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| Titel |
Capillary-Driven Solute Transport and Precipitation in Porous Media during Dry-Out |
| VerfasserIn |
Holger Ott, Matthew Andrew, Martin Blunt, Jeroen Snippe |
| 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 |
250094623
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| Publikation (Nr.) |
 EGU/EGU2014-10046.pdf |
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| Zusammenfassung |
| The injection of dry or under-saturated gases or supercritical (SC) fluids into water bearing
formations might lead to a formation dry-out in the vicinity of the injection well. The dry-out
is caused by the evaporation/dissolution of formation water into the injected fluid
and the subsequent transport of dissolved water in the injected fluid away from
the injection well. Dry-out results in precipitation from solutes of the formation
brine and consequently leads to a reduction of the rock’s pore space (porosity) and
eventually to a reduction of permeability near the injection well, or even to the loss of
injectivity.
Recently evidence has been found that the complexity of the pore space and the respective
capillary driven solute transport plays a key role. While no effective-permeability (Keff)
reduction was observed in a single-porosity sandstone, multi porosity carbonate rocks
responded to precipitation with a strong reduction of Keff. The reason for the different
response of Keff to salt precipitation is suspected to be in the exact location of the
precipitate (solid salt) in the pore space.
In this study, we investigate dry-out and salt precipitation due to supercritical CO2
injection in single and multi-porosity systems under near well-bore conditions. We image
fluid saturation changes by means of μCT scanning during desaturation. We are able to
observe capillary driven transport of the brine phase and the respective transport of solutes on
the rock’s pore scale. Finally we have access to the precipitated solid-salt phase and their
distribution. The results can proof the thought models behind permeability porosity
relationships K(Ï) for injectivity modeling. The topic and the mechanisms we show are of
general interest for drying processes in porous material such as soils and paper. |
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