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| Titel |
Verification of geomechanical integrity and prediction of long-term mineral trapping for the Ketzin CO2 storage pilot site |
| VerfasserIn |
Thomas Kempka, Marco De Lucia, Michael Kühn |
| 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 |
250092971
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| Publikation (Nr.) |
 EGU/EGU2014-7337.pdf |
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| Zusammenfassung |
| Static and dynamic numerical modelling generally accompany the entire CO2 storage site life
cycle. Thereto, it is required to match the employed models with field observations on a
regular basis in order to predict future site behaviour. We investigated the coupled
processes at the Ketzin CO2 storage pilot site [1] using a model coupling concept
focusing on the temporal relevance of processes involved (hydraulic, chemical
and mechanical) at given time-scales (site operation, abandonment and long-term
stabilization). For that purpose, long-term dynamic multi-phase flow simulations [2],
[3] established the basis for all simulations discussed in the following. Hereby,
pressure changes resulting in geomechanical effects are largest during site operation,
whereas geochemical reactions are governed by slow kinetics resulting in a long-term
stabilization.
To account for mechanical integrity, which may be mainly affected during site
operation, we incorporated a regional-scale coupled hydro-mechanical model. Our
simulation results show maximum ground surface displacements of about 4 mm,
whereas shear and tensile failure are not observed. Consequently, the CO2 storage
operation at the Ketzin pilot site does not compromise reservoir, caprock and fault
integrity.
Chemical processes responsible for mineral trapping are expected to mainly occur during
long-term stabilization at the Ketzin pilot site [4]. Hence, our previous assessment [3] was
extended by integrating two long-term mineral trapping scenarios. Thereby, mineral trapping
contributes to the trapping mechanisms with 11.7 % after 16,000 years of simulation in our
conservative and with 30.9 % in our maximum reactivity scenarios. Dynamic flow
simulations indicate that only 0.2 % of the CO2 injected (about 67,270 t CO2 in total) is in
gaseous state, but structurally trapped after 16,000 years. Depending on the studied long-term
scenario, CO2 dissolution is the dominating trapping mechanism with 68.9 % and 88.1 %,
respectively.
We verified the mechanical integrity of the storage system during site operation and
predicted the trapping mechanisms for the Ketzin pilot site based on a time-dependent
integration of relevant processes for a time period of 16,000 years. Supported by our coupled
modelling results, we conclude that CO2 storage at the Ketzin site is safe and reliable on the
pilot scale.
References
[1] Martens, S., Kempka, T., Liebscher, A., Lüth, S., Möller, F., Myrttinen, A., Norden,
B., Schmidt-Hattenberger, C., Zimmer, M., Kühn, M. Europe’s longest-operating on-shore
CO2 storage site at Ketzin, Germany: a progress report after three years of injection.
Environmental Earth Sciences 2012 67(2): 323-334.
[2] Kempka, T., Kühn, M. Numerical simulations of CO2 arrival times and reservoir
pressure coincide with observations from the Ketzin pilot site, Germany. Environmental Earth
Sciences 2013 70(8): 3675-3685.
[3] Kempka, T., Klein, E., De Lucia, M., Tillner, E., Kühn, M. Assessment of Long-term
CO2 Trapping Mechanisms at the Ketzin Pilot Site (Germany) by Coupled Numerical
Modelling. Energy Procedia 2013 37: 5419-5426.
[4] Klein, E., De Lucia, M., Kempka, T., Kühn, M. Evaluation of long-term mineral
trapping at the Ketzin pilot site for CO2 storage: An integrative approach using geochemical
modelling and reservoir simulation. International Journal of Greenhouse Gas Control 2013
19: 720-730. |
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