The offshore Adriatic Basin holds more than 50% of Italian gas reserves together with significant volumes of oil. A number of large and giant‐size biogenic gasfields and medium to large oilfields have been discovered here during the past 60 years. Two petroleum systems have been identified: a Plio‐Pleistocene biogenic gas system, and an Upper Triassic – Lower Jurassic oil system. These systems are described in this paper within a regional geological framework, with particular focus on petroleum system elements (source, reservoir, seal, trap and charge). The biogenic gas play was for several decades the prime focus of Italian E&P efforts throughout the Adriatic area but is now mature, and significant additional discoveries are unlikely to be made without a breakthrough in DHI (direct hydrocarbon indicator) technology. The Mesozoic oil play is as yet unproved in the northern Adriatic area, where large anticlinal structures at depths of up to ca. 6000 m are available for exploration and constitute high‐risk – high‐reward targets. By contrast, the play is proved in the Central and Southern Adriatic where several oilfields are currently producing. Exploration targets still exist here and may generate medium‐sized discoveries although the prevalent heavy‐oil phase may jeopardize their economic value.

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The aim of this work is to provide a synthetic history of the Italian upstream oil and gas industry, from its early start until today. Among European countries, Italy has one of the richest abundance of evidence of hydrocarbon seepages. The populations that have inhabited the country during the various historical periods took advantage of these phenomena, harvesting oil and bitumen from the surface. A testimony of such activity is an ingot of purified bitumen dated as first century AD found in central Italy. In the nineteenth century, seepages attracted the interest of oil companies that began to explore the Apennines. The drilling of the first modern oil well was realized in 1860 near Ozzano (Parma). The first onshore seismic reflection survey was acquired in 1940. The well Caviaga-1 was drilled in 1944 near Milan, discovering a gas field of 12.5 Bcm. It was one of the major European gas fields and it marked the starting point of the modern Italian petroleum industry. The widespread use of seismic reflection triggered an intense period of exploration. The first material oil discoveries were Ragusa (in 1954) and Gela (in 1956), both in Sicily. By the mid-1950s, the first offshore seismic survey started in the Adriatic Sea. In 1959, the drilling of well Gela 21, the first offshore well in Europe, boosted further exploration possibilities. During the following decades, the level of exploration and production (E&P) activities remained high, while from the beginning of the third millennium there has been a general slowdown. Since 2007, the level of exploration drilling has dropped to under 10 wells per year. In 2014, this negative trend was further confirmed with no exploratory wells drilled. The causes of this decline derive from the exploration maturity of the biogenic gas play and from the heavy bureaucratic processes involved in obtaining authorization. However, the main cause is probably the strong opposition from environmentalist associations to any kind of petroleum activities.