CHARACTERIZATION OF LEAKY FAULTS - STUDY OF WATER-FLOW IN AQUIFER-FAULT-AQUIFER SYSTEMS

Leaky faults provide important flow paths for fluids to move undergrou nd. It is often necessary to characterize such faults in engineering p rojects such as deep well injection of waste liquids, underground natu ral gas storage, and radioactive waste isolation. To provide this char acterization, analytical solutions are presented for groundwater flow through saturated aquifer-fault-aquifer systems assuming that both the aquifers and the fault are homogeneous and that the fault has an insi gnificant effect on aquifer hydraulic properties. Three different cond itions are considered: (1) drawdown in the unpumped aquifer is negligi bly small; (2) drawdown in the unpumped aquifer is significant, and th e two aquifers have the same diffusivity; and (3) drawdown in the unpu mped aquifer is significant, and the two aquifers have different diffu sivities. Methods are presented to determine the fault transmissivity from pumping test data.