3D modeling of the deep geothermal Potential of Hesse - Input data and Potential expulsion

Abstract

Within the scope of the research project "3D-modelling of the deep geothermal potentials of Hesse" the deep geothermal potential of the Federal State of Hesse was quantified and assessed in a qualitative analysis. The quantification of the heat stored under ground and the qualitative analysis was done for different geothermal systems. These are hydrothermal and petrothermal systems, as well as fault zones and deep borehole heat exchangers.

For the assessment of the deep geothermal potential, knowledge of the geological structure and the geothermal properties of the potential reservoir rocks are indispensable. Therefore, a 3D model of the deep geothermal potential of the Federal State of Hesse (Germany) has been developed (cf. Arndt et al. 2011). Systematic measurements of thermophysical and hydraulic rock properties such as thermal conductivity, heat capacity and permeability of relevant geologic formations have been combined with in-situ temperature measurements, hydrothermal upwelling zones, characteristics of geological faults and were added to the 3D geological structural model. Using a multiple criteria approach, the various rock and reservoir properties were assessed incorporating their relevance for the different geothermal systems to allow the qualitative analysis. Therefore, threshold values for each parameter were defined specifying whether the potential is very high, high, medium, low or very low. This method was tested for the one-dimensional case (virtual drilling) and the two-dimensional case (geological-geothermical cross-sections) before being applied to the 3D model.

The resulting geothermal model, which incorporates the quantification and the qualitative analysis, is an important tool, which can be used at an early stage of the planning phase for the design of geothermal power plants. Furthermore, it allows quantification of the deep geothermal potential and is intended to be an instrument for public information.