HR: 1330h
AN: H32A-0542    [PDF]
TI: Simulating Remediation of $CO_2$ Leakage from Geological Storage Sites
AU: * Zhang, Y
EM: yqzhang@lbl.gov
AF: Earth Sciences Division Lawrence Berkeley National Laboratory Earth Sciences Division Lawrence Berkeley National Laboratory, One Cyclotron Road, Mail Stop 90-1116, Berkeley, CA 94720 United States
AU: Oldenburg, C M
EM: cmoldenburg@lbl.gov
AF: Earth Sciences Division Lawrence Berkeley National Laboratory Earth Sciences Division Lawrence Berkeley National Laboratory, One Cyclotron Road, Mail Stop 90-1116, Berkeley, CA 94720 United States
AU: Benson, S M
EM: smbenson@lbl.gov
AF: Earth Sciences Division Lawrence Berkeley National Laboratory Earth Sciences Division Lawrence Berkeley National Laboratory, One Cyclotron Road, Mail Stop 90-1116, Berkeley, CA 94720 United States
AB: One strategy to reduce net greenhouse gas emissions is to inject carbon dioxide ($CO_2$) deep into subsurface formations where presumably it would be stored indefinitely. Although geologic storage formations will be carefully selected, $CO_2$ 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, $CO_2$ 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 $CO_2$ leakage from geologic storage sites. We use the integral finite-difference code TOUGH2 to simulate the remediation of $CO_2$ in subsurface systems. We consider the components of water, $CO_2$ 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 $CO_2$ 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 $CO_2$ plume half-life, defined as the time required for one-half of the $CO_2$ mass to be removed. Initial simulations show that barometric pressure fluctuations enhance the removal of $CO_2$ from the vadose zone, but that $CO_2$ trapped near the water table is difficult to remove by either passive or active remediation approaches. This work was supported by a Cooperative Research and Development Agreement (CRADA) between BP Corporation North America, as part of the $CO_2$ Capture Project (CCP), and the U.S. Department of Energy (DOE) through the National Energy Technologies Laboratory (NETL), and by the U.S. Department of Energy under contract DE-AC03-76SF00098.
DE: 1875 Unsaturated zone
DE: 1899 General or miscellaneous
SC: Hydrology [H]
MN: 2003 Fall Meeting