Assessment of the Olafsfjordur low-temperature geothermal field, N-Iceland

Abstract

In this report, an assessment is made of the Olafsfjordur (Laugarengi) low-temperature geothermal field in central northern Iceland using available data from geological surveying, temperature logging, well tests and lumped parameter modelling. It is one of the geothermal fields that supplies the town of Olafsfjordur with hot water for space heating and tapwater. Main feed zones in wells were found from circulation losses during drilling and temperature logs. In a lumped parameter model used in this study, calibration was based on data accumulated over a 5 year period of observations of the reservoir response to production. The obtained data were used for predicting the reservoir response to various constant production rates over the next 5 years. The present trend of drawdown can be maintained at an average production rate no larger than 20 l/s. Interpretation of well tests and lumped modelling indicate low transmissivity and permeability but fractures and dykes play a major role in the hydrogeological systems and control the hydrogeothermal activity of this area.