Numerical Simulation of Tracer Testing Data at the Uenotai Geothermal Field, Japan

Abstract

Numerical simulation of tracer testing data is conducted based on hydrogeology parameters inferred from pressure interference data. By incorporating both of pressure interferences and tracer testing data, pertinent values of average fracture spacing and rock-matrix permeability can be estimated. Relatively good match of tracer return curves are obtained. It is necessary to assign very small fracture porosity (product of fracture-zone porosity and fracture-zone volume fraction) between wells in order to match tracer return curves. Our 3-D simulation model predicts a large-scale distribution of two-phase zone due to production; this is partly confirmed by a good match between the observed and calculated discharge enthalpy of the production well.