From Bulletin 1999, N.1

RAVENNA AND ITS IMPORTANCE IN ITALY'S HYDROCARBON HISTORY

Ravenna, city of great historical importance, holds a prestigious place in Italy's hydrocarbon history. Indeed, it was here that the giant Ravenna onshore gas field, first in a long line of discoveries which then continued offshore in 1960, was discovered in 1952 and confirmed the Adriatic Sea's prominent position in Europe as regards gas reserves. And it was here in Ravenna that Italian offshore techniques, which would become first in Europe, were born.

Hydrocarbon exploration arrives in Romagna

It all began in the Fifties when AGIP, in the wake of the exploration successes in the Po Valley, progressively moved towards the South, into the Romagna region. At least eight seismic crews were working in the Po Valley, looking for structures, while around twenty drilling rigs immediately controlled the structures identified which, in the event of success, were subsequently developed.

The Ravenna 1^st gas discovery

It was in this way that in 1952 the Western Geophysical Company's seismic crew, which had set up its base at Forlì, reached Ravenna and the seismic lines recorded immediately identified a large structure which AGIP decided to drill. On September 15 of the same year the Ravenna 1 well (onshore) reached a depth of 1,740 metres and gas shows were recorded. Oreste d'Agostino, site geologist at that time (he would then become Managing Director of Exploration) still remembers those moments with great emotion. The electric logs identified a high resistivity zone between 700 metres and bottom hole, which then proved to be gas bearing during the tests. The fortunate run of the Ravenna District gas discovery successes had begun.

Seismic surveys identified numerous other structures which all proved to be gas bearing. The onshore reservoirs Alfonsine, Cotignola, Santerno, Imola and Selva were discovered in this way. The work took on such importance that AGIP decided to create a District office in Ravenna, whose first manager was Egidio Egidi, who would then become Chairman first of AGIP and then of ENI.

The early stages of exploration in the Adriatic

The time was ripe for expansion of exploration activities into the Adriatic where geologists envisaged an extension of the Po Valley. In the mid-Fifties AGIP carried out an offshore seismic survey in this sea which identified the presence of numerous structures. In 1959 Scarabeo 1 began drilling the first well offshore Ravenna, called Ravenna Mare 1, which, however, proved dry as did Ravenna 2. Success came with the third discovery, Ravenna Mare 3, which marked a turning point in Italy's hydrocarbon exploration and production sector, opening up offshore scenarios until then ignored in Europe. Indeed, the first offshore well in Western Europe was drilled in Italian seas. This was Gela 21, in Sicily in 1959, followed by Ravenna Mare 1.

The new Italian oil law for offshore activities

However Italy has no legislation governing offshore exploration and production activities. In the early Sixties ENI-AGIP set up studies to propose a law for the offshore sector which would then be used as a model for all the other European countries. In 1967, the Parliament launched a law which opened up Italian seas to hydrocarbon exploration.

After that, offshore activities in the Adriatic expanded, moving further away from the coastline and the series of discoveries continued. At the end of the Sixties, gas production exceeded 10 billion cubic meters per year with the District of Ravenna producing 30% of this amount. Production continued to increase over the years. In 1998 gas production from the District of Ravenna was 13 billion cubic metres per year, on a total of 18 billion cubic metres produced by ENI-AGIP in Italy.