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| Titel |
Numerical simulation of CO2 storage at Ketzin: Evaluation of model approaches |
| VerfasserIn |
Ursula Lengler, Marco De Lucia, Mich. Kühn |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250040143
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| Zusammenfassung |
| Numerical modelling of multiphase flow is an essential tool to ensure the viability of
long-term and safe CO2 storage in geological formations. Uncertainties arising from the
heterogeneity of the formation and lack of knowledge of spatially variable formation
properties need to be assessed in order to create a model that can reproduce the data available
from monitoring.
At the Ketzin test site (CO2SINK) monitoring data used for history matching are injection
pressure and CO2 gas arrival times at two observation wells. The CO2 breakthrough at the
first observation well, 50 m from injection, was in good agreement with the predictions made
by different modelling approaches, whereas the arrival of the CO2 at the second observation
well, 112 m from injection, occurred notably later than predicted. The reasons for this
discrepancy between predicted and observed arrival times are under further investigation.
The impact of spatial variability of the permeability within the fluviatile sandy
channel-(string)-facies rocks of the Stuttgart Formation was studied with 2D vertical and
horizontal models in a stochastic Monte-Carlo framework. The flow path in 2D
vertical models is dominated by buoyancy and overlays the effects due to spatial
heterogeneity, i.e. the second arrival time cannot be predicted by 2D vertical models. At
the contrary, 2D horizontal, heterogeneous models are able to match the second
arrival time with finite probability. To match the temporal injection pressure, the
sandstone channel width of the 2D horizontal model was adjusted as well as the
permeability.
The study concluded that the heterogeneity within a sandstone channel cannot be the only
reason for the late CO2 arrival. The decisive factor is possibly the heterogeneity of the
geometry and location of the fluviatile sandy channel-(string)-facies rocks and the small scale
heterogeneity emphasizes this effect.
The different model approaches (1D, 2D vertical, 2D horizontal, homogeneous,
heterogeneous) are compared and evaluated regarding the assignments to cope with (i.e.
storage capacity, max. CO2 gas extent, injectivity). |
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