Natural hydrocarbon seepage in the Italian offshore

Italy hosts the largest petroleum systems in southern Europe and is the third EU country for oil reserves after Norway and UK and fifth for gas reserves (as 2015). Of the 167 fields currently in production, about 60 are located in the Italian offshore and specifically in the Adriatic and Ionian region (Adriatic Sea, Ionian Sea, Strait of Sicily), which corresponds to the "marine zones" A, B, D, F and G of the Italian continental shelf, open for hydrocarbon exploration and exploitation under the governance of the Ministry of Economic Development. Italy is third for offshore gas, sixth for oil production (as 2012) among EU countries. Petroleum systems in the Italian seas can be grouped into: biogenic gas in the terrigenous Plio-Quaternary wedges (northern and central Adriatic, Panda field); thermogenic gas in the terrigenous Tertiary foredeep systems (Luna field); oil and thermogenic gas in the Mesozoic carbonates (southern Adriatic, Rospo, Gela, Vega fields). In addition to these deep reservoirs, the Italian seas are characterized by the presence of significant hydrocarbons in the shallow sediments, which sometimes seep to the seabed and the water column. This study aims to produce the definitive map of the natural emissions of hydrocarbons at the seabed and in the water column in the Italian seas, by analysing high resolution seismic reflection data obtained using high frequency systems, bathymetric and reflectivity data of the sea-bottom and the water column acquired with the ultimate generation of multi-beam systems, owned by CNR-ISMAR. Where no CNR-ISMAR data are available, information from literature will be used. The objectives are: morphological classification (volcanoes and mud diapirs, pockmarks); detection of flares in the water column; geochemical characterization, when achievable, between biogenic and thermogenic gas; link to deep sources, such as diapirs and faults; a better understanding of the causal relationship with slope instability and soft-sediment deformation (geohazard), especially in the vicinity of Oil&Gas plants.