Two-dimensional Simulation of the Krafla-Hvitholar Geothermal Field, Iceland

Abstract

The Hvitholar geothermal field is a part of the Krafla geothermal area in north- eastern Iceland. It has been exploited since 1984 for electrical production. Three wells have been drilled in the field to depths of 1200 - 1968 m. The two producers (KJ-21 and KJ-22) have a total flow capacity of 60 kg/s, sufficient for generation of 14 MW,. The reservoir pressure in the field has declined by about 15 bar since 1982. A two-dimensional model of the natural state of the reservoir has been developed The model is a vertical cross section. The physical processes considered include mass transport, conductive and convective heat transfer, boiling, and condensation. The model adequately matches all relevant data from the field The natural flow of hot fluids through the reservoir is estimated to be somewhat less than 10 kg/s. ?be natural state model was calibrated against the production history of the field, and three Merent future production schemes were evaluated At current production rates, the field is expected to last no more than another decade.