Domestic Well Capture Zone and Influence of the Gravel Pack Length
Domestic Well Capture Zone and Influence of the Gravel Pack Length
复制标题
国内井捕获带及砾石充填长度的影响
作者：
J. Horn;T. Harter
北美和其他地方的国内威尔斯井通常建造在相对较浅的深度处，并且砂或砾石充填延伸到井的进口筛管（浅井密封）上方很远。这些国内威尔斯井的震源区和扩展砾石充填对震源区的影响通常是未知的，并且几乎没有资源可用于估计这些。在本文中，我们使用详细的高分辨率地下水建模来估计位于冲积含水层中的典型家用井的捕获区（源区）。一个简单的分析模型相比，含水层和砾石充填的水力传导率范围很广的结果。分析模型的校正因子是根据数值结果与分析模型的统计回归计算的。该工具可用于在各种条件下估计国内油井的源面积。我们表明，延长砾石充填井筛以上可能会显着有助于国内井的整体流入，特别是在渗透性较低的含水层，其中的贡献可能从20%到50%的范围内，延长砾石充填可能会导致一个显着拉长捕获区，在某些情况下，捕获区的长度几乎翻了一番。因此，将砾石充填物延伸到进口筛管上方很远的地方会大大增加水源的脆弱性。
Domestic wells in North America and elsewhere are typically constructed at relatively shallow depths and with the sand or gravel pack extending far above the intake screen of the well (shallow well seal). The source areas of these domestic wells and the effect of an extended gravel pack on the source area are typically unknown, and few resources exist for estimating these. In this article, we use detailed, high‐resolution ground water modeling to estimate the capture zone (source area) of a typical domestic well located in an alluvial aquifer. Results for a wide range of aquifer and gravel pack hydraulic conductivities are compared to a simple analytical model. Correction factors for the analytical model are computed based on statistical regression of the numerical results against the analytical model. This tool can be applied to estimate the source area of a domestic well for a wide range of conditions. We show that an extended gravel pack above the well screen may contribute significantly to the overall inflow to a domestic well, especially in less permeable aquifers, where that contribution may range from 20% to 50% and that an extended gravel pack may lead to a significantly elongated capture zone, in some instances, nearly doubling the length of the capture zone. Extending the gravel pack much above the intake screen therefore significantly increases the vulnerability of the water source.