| Title | A New Approach to Estimating the Geothermal Potential of Faults in Germany |
|---|---|
| Authors | Thorsten AGEMAR, Jessica-Aileen ALTEN, Klaus KÜHNE, Jörg KUDER, Evelyn SUCHI, Josef WEBER, Rüdiger SCHULZ |
| Year | 2015 |
| Conference | World Geothermal Congress |
| Keywords | fault, reservoir, geothermal potential, Germany, information system |
| Abstract | Tectonic processes have resulted in the deformation of rocks and the formation of faults. Tectonic forces associated with the movement along faults may result in further fracturing. The properties of the resulting fractures reflect the relationship between the mechanical properties of the rocks involved and the stress field within which the fracturing occurs. The flux that can be obtained from highly fractured rocks is generally much greater than that which can be obtained from matrix rocks. Currently, geothermal energy exploration in Germany focuses on deep aquifers. Faults are not yet considered as primary geothermal targets. However, in the Upper Rhine Graben area and in the South German Molasse Basin, project developers frequently try to intersect fault zones during drilling in order to gain access to a larger part of the reservoir. Depending on interconnectedness, aperture, and dimensions, fault zones may substantially increase achievable flow rates for geothermal facilities. Furthermore, in some locations with high geothermal potential, upwelling of deep groundwater is connected to faults. Characterizing faults in a way that adequately allows predictions to be made about transmissivity is difficult. Knowledge of the fault history and geometry is a first step for the estimation of the geothermal potential of a fault system. Rough estimates can be made by setting boundary values for thermal and hydraulic properties of fault zones. The Leibniz Institute for Applied Geophysics (LIAG) operates GeotIS (http://www.geotis.de), an internet-based information system on geothermal resources. This information system provides data on deep sedimentary rocks suitable for geothermal energy exploitation. Currently, GeotIS contains only simplified and incomplete information on faults. The first objective of our project is therefore the compilation of data on hydraulic properties, size and the geometry of deep reaching faults. Another major objective is to enhance the functionality of GeotIS to enable the storage and retrieval of more sophisticated geometries and hydraulic data. |