Liquid permeability of sedimentary rocks is relevant in several contexts, but gas permeability is easier to measure, so liquid permeability is typically estimated from gas permeability via empirical or semiempirical correction procedures. A frequently used and trusted procedure is the well-known Klinkenberg correction, which is based on the pressure dependence of gas permeability. However, from gaseous and liquid flow-through experiments on a series of Fontainebleau, Castlegate, Bentheim, and Obernkirchen sandstones, this study indicates that the equivalent liquid permeability derived from gas permeability via the Klinkenberg correction only compares with liquid permeability, when the gaseous flow adheres to Darcy’s law. The lower and upper limits to Darcy flow are defined by the Knudsen and Reynolds numbers, respectively. Both numbers can be estimated from porosity and pore-throat distribution, so from these properties, it is possible to assess the flow and pressure limits for the applicability of the Klinkenberg correction. For the studied sandstones, non-Darcy flow is indicated for the largest pores with diameters above approximately 10 μm, causing an erroneous Klinkenberg correction. Knudsen diffusion takes place in pores smaller than approximately 0.1 μm, but the contribution to the overall gas permeability of these small pores is, however, insignificant in these sandstones. Liquid permeability modeled from contributions from each pore size by using Kozeny’s equation and surface relaxation times from nuclear magnetic resonance data shows that the largest pores have no positive effect on permeability because of the existence of pore throats; instead, they may have a negative effect on permeability because of turbulence.

中文翻译：

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砂岩的气体、Klinkenberg 和液体渗透率比较：流态和孔径

沉积岩的液体渗透率与多种情况相关，但气体渗透率更容易测量，因此液体渗透率通常通过经验或半经验校正程序根据气体渗透率估算。一个经常使用且值得信赖的程序是众所周知的 Klinkenberg 校正，它基于气体渗透率的压力相关性。然而，从一系列 Fontainebleau、Castlegate、Bentheim 和 Obernkirchen 砂岩的气体和液体流通实验中，这项研究表明，通过 Klinkenberg 校正从气体渗透率导出的等效液体渗透率仅与液体渗透率进行比较，当气体流遵守达西定律。达西流的下限和上限分别由 Knudsen 和 Reynolds 数定义。这两个数字都可以通过孔隙度和孔喉分布来估计，因此根据这些属性，可以评估 Klinkenberg 校正适用性的流量和压力限制。对于所研究的砂岩，直径超过约 10 μm 的最大孔隙显示为非达西流，导致错误的 Klinkenberg 校正。Knudsen 扩散发生在小于约 0.1 μm 的孔隙中，但在这些砂岩中对这些小孔隙的整体气体渗透率的贡献微不足道。使用 Kozeny 方程和核磁共振数据的表面弛豫时间对每个孔径的贡献建模的液体渗透率表明，由于孔喉的存在，最大的孔隙对渗透率没有积极影响；反而，