Experimental Geochemical Studies Relevant to Carbon Sequestration [electronic resource]
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| Online Access: |
Online Access (via OSTI) |
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| Format: | Government Document Electronic eBook |
| Language: | English |
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Washington, D.C. : Oak Ridge, Tenn. :
United States. Department of Energy ; distributed by the Office of Scientific and Technical Information, U.S. Department of Energy,
2001.
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| Abstract: | The authors are conducting laboratory studies to determine: (i) the thermophysical properties and phase relations of CO₂CH₄-H₂O fluids; (ii) the magnitude of stable isotope partitioning during calcite precipitation; and (iii) the utility of natural isotopic tracers in quantifying CO₂ residence times, storage capacity and reaction mechanisms in the subsurface. The ultimate aim of the research on CO₂-CH₄H₂O fluids is to develop a comprehensive equation of state for binary and ternary mixtures of CO₂, CH₄ and H₂O at pressure-temperature (P-T) conditions representative of those in deep gas fields and saline aquifers. To acquire the data needed to create the model, two unique, custom-designed devices at the Oak Ridge National Laboratory--a high pressure vibrating-tube densimeter, and a hydrogen-service internally heated pressure vessel--are being used to measure the densities, excess molar volumes, miscibility limits and activity-composition relations of CO₂H₂O, CH₄-H₂O and ternary CO₂-CH₄-H₂O mixtures at P-T conditions near the vapor-saturation phase boundary in the H₂O system. In another project, experiments are being conducted to determine the kinetics of carbonate precipitation from CO₂-rich saline waters, and associated isotope partitioning. Both inorganic and microbially mediated processes are being investigated under environmental conditions encountered during CO₂ injection into the subsurface. Our results indicate that the behavior of isotopes, especially oxygen isotopes, is affected by the composition of water and the precipitation rate of carbonate minerals. We have also observed significant carbon isotope partitioning (4 to 8{per_thousand}) between CO₂ and hydrocarbon-saturated rock (an EOR injection scenario) reacted statically at 25 C. These preliminary results suggest that a light isotopic component of CO₂ may be retained in the reservoir, leading to isotopically heavier CO, further down the flow path. |
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| Item Description: | Published through SciTech Connect. 01/10/2001. "p00-109112" First National Conference on Carbon Sequestration, Washington, DC (US), 05/15/2001--05/17/2001. Blencoe, J.G. |
| Physical Description: | 1 pages : digital, PDF file. |