school energy&environment

Hydrocarbons in Italy

The geology of our country (Italy)  is very complex and the peninsula consequently has a complicated sedimentary and structural order,  that is not very calm. This has not favoured the formation of large and extensive oil fields, but has created local situations that are favourable for the formation of numerous oil provinces that are reasonably important, even though their extension is not great.
Our country can, from a tectonic point of view, be subdivided into 4 “districts”. These are all tied to the presence of the mountain ranges of the Alps and Apennines:

• a “rear-arch” field ,  an area that is not greatly deformed, consisting in the Tyrrhenian Sea;
• a mountain range area, that consists in the big “arch”  that stretches from the Alps to the Apennines, and that forms the backbone of the Calabria and Sicily regions;
• a “fore-rift” area, a depressed field that is not greatly deformed,  that is located in front of the mountain ranges advancing on the so-called “fore-country”, consisting of the borders of the Adriatic Sea, the Ionian Sea and the Sicily Channel;
• the “fore-country” area, an area that is still not deformed, towards which the mountain ranges that are forming move,   which consists in the Po Valley, the Adriatic Sea, South East Sicily and the Sicily Channel.

The most important Italian provinces for oil are the Northern area of the Adriatic Sea, the Po Valley (gas and oil), the Pescara field (oil and gas) the Southern Area of the Adriatic (oil and gas), the Southern Apennines (oil),  the Fossa Bradanica in the Puglia region (gas and oil) the off-shore platforms of the Calabria region (gas), Central Sicily (gas) and the Pelagic fields (oil).
The most important oil reserves are in  Val d’Agri (Potenza) and Villafortuna-Trecate (Novara).  Val d’Agri is the province with the greatest oil reserves in Italy. Hydrocarbons are to be found in the anticline folds  of the Mesozoic calcareous areas of the Apulian Platform, covered by the slopes of the Apennines in the Campania and Basilicata regions. The presence of oil and gas on the surface  have been reported in Tramutola. These escaped from deeper traps following the tectonic deformations in the Apennine mountain range. In the Villafortuna-Trecate fields,  hydrocarbons are in Mesozoic carbonate rocks that were fractured due to the Alpine deformations buried below the Po Valley, with one of the deepest liquid hydrocarbon fields in the world  (6,200 m).
The distribution of the principal oil provinces in Italy, clearly reflects the geological situation: the comparison between a structural map of our country and a map of the main fields, in fact, shows that approximately 40% of the reserves are in mountain range areas (like the reserves of the Southern Apennines and Central Sicily), while the remaining 60% are in the fore-rifts and fore-country areas – the reserves in the Northern Adriatic Sea and the Po Valley, closed between the front of the Alps and the front of the Apennines that are moving towards each other; the Pescara field and the Southern Adriatic field are closed between the Apennines; and the Dinaridi around the Dinara Mountain area to the East, and the off-shore platforms of the Calabria region, South-Eastern Sicily and the Sicily Channel. From a simple comparison of the two maps, it is quite easy to see the controlling influence of the geological and structural order of a region on the distribution and importance of the hydrocarbon reserves we may hope to find therein.