3D modelling of the Reykir geothermal areas in Mosfellssveit, Iceland

Abstract:

The Reykir geothermal areas in Mosfellssveit has been utilized since the early 20th century and has been one of the main production areas of Reykjavík Energy from the beginning of systematic district heating. Due to the long history of exploration and utilization of the Reykir areas the data is extensive and still in its original state from when the research reports were published. The original data was preserved in a standardized digital form and used to revisit the area´s original conceptual model. From this, a three dimensional (3D) model of the area was built, to display the preserved data. The 3D model was created in Leapfrog Geothermal modelling software and includes the 3D interpretation of stratigraphic sequences, rock temperature isotherms, subsurface hydrothermal alteration zones, and wells of the Reykir geothermal areas. All geochemical data is only in 2D format, therefore, isoconcentration maps for silica were plotted to demonstrate cold water inflow in the geothermal system. The resulting model shows good correlation to original data and coincides with the key geological features of the geothermal area. The 3D model presented in this study gives a representable lithological and thermal image of the Reykir areas serving as a digital platform for future resource management.