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Modeling of Near-Surface Leakage and Seepage of CO(sup 2) for Risk Characterization.

DE141149937

Publication Date	2014
Personal Author	Oldenburg, C. M.; Unger, A. A. J.
Page Count	23
Abstract	The injection of carbon dioxide (CO2) into deep geologic carbon sequestration sites entails risk that CO2 will leak away from the primary storage formation and migrate upwards to the unsaturated zone from which it can seep out of the ground. We have developed a coupled modeling framework called T2CA for simulating CO2 leakage and seepage in the subsurface and in the atmospheric surface layer. The results of model simulations can be used to calculate the two key health, safety, and environmental (HSE) risk drivers, namely CO2 seepage flux and nearsurface CO2 concentrations. Sensitivity studies for a subsurface system with a thick unsaturated zone show limited leakage attenuation resulting in correspondingly large CO2 concentrations in the shallow subsurface. Large CO2 concentrations in the shallow subsurface present a risk to plant and tree roots, and to humans and other animals in subsurface structures such as basements or utility vaults. Whereas CO2 concentrations in the subsurface can be high, surfacelayer winds reduce CO2 concentrations to low levels for the fluxes investigated. We recommend more verification and case studies be carried out with T2CA, along with the development of extensions to handle additional scenarios such as calm conditions, topographic effects, and catastrophic surface-layer discharge events.
Keywords	Carbon dioxide injection Leaks Seepage Risk assessment Geologic formations Health effects Sequestration Site characterization Subsurface structures Topography
Source Agency	Technical Information Center Oak Ridge Tennessee
NTIS Subject Category	68A - Air Pollution & Control 48F - Geology & Geophysics
Corporate Authors	Lawrence Berkeley National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	201503

Modeling of Near-Surface Leakage and Seepage of CO(sup 2) for Risk Characterization.

Modeling of Near-Surface Leakage and Seepage of CO(sup 2) for Risk Characterization.
DE141149937

Publication Date	2014
Personal Author	Oldenburg, C. M.; Unger, A. A. J.
Page Count	23
Abstract	The injection of carbon dioxide (CO2) into deep geologic carbon sequestration sites entails risk that CO2 will leak away from the primary storage formation and migrate upwards to the unsaturated zone from which it can seep out of the ground. We have developed a coupled modeling framework called T2CA for simulating CO2 leakage and seepage in the subsurface and in the atmospheric surface layer. The results of model simulations can be used to calculate the two key health, safety, and environmental (HSE) risk drivers, namely CO2 seepage flux and nearsurface CO2 concentrations. Sensitivity studies for a subsurface system with a thick unsaturated zone show limited leakage attenuation resulting in correspondingly large CO2 concentrations in the shallow subsurface. Large CO2 concentrations in the shallow subsurface present a risk to plant and tree roots, and to humans and other animals in subsurface structures such as basements or utility vaults. Whereas CO2 concentrations in the subsurface can be high, surfacelayer winds reduce CO2 concentrations to low levels for the fluxes investigated. We recommend more verification and case studies be carried out with T2CA, along with the development of extensions to handle additional scenarios such as calm conditions, topographic effects, and catastrophic surface-layer discharge events.
Keywords	Carbon dioxide injection Leaks Seepage Risk assessment Geologic formations Health effects Sequestration Site characterization Subsurface structures Topography
Source Agency	Technical Information Center Oak Ridge Tennessee
NTIS Subject Category	68A - Air Pollution & Control 48F - Geology & Geophysics
Corporate Authors	Lawrence Berkeley National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	201503