Transcript Poster

Triassic geothermal clastic reservoirs in
the Upper Rhine Graben
Temperature at 5km
The goal of this study is to make a first assessment of the
Buntsandstein reservoirs (lower Trias) at the Rhine Graben
regional scale in order to delimit the most favourable areas for
exploration and exploitation of the geothermal resource.
> In France, the main exploited low enthalpy
Temperature at 1500m
> In this framework,
geothermal reservoirs lie within the Jurassic
fractured limestone formation of Dogger located in
the central part of Paris Basin, where 34 doublets
have been heating 600 000 people for 30 years.
The development of renewable energy combined
with the energy demand implies to search other
geothermal reservoirs either below the Paris area
or either in other promising areas in the country.
Ademe and BRGM
co-funded the
CLASTIQ project
(CLAyed SandSTones
In Question), in order
to study the deep
geothermal potential
of the Rhine Graben
for heat production, or
even electricity if
temperature
conditions are high
enough.
Dogger
Trias
Structural map of the Upper Rhine Graben and temperature distribution
extrapolated at 1500m depth (GGA Hannover database in Genter at al., 2004).
Cross-section though the Paris basin
Promising geothermal area in France. Green: area with
geothermal installations, orange: promising areas; red: high
potential geothermal area.
> The Rhine Graben is a
> The geothermal resource is
Cenozoic graben belonging to
located
in
argillaceous
and
the west European rift system
(Ziegler, 1990). It is well-known clastic formation of the lower
Triassic
unit,
namely
the
because of numerous studies
Buntsandstein
formation.
for petroleum and mining
exploration (boreholes,
geophysical surveys…). Several
major subsidence phases
related to the Rhine graben
tectonics generated variable
sediment thicknesses.
> This study is based on old
maps from Geothermal
Synthesis of the Upper Rhine
Graben (Munck et al., 1979)
published by the Commission of
European Communities. We
have digitalized and
georeferenced the
characteristic maps of
Buntsandstein formation (top
depth of the layer, bottom depth
of the layer and temperature at
the top). The digitalized data
have been interpolated by
kriging in taking into account
the presence of faults.
Soultz
Rhine river Baden-Baden
Core of Buntsandstein sandstones.
Tertiary
Depth of the top of the Buntsandstein from
Munck et al., 1979.
Jurassic
Paleozoic crystalline
basement
Schematic geological map.
>We obtain 500m resollution grid map of:
Top of Buntsandstein
Buntsandstein
Cross-section through the Rhine Graben.
Thickness of
Buntsandstein
Temperature at the
top of Buntsandstein
•The depth of the top of the Buntsandstein;
•The thickness of the Buntsandstein;
•The temperature at the top of the
Buntsandstein.
>To quantify the geothermal resource, we
calculate the quantity of heat in the reservoir
volume.
>However, only a part of this resource could
be extracted. The recovery factor R quantifies
the exploitable reserve.
Heat in place
Q = r . Cv . V . (Ti - Tf)
(Muffler & Cataldi, 1978)
Heat exploitable
Qexpl = Q . R
Recovery factor
Temperature factor
Geometric factor
R = RT . RG
RT = (Ti – Tinj) / (Ti – Tf)
RG = 0.33
Exploitable heat in the Buntsandstein
Heat in place in the
Buntsandstein
for doublet in aquifer (Lavigne, 1978)
r : rock density (2200 kg/m3)
Cv : heat capacity (710 J/Kg.K)
Ti : initial temperature of rock
Tf : final temperature of rock (10°C)
Some promising areas have been
identified and some new geophysical
acquisition such as 2D or 3D seismic profiles
should be very helpful in providing relevant
information about the reservoir structure.
Tinj : injection temperature (25°C)
Authors
1BRGM
Dpt Geothermal Energy, 2EEIG Heat Mining, 3BRGM GEO
ENGINE Final Conference – Vilnius, Lithuania – 12-15 February 2008
It appears that the north part of the Upper
Rhine Graben constitutes a more favorable
area than the south part. In the north part,
the top of the Buntsandstein reservoir is
located around 2000-3000m depth with a
temperature of about 150°C and its
sandstone thickness is around 500-600m.
The exploitable geothermal potential is
between 15 and 30 GJ/m2 (7 GJ/m2 for the
exploited Dogger in the Paris Basin).
This study confirms that the Buntsandstein
formation in the Upper Rhine Graben has a
good geothermal potential for heat or even
electricity production.
V : reservoir volume
Dezayes Chrystel1, Genter Albert2, Tourlière Bruno3
Results
References:
Genter A., Guillou-Frottier L., Breton J.P., Denis L., Dezayes Ch., Egal E., Feybesse J.L., Goyeneche O., Nicol N., Quesnel F.,
Quinquis J.P., Roig J.Y., Schwartz S. (2004) - Typologie des systèmes géothermiques HDR/HFR en Europe. Rapport final.
BRGM/RP-53452-FR, 165 p., 75 fig., 10 tabl.
Lavigne J. (1978) – Les resources géothermaiques françaises. Possibilités de mise en valeur. Ann. Des Mines, April, p.1-16.
Muffler P. & Cataldi R. (1978) – Methods for regional assessment of geothermal resources. Geothermics, 7, p.53-89.
Munck F., Walgenwitz F., Maget P., Sauer K, Tietze R. (1979) – Synthèse géothermique du Fossé rhénan Supérieur. Commission
of the European Communities. BRGM Service Géologique Régional d’Alsace – Geologisches Landesamt Baden-Württemberg.
Ziegler P. (1992) – European Cenozoic rift system. Tectonophysics, 2008, p.91-111.
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