Transport Properties of Lavoux Limestone at Various Stages of CO2-Like Acid-Rock Alteration

Since 2005, the French National Research Agency supports several scientific projects intended to select, validate and implement a geological site for CO2 storage in France. The work presented in this paper was carried out within the Geocarbone-Injectivity project, aimed to study the suitability of a carbonate deep saline aquifer located in the Paris basin for a geological CO2 storage. A geological analog to the aquifer rock was chosen in order to perform several petrophysical and transport characterizations. Measured parameters were intrinsic permeability, inertia coefficient, Klinkenberg coefficient, relative permeabilities and transport properties such as the dispersion coefficient and the stratification factor. Samples of Lavoux limestone were characterized in their original state and also after a phase of CO2-like acid-rock alteration. Results show sensible changes in porosity, permeability and inertia coefficient and almost no change in relative permeabilities, dispersion coefficient and stratification coefficient. These results mean that the CO2 injectivity would be maintained and even enhanced during its injection in the considered Dogger formation. Nevertheless, to confirm this observation, additional experimental and modeling work should be performed, taking into account the potential fine migration. A permeability alteration could be expected due to these fine displacements. (authors)