现出与升压阶段相同的变化趋势。随温度升高，应变随气体压力变化的斜率增大。（2）升压阶段，随气体压力升高，渗透率呈二次抛物线型变化，约在气体压力为3.0 MPa左右到达最小；降压阶段，随气体压力减小，渗透率先略有减小后增大，升压阶段渗透率大于降压阶段渗透率。（3）升压阶段滑脱效应引起的渗透率变化量大于降压阶段的变化量，且滑脱效应所引起的渗透率变化量随气体压力增加呈幂指数函数降低。

Experimental study of migration laws of gas during loading-unloading process at different temperatures

Using the self-developed triaxial servo-controlled seepage equipment for thermo-fluid-solid coupling of coal containing methane, a series of tests is conducted on coal samples during the process of gas loading-unloading at different temperatures to simulate the seepage characteristis of coal under the condition of temperature increase induced by increasing depth of mining. Meanwhile, parallel experiments on helium are also carried out to investigate the slippage effect of low permeability coal seam. The experimental results are shown as follows: (1) During the loading process, the axial strain increases and radial strain decreases linearly with the increase of gas pressure. During the unloading process, the strain of coal shows the same trend with the loading. The slope of strain varies with increasing gas pressure and temperature. (2) During the loading process, the permeability of coal shows a quadratic parabola trend with the increase of gas pressure, and it reaches the minimum at about 3.0 MPa. At the early unloading stage, the permeability of coal decreases slowly and then increases with the decrease of gas pressure. The permeability of coal during the loading process is lager than that during the unloading process. (3) Variation of permeability caused by slippage effect during loading process is greater than the amount of unloading process. What’s more, variation of permeability caused by slippage effect declines in an exponential function with the increase of gas pressure.