HR: 1340h
AN: H13F-1662    [Abstracts]
TI: Quick Assessment of CO2 Storage Capacity in Pressure-Constrained Saline Aquifers with Different Hydrogeologic Properties
AU: * Zhou, Q
EM: qzhou@lbl.gov
AF: Lawrence Berkeley National Laboratory, One Cyclotron Road, MS90-1116, Berkeley, CA 94720, United States
AU: Birkholzer, J
EM: JTBirkholzer@lbl.gov
AF: Lawrence Berkeley National Laboratory, One Cyclotron Road, MS90-1116, Berkeley, CA 94720, United States
AU: Tsang, C
EM: CFTsang@lbl.gov
AF: Lawrence Berkeley National Laboratory, One Cyclotron Road, MS90-1116, Berkeley, CA 94720, United States
AU: Rutqvist, J
EM: JRutqvist@lbl.gov
AF: Lawrence Berkeley National Laboratory, One Cyclotron Road, MS90-1116, Berkeley, CA 94720, United States
AB: Abstract: Saline aquifers of high permeability bounded by overlying/underlying seals may be surrounded laterally by low-permeability zones, possibly caused by natural heterogeneity and/or faulting. CO2 injection into and storage in such a "closed" system with impervious seals or a "semiclosed" system with nonideal seals is different from that in an "open" system, from which displaced brine can easily escape laterally. In a closed or semiclosed system, pressure buildup caused by continuous industrial-scale CO2 injection is a limiting factor affecting CO2 storage capacity to avoid geomechanical damage. In this research, a method was developed, under simplifications and assumptions, for quick assessment of CO2 storage capacity and efficiency factor in a pressure-constrained, closed or semiclosed system. This quick-assessment method was based on the fact that accumulated, injected CO2 displaces native brine of an equivalent volume. The equivalent volume was calculated based on (1) additional pore volume of the target formation expanded by pore and brine compressibilities under storage conditions of pressure buildup, (2) expanded pore volume within the seals, and (3) cumulative leakage of displaced brine through the seals. To validate this method, a TOUGH2/ECO2N model was developed, for a two-dimensional radial system, to simulate transient pressure buildup and CO2 plume evolution in response to an industrial-scale CO2 injection. To test the validity range, simulations for various conditions of the formation-seal system were used: (1) radial extent varying from 10 to 100 km, (2) pore compressibility and permeability of the storage formation, and (3) a realistic range of seal's&p permeability from 10-20 to 10-17 m2. Through these detailed numerical simulations, the transient, domain- averaged pressure buildup over the injection period and the storage efficiency for the entire injection period were obtained, and compared with those estimated through the quick-assessment method. The good agreement indicates that the proposed method can produce reasonable approximations for the formation-seal system of various geometric and hydrogeologic properties. This implies that the detailed, two-phase flow conditions, CO2 dissolution, and non-uniform pressure buildup can be neglected in estimating CO2 storage capacity at early stages of site selection and characterization. In addition, the sensitivity of pressure buildup and CO2 plume evolution to the various geometric and hydrogeologic properties of the formation-seal system is presented through the detailed modeling.
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 1847 Modeling
SC: Hydrology [H]
MN: 2007 Fall Meeting