The detailed mechanisms of the sealing of a single fracture, from hydration to almost complete closure by increase of confining pressure, as monitored from in situ synchrotron X-ray microtomography during the flow of carbonated water, is here shown for the first time. Different mechanisms play the key role at different stages in the evolution of the fracture. Hydration mechanically weakens the surfaces of the fracture and induces a first closure due to microcracking at the asperity contacts, increasing their size and creating choke points. Increase in confining stress promptly hydraulically seals the fracture by closing the main choke point, with a relative small deformation of the sample. Finally, the more pervasive mechanical deformation observed at higher stresses almost completely seals the whole fracture. The evolution of the sample has been described and quantified using 4D image processing, focusing on the evolution of aperture and digital volume correlation. Hydraulic properties of the sample at different stages have been modeled via Stokes flow simulation, and the results compared to the morphometric analysis, finding positive correlations with the average fracture aperture variation along the flowpath in function of confining pressure. Opalinus Clay is found to be a rock markedly prone to sealing in case of flow with carbonated water; this behavior is the result of the large fraction of clays and of its microstructure, lacking both cementing phases and large stiff particles. CO₂ in this sample has no evident role in the evolution of the fracture; chemically induced weathering on the surface has not been detected, in contrast with the behavior observed in samples with carbonates as cementing phase.

密封的详细机制，从水化到封闭压力的增加，几乎可以完全封闭，如监测 原位首次显示了碳酸水流动过程中的同步加速器X射线显微断层摄影术。不同的机制在骨折发展的不同阶段起着关键作用。水合作用会机械地削弱骨折表面，并由于粗糙接触处的微裂纹而导致首次闭合，从而增大了裂缝的尺寸并产生了阻塞点。限制应力的增加会通过关闭主节流点来迅速液压密封裂缝，而样品的变形相对较小。最后，在较高应力下观察到的更普遍的机械变形几乎完全密封了整个裂缝。已经使用4D图像处理描述并量化了样品的演化，重点是孔径和数字体积相关性的演化。已通过斯托克斯流模拟对样品在不同阶段的水力特性进行了建模，并将结果与​​形态分析进行了比较，发现与沿约束力的函数沿流路的平均裂缝孔径变化呈正相关。Opalinus Clay被发现是岩石，如果与碳酸水一起流动，则很容易封闭。这种现象是由于粘土的大部分及其微观结构的结果，既缺乏胶结相又缺乏大的硬质颗粒。一氧化碳 Opalinus Clay被发现是很容易在充入碳酸水的情况下封闭的岩石。这种行为是由于粘土的大部分及其微观结构的结果，既缺乏胶结相又缺乏大的硬质颗粒。一氧化碳 Opalinus Clay被发现是岩石，如果与碳酸水一起流动，则很容易封闭。这种行为是由于粘土的大部分及其微观结构的结果，既缺乏胶结相又缺乏大的硬质颗粒。一氧化碳该样品中的₂在裂缝的演化中没有明显的作用；与在以碳酸盐为胶结相的样品中观察到的行为相反，未检测到化学诱导的表面风化。