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| Titel |
On the impact of spatial heterogeneous permeability distributions on the development of free convection cells in the Perth Basin, Australia. |
| VerfasserIn |
Jan Niederau, Anozie Ebigbo, Sebastian Freitag, Gabriele Marquart, Christoph Clauser |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250092936
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| Publikation (Nr.) |
 EGU/EGU2014-7301.pdf |
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| Zusammenfassung |
| Recent increase in exploration of the geothermal energy potential of the Perth Metropolitan
Area (PMA) results in the need for reliable and robust reservoir models in order to explore
rock properties and temperature distributions in the subsurface, where free convection in the
main reservoir (Yarragadee Aquifer) is likely to occur [1]. While the structure of the Perth
Basin has been refined recently, the heterogeneity and spatial complexity of permeability was
up till now mainly neglected.
An integrated, three dimensional tectonostratigraphic model of the PMA is constructed, using
the modeling software “3D GeoModeller” and data of numerous artesian and petroleum
wells. Comprising the region around the city of Perth, the model covers an area of about 5000
km2 up to a depth of 4.5 km, with focus on adequate representation of the main
reservoir.
We further construct a numerical model for fluid flow and heat transport in the Yarragadee
Aquifer. Porosity distributions are deduced from well logs and linked to permeability
by a calibrated correlation, based on a fractal approach. Three different cases are
simulated using the FD code SHEMAT-Suite, in order to assess the influence of spatial
heterogeneity of porosity and permeability on the development of free convection
cells.
constant porosity and permeability for the entire aquifer
porosity and permeability decreasing with depth, thus reflecting compaction
a conditional random permeability field within prescribed limits and for given
correlation length
In order to improve understanding of model correctness, as well as identification and comparison
of convection cells in different simulations, we are developing a specialized visualization tool
tailored to this purpose.
The three different scenarios show distinctions in the distribution of convection cells. Where
the Yarragadee Aquifer is in contact with overlying aquifers, regions of downflow develop.
These in turn have a strong impact on the regional flow field and therefore temperature. The
heterogeneous distribution of permeability seems to control the convection pattern on a
smaller scale.
References
[1]Schilling, O., Sheldon, H.A., Reid, L.B., Corbel, S. 2013. Hydrothermal models
of the Perth metropolitan area, Western Australia: implications for geothermal energy.
Hydrogeology Journal, Vol. 21, 605–621. |
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