Yousif K. Kharaka James J. Thordsen Juske Horita Athanasios Karamalidis Craig Griffith J. Alexandra Hakala Gil Ambats David R. Cole Tommy J. Phelps Michael A. Manning Paul J. Cook Susan D. Hovorka Jiemin Lu 2012 <p>A highly integrated geochemical program was conducted at the Cranfield CO₂-enhanced oil recovery (EOR) and sequestration site, Mississippi, U.S.A.. The program included extensive field geochemical monitoring, a detailed petrographic study, and an autoclave experiment under in situ reservoir conditions. Results show that mineral reactions in the Lower Tuscaloosa reservoir were minor during CO₂ injection. Brine chemistry remained largely unchanged, which contrasts with significant changes observed in other field tests. Field fluid sampling and laboratory experiments show consistently slow reactions. Carbon isotopic composition and CO₂ content in the gas phase reveal simple two-end-member mixing between injected and original formation gas. We conclude that the reservoir rock, which is composed mainly of minerals with low reactivity (average quartz 79.4%, chlorite 11.8%, kaolinite 3.1%, illite 1.3%, concretionary calcite and dolomite 1.5%, and feldspar 0.2%), is relatively unreactive to CO₂. The significance of low reactivity is both positive, in that the reservoir is not impacted, and negative, in that mineral trapping is insignificant.<br></p> application/pdf 10.1016/j.chemgeo.2011.10.020 en Elsevier CO₂–rock–brine interactions in Lower Tuscaloosa Formation at Cranfield CO₂ sequestration site, Mississippi, U.S.A. article