Simulating Remediation of CO2 Leakage from Geological Storage Sites
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division
One strategy to reduce net greenhouse gas emissions is to inject carbon dioxide (CO2) deep into subsurface formations where presumably it would be stored indefinitely. Although geologic storage formations will be carefully selected, CO2 injected into a target formation may unexpectedly migrate upwards and ultimately seep out at the ground surface, creating a potential hazard to human beings and ecosystems. In this case, CO2 that has leaked from the geologic storage site is considered a contaminant, and remediation strategies such as passive venting and active pumping are needed. The purpose of this study is to investigate remediation strategies for CO2 leakage from geologic storage sites. We use the integral finite-difference code TOUGH2 to simulate the remediation of CO2 in subsurface systems. We consider the components of water, CO2 and air, and model flow and transport in aqueous and gas phases subject to a variety of initial and boundary conditions including passive venting and active pumping. We have investigated the time it takes for a gas plume of CO2 to be removed from the vadose zone both by natural attenuation processes and by active extraction wells. The time for removal is parameterized in terms of a CO2 plume half-life, defined as the time required for one-half of the CO2 mass to be removed. Initial simulations show that barometric pressure fluctuations enhance the removal of CO2 from the vadose zone, but that CO2 trapped near the water table is difficult to remove by either passive or active remediation approaches.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE; BP Corporation North America (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 1349751
- Report Number(s):
- LBNL-53677-Abs
- Country of Publication:
- United States
- Language:
- English
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