The effect of well-storage capacity on the interpretation of tracer test in fractured chalk

A multi-tracers test was conducted in sub-vertical fractures in a low permeable Eocene chalk aquitard in the northern Negev desert, Israel. Tracers' solution containing uranine, LiCl₂ and 2,4,6-tribromophenol were injected into one well; samples were collected in the pumped well, located 10 m apart, and analyzed for tracers' concentrations. The model of parallel plates was used for interpretation of results. Boundary conditions at the fracture inlet and outlet account for the mixing and dilution of tracers within injection and pumping boreholes. The model parameters were estimated by solving inverse problem for each tracer. It was found that storage capacity of the pumping well affects values of model parameters, such as equivalent fracture aperture, flow velocity, and dispersivity.