Capacity: an experimental numerical test into an offshore saline aquifer in the Adriatic Sea (Italy) Claudia Cangiano * , Giuseppina Ciampa * , Roberto Guandalini * , Fabio Moia * , Sergio Persoglia**, Federica Donda** The 5 th Trondheim Conference on CO 2 Capture, Transport and Storage Trondheim Norway, 16-17 Giugno, 2009 PRESENTAZIONE POWER POINT * ERSE SPA ** OGS – NATIONAL INSTITUTE OF OCEANOGRAPHY AND EXPERIMENTAL GEOPHYSICS An experimental test of CO 2 injection into an offshore saline aquifer in the Adriatic Sea, is a main part of the research program named “Italian Geological Sites for CO 2 Geological Sequestration” which has been financed in 2008 by the Italian Ministry of Economic Development with the Research Fund for the Italian Electrical System. As well-known, Italy is a country with a very complex geology and the absence of large, well stratified and homogeneous potential reservoirs does not allow the use of simplified and easy approaches in order to identify potential storage sites and their capacity. In this framework we developed a methodology of analysis with properly developed tools that include a GIS data base manager, a fluid dynamic simulator, a chemical module and a module linking to a geo-mechanical simulator; the acquirement of geological data, definition of simulation parameter, run control and final result analysis has been performed by a properly developed graphic user interface, fully integrated and calculation platform independent. The CO 2 reservoir potential site found in this project, is located in an offshore sector of the middle Adriatic Sea and the geological model has been defined by using a set of deep wells and seismic reflections surveys mainly realized for hydrocarbon exploration by the major national hydrocarbon company. We also considered the presence of fresh, saline or brackish water, gas/oil, the underground temperatures, seismic velocity and electric resistance of geological materials from different logs and porosity, permeability and geochemical characteristics of rocks. The reservoir shows a very irregular shape with a maximum extension estimated in 56×22 km and a thickness variable from 0.2 to 0.5 km at a mean depth of 1.5 km. The saline aquifer is located in a sandy geological formation, Porto Garibaldi formation of Pleistocene-medium Pliocene age, which ends as pinch- out mode; the caprock is represented by a thick – from 400 to 980 meters – impermeable clay formation (Argille del Santerno of Pleistocene-Pliocene age) with some thin sandy layers. The numerical analysis have been carried out injecting an amount of 1.5 Mtons/year of CO 2 during a period of 30 years, considering also the solubility and mineral trapping aspects, and focusing results in terms of risk assessment on the short, medium and long period. The irregular structure of the reservoir and the variability of materials have forced the consideration of a fully detailed 3D numerical model, realized from the geological data by means of a mesh generator developed in the frame of the project, with a total of 855600 cells variably spaced. The results obtained in terms of prediction of the CO 2 plume location and fate, of the pressure build up and of the CO 2 sequestration effects, have shown that the site storage capacity and the physical conditions after injection seem to match the requirements for a CCS-Carbon Capture and Sequestration Project also from the safety point of view, and suggest the expedience of a second level analysis to better assess the impact of geo- mechanical stresses and local displacements.