PETROLEUM-EXPLORATION IN ITALY - A REVIEW

Petroleum exploration in Italy began in the second half of the 19th century, but the first consistent discoveries were only made after World War 11. At present, the original reserves of the Italian petroleum fields amount to about 160 million tons of oil and 720 billion cubic metres of gas; domestic production in 1990 was 4.6 million tons of oil and 17.3 billion cubic metres of gas. The lithology of the Italian sedimentary sequences was controlled by the geodynamic evolution of the western margin of the Adria plate. The Permian-Triassic continental and shallow water environments pre-dating the break-up of Pangea were followed by subsiding carbonate platforms and basins in the Mesozoic. Tertiary compressive tectonics, induced by the subduction of the Adria continental margin, produced a complex thrust belt, bordered by a migrating foredeep filled with clastic sediments. Most of the oil and a minor part of the gas were generated by Middle Triassic-Lower Jurassic shaly and carbonate source rocks. Most of the gas was sourced by Pliocene-Pleistocene clays in the foredeep turbiditic deposits and has a bacterial origin. A short review, integrated with some actual examples of typical fields (Cortemaggiore, Costa Molina, Settala, Agostino-Porto Garibaldi, Barbara, Candela-Palino, Rospo, Vega), exemplifies the different plays in the main tectonic domains.