Impact of Fault Zone Characterization Uncertainties on Leakage Risk Assessment of CO2 Sequestration Sites
Abstract
Geologic carbon sequestration is considered as a key technology for reducing greenhouse gas in the atmosphere. However, leakage of CO2 from any potential reservoir could seriously compromise the goal of long-term storage. Furthermore leakage of brine could potentially contaminate overlying aquifers. Therefore understanding the likelihood and rate of potential fluid leakage is a key step toward the feasibility of this technology. Faults and fractures are one of the main pathways for fluid (brine or CO2) migration outside of the storage interval. Several methodologies have been generally used to assess the sealing/leaking properties of faults, considering factors such as gauge formation processes, host rock permeability, clay content, diagenesis, in situ stress, etc. However, it is well known that faults are extremely heterogeneous and their properties vary both spatially and temporally. Furthermore, little in-situ characterization of fault zones exists, leading to very high uncertainties on model input parameters. In this work, we applied a methodology to quantify leakage rates of CO2 or brine through faults from deep saline reservoirs. We combine hydromechanical simulations with uncertainty quantification of geological and geomechanical model parameters to understand the impact of these uncertainties on predicting the magnitude of potential fluid leakage. 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 2011
- Bibcode:
- 2011AGUFM.H41K..08C
- Keywords:
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- 1822 HYDROLOGY / Geomechanics;
- 1847 HYDROLOGY / Modeling