Abstract We propose a radial differential pressure decay (RDPD) method to measure the apparent permeability in shale matrix. The experimental design extends the upper limit of pressure in conventional methods. The experimental error caused by the dispersiveness of sample size and the irregularity of particle shape is reduced by utilizing precisely prepared micro-plug samples with highly uniform diameters, and the reliability of the result is improved substantially. The late-time approximate solution for cylindrical samples based on the experimental configuration is presented for data interpretation and verified with the numerical simulation. The experiments based on shale matrix samples are demonstrated. The results reveal that the RDPD method can capture a differential pressure decay curve precisely, which can be closely fitted through the late-time solution. It also has great potential for various tight porous media. This method sets the stage for the accurate investigation of gas transport mechanisms in tight porous media in future work.

中文翻译：

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微塞样品径向压差衰减法测定页岩基质表观渗透率

摘要 我们提出了一种径向压差衰减（RDPD）方法来测量页岩基质中的表观渗透率。实验设计扩展了常规方法中的压力上限。利用精确制备的直径高度均匀的微塞样品，减少了由于样品尺寸分散和颗粒形状不规则而引起的实验误差，大大提高了结果的可靠性。提出了基于实验配置的圆柱形样品的后期近似解，用于数据解释并通过数值模拟进行验证。展示了基于页岩基质样品的实验。结果表明，RDPD 方法可以精确地捕获压差衰减曲线，可以通过后期解决方案紧密拟合。它对于各种致密多孔介质也具有巨大的潜力。该方法为在未来的工作中准确研究致密多孔介质中的气体传输机制奠定了基础。