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The role of CO 2 in CH 4 exsolution from deep brine: Implications for geologic carbon sequestration
Author(s) -
Oldenburg Curtis M.,
Doughty Christine,
Spycher Nicolas
Publication year - 2013
Publication title -
greenhouse gases: science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.45
H-Index - 32
ISSN - 2152-3878
DOI - 10.1002/ghg.1370
Subject(s) - supercritical fluid , solubility , brine , dilution , saturation (graph theory) , carbon sequestration , plume , carbon dioxide , methane , permeability (electromagnetism) , geology , petroleum engineering , mineralogy , chemistry , thermodynamics , biochemistry , physics , mathematics , organic chemistry , combinatorics , membrane
The partial pressure exerted by dissolved CO 2 in water (aqueous phase) containing dissolved CH 4 at concentrations near‐saturation can lead to the formation of a CH 4 ‐rich gas phase. We have used numerical simulation with TOUGH2/EOS7C to investigate the process of CH 4 exsolution caused by CO 2 injection for geologic carbon sequestration. We validated the solubility model in TOUGH2/EOS7C against published measurements of solubility and corresponding Henry's Law coefficients. We verified our simulation results against a previously published 1D test problem, and investigated the effects of numerical dispersion on the CH 4 exsolution and flow processes. In 2D radial simulations of a model system, we found that highly concentrated CH 4 gas regions form at the leading edge of the CO 2 injection front. Because the gas saturations are small in the CH 4 ‐rich gas regions in the generic system studied here, (i) CH 4 exsolution does not appear to be a problem for seismic monitoring of CO 2 plumes, (ii) reservoir pressurization due to dilution of supercritical CO 2 by CH 4 does not appear to be a concern, and (iii) relative permeability to water is not strongly reduced.