多孔介质气体渗透率测试理论、方法、装置及应用

Test theory,method and device of gas permeability of porous media and the application

在深部能源开采及废物存储等领域,渗透率是一个重要指标。测试方法、流体介质和温度波动都会对渗透率的精确测试带来干扰。首先推导和归纳了基于入口端压力/流量和出口端压力/流量的稳态法渗透率计算公式,结果表明,基于入/出口端压力计算结果差异较大,而基于入/出口端流量法计算结果较为接近,并探讨差异背后的原因。进一步对比分析基于压力衰减的稳态法和瞬态法的测试结果,给出4种稳态法和瞬态法的选择参考建议。针对不同流体介质对渗透测试的影响,选取水、酒精和气体进行系统分析,探讨不同介质对渗透率测试结果影响的机制;对于低渗介质气体渗透测试温度波动敏感性大的现象,提出一种基于温度波动消除理论的计算方法,该方法对于低渗介质测试温度消除效果较好;最后,给出不同领域的应用,探讨和分析围压、轴压、饱和度和温度对渗透演化的影响,验证测试理论、方法及装置的适应性,为后续相关渗透测试方法及流体介质的选取提供了借鉴和参考。

In the fields of deep energy exploitation and waste storage,permeability is an important indicator. The test method,fluid phase and temperature fluctuation will influence the accurate measurement of the permeability. In this study,the steady-state permeability models based on the inlet/outlet pressure and flow rate were derived and summarized. It was revealed that the results based on the inlet/outlet pressure are quite different while the results based on the inlet/outlet flow rate are relatively close. The reasons for the difference were thereby discussed. In addition,the suggestions for the selection of four steady-state and transient methods were elucidated by comparing the test results of steady-state and transient methods pressure decay. Water,alcohol and gas were selected to investigate the impact of different fluids on permeability test results. It is found that the gas permeability test in low permeability media is sensitive to the temperature fluctuation. To solve this problem,a model based on the temperature fluctuation elimination theory was proposed. Finally,the effects of the confining pressure,the axial pressure,the water saturation and the temperature on permeability evolution were demonstrated and analyzed through the applications in diverse fields,verifying the adaptability of the test theory,method and experimental device. The research work provides a basis for the selections of permeation test methods and fluid phases.