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Caprock Interactions with the Supercritical CO2 and Brine: A Labratory Study of the Effects of Simulated Geological CO2 Sequestration on Shales from the Black Warrior River Basin, Alabama L

A better understanding of the brine-rock- supercritical CO2 interaction is needed to evaluate the risks of geologic CO2 sequestration. The geochemical effects of brine and supercritical CO2 were examined via laboratory modeling of in situ conditions on two reservoir caprocks in the Black Warrior River Basin, the Pottsville and Parkwood Formations. The clay fraction was extracted and treated at ~ 100 bar and 363 K (90 °C) over periods of up to 70 hours. Supercritical CO2 was introduced as dry ice in a pressurized vessel. Samples were observed using XRD, WD-XRF, AA, SEM, and EDS. Clay fractions contained Fe-chlorite, illite, kaolinite, and quartz. Results show the dissolution of illite, CO2-brine induced cation exchange ok K+, and the dissolution of silicate minerals. Steady-state K/Si ratios in the fluid suggest quartz re-precipitation. These interactions could adversely affect the long-term storativity of the caprock and point to a need for further study.

Identiferoai:union.ndltd.org:GEORGIA/oai:digitalarchive.gsu.edu:geosciences_theses-1048
Date15 August 2012
CreatorsRaines, Jessica E.
PublisherDigital Archive @ GSU
Source SetsGeorgia State University
Detected LanguageEnglish
Typetext
Formatapplication/pdf
SourceGeosciences Theses

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