Leakage from gravity currents in a porous medium. Part 2. A line sink
Leakage from gravity currents in a porous medium. Part 2. A line sink
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DOI：
10.1017/s002211201000491x
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发表时间：
2011-01
影响因子：
3.7
通讯作者：
D. Vella;J. Neufeld;H. Huppert;J. Lister
中科院分区：
文献类型：
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作者：
D. Vella;J. Neufeld;H. Huppert;J. Lister
我们考虑浮力驱动的重力流在由水平不渗透边界界定的多孔介质中的传播。电流由在某一点注入的恒定通量馈送，并通过距注入点一定距离的线路汇漏器泄漏。这是盖层断层如何损害二氧化碳地质封存的理想化模型。存储效率的时间演变（定义为不泄漏的情况下存储流体的速率与注入流体的速率的瞬时比率）特别令人感兴趣。我们表明，“存储效率”在时间 t 内以 t−2/5 的方式衰减，该时间与电流到达故障所需的时间相比很长。这种代数衰减与通过圆形水槽泄漏的情况相反（Neufeld 等人，J. Fluid Mech.，2010 年），其中存储效率衰减得更慢，如 1/lnt。在二氧化碳地质封存的背景下讨论了预测的储存效率衰减的影响。使用挪威斯莱普纳示范项目的典型参数值，我们表明，如果注入点约 12 公里范围内的盖层不存在明显断层，则在数千年的时间尺度上，存储效率应保持在 90% 以上。
We consider the propagation of a buoyancy-driven gravity current in a porous medium bounded by a horizontal, impermeable boundary. The current is fed by a constant flux injected at a point and leaks through a line sink at a distance from the injection point. This is an idealized model of how a fault in a cap rock might compromise the geological sequestration of carbon dioxide. The temporal evolution of the efficiency of storage, defined as the instantaneous ratio of the rate at which fluid is stored without leaking to the rate at which it is injected, is of particular interest. We show that the ‘efficiency of storage’ decays like t−2/5 for times t that are long compared with the time taken for the current to reach the fault. This algebraic decay is in contrast to the case of leakage through a circular sink (Neufeld et al., J. Fluid Mech., vol. 2010) where the efficiency of storage decays more slowly like 1/lnt. The implications of the predicted decay in the efficiency of storage are discussed in the context of geological sequestration of carbon dioxide. Using parameter values typical of the demonstration project at Sleipner, Norway, we show that the efficiency of storage should remain greater than 90% on a time scale of millennia, provided that there are no significant faults in the cap rock within about 12km of the injection site.