In this paper our interest is in the effect of minerals on the carbon dioxide
concentration. The dissolution of carbon dioxide in the
oleic phase depends on the mineral content and can in itself reduce the amount
of oil left behind and thus increase the recovery of oil. The calculation of the concentration of carbon dioxide requires the
determination of the activity coefficients of all chemical species in the
aqueous phase, which thus determine the ratio of carbon dioxide dissolved in
the aqueous phase and the carbon dioxide in the oleic phase. It is the purpose of the paper to provide the complete geochemical background
for the modeling of carbonated water and carbon dioxide injection in a calcite.