Abstract: A pneumatically inflated packer assembly includes spaced upper and lower inflatable sleeves which expand radially to anchor the assembly at a desired depth within a well screen. A porous, elastic bag exteriorly covers these sleeves so that the expanded sleeves stretch and tension the bag such that its intermediate portion between the sleeves tends to expand into cylindrical form so that it lies closely adjacent or against the interior surface of the well screen. In this way, a supply of porous material such as sand housed in an open space above the lower sleeve and below the upper sleeve is free to flow or migrate radially outwardly to substantially completely fill the cross section of the well screen. Groundwater flow into the well is now constrained to flow horizontally through the sand so that its direction and flow rate may be measured by a probe penetrating into the sand.

Abstract: Flow characteristics of a fluid through a permeable solid medium are determined by introducing a predetermined quantity of thermal energy at a highly localized point within the medium and subsequently mapping temperatures around such point to determine the direction and rate of fluid flow through the medium.