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| Titel |
Assessment of brine migration risks along vertical pathways due to CO2 injection |
| VerfasserIn |
Alexander Kissinger, Holger Class |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250101146
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| Publikation (Nr.) |
 EGU/EGU2015-15189.pdf |
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| Zusammenfassung |
| Global climate change, shortage of resources and the growing usage of renewable energy
sources has lead to a growing demand for the utilization of subsurface systems. Among these
competing uses are Carbon Capture and Storage (CCS), geothermal energy, nuclear waste
disposal, “renewable” methane or hydrogen storage as well as the ongoing production of
fossil resources like oil, gas and coal. Additionally, these technologies may also create
conflicts with essential public interests such as water supply. For example, the injection of
CO2 into the subsurface causes an increase in pressure reaching far beyond the actual radius
of influence of the CO2 plume, potentially leading to large amounts of displaced salt
water.
In this work we focus on the large scale impacts of CO2 storage on brine migration but
the methodology and the obtained results may also apply to other fields like waste water
disposal, where large amounts of fluid are injected into the subsurface. In contrast to
modeling on the reservoir scale the spatial scale required for this work is much
larger in both vertical and lateral direction, as the regional hydrogeology has to be
considered.
Structures such as fault zones, hydrogeological windows in the Rupelian clay or salt
domes are considered as potential pathways for displaced fluids into shallow systems and
their influence has to be taken into account. We put the focus of our investigations on the
latter type of scenario, since there is still a poor understanding of the role that salt diapirs
would play in CO2 storage projects.
As there is hardly any field data available on this scale, we compare different levels of
model complexity in order to identify the relevant processes for brine displacement and
simplify the modeling process wherever possible, for example brine injection vs. CO2
injection, simplified geometries vs. the complex formation geometry and the role of salt
induced density differences on flow.
Further we investigate the impact of the displaced brine due to CO2 injection and
compare it to the natural fluid exchange between shallow and deep aquifers in order to asses
possible damage. |
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