Geochemical reactions add complexity to the characterization and prediction of fracture hydraulic properties because they depend on factors that are highly heterogeneous, such as mineral composition. However, systematic analyses of fracture evolution in mineralogically heterogeneous systems are still limited. In this study, we investigated fracture evolution in multimineral systems using a reduced dimension reactive transport model. The model was developed and tested based on experimental studies and addresses the complex morphological and geochemical changes that arise from the presence of multiple minerals of different reactivities. Numerical experiments were performed using randomly generated initial fracture geometries based on representative geostatistics, different categories of mineral composition, and a range of flow rates that are relevant to geologic carbon storage systems. The simulation results showed distinct dissolution regimes at different flow rates, each of which produced characteristic dissolution patterns and temporal evolutions of chemical reactions and fracture hydraulic properties. Overall, as flow rate increases, fracture evolution shifts from compact dissolution to fracture channelization to uniform dissolution. The corresponding flow rate for a given dissolution regime, however, varies considerably with mineral composition. Fracture evolution, especially in the flow regime that induces fracture channelization, is also affected by initial fracture geometry. The numerical experiments were used to develop a multireaction Damköhler number (mDa) for the prediction of fracture evolution, and fracture channelization in particular, in multimineral systems. The multireaction Damköhler number also provides a useful framework for the evaluation of caprock integrity in geologic carbon storage systems.

中文翻译：

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多矿物系统中的断裂演化：矿物成分，流速和断裂孔非均质性的作用

地球化学反应增加了裂缝水力特性的表征和预测的复杂性，因为它们取决于高度异质的因素，例如矿物成分。但是，对矿物异质系统中裂缝演化的系统分析仍然有限。在这项研究中，我们使用降维反应运输模型研究了多矿物系统中的裂缝演化。该模型是在实验研究的基础上开发和测试的，解决了由于存在多种具有不同反应性的矿物而引起的复杂的形态和地球化学变化。数值实验是根据具有代表性的地统计学，不同类别的矿物组成，使用随机生成的初始裂缝几何形状进行的，以及与地质碳存储系统相关的一系列流量。模拟结果显示了在不同流速下不同的溶解方式，每种溶解方式都产生了特征性的溶解模式，以及化学反应和裂缝水力特性的时间演变。总体而言，随着流速的增加，裂缝演化从致密溶蚀转变为裂缝通道化，再到均匀溶解。但是，对于给定的溶出度，相应的流速随矿物成分的不同而有很大差异。裂缝的演化，特别是在引起裂缝通道化的流动状态下，也受到初始裂缝几何形状的影响。数值实验用于建立多反应的达姆勒数（mDa），以预测裂缝的发展，尤其是裂缝的通道化。在多矿物系统中。多重反应Damköhler编号还为评估地质碳存储系统中盖层完整性提供了有用的框架。