Review: Hydraulics of water wells—head losses of individual components

Abstract

Knowledge about the hydraulics of water wells is important to optimize their energy efficiency. By minimizing head losses around the well, energy consumption and ageing processes can be limited, thereby prolonging the well's service life. The contribution of the individual components to total head loss (drawdown) in the well is analyzed in detail. The single most important contributor to drawdown is commonly the aquifer. Its hydraulic conductivity can only be improved slightly through development. The second most important contributor is the formation of a wellbore skin layer. This occurs if no proper well development was performed after drilling; the layer contains remnants of drilling-fluid additives or mobilized fine aquifer particles. The head loss caused by groundwater flow in the gravel pack, through the screen slots and inside the well, was found to be small. Thus, well development is the most important measure to influence well performance and energy efficiency. For longer operation times and pumped volumes, the energy gains outperform the cost for the development.

述评:水井水力学—水流定律和几何学的影响

“…aquifer thickness, hydraulic conductivity, radius of the cone of depression, (natural) water level fluctuations and porosity. A paper related to this study (Houben 2015) shows the practical application of the analytical models discussed here for well design and investigates the relative contributions of individual well components to total head loss and how they may be improved. bulk density of aquifer material (M/L 3 ) τ tortuosity ф porosity ф e effective porosity ϑ angle between flow direction and gravitation ϕ 0 grain geometry factor Constants g 9.81 m/s 2 ρ ρ w =1,000 kg/m 3 μ 0.001 kg/s·m ν 1.01·10 −6 m 2 /s…”

“…Weisbach 1845; Smreker 1878Smreker , 1914Forchheimer 1901a, b;Thiem 1906;Sichardt 1928;Kozeny 1933;Nahrgang 1954Nahrgang , 1965Heinrich 1964;Klotz 1971) and is, thus, often ignored or sometimes even cited or interpreted incorrectly. In a paper related to this study (Houben 2015), the practical consequences of well hydraulics for well design are discussed in detail for all of the individual well components.…”

Non-Darcian flow to a partially penetrating well in a confined aquifer with a finite-thickness skin

“…The well skin is usually developed outside the wellbore because of the well construction (Novakowski 1989;Park and Zhan 2002;Chang and Chen 2002;Yeh and Yang 2006;Yeh and Chang 2013;Houben 2015b). In general, the well skin can be classified into two types, the infinitesimal skin and finite thickness skin.…”

Analysis of Wellbore Skin Samples—Typology, Composition, and Hydraulic Properties

“…Despite its minute thickness, wellbore skin can significantly increase head losses since its hydraulic conductivity is often considerably lower than that of the aquifer and the gravel pack. The drawdown it causes can be one of the largest contributors to total well loss (Houben ).…”