8.11.2007engine leiden combining areal underground and infrastructure data to minimize exploration...

8.11.2007 ENGINE Leiden

Combining Areal Underground and Infrastructure Data to Minimize Exploration and Economic Risks

Thomas Kohl, GEOWATT AG

Clément Baujard, GEOWATT AG

Example of West SwitzerlandGeothermal ProductivityEconomic AnalysisSocietal Needs

Engine: ENhanced Geothermal Innovative Network for Europe


Investigation of National Swiss Geothermal Ressources


Geothermal Potential

Heat in Place

cP specific heat capacity of rock [J m‑3 K‑1],

V Volume of resource [m3],

Tprod Temperature of produced fluid [°C]

Treinj Temperature of re-injected fluid [°C].

Transient Production

(cP)f specific heat capacity of fluids [J m‑3 K‑1]

Q produced flow rate [m3 s‑1].

)( reinjprodPHIP TTVcE

t

reinjprodfP

t

thut

dtTTQc

dtpE

)()(


Utilization Scenario

Doublet System:Negligible temperature drawdown

over t=30 yrAnalytic solution (Gringarten, 1978):

Necessary surface area Sustainable flow rate Reservoir geometry

Utilizable heat energy

= f(Tr, T, V, …)

in individual reservoir zone

Dynamic approach:

reservoir depletion

Distance x

Transmissivity

21 /3ln

4

wi

bi rztcQ

PTrQ


Resource Analysis: Workflow

Data research Geological data Well data Geophysical data (seismic profiles…) Hydrogeological data (pumping tests, chemical…)

3D Geological model

3D Temperature model Thermal properties from well data Calibration of temperature on well data

Extraction of temperature on aquifers

Computation and mapping of geothermal potential for identified aquifer

Identification of zones of great potential, cross-checking with surface data


3D Temperature field in domains

Conversion of the geological model into FE

Attribution of petrophysical data to units

Simulation of the temperature using FRACTure

Parameters: • Surface temperature, • geologic model,• Thermal conductivity, • Basal heat flow distribution


Developing Thermal Calibration Model

-10000

-5000

0

640000

650000

660000

670000

680000

690000

700000

240000

250000

260000

270000

280000

Temp [°C]4003753503253002752502252001751501251007550250

Weiach

Benken

Lindau

Riniken

Leuggern


Thermal Calibration Model

Temperature along Top 500m Crystalline

-10000

-5000

0

640000

650000

660000

670000

680000

690000

700000

240000

250000

260000

270000

280000

Temp. [°C]: 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210


Hydrogeological Parameters

Crystalline Basement Top 500m

Depth dependency Bimodal Distribution

0

5

10

15

20

25

Hydraulische Leitfähigkeit [Log (K)]

An

zah

l [-]

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Anzahl

Kumulativ

Verteilung 1

Verteilung 2


Identifying aquifers

Aquifer Hydraulic conductivity

Thickness

Upper Marine Molasse

2.10-7 ms-1 50-700m

Upper Muschelkalk

1.10-7 ms-1

to 1.10-4 ms-1

<70m>

Altered Crystalline

1.10-8 ms-1

to 1 10-6 ms-1

<500m>


Potential Geothermal Energy West Switzerland (Upper Muschelkalk)

Key Parameters: Geometry of the aquifer Temperature at depth Hydraulic conductivity


Economic modelingConcepts

Parameters: Heat production or electricity production

• Option 1: Pure Heat Production • Option 2: Pure Electricity Production• Option 3: Coupled Electricity & Heat Production

Depth of the borehole Drilling costs

• Fixed at 1500€/m or 2200€/m• Increasing with depth

Conversion efficiency:• Increasing with depth

Operational efforts: • pump energy needs

Market selling prices and buying prices of heat and electricity

Annuity of loans …


Economic modelingResults

Typical results of a parameter study (not definitive)

Electricity costs CHF/kWh


Conclusion

Resource analyses are a powerful tool to quantify and map the geothermal potential of a region

It allows to identify the most interesting regions The geothermal potential can be easily integrated in GIS

• Planning tool for local authorities

The risk can be expressed in a probable cost model The energy demand could be covered from geothermal,

• However: under realistic premises only to a small amount

Don't overestimate the geothermal potential!

8.11.2007engine leiden combining areal underground and infrastructure data to minimize exploration...

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