Thermostat
Project
Thermal and hydraulic rock properties
of paleozoic, mesozoic and tertiary rocks
A
major obstacle in geothermal energy
development lies in the high risk of failure
due to the unknown thermal and hydraulic
properties of the target rocks at depth. To
overcome the insufficient knowledge of rock
properties at depth, a project funded by the
German Federal Environment Ministry has been
initiated to compile a statistically
significant database of thermal and hydraulic
properties of subsurface rocks in Germany.
Geophysica was ordered for workings in the
field of log analysis and thermal property
prediction by the Institute of Applied
Geophysics and Geothermal Energy of Aachen
University, the principal investigator of the
project.
We
selected samples and data sets from core and
data archives of the State Geological Surveys
and from industrial exploration wells (hydrocarbons,
coal and lignite). In the first stage of the
project we provided a statistically
representative database of thermal and
hydraulic properties for the
lithostratigaphical units in the western part
of the Molasse Basin in Southern Germany and
the adjacent Triassic and Jurassic landscapes
north of the Molasse (Swabian Alp). During the
second stage of the project we attended the
subsurface rocks of the western part of North
Rhine Westphalia (Lower
Rhine Embayment, Ruhr Area, Rhenish
Massif).
Data
from direct measurements on core samples were
combined with the interpretation of
geophysical borehole measurements and
complementary mineralogical analyses to derive
statistical moments of the desired properties
for selected main rock types. Additionally, we
considered spacial facies changes and the
effects due to variations of temperature and
pressure increase with depth. In the beginning
of our studies we selected and sampled
relevant rock series from the target areas. In
parallel different analytical methods were
enhanced to support the project tasks. These
techniques were related to the rapid and
cost-efficient derivation of permeabilities
from nuclear magnetic resonance (NMR)
measurements and to the quantification of
uncertainty with respect to rock properties
and state variables in geothermal reservoirs,
respectively. Our results improved the
database of geothermal relevant information
and facilitate the commercial and area-wide
exploration of geothermal energy in Germany.
Regions
of interest, covering a wide spectrum of
paleozoic, mesozoic and tertiary rocks.
Definition
of petrophysical relationships to relate
thermal conductivity to rock composition and
rock porosity.
Cross-hole
correlation of thermal conductivity profiles
for sediments of the middle Jurassic drilled in
south Germany. Thermal conductivity profiles
were generated from wireline log data.
Final
Report 1
(Western Molasse Basin and Swabian Alp)
Final
Report 2
(Eastern Molasse Basin and Lower Rhine
Embayment)
Scientific
Puplication in
"Geothermics"
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