Geomechanical Reservoir Response to CO2 Injection at SNØHVIT, Norway
Abstract
Pressure build-up during a large-scale CO2 injection increases the potential for seal failure, fault reactivation, leakage and induced microseismicity. Careful geomechanical analysis is necessary to predict and potentially manage these effects. In the present work we investigate the geomechanical reservoir response to the CO2 injection in the Tubåen Fm at the Snøhvit site taking into account the potential compartmentalization of the storage reservoir and the in situ stress uncertainty. Compartmentalization has been suspected due to the unexpected pressure rise during operations in the storage reservoir, which led to a considerable decrease in the estimated total capacity and to the abandonment of injection operations in the Tubåen Fm. The high uncertainty in the in situ stress field makes predictions difficult, and therefore uncertainty quantification analysis is a vital component of this work. The Snøhvit gas field is located offshore in the northern Norwegian Sea (Barents Sea). CO2 is injected in the Tubåen Fm. at approximately 2600 m depth. The Tubåen Fm. corresponds to a delta plain environment dominated by fluvial distributary channels which potentially contribute to the suspected compartmentalization. Structurally the area is extensively faulted, with a dominant east-west-trending fault system, and other faults at high angles to this trend, leading to complex fault interactions. This makes fault compartmentalization a strong possibility as well. Given the injection pressure history, geometry of major faults, available estimates of the in situ stress tensor, and reservoir characteristics, we investigate the geomechanical response of the system to the CO2 injection, focusing in particular on addressing the potential reservoir compartmentalization and its impacts on injection performance, CO2 distribution and migration outside of the storage interval. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.H21L..07C
- Keywords:
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- 1822 HYDROLOGY Geomechanics;
- 8168 TECTONOPHYSICS Stresses: general