The geo-database of caprock quality and deep saline aquifers distribution for geological storage of CO2 in Italy

One of the most promising options to stabilize and reduce the atmospheric concentration of greenhouse gases is Carbon Capture and Storage (CCS). This technique consists of separating CO2 from other industrial flue gases and storing it in geological reservoirs, such as deep saline aquifers, depleted oil and/or gas fields, and unminable coal beds. A detailed reworking of all available Italian deep-drilling data was performed to identify potential storage reservoirs in deep saline aquifers. Data were organized into a GIS geo-database containing stratigraphic and fluid chemistry information as well as physiochemical characteristics of the geological formations. Caprock efficiency was evaluated via numerical parameterization of rock permeabilities, defining the 'Caprock Quality Factor' (Fbp) for each well. The geo-database also includes strategic information such as the distribution of deep aquifers, seismogenic sources and areas, seismic events, Diffuse Degassing Structures, heat flow, thermal anomalies, and anthropogenic CO2 sources. Results allow the definition of potentially suitable areas for future studies on CO2 geological storage located in the fore-deep domains of the Alps and Apennines chains, where efficient marly-to-clayish caprocks lie above deep aquifers hosted in sands or limestones. Most of them are far form seismogenic sources and Diffuse Degassing Structures. -- Highlights: → Proposal of a methodology to identify suitable areas for geological storage of CO2 on the Italian territory. → Research of areas where caprock units (marls-claystones) lie above deep reservoir rocks (sandstones-fractured limestones) hosting saline aquifer. → Working dataset of available wells composite logs drilled for oil exploration in Italy during the last 50 years. → Construction of caprock quality and deep saline aquifers presence geo-database compared to main geological risk factors. → Results show potential areas on the Italian territory having main prerequisites for the identification of potential CO2 storage structures