Abstract Argon gas and liquid (dodecane) permeability measurements in two mixed quality siliceous mudstone samples within the Wolfcamp formation demonstrate that it is possible to close multiple bedding parallel open artificial micro-fractures and obtain representative matrix permeability by applying two confining stress cycles at a constant pore pressure under effective stresses ranging from 6.9 MPa to 59.7 MPa. The clearly micro-fractured sample exhibited a three-order decrease in permeability from 4.4 × 10−17 m2 to 2.1 × 10−20 m2. In contrast, the relatively intact sample exhibited initial liquid permeability of 1.6 × 10−19 m2 that declined gradually with stress to 3.0 × 10−20 m2. In this study, we developed a new permeability testing protocol and analytical approaches to interpret the evolution of micro-fractures and estimate the matrix permeability based on initial pulse-decay gas permeability measurements. The insights gained are useful to identify pore-scale controls on fluid flow behavior using SEM petrography and pore-space characterization and validate fundamental fluid flow mechanisms examined using pore-scale numerical models.

中文翻译：

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Wolfcamp 样品中的气体和液体渗透率测量

摘要 Wolfcamp 地层内两个混合质量硅质泥岩样品的氩气和液体（十二烷）渗透率测量表明，通过在恒定条件下施加两个围压循环，可以关闭多层平行开放人工微裂缝并获得具有代表性的基质渗透率。有效应力范围为 6.9 MPa 至 59.7 MPa 下的孔隙压力。明显微裂缝的样品表现出渗透率从 4.4 × 10-17 m2 下降到 2.1 × 10-20 m2 的三阶下降。相比之下，相对完整的样品表现出 1.6 × 10-19 m2 的初始液体渗透率，随着应力逐渐下降至 3.0 × 10-20 m2。在这项研究中，我们开发了一种新的渗透率测试协议和分析方法来解释微裂缝的演变并基于初始脉冲衰减气体渗透率测量估计基质渗透率。获得的见解有助于使用 SEM 岩相学和孔隙空间表征识别对流体流动行为的孔隙尺度控制，并验证使用孔隙尺度数值模型检查的基本流体流动机制。