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NAC 13
Economic risk reduction of geothermal energy projects:
Case study of the Delft Sandstone
A.G. Vondrak, M.E. Donselaar, C.J.L. Willems, D.K. Munsterman,
A.A. Van De Weerd and C.T.A.M. Leo
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Geothermal energy
• Green energy
• First project in 2007
• Costs 15 million
• Greenhouse heating
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Study objective
• Reduce economic risks for geothermal projects
– Reduce uncertainties of reservoir characteristics
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Geothermal energy in the Netherlands
• Doublets
• Closed system
• Injection and production well
• Six active doublets in the WNB
Reservoir
Heat exchanger
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West Netherlands Basin
• First doublet
• Cretaceous reservoir rocks
• Late Jurassic rifting
• Late Cretaceous inversion
Modified from Herngreen and Wong,2007
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Stratigraphic scheme West Netherlands Basin
• Four important members
• Delft Sandstone main target
• In whole WNB a dominant sandstone
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Nieuwerkerk Fm
• Fluvial deposits
• NW-SE trend
• Constrained by fault activity
• Occurs in all sub-basins
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Nieuwerkerk Fm
• Fluvial deposits
• NW-SE trend
• Constrained by fault activity
• Occurs in all sub-basins
HON sub-basin
PNA-GT sub-basin
VDB sub-basin
Structural high
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Cross section PNA-GT-02 VDB-GT-04 HON-GT-01
& -02 W E
Base Rijswijk
Base Upper North Sea Group
Base Chalk Group Base Niewerkerk Fm
Base Delft Sst?
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• Current knowledge from structural highs
• Architecture of the fluvial Delft Sandstone reservoir is difficult to predict
• Economic risk depends on well placement
Problem statement
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• Current knowledge from structural highs
• Architecture of the fluvial Delft Sandstone reservoir is difficult to predict
• Economic risk depends on well placement
Problem statement
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Stratigraphic correlations
• Biostratigraphical correlation: – Age
– Depositional environment
• Well correlations
• Seismic correlations
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Original hypotheses
Van Adrichem Boogaert & Kouwe, 1997
DeVault & Jeremiah, 2002
One continuous Delft Sst. in the WNB
No Delft Sst.
Thick, stacked channel complexes in the WNB
10km
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Preliminary dating results
VDB-GT- 04
Ap
tian
B
arre
mia
n
Hau
teri
vian
Va
lan
gin
ian
R
yaza
nia
n
Lower
Lower
Lower
Upper
Upper
Upper
Berkel
HON-GT- 01
PNA-GT- 01
PNA-GT- 02
Rijswijk
Delft
W E
Biostratigraphical analyses done by TNO D.K. Munsterman
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Well panel VDB-GT-04 HON-GT-01 PNA-GT-01 PNA-GT-02
Top Rodenrijs
Base Rodenrijs
Top Delft
Valanginian
Ryazanian
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Conclusion - hypothesis
• Not one Delft Sandstone
• Fluvial system stepped from one sub-basin to the next
PNA-GT-02 VDB-GT-04
Lagoonal
Terrestrial
HON-GT-01
Ryzanian
Valanginian
Barremien
Delft 1
Delft 3
Delft 2
Flood plain Delft 1
Floodplain Delft 3
Hauterivian
W E
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Geothermal implications
• Reduced uncertainties in reservoir characteristics important for economic risk reduction – Use reservoir characteristics from specific sub-basin
– Placement of doublets in NW-SE direction
Reservoir
Heat exchanger
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Next step
• Include new biostratigraphical data
• Include regional seismic interpretation
• Verify hypothesis with well data
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Thank you
