论文部分内容阅读
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。
By using self-developed gas-coal-thermal-fluid-solid coupling three-axis servo flow seepage device, the seepage properties of briquette samples under gas pressure rise and fall under different temperature conditions were studied experimentally to simulate Permeability of coal under elevated temperature. At the same time, parallel experiments of helium under the same conditions were conducted to investigate the slippage effect of low permeability reservoirs. The results show that: (1) In the step-up phase, the axial strain increases and the radial strain decreases, which changes approximately linearly. At the depressurization stage, with the decrease of the gas pressure, the strain shows the same trend as the step-up phase. As the temperature increases, the slope of the strain changes with the gas pressure. (2) During the step-up phase, with the increase of gas pressure, the permeability shows a quadratic parabola change, reaching a minimum at a gas pressure of about 3.0 MPa. In the step-down phase, with a decrease in gas pressure, the permeability decreases slightly first Increase, step-up stage permeability is greater than the step-down stage permeability. (3) The variation of permeability caused by the slippage effect in the step-up stage is larger than the change of the step-down stage, and the change of permeability caused by the slippage effect decreases exponentially with the increase of the gas pressure.