CO2 geological storage in the Italian carbonate successions

Carbonate successions have a large distribution in the Italian territory, both onshore and offshore, and they are commonly hydrocarbons exploration targets. However, an evaluation of the suitability of these sedimentary successions for CCS projects has never been performed. The present study has allowed for the first time the recognition and the geological and structural characterization of areas potentially suitable for CO2 geological storage in carbonate rocks in Italy. To achieve this objective, public available well data and 2D multichannel seismic profiles were analyzed and interpreted, allowing to define eight areas (Malossa-San Bartolomeo, Lachiarella-Binasco, Abruzzi offshore, Abruzzo-Molise, Southern Adriatic, Northern Bradanic Trough, Southern Bradanic Trough, Sicily Channel) characterized by potential reservoirs in carbonate rocks sealed by relatively thick and laterally continuous caprocks. The present results have also highlighted marked spatial heterogeneities in the recognized reservoirs, inferred to result from primary depositional processes, diagenesis and fracturing due to tectonic events. Most reservoirs were recognized within shallow marine carbonate platform succession, among which the most suitable for CCS purposes are those composed of dolostones, showing maximum porosity and permeability values of 25% and 400-450 mD, respectively. Among the identified areas, the so called “Sicily Channel” and “Abruzzi offshore” are probably those most promising because of their location in offshore settings, closeness to significant sources of CO2 and distance from the main seismogenetic tectonic structures, as well as for the occurrence of one or multiple reservoir-caprock systems. However, the information provided by this study is at a regional scale, and therefore more detailed analyses are needed to identify and characterize potential individual storage sites for CCS projects.