Linking Structural and Transport Properties in Three‐Dimensional Fracture Networks
Linking Structural and Transport Properties in Three‐Dimensional Fracture Networks
复制标题
连接三维裂缝网络中的结构和传输特性
DOI：
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发表时间：
2019
期刊：
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通讯作者：
P. Kang
中科院分区：
文献类型：
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作者：
J. Hyman;M. Dentz;A. Hagberg;P. Kang
我们研究了稀疏三维离散裂隙网络中的大尺度粒子运动和溶质突破，其特征在于幂律分布的裂隙长度。我们考虑的三个网络具有相同的断裂强度值，但表现出不同的逾渗密度，几何性质和拓扑结构。我们考虑了两种不同的平均传输模型来预测溶质突破，流管模型和伯努利连续时间随机游走模型，这两种模型都提供了对网络内流场的见解。流管模型提供了可接受的预测，在短距离的网络中的两个，但在所有情况下，未能预测突破时间在出口平面，这表明，颗粒运动在这样的裂缝网络不能被其特征在于由一个恒定的速度之间的入口和控制平面的突破曲线被检测到。相反，网络的结构要求粒子在系统中移动时进行频繁的速度转换。尽管相对广泛的分布的裂缝半径和相对较少的独立的速度转换，连续时间的随机游走方法的初始速度分布的条件下，提供了合理的预测突破曲线在不同的距离从入口。这些平均传输模型的应用提供了一个更丰富的理解的链接从裂缝网络结构的流动和传输性能。
We investigate large‐scale particle motion and solute breakthrough in sparse three‐dimensional discrete fracture networks characterized by power law distributed fracture lengths. The three networks we consider have the same fracture intensity values but exhibit different percolation densities, geometric properties, and topological structures. We considered two different average transport models to predict solute breakthrough, a streamtube model and a Bernoulli continuous time random walk model, both of which provide insights into the flow fields within the networks. The streamtube model provides acceptable predictions at short distances in two of the networks but fails in all cases to predict breakthrough times at the outlet plane, which indicates that particle motion in such fracture networks cannot be characterized by a constant velocity between the inlet and control plane at which the breakthrough curve is detected. Rather, the structure of the network requires that frequent velocity transitions be made as particles move through the system. Despite the relatively broad distribution of fracture radii and relatively small number of independent velocity transitions, the continuous time random walk approach conditioned on the initial velocity distribution provides reasonable predictions for the breakthrough curves at different distances from the inlet. The application of these averaged transport models provides a richer understanding of the link from the fracture network structure to flow and transport properties.