Capillary Fracturing in Granular Media
Capillary Fracturing in Granular Media
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DOI：
10.1103/physrevlett.108.264504
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发表时间：
2012-06-28
影响因子：
8.6
通讯作者：
Juanes, Ruben
中科院分区：
文献类型：
--
作者：
Holtzman, Ran;Szulczewski, Michael L.;Juanes, Ruben
本文研究了可变形非粘性颗粒介质中不混溶流体的驱替问题。在实验上，我们将空气注入到水饱和的玻璃珠的薄层中，并观察入侵形态。控制参数是注射速率、珠粒尺寸和围压。我们确定了三个入侵制度：毛细管指进，粘性指进，和“毛细管压裂”，毛细管力克服摩擦阻力，诱导开放的管道。我们推导出两个无量纲数，管理不同的制度之间的过渡：修改后的毛细管数和压裂数。实验和分析预测的出现，在细粒介质在低围压下，一种现象，可能在许多自然过程中发挥了根本性的作用，如原油运移，甲烷排放从湖泊沉积物，和干燥裂缝的形成。
We study the displacement of immiscible fluids in deformable, noncohesive granular media. Experimentally, we inject air into a thin bed of water-saturated glass beads and observe the invasion morphology. The control parameters are the injection rate, the bead size, and the confining stress. We identify three invasion regimes: capillary fingering, viscous fingering, and "capillary fracturing," where capillary forces overcome frictional resistance and induce the opening of conduits. We derive two dimensionless numbers that govern the transition among the different regimes: a modified capillary number and a fracturing number. The experiments and analysis predict the emergence of fracturing in fine-grained media under low confining stress, a phenomenon that likely plays a fundamental role in many natural processes such as primary oil migration, methane venting from lake sediments, and the formation of desiccation cracks.