A method for testing formations of very low permeability is presented. The method is based on an analytical solution that describes the decay of a head change caused by pressurizing the volume of water stored in a shut‐in well. Type curves prepared from this solution are matched with observed data to determine the hydraulic properties of the formation tested. The test is similar to the conventional slug test; however, its much shorter duration makes the testing of extremely tight formations feasible.

Methods of analyzing ‘slug test’ data are reviewed, and additional type curves for the analysis of test data from formations with very low storage coefficients are presented.

Numerical simulation models of the simultaneous transport of water and heat in porous media offer a useful technical tool for the evaluation of aquifers for the storage of heat energy. During the past several years, such models have been developed in the U.S. Geological Survey and in other institutions and have been tested by comparing computed results with analytical solutions. To more completely assess the performance of these simulation models, the U.S. Geological Survey and the Energy Research and Development Agency co‐funded Auburn University to conduct a field experiment of heat storage in an aquifer near Mobile, Alabama. The data collected during the experiment were analyzed, and a simulation model of the aquifer system was constructed. Simulation of the experiment history indicates that the model can satisfactorily reproduce the observed behavior of the system. Heat capacity of the aquifer matrix and anisotropy of the aquifer permeability were found to be significant system parameters. An extensive evaluation of parameter sensitivity was not possible because experimental problems resulted in some unreliable data, but the utility of numerical models for simulating thermal energy storage in aquifers was clearly demonstrated.

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