Exploration and Development of the the Hveravellir Geothermal Field, N-Iceland

Abstract

The Hveravellir geothermal field, N-Iceland is one of Iceland's traditionally famous geothermal fields with its boiling hot springs and spouting geysers. The geothermal activity is mainly located on N-S trending lineaments, and limited to an area of 1600 m x 300 m. Total natural discharge from the geothermal field was 55-60 l/s prior to drilling. The largest hot spring is Ystihver, that discharged 17-19 l/s, prior to drilling, and has been reported to erupt to a height of 15-25 m for a period of 1/2 -1 minute.
According to geophysical data, the main fracture system in the area is a N-S trending one, involving several faults/fractures. Most of the surface geothermal activity is located along these faults, and the main hot springs found where they are intersected by structures or fractures of different trend, NW-SE, or NNE-SSW. The recharge towards the field appears to be from southeast. Geochemical data indicates reservoir temperatures close to 130?C.
In the late 1800s, Hveravellir or Reykir (the old name) became a centre for vegetable cultivation, and later a greenhouse industry, utilizing the benefits of the geothermal heat. In 1970, it was decided to develop the field further to provide hot water for space heating of Husavik, a town with a population of about 2500, located on the coast, about 18 km north of the geothermal field. An asbestos pipeline was constructed to connect the Husavik district heating system to the Hveravellir hot springs. Growing population and utilization called for more hot water, so in 1974, a 450 m deep well, HV-1 was drilled, that gave in free flow 44 l/s of 126?C hot water. Utilization was, however, limited to temperatures below 100?C due to the properties of the pipeline. In the late 1990s new ideas for utilization of geothermal water at Husavik, both for industrial purposes and electrical production, led to a new exploration effort, involving gradient wells and drilling of new production wells, HV-10 (61 l/s 124?C) and HV-16 (8 l/s 116?C). The total free flow from the three production wells is now 95 l/s of 124?C hot water. A new main steel pipeline and the new Husavik Energy Centre were completed in 2000, providing heat, steam and electricity, through a Kalina binary system, for the town of Husavik.