How appropriate is the Thiem equation for describing groundwater flow to actual wells?

How appropriate is the Thiem equation for describing groundwater flow to actual wells? | Dans quelle mesure l’équation de Thiem est-elle appropriée pour décrire l’écoulement des eaux souterraines vers des puits réels? Qué tan apropiada es la ecuación Thiem para describir el flujo del agua subterránea en pozos reales? 描述地下水流流到实际井中的提姆方程有多合适? Quão apropriada é a equação de Thiem para descrever o escoamento de águas subterrâneas a poços reais?

2016

The Thiem equation of radial groundwater flow to a well is more than 100 years old and is still commonly used. Here, deviations caused by some of its simplifications are quantified by comparing the analytical to a numerical model that allows the implementation of more complex geometries. The assumption of horizontal flow in the Thiem equation, which necessitates uniform inflow over the entire screen length of the fully penetrating well, was found to cause deviations from actual pumping wells where the pump is placed above the screen, resulting in non-uniform inflow and additional drawdown. The same applies to partially penetrating wells, where inflow peaks and additional drawdown occur, especially when the well is screened in the lower part of the aquifer. The use of the Thiem equation in the near-field of a well should thus be restricted to situations where the screen inflow is relatively uniformly distributed, e.g. when it covers large portions of the aquifer thickness. The presence of a gravel pack and a background gradient, on the other hand, are of limited importance.

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