Reservoir assessment of the Sudurhlídar geothermal field in Krafla, NE-Iceland

Abstract

The Sudurhlídar geothermal field is the eastern part of the Krafla geothermal area in Northeast Iceland. Six wells were drilled in the Sudurhlídar field in the period 1980-1982. Five of the wells were productive and are connected to the Krafla power plant. Temperature and pressure logs from the wells have been analysed and formation temperature and initial pressure profiles estimated. Based on this work a natural conceptual model has been put forward. The model assumes that the reservoir is bounded by impermeable faults to the west and to the east. Recharge of approximately 250°C hot water is predicted to be into the southeastern part of the well field, below 1 km depth. Near the recharge zone the reservoir is in subcooled liquid conditions but further away, boiling conditions prevail from surface to at least 2.2 km depth. Lumped modelling was applied to study and predict the behaviour of the reservoir during exploitation. The generating capacity of the system was assessed by using volumetric methods. The lumped modelling suggests a reservoir area of 10 km2 and the volumetric assessment gives a 15-35 MWe power potential for a reservoir area of 3 km2, and 30-70 MWe for a possible area of 7 km2.