Screening, classification, capacity estimation and reservoir modelling of potential CO2 geological storage sites in the NW Adriatic Sea, Italy

In Italy, the central-northern Apennines and Adriatic Sea domains have been identified as potential CO2 storage areas. Although capacity estimates have been undertaken at a regional scale, more detailed research is required to reduce uncertainty. The present study helps address this gap by conducting a detailed screening of a representative area in the north-western Adriatic Sea for suitable CCS sites, using an extensive dataset composed of both public and private seismic and borehole data. Work included selecting suitable sites based on proposed selection criteria, calculating their theoretical and effective storage capacities applying a probabilistic approach, and then performing dynamic flow modelling on one of the selected sites that is representative of fractured carbonate reservoirs. Based on the screening results, a total of 21 out of 38 structures were selected as having the required characteristics suitable for CO2 storage. As expected, the clastic rock reservoirs have the greatest potential capacity, although some fractured carbonate reservoirs did yield important volumes due to their dual porosity / permeability characteristics. Modelling of one such site highlighted the complex interplay between primary and secondary porosity / permeability on plume migration and capacity estimation. Our results highlight the need to integrate analytical calculations with dynamic simulations for more detailed, site-specific studies to improve the estimates of CO2 storage capacity.