Abstract Understanding vapor transport of water in nanoporous shale is challenging due to the coexistence of multiple water phases within a multi-mineral aggregate with complex multiscale pore architecture. We explore this response through dynamic vapor sorption experiments and modeling on two shale samples with differing fractions of hydrophilic clays and contrasting pore architecture. Measured diffusion coefficients of water vapor in the two shales are of the order of magnitude of 10−12 - 10−10 m2/s, increasing with relative humidity (Rh) except at high Rh during adsorption process. The drop in diffusivity at high Rh during adsorption results from the impeding effect of capillary-occluding air bubbles and flattening of the pore-entry menisci. We propose a model for water vapor transport accommodating surface flow of adsorbed water and viscous flow of capillary water – with active mechanisms operational in different pore size populations. Actual pore size distributions (PSDs) are characterized by low pressure nitrogen adsorption. Predictions from the proposed transport model, utilizing these measured PSDs, are consistent with the measured diffusion behavior during desorption, also replicating water uptake behavior across the full spectrum of 0 0.6. Surface flow of the adsorbed phase contributes predominantly to the total flux over a wide range of Rh ( 0.98). In terms of pore size effects, macropores (> 50 nm) contribute little to the total water adsorption but comprise more than of the 68% total water flux. Conversely, micropores (

中文翻译：

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纳米多孔页岩中水汽吸附和输运的评价和建模

摘要 由于具有复杂多尺度孔隙结构的多矿物聚集体中多种水相共存，因此了解纳米多孔页岩中水的蒸汽传输具有挑战性。我们通过动态蒸汽吸附实验和对具有不同比例的亲水粘土和对比孔隙结构的两个页岩样品进行建模来探索这种响应。两个页岩中测量的水蒸气扩散系数在 10-12 - 10-10 m2/s 的数量级，随着相对湿度（Rh）增加，吸附过程中除高 Rh 外。吸附过程中高 Rh 下扩散率的下降是由于毛细管闭塞气泡的阻碍作用和进入孔的弯液面变平所致。我们提出了一种水蒸气传输模型，可适应吸附水的表面流动和毛细管水的粘性流动——具有在不同孔径群体中运行的主动机制。实际孔径分布 (PSD) 的特征在于低压氮吸附。利用这些测得的 PSD，所提出的传输模型的预测与解吸过程中测得的扩散行为一致，也复制了整个 0 0.6 范围内的吸水行为。吸附相的表面流动在很宽的 Rh (0.98) 范围内对总通量有主要贡献。在孔径效应方面，大孔 (> 50 nm) 对总水吸附的贡献很小，但占总水通量的 68% 以上。相反，微孔（利用这些测量的 PSD，所提出的传输模型的预测与解吸过程中测量的扩散行为一致，也复制了整个 0 0.6 范围内的吸水行为。吸附相的表面流动在很宽的 Rh (0.98) 范围内对总通量有主要贡献。在孔径效应方面，大孔 (> 50 nm) 对总水吸附的贡献很小，但占总水通量的 68% 以上。相反，微孔（利用这些测得的 PSD，所提出的传输模型的预测与解吸过程中测得的扩散行为一致，也复制了整个 0 0.6 范围内的吸水行为。吸附相的表面流动在很宽的 Rh (0.98) 范围内对总通量有主要贡献。在孔径效应方面，大孔 (> 50 nm) 对总水吸附的贡献很小，但占总水通量的 68% 以上。相反，微孔（在孔径效应方面，大孔 (> 50 nm) 对总水吸附的贡献很小，但占总水通量的 68% 以上。相反，微孔（在孔径效应方面，大孔 (> 50 nm) 对总水吸附的贡献很小，但占总水通量的 68% 以上。相反，微孔（