PREDICTION OF FLOW AND HYDRAULIC-HEAD FIELDS FOR VERTICAL CIRCULATION WELLS

A vertical circulation well is a well completed in two intervals with extraction induced in one interval and injection induced in the other, generating a circulating flow field near the well. A vertical circulation well may be used to remediate contaminated ground water by air stripping the extracted water and then reinjecting the clean water; by introducing oxygen and/or nutrients to the extracted water before reinjecting ft, thereby stimulating the natural bioremediation of the water; or by injecting appropriate chemicals or microbes, effecting remediation of the circulated water. This paper summarizes an analytical technique for predicting the steady-state hydraulic head and flow fields caused by the operation of multiple vertical circulation wells in a confined aquifer with a regional gradient. The method begins with the hydraulic head solution for a point sink in an infinite aquifer. The point sink is then integrated to derive the solution for a line sink. Linear superposition is applied to obtain the hydraulic head resulting from multiple line sinks and sources in a homogeneous confined aquifer. This solution is then differentiated to obtain the hydraulic head gradient and three-dimensional velocity field. The velocity field is numerically integrated by an adaptive Runge-Kutta scheme to obtain the pathlines of three-dimensional flow.