Abstract 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.

Abstract: Mud volcanoes occur in many petroliferous basins and are associated with significant drilling hazards. To illustrate the type of information that can be extracted from limited petrophysical datasets in such geomechanically complex settings, we use P-wave velocity data to calculate the mechanical properties and stresses on a two-dimensional vertical section across a mud volcano in the Azeri-Chirag-Guneshly field, South Caspian Basin. We find that: (1) the values of the properties and stresses calculated in this way have realistic magnitudes; (2) the calculated pore fluid pressures show spatial variations around the mud volcano that potentially highlight areas of fluid recharging after the most recent eruption; and (3) the information obtained is sufficient to provide helpful indications of the width of the drilling window. Although calculations of this kind may be readily improved with more sophisticated petrophysical datasets, the simplicity of this approach makes it attractive for reconnaissance surveys designed to identify targets worthy of further investigation in developing our understanding of mud volcano geomechanics, or which could be used to help formulate drilling strategies. Correction notice: The original version was incorrect. All instances of mbsf (metres below seafloor) should have read mbsl (metres below sea-level).

Abstract The LUSI mud volcano in the sub-district of Porong, Sidoarjo, East Java, Indonesia started to erupt on 29 May 2006. An almost continuous eruption of a mixture of mud, water and gas has occurred around this area since this date. The eruption triggered vertical and horizontal ground deformation. From June 2006 to December 2010, 14 global positioning system campaigns were conducted to observe the ground deformation using c . 50 stations sparsely located up to 10 km from the eruption centre. Field observations of cracks, terrestrial laser scanning and geo-electrical measurements have also been used to infer the ground deformation signature around the LUSI mud volcano. More than 150 pairs of interferograms generated from 66 ALOS PALSAR images from June 2006 to December 2009 have also been used to study the ground deformation caused by the LUSI mud volcano. The LUSI mud eruption began only 200 m from where the Lapindo Inc. oil company was drilling for oil and gas. The drilling may have pierced a deeper high-pressure zone, causing an underground blow-out of the drillhole into a hydrofracture. Alternatively, the magnitude 6.3 Yogyakarta earthquake, which was located c . 275 km from the eruption site and occurred two days before the LUSI eruption, may have shaken the area sufficiently to cause the eruption by reactivating a fault in the region and liquefying the mud. These two hypotheses for triggering the mud volcano have been argued vehemently and still remain controversial. The ground deformation signatures provide important clues to understanding the trigger for the eruption and to solve this controversy. Co-seismic fault reactivation has its own typical ground deformation signature. This study used global positioning system and InSAR techniques, as well as field observations of cracks, terrestrial laser scanning and geo-electrical measurements, to determine the signature of ground deformation around the LUSI mud volcano and to explain the triggering mechanism.