Effects of Fracture Surface Roughness on Macroscopic Fluid Flow and Solute Transport in Fracture Networks
Effects of Fracture Surface Roughness on Macroscopic Fluid Flow and Solute Transport in Fracture Networks
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DOI：
10.1007/s00603-013-0497-1
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发表时间：
2014-11
影响因子：
6.2
通讯作者：
Zhihong Zhao;Bo Li;Yujing Jiang
中科院分区：
文献类型：
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作者：
Zhihong Zhao;Bo Li;Yujing Jiang
在基质渗透率低/可忽略的裂隙岩石中，流体流动和质量传输主要发生在相连的裂隙内(Boutt等人。2006)。准确地了解岩石中流体在裂隙网络中的流动和溶质迁移是许多应用中的关键问题，如地下核废料储存库、二氧化碳封存和增强型地热系统。岩石裂缝是典型的粗糙壁，表面粗糙度决定了接触的粗糙度的位置和分布，导致流体在曲折的路径中流动，并降低了整体裂缝电导(Boutt等人。2006)。已经证明，裂缝表面粗糙度对单个裂缝中的流体流动和传输过程有显著影响，并且岩石裂缝的机械孔径通常大于其水力孔径(曾和威瑟斯彭1983；Zimmerman和Bodvarsson 1996；Boutt等人)。2006年；Li等人。2008年)。然而，局部裂缝中这种减小的水力孔径(由于粗糙度)对复杂裂缝系统中宏观流体流动和溶质传输的影响仍然不清楚，为了简单起见，以前的大多数研究都假设离散裂缝网络模型中的水力和机械孔径相同(Min等人)。2004a；巴格巴南和京2008；赵等人。2011年)。因此，在本研究中，我们模拟了两种不同裂隙网络中的流动和运移过程，旨在从裂隙网络的宏观尺度上研究裂隙局部表面粗糙度对流体流动和溶质运移过程的影响。
In fractured rocks of low/negligible matrix permeability, fluid flow and mass transport dominantly occur within the connected fractures (Boutt et al. 2006). An accurate understanding of fluid flow and solute migration through fracture networks in rocks is a critical issue in many applications, such as underground nuclear waste repositories, CO2 sequestration, and enhanced geothermal systems. Rock fractures are typically rough-walled, and surface roughness determines the location and distribution of contacting asperities, causes fluid flow in tortuous paths, and reduces the overall fracture conductance (Boutt et al. 2006). It has been demonstrated that fracture surface roughness has a significant impact on fluid flow and transport processes in single fractures, and that the mechanical aperture of a rock fracture is usually larger than its hydraulic aperture (Tsang and Witherspoon 1983; Zimmerman and Bodvarsson 1996; Boutt et al. 2006; Li et al. 2008). However, the effects of this reduced hydraulic aperture (due to roughness) in local fractures on macroscopic fluid flow and solute transport in complex fracture systems are still not clear, and most previous studies assumed identical hydraulic and mechanical apertures in discrete fracture network models for simplicity (Min et al. 2004a; Baghbanan and Jing 2008; Zhao et al. 2011). Therefore, in this study, we simulated flow and transport processes in two different fracture networks, aiming to investigate the influences of local surface roughness of fractures on fluid flow and solute transport processes at the macroscopic scales of fracture networks.