A Tracer Test on Well IDDP-2, Reykjanes, Iceland

Abstract

By drilling holes to about 5 km depth, the Iceland Deep Drilling Project (IDDP) intends to evaluate whether energy extraction from deep geothermal resources at supercritical conditions is feasible. Well IDDP-1 was drilled in Krafla but hit magma at about 2100 m depth and was not drilled deeper. Well IDDP-2 is planned at Reykjanes and at the end of drilling an injection test will be perfomed during which a tracer test is planned to establish whether there is a connection between the deep environment and the 1000-2500 m deep geothermal system that is already being produced in the area. Molecular tracers that have been shown to be stable at the high temperatures (380-600°C) anticipated in the IDDP-2 well are not known and therefore elemental radioactive tracers will probably be used. Informal collaboration has already been established between the IDDP Chemistry Group and research teams in the US and Europe that have experience in using radioactive tracers for geothermal investigations. Current plans involve using 85Kr as a vapour phase tracer, 3H in H2O as a vapour and liquid phase tracer and 125I as a liquid phase tracer.