Feasibility of Large-Scale Ocean CO2 Sequestration

This report covers research accomplished during CY 2006 under a modification of a previous award. During this period we completed analysis of the acoustic detection and modeling of a rising deep-sea liquid CO{sub 2} plume, and published the results in a major journal. The results are applicable to detection of leakage of CO{sub 2} from the sea floor, either from natural CO{sub 2} vents, or from purposefully disposed CO{sub 2} in sub-sea geologic formations. In April 2006 we executed, in collaboration with colleagues from Massachusetts Institute of Technology, Oak Ridge National Laboratory, and Canada a novel at sea experiment on the creation of a sinking plume of a CO{sub 2} hydrate composite paste, extruded through nozzles designed by ORNL. The work showed that a sinking, and slowly dissolving, mass can be created at depths where the pure liquid (above) would rise far and fast. In August 2006 we executed a cruise to the massive exposed methane hydrates in Barkley Canyon, off-shore Vancouver Island. There we cored the exposed hydrates, and exposed the specimens on the sea floor at 850m depth to liquid CO{sub 2} in a 3 liter closed container. The object was to examine possible inter-conversion of methane hydrate to CO{sub 2} hydrate with liberation of methane gas, and sequestration of the CO{sub 2} as a solid. Each of these complex experiments was successfully executed and the results reported in major journals and/or at national meetings