Role of horizontal bores in improving the yield of large diameter wells in low permeability aquifers
Role of horizontal bores in improving the yield of large diameter wells in low permeability aquifers
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DOI：
10.1007/s40899-022-00660-x
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发表时间：
2022-04
影响因子：
2.1
通讯作者：
B. Yadav;K. Rushton
中科院分区：
文献类型：
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作者：
B. Yadav;K. Rushton
大直径井成功地从低渗透含水层中抽取地下水，确保了许多干旱和半干旱地区的可持续供水。通过提供从井底部附近钻出的水平孔，可以提高效率；这些孔通常是无衬里的。如果发生非层流流动，这些钻孔中的水力条件可能会限制其有效性。本文描述了描述含水层、井和井中条件的概念和计算模型，在这些情况下可能会发展层流、过渡流或湍流。当钻孔没有衬里时，摩擦因数是未知的，因此无法计算雷诺数；因此，采用了等效电导率方法。印度拉贾斯坦邦的一口大直径井被用来探索系统中的条件如何随着时间的变化而变化。通过复制大直径水平井抽水试验的数据，验证了计算模型；采油阶段持续了200多天，是至关重要的。研究了该井在较长时间段内的运行情况，比较了无井和有井的响应情况。当模拟抽水30天时，随着从离井更远的地方从地下水位收集水的孔的增加，系统的产量增加。
Large diameter wells successfully abstract groundwater from aquifers with low permeabilities and ensures sustainable water supply in many arid and semi-arid regions. Their efficiency can be enhanced by the provision of horizontal bores drilled from near the bottom of the wells; these bores are often unlined. Hydraulic conditions in these bores can limit their effectiveness if non-laminar flows occur. This paper describes conceptual and computational models which represent conditions in an aquifer, in the well, and in the bores, where laminar, transitional, or turbulent flows can develop. When a bore is unlined, the friction factor is unknown; hence the Reynolds number cannot be calculated; consequently, an equivalent conductivity approach is adopted. A large diameter well in Rajasthan, India, is used to explore how conditions in the system change with time. The computational model is verified by replicating data from a pumping test in a large diameter well with horizontal bores; the recovery phase, extending over more than 2 days, is of crucial importance. The operation of the well for longer time periods is investigated, comparing responses without and with bores. When simulating pumping for 30 days, the yield of the system is increased with the bores collecting water from the water table at greater distances from the well.