Still Needed Data for Successful Deep CO2 Sequestration

Abstract

Despite chemical knowledge about CO2 that extends back centuries, some data bases are still evolving that are needed to predict even the sub-critical CO2 behavior down the geothermal gradient's P- and T-values which will be encountered in sequestration utilizing deep mines and wells. These needed data include IR-spectral interpretations of CO2 molecular structure as P and T change; the unraveling of the Joule Thomson coefficient (heating or cooling?) that changes algebraic polarity around 106 Pa; more exact equations of state (EOS) that correlate to potential CO2 polarity changes in molecular structure; newer EOS than those that have currently been derived by templating directly measured data; and focus is needed on the EOS-derived properties, like fugacity. Also, natural analogues like (1) the carbonate stability in metamorphic silicate-carbonation facies and (2) Lake Nyos aqueous geochemistry with concern about the potential redox-equilibria-predicted presence of CO (and graphite), as well as CO2.