Mechanisms driving groundwater flow near salt domes
Mechanisms driving groundwater flow near salt domes
复制标题
盐丘附近地下水流的驱动机制
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
J. Hanor
中科院分区：
文献类型：
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作者：
David G. Evans;J. Nunn;J. Hanor
盐丘附近的地下水流动是复杂的，因为地下水受到各种驱动力的影响，包括压力流体的释放、大的横向密度梯度和区域水头梯度。最近的地球化学和地球物理观测表明，在一些盐丘附近出现了向上流动的地下水，这证明了这种环境的复杂性。为了评价不同驱动盐丘附近地下水流动机制的相对重要性，作者建立了一个耦合地下水流动、热输运和溶解盐输运的数值模型，并考虑了盐底辟作用。计算表明，当区域背景盐度大于15%（路易斯安那州南部盐丘省许多地区的典型值）时，由于热对流，地下水向上流动可能发生。对于较低的背景盐度，溶解会导致穹顶附近含盐地下水下沉，导致等温线下降。虽然高压流体的释放难以量化，但它仍然是推动一些盐丘附近地下水向上流动的可能机制。
Groundwater flow near salt domes is complex because groundwater is subject to a variety of driving forces including the release of geopressured fluids, large lateral density gradients, and regional hydraulic head gradients. The complexity of this environment is born out by recent geochemical and geophysical observations that indicate the occurrence of upward groundwater flow near some salt domes. In order to evaluate the relative importance of different mechanisms driving groundwater flow near salt domes, the authors have developed a numerical model that couples groundwater flow, heat transport, and transport of dissolved salt, and accounts for salt diapirism. The calculations indicate that upward groundwater flow can occur as the result of thermal convection when the regional background salinity is greater than 15 weight percent, a value typical of many areas of the south Louisiana salt dome province. For lower background salinities, dissolution causes salt-laden groundwater near the dome to sink, leading to depressed isotherms. While the release of geopressured fluids is difficult to quantify, it remains a likely mechanism for driving upward groundwater flow near some salt domes.