Gaining and losing sections of horizontal wells

The flux along a horizontal well in uniform flow is examined using an analytic three‐dimensional, steady model. Wells with uniform head and low pumping rates have gaining sections along which water enters the well and losing sections along which water exits. Such a well may provide a conduit for contaminated groundwater to be drawn into the well, conveyed a large distance, and injected into an uncontaminated region of an aquifer. Dimensionless ratios of the well's length L and radius R, aquifer thickness H, and uniform flow rate U are developed to quantify the minimum pumping rate Qmin at which no losing section occurs. The ratio Qmin/(ULH) is presented as a nomograph usingR/H and L/H for placement parallel to flow and is 6πR/H for placement perpendicular to flow, and a parabolic relationship between these limiting cases is developed for placement oblique to flow. Capture zone geometry is quantified using Qmin/(ULH).