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| Titel |
An analytical approach of CO2 injection induced caprock deflection |
| VerfasserIn |
Chao Li, Paul Barès, Lyesse Laloui |
| 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 |
250087091
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| Publikation (Nr.) |
 EGU/EGU2014-1106.pdf |
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| Zusammenfassung |
| CO2 storage in geological formation, especially in deep aquifers, is becoming a compromising method to reduce the impact of CO2 on the greenhouse effect. Practically, large-volume (>1Mt/year) of CO2 could be injected into a deep aquifer. However, the response of such system is complex because of coupling between the flow and mechanical responses. High rate injection could result in an abrupt fluid pressures build-up, deforming the aquifer and result in surface uplifting, which highly affect public acceptation to the CO2 storage projects.
The study focuses on a specific problem related to the surface uplift induced by the injection of CO2 at depth. The methodology in this study includes the development of a mathematical model that incorporates elastic behaviour of storage mediums and two immiscible fluids (CO2 and water) flow within the aquifers while surface rock layer is modelled as a thin plate. Governing equations are solved for the axisymmetric flexure deflection due to a constant rate injection of CO2. Coupling between porosity and permeability is included via an iterative schema. Numerical integration stability has been improved as well.
Results show that this semi-analytical solution is capable to capture the pressure build-up during the very early stage of injection, resulting in a high rate surface uplift. With hydromechanical effects, pressure tends to stabilize and surface deformation rate decreases. Compared to FEM simulation, the calculation time carried out by the semi-analytical solution is very short. It can be employed as a preliminary design tool for risk assessment such as injection rate, porosity, rock properties and geological structures. This semi-analytical solution provides a convenient way to estimate the influence of high rate injection of CO2 on the surface uplift. The methodology in this development can easily incorporate other pressure distributions. Thus one can benefit from the advances in hydrology researches as well. |
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