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| Titel |
Effective Wettability Measurements of CO2-Brine-Sandstone System at Different Reservoir Conditions |
| VerfasserIn |
Ali Al-Menhali, Samuel Krevor |
| 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 |
250088218
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| Publikation (Nr.) |
 EGU/EGU2014-2304.pdf |
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| Zusammenfassung |
| The wetting properties of CO2-brine-rock systems will have a major impact on the
management of CO2 injection processes. The wettability of a system controls the flow and
trapping efficiency during the storage of CO2 in geological formations as well as the
efficiency of enhanced oil recovery operations. Despite its utility in EOR and the continued
development of CCS, little is currently known about the wetting properties of the
CO2-brine system on reservoir rocks, and no investigations have been performed
assessing the impact of these properties on CO2 flooding for CO2 storage or EOR.
The wetting properties of multiphase fluid systems in porous media have major
impacts on the multiphase flow properties such as the capillary pressure and relative
permeability. While recent studies have shown CO2 to generally act as a non-wetting phase
in siliciclastic rocks, some observations report that the contact angle varies with
pressure, temperature and water salinity. Additionally, there is a wide range of reported
contact angles for this system, from strongly to weakly water-wet. In the case of
some minerals, intermediate wet contact angles have been observed. Uncertainty
with regard to the wetting properties of CO2-brine systems is currently one of the
remaining major unresolved issues with regards to reservoir management of CO2
storage. In this study, we make semi-dynamic capillary pressure measurements of
supercritical CO2 and brine at reservoir conditions to observe shifts in the wetting
properties. We utilize a novel core analysis technique recently developed by Pini et al in
2012 to evaluate a core-scale effective contact angle. Carbon dioxide is injected
at constant flow rate into a core that is initially fully saturated with water, while
maintaining a constant outlet pressure. In this scenario, the pressure drop across the core
corresponds to the capillary pressure at the inlet face of the core. When compared with
mercury intrusion capillary pressure measurements, core-scale effective contact
angle can be determined. In addition to providing a quantitative measure of the
core-averaged wetting properties, the technique allows for the observation of shifts in
contact angle with changing conditions. We examine the wettability changes of
the CO2-brine system in Berea sandstone with variations in reservoir conditions
including supercritical, gaseous and liquid CO2injection. We evaluate wettability
variation within a single rock with temperature, pressure, and salinity across a range of
conditions relevant to subsurface CO2 storage. This study will include results of
measurements in a Berea sandstone sample across a wide range of conditions representative
of subsurface reservoirs suitable for CO2 storage (5-20 MPa, 25-90 oC, 0-5 mol
kg-1). The measurement uses X-ray CT imaging in a state of the art core flooding
laboratory designed to operate at high temperature, pressure, and concentrated brines. |
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