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Title: Constraints on the magnitude and rate of CO2 dissolution at Bravo Dome natural gas field

The injection of carbon dioxide (CO2) captured at large point sources into deep saline aquifers can significantly reduce anthropogenic CO2 emissions from fossil fuels. Dissolution of the injected CO2 into the formation brine is a trapping mechanism that helps to ensure the long-term security of geological CO2 storage. We use thermochronology to estimate the timing of CO2 emplacement at Bravo Dome, a large natural CO2 field at a depth of 700 m in New Mexico. Together with estimates of the total mass loss from the field we present, to our knowledge, the first constraints on the magnitude, mechanisms, and rates of CO2 dissolution on millennial timescales. Apatite (U-Th)/He thermochronology records heating of the Bravo Dome reservoir due to the emplacement of hot volcanic gases 1.2–1.5 Ma. The CO2 accumulation is therefore significantly older than previous estimates of 10 ka, which demonstrates that safe long-term geological CO2 storage is possible. Here, integrating geophysical and geochemical data, we estimate that 1.3 Gt CO2 are currently stored at Bravo Dome, but that only 22% of the emplaced CO2 has dissolved into the brine over 1.2 My. Roughly 40% of the dissolution occurred during the emplacement. The CO2 dissolved after emplacement exceeds the amountmore » expected from diffusion and provides field evidence for convective dissolution with a rate of 0.1 g/(m2y). Finally, the similarity between Bravo Dome and major US saline aquifers suggests that significant amounts of CO2 are likely to dissolve during injection at US storage sites, but that convective dissolution is unlikely to trap all injected CO2 on the 10-ky timescale typically considered for storage projects.« less
 [1] ;  [2] ;  [3] ;  [1]
  1. Univ. of Texas, Austin, TX (United States). Jackson School of Geosciences, Dept. of Geological Sciences
  2. Univ. of Texas, Austin, TX (United States). Jackson School of Geosciences, Dept. of Geological Sciences; Univ. of Texas, Austin, TX (United States). Inst. of Computational Engineering and Sciences
  3. Univ. of Houston, TX (United States). Dept. of Earth and Atmospheric Sciences
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 111; Journal Issue: 43; Journal ID: ISSN 0027-8424
National Academy of Sciences, Washington, DC (United States)
Research Org:
Energy Frontier Research Centers (EFRC). Center for Frontiers of Subsurface Energy Security (CFSES)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Contributing Orgs:
CFSES partners with University of Texas at Austin (lead); Sandia National Laboratory
Country of Publication:
United States
54 ENVIRONMENTAL SCIENCES; nuclear (including radiation effects); carbon sequestration; geological carbon storage; noble gases; porous media convection; thermochronology