Geothermal Resource Mapping of Northern Switzerland

1
Geothermal Resource Mapping of Northern
Switzerland

• Thomas Kohl,
• Nathalie Andenmatten-Bertoud,
• S. Signorelli,
• L. RybachGeowatt AG, Zurich, Switzerland

2
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
3D determination of subsurface structures

• Northern Switzerland

• Well investigated for research of nuclear waste
  deposit
• Borehole, seismic profiles, geophysical
  geological interpretation

4
Geological 3D mapping

• Geological surface interpolation with GOCAD
  software from data basis
• Example top Malm Muschelkalk layers with
  borehole marker

5
Development of local numerical model

• Triangulation of surfaces
• Tetrahedrization of geological model
• Construction of Finite Element Mesh

6
Numerical patch test
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Petrophysical Data

• Measured and averaged parameters from Weiach

8
Local temperature calculation

• Calculation of thermal and hydraulic
  fieldExample Weiach

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Temperature Data

• Weiach

• Benken

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Transmissivity evaluation

• Evaluation from existing data

• Thermal evaluation
• heat flow variation background vs. local value
• Peclet Analysis from regional borehole
  distributionrelating heat flow variation to vD
• With assumption on head gradient
  gtTransmissivity estimation

T
j2
z
j1
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Utilization Scenario

• Doublet System
• Calculation over time span Dt

• Transient Gringarten (1978) solution
• Necessary surface area
• Sustainable flow rate
• Reservoir geometry
• gt Utilizable heat energy f(t, Tr, T, V, )
  in individual reservoir zone

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Example Resource Potential

• Northern Switzerland
• Resource of altered crystalline basement for 30
  yr production
• Surface area lt1km2

Similar evaluation for sedimentary aquifers
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From Local to Regional Models
Weiach Local Model
Benken Local Model
110mW/m2.
Weiach
90mW/m2.
Boettstein Local Model 100 110mW/m2.
Eglisau
Zurzach
Benken
Kaisten Local Model 110mW/m2.
Kaisten
Lindau Local Model
80mW/m2.
Kloten
Ruchfelden
Riniken Local Model
110mW/m2.
Nordschweiz Regional Model
Riniken
Basserdorf
Beznau
Birmenstorf
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Prel. Temperature Distribution in 2000m b.s.l
N
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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