Head gradient control in aquifers used for fluid storage

Attempts to store fluids in confined aquifers will sometimes be frustrated by regional groundwater flow and/or by buoyancy drift due to density differences between the stored fluid and the native groundwater. Such effects can largely be overcome through the use of gradient control wells. A procedure based on linear programing can be used for the initial design of a well field that will create a zero gradient or a finite gradient in a given region. The finite difference form of the steady state groundwater equation provides one set of constraints, while the gradient condition in the storage region provides a second set. A standard linear programing solution routine is then used to provide the minimum pumping rates and head distribution consistent with the constraints and the chosen well array.