HR: 1340h
AN: GC13A-1213    [Abstracts]
TI: The "Half-Life" of Injected CO₂: The Immobilization of Injected CO₂ by Capillary Trapping
AU: * Hesse, M
EM: mhesse@stanford.edu
AF: Department of Petroleum Engineering, Stanford University, 065 Green Earth Sciences Bldg. 367 Panama Street , Stanford, CA 94305 United States
AU: Tchelepi, H
EM: tchelepi@stanford.edu
AF: Department of Petroleum Engineering, Stanford University, 065 Green Earth Sciences Bldg. 367 Panama Street , Stanford, CA 94305 United States
AB: Leakage of injected CO₂ is a major concern in saline aquifer storage of anthropogenic CO₂. Therefore the time over which CO₂ is still available for leakage is an important timescale in aquifer CO₂ storage. Capillary trapping in the wake of the CO₂ plume is the major mechanism reducing the amount of CO₂ that is available for leakage. We use a semi analytical model to assess the time scales over which the CO₂ is immobilized. Assuming homogeneous system and sharp interface the problem reduces to a non-linear heat equation with a discontinuous coefficient. A scaling law with an non-rational exponent governs the reduction of the mobile CO₂. The anomalous exponent is determined by a non-linear eigenvalue problem. The analysis of Kochina et al.. (1983) has been extended to a sloping aquifer. The eigenvalue problem has been solved numerically. And results are compared to numerical solutions of the governing one dimensional heat equation, as well as results obtained from full reservoir simulations. The time necessary to reduce the mobile CO₂ by half decreases with increasing permeability, density difference and dip of the aquifer. Results are uesful in assesing suitability of saline aquifers and designing the monitoring strategy.
DE: 4445 Nonlinear differential equations
DE: 4470 Renormalization group methods
DE: 4475 Scaling: spatial and temporal (1872, 3270, 4277)
SC: Global Climate Change [GC]
MN: Fall Meeting 2005