The evolution of heterogeneous and anisotropic media in the uniform dissolution regime (low Damköhler number) is studied here using a numerical network model. The uniform dissolution extensively homogenizes the medium and therefore the flow field. The homogenization is further enhanced when the surface reaction is transport controlled—when slow diffusion of dissolved ions away from the mineral surface leads to the reduction of the global dissolution rate. Under those conditions, diffusive transport is more effective in narrow channels, which selectively enlarge, leading to an initial steep rise of the permeability. However, as dissolution proceeds, the void space widens and the overall dissolution rate drops, and permeability enhancement slows down. Finally, we review the relevance of these results to various processes in geological systems ranging from diagenesis and karst evolution, to carbon geosequestration. These findings provide fundamental insights into reactive transport processes in fractured and porous media and evolution of permeability, tortuosity, anisotropy, and bulk reaction rates in geological systems.

中文翻译：

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各向异性介质中的反应流和均质化

本文使用数值网络模型研究了均匀溶解状态下（低达姆勒数）非均质和各向异性介质的演化。均匀的溶出使介质均匀，从而使流场均匀。当对表面反应进行传输控制时，当溶解离子从矿物表面缓慢扩散导致整体溶解速率降低时，均匀化会进一步增强。在这些条件下，扩散输送在狭窄的通道中更为有效，狭窄的通道有选择地扩大，导致渗透率开始急剧上升。但是，随着溶解的进行，空隙空间变宽，总体溶解速率下降，渗透性增强减慢。最后，我们回顾了这些结果与地质系统从成岩作用和岩溶演化到碳固存的各种过程的相关性。这些发现提供了对裂隙和多孔介质中反应运移过程以及地质系统中渗透率，曲折度，各向异性和整体反应速率的演变的基本认识。