MAIN LABORATORY ISSUES TO EVALUATE THE SEQUESTRATION OF CARBON DIOXIDE IN CARBONATE AQUIFERS
The most important objectives of the laboratory work presented here were aimed at investigating how the chemical composition of the natural formation brine and different minerals present in the carbonate formations interact with CO2 injection under supercritical conditions. The study focused on the alteration of the petrophysical properties of the carbonate reservoir rocks resulting from the interaction of rock/ formation brine and injected CO2. Conventional and Neutron Magnetic Resonance (NMR) core analyses indicated that that low pore volume of CO2 injection caused substantial reduction in the petropysical properties of the samples, permeability and porosity. The permeability was reduced by about 50% and the pore volume and porosity by about 25%. In contrast, the injection of high pore volume of CO2 showed a slight increase in the petrophysical properties. The static interaction between supercritical CO2 and natural formation brine showed a precipitate formed primarily by calcite, dolomite, gypsum, halite and other mineral salts.