Characterization of a potential CO2 storage site in a carbonate aquifer - Example from the South Adriatic offshore

The Southern Adriatic Sea is one of the five perspective areas for CO2 storage being evaluated under the FP7 European SiteChar project. This site is the most challenging among those studied in this project, since the potential reservoir is hosted in a carbonate formation. In a first instance, the 3D geological static model at both regional and local scale, was constructed, based on the analysis and the interpretation of the available geological, geophysical and borehole data. Coupled fluid flow and geomechanical modeling has been also performed, through the simulation of various scenarios (i.e. open, closed or mid-opened faults, in situ different stress regimes). Dynamic modeling shows that CO2 injection-induced overpressure extends up to 30 km when faults are open, and that sealing capacity of the faults impacts the stress field and the propagation of the CO2 plume around the injection point. The site characterization procedure that has been applied on the Southern Adriatic offshore can be considered as an example that could be adopted when investigating reservoir carbonate formations, especially where crucial information for modeling are missing and need to be derived through an analytical approach.