A Study of Effective and Accurate Finite Difference Method for the Tracer Response Analysis

Abstract

Tracer test is one of the most useful tools to evaluate geothermal reservoirs, since tracer response provides valuable information about geothermal reservoirs and underground fluid flow behavior. In this study, tracer response analysis is examined on the basis of the finite difference method. Using a model of geothermal reservoirs with a large planar dominant flow path, TVD schemes are compared with the first and the third order upwind schemes. Examination of time integration methods and grid spacing is made. The selection of grid points for the evaluation of tracer concentration at outlet on tracer response curves is also discussed. As the result, we found that the finite difference method using TVD shceme with φ=-1 and the first order explicit Euler method as the time integration method is an effective and accurate one when the grid spacing and the grid points for the evaluation of tracer concentration at outlet are set adequately.