Tracer Test at Reykjanes Geothermal Field

Abstract

HS Orka owns and operates 100 MW geothermal power plant at Reykjanes, Iceland. In August 2013 a two phase tracer test, one for the liquid phase and one for the steam phase, was carried out in Reykjanes geothermal field. The objective was to explore hydrological properties and pathways in the geothermal system at Reykjanes. The chemical tracers chosen for this test were 2,7 naphtalene disulfonic acid (2,7-NDS) for the liquid phase and methanol for the steam phase. The two phase tracer was injected into an injection well located to the east of the main production field, directionally drilled and cased down to 719 m. Samples of both brine and condensate have been collected from the beginning from each of the production wells, frequently for the first month, then twice a week for one month and weekly after that. Achieved experience from the two phase tracer test, encourage a tracer test on a newly drilled well located on a proposed injection area, approx. 1 km north east to the production area. The objective is to explore the connection between the proposed injection site and the production part of the area. In January 2014 the liquid tracer 2 naphtalenesulfonate (2-NS) was injected into the proposed injection well. Sampling will coincide with the two phase tracer test. Interpretation of the two phase tracer test is underway and will be presented in the paper as well as proceeding of current tracer test.