Numerical modelling of the Hveragerði high temperature field
Author: Ragna Björk Bragadóttir
Year: 2019
Supervisors: Gunnar Gunnarsson, Einar Jón Ásbjörnsson
Abstract:
The Hveragerdi geothermal field is located 40 km South-East of Reykjavik, Iceland. The field is on the eastern margin of the Western Rift Zone and on the western end of the South Iceland Seismic Zone. North-East of the field is the Hengill Area, where the Hellisheidi and Nesjavellir geothermal power plants are located. The geothermal field has been used for district heating since the 1920s and in 1952 the Hveragerdi municipality district heating utility was established, thus becoming one of the first district heating utility in Iceland. With the rapid population and industry growth in and around the municipality of Hveragerdi, the need for stable thermal power has increased. In order to sustain the high service standards that are set for district heating in Iceland, it is foreseen that additional thermal production capacity will be needed in the area. In order to estimate the optimal and sustainable production in the field, a thorough understanding of its characteristics is needed.
Although the Hveragerdi district heating utility is one of the oldest in Iceland, very little is known about the Hveragerði geothermal field and its production capacity. A better understanding of the field could result in a more sustainable and optimal thermal power production.
Available data for the Hveragerði geothermal field were collected and compiled in order to get an idea on how it is structured. Formation temperatures of wells were estimated, and from the available information a numerical model was developed using TOUGH2. The model was then calibrated using the formation temperatures. The production history of the field was estimated and using the calibrated numerical model the production was simulated to date. There is a good match between the calculated formation temperatures and the formation temperatures estimated from downhole temperature data. The production simulation shows that there is a relatively little drawdown in the field and there is a good possibility that more mass could be produced from the field.