For the Base Scenario identified for the IEA Weyburn Project, modeling of CO2 migration within the geosphere indicated that up to 75% of the initial CO2-in-place (at the end of EOR) remained within, and in the vicinity of, the EOR region. No CO2 enters the biosphere within the simulation period of 5,000 years.
Modeling of leakage via abandoned wells focused on the performance of degraded cement sealing combined with the variability of properties and CO2 distribution in the reservoir. The conservative treatments incorporated in stochastic modeling provided upper bounding results indicating that the maximum possible leakage after 5,000 years is approximately 0.14% of the initial CO2-in-place. However, the likely cumulative leakage after 5,000 years, however, is less than 0.001% of the initial CO2-in-place.
These results mean that if the Weyburn CO2 storage system evolves as expected, the goal of storing greenhouse gas CO2 will be achieved. Future assessments should focus on alternative scenarios, including seismic activity, open wellbores, and human intrusions.
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