ausblenden:
Schlagwörter:
-
Zusammenfassung:
Knowledge of structural, hydraulic and thermal conditions of the subsurface is fundamental for the planning
and use of hydrothermal energy. In the framework of a project under the Danish Research program ‘Sustainable
Energy and Environment’ funded by the ‘Danish Agency for Science, Technology and Innovation’, fundamental
geological and geophysical information of importance for the utilization of geothermal energy in Denmark was
compiled, analyzed and re-interpreted. A 3D geological model was constructed and used as structural basis for the
development of a national subsurface temperature model. In that frame, all available reflection seismic data were
interpreted, quality controlled and integrated to improve the regional structural understanding. The analyses and
interpretation of available relevant data (i.e. old and new seismic profiles, core and well-log data, literature data)
and a new time-depth conversion allowed a consistent correlation of seismic surfaces for whole Denmark and
across tectonic features. On this basis, new topologically consistent depth and thickness maps for 16 geological
units from the top pre-Zechstein to the surface were drawn. A new 3D structural geological model was developed
with special emphasis on potential geothermal reservoirs.
The interpretation of petrophysical data (core data and well-logs) allows to evaluate the hydraulic and thermal
properties of potential geothermal reservoirs and to develop a parameterized numerical 3D conductive subsurface
temperature model. Reservoir properties and quality were estimated by integrating petrography and diagenesis
studies with porosity-permeability data. Detailed interpretation of the reservoir quality of the geological formations
was made by estimating net reservoir sandstone thickness based on well-log analysis, determination of mineralogy
including sediment provenance analysis, and burial history data.
New local surface heat-flow values (range: 64–84 mW/m2) were determined for the Danish Basin and predicted
temperatures were calibrated and validated by borehole temperature observations. Finally, new temperature
maps for major geological reservoir formations (Frederikshavn, Haldager Sand, Gassum and Bunter Sandstone/
Skagerrak formations) and selected constant depth intervals (1 km, 2 km, etc.) were compiled.
In the future, geothermal energy is likely to be a key component in Denmark’s supply of energy and integrated
into the district heating infrastructures. A new 3-year project (GEOTHERM) under the Innovation Fund Denmark
will focus on addressing and removing remaining geological, technical and commercial obstacles. The presented
3D geothermal model will be an important component in more precise assessments of the geothermal resource,
production capacity and thermal LifeCycle.
