1. 04 October 2004New and Classical Uses of Heat Flow Studies, Aachen1 Geothermal Resource Mapping of Northern Switzerland Thomas Kohl, Nathalie Andenmatten-Bertoud, S. Signorelli, L. Rybach Geowatt AG, Zurich, Switzerland

2. 04 October 2004New and Classical Uses of Heat Flow Studies, Aachen2 Background Project goal: –Interpretation of Swiss Resource potential in main populated area –3D geological modeling –Numerical analysis –GIS interpretation Conventional resource mapping: –Total Energy = f(T,V) –Utilizable Energy = total Energy x recovery factor Here: –3D subsurface structures –Evaluation of transmissivity –Assumption of utilization scenario –Utilization energy = f(Tr, T, ….) –Combination with GIS tools

3. 04 October 2004New and Classical Uses of Heat Flow Studies, Aachen3 3D determination of subsurface structures Northern Switzerland Well investigated for research of nuclear waste deposit –Borehole, seismic profiles, geophysical & geological interpretation

4. 04 October 2004New and Classical Uses of Heat Flow Studies, Aachen4 Geological 3D mapping Geological surface interpolation with GOCAD software from data basis Example top Malm & Muschelkalk layers with borehole marker

5. 04 October 2004New and Classical Uses of Heat Flow Studies, Aachen5 Development of local numerical model –Triangulation of surfaces –Tetrahedrization of geological model –Construction of Finite Element Mesh Leuggern Böttstein Benken Weiach

6. 04 October 2004New and Classical Uses of Heat Flow Studies, Aachen6 Numerical patch test

7. 04 October 2004New and Classical Uses of Heat Flow Studies, Aachen7 Petrophysical Data Measured and averaged parameters from Weiach

8. 04 October 2004New and Classical Uses of Heat Flow Studies, Aachen8 Local temperature calculation Calculation of thermal and hydraulic field: Example Weiach

9. 04 October 2004New and Classical Uses of Heat Flow Studies, Aachen9 Temperature Data Weiach Benken

10. 04 October 2004New and Classical Uses of Heat Flow Studies, Aachen10 Transmissivity evaluation Evaluation from existing data Thermal evaluation: –heat flow variation: background vs. local value –Peclet Analysis from regional borehole distribution: relating heat flow variation to v D –With assumption on head gradient =>Transmissivity estimation j2j2 j1j1 T z

11. 04 October 2004New and Classical Uses of Heat Flow Studies, Aachen11 Utilization Scenario Doublet System: Calculation over time span  t Transient Gringarten (1978) solution: –Necessary surface area –Sustainable flow rate –Reservoir geometry => Utilizable heat energy = f(t, Tr, T, V, …) in individual reservoir zone Distance  x Transmissivity

12. 04 October 2004New and Classical Uses of Heat Flow Studies, Aachen12 Example: Resource Potential Northern Switzerland: Resource of altered crystalline basement for 30 yr production Surface area <1km 2 Borehole  j [mW m -2 ] Tr [m 2 /s]P[W]Recovery Factor Weiach255 x 10 -6 3 x 10 7 5% Böttstein204 x 10 -6 2 x 10 7 4% Leuggern204 x 10 -6 2 x 10 7 4% Benken0000% Similar evaluation for sedimentary aquifers

13. 04 October 2004New and Classical Uses of Heat Flow Studies, Aachen13 Benken Basserdorf Lindau Local Model Benken Local Model Kloten Nordschweiz Regional Model Boettstein Local Model 100 – 110mW/m 2. Weiach Boettstein - Leuggern 110mW/m 2. 90mW/m 2. 80mW/m 2. Beznau Birmenstorf Riniken Local Model 110mW/m 2. Weiach Local Model Kaisten Local Model 110mW/m 2. Eglisau Ruchfelden Riniken Zurzach Kaisten From Local to Regional Models

14. 04 October 2004New and Classical Uses of Heat Flow Studies, Aachen14 Permocarbon Trog Rand Temperatur: Legend: N Prel. Temperature Distribution in 2000m b.s.l

15. 04 October 2004New and Classical Uses of Heat Flow Studies, Aachen15 Conclusion Evaluation of 3D geology and regional temperature field Individual assessment of recovery factor and production time Cost analysis possible (borehole depth, geological structures, …) Future combination with GIS tools