By Guidi, Francesco; di Cesare, Franco; Cippitelli, Giuseppe - IAASM

JOURNEY THROUGH THE PAST
CAVIAGA GAS FIELD
By Guidi, Francesco; di Cesare, Franco; Cippitelli, Giuseppe
THE AUTHORS EXPRESS THEIR APPRECIATION TO DOCTOR RICCARDO COEN, FORMERLY
EXPLORATION MANAGER WITH AGIP PETROLEUM IN HOUSTON, (TEXAS) FOR HIS
INSIGHTFUL SUGGESTIONS.
1. Inflammable Air Native from the Marshland
Alessandro Volta, Italian physicist and inventor, known for his pioneering work in
electricity, was the first scientist to study methane and to understand its origin. In 1774 he
was a Professor of Physics at the Royal School of Como. While on his summer holidays, in
1776, on Lake Maggiore, his boat went alongside the reeds near Angera. Volta began to
poke the muddy bottom of the water with a stick and saw lots of gassy bubbles floating up
to burst on the surface. He collected some samples of the marsh gas and discovered it was
inflammable. He called it inflammable air from marshlands. It was what we nowadays
call methane.
Fig 1:
Alessandro Volta, born in Como, Italy, from a noble
family on 1746 and died on 1827 at the age of 82.
Prolific inventor he is well remembered for his
invention of the electric battery and studies on
methane.
In 1800 he invented the “Voltaic Pile” which was the
first “wet cell battery” that produced a reliable,
steady current of electricity.
For the first time, Alessandro Volta recognizes the source of this inflammable gas when he
states: and it is very likely that this inflammable air originates from vegetables soaked and
dissolved in water.
It is interesting to note that the first natural gas discovery in Europe occurred in the little
village of Caviaga, in the Po Valley, approximately 100 kms South-East of Como.
As far as the current global forecast is concerned, the widely accepted assessment is that
natural gas is the most important energy source in the world: the 2030 projections of BP’s
Statistical Review clearly state oil continues to suffer a long run decline in market share, while
gas steadily gains. (fig 2).
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Fig 2: BP Energy Outlook 2030
Following the above brief historical introduction, the evolution of the gas industry in Italy
will now be reviewed.
___________________________________________
2. Gas in Italy
The Caviaga gas field has been the spark that allowed Italy to become an industrialized
Country and overcome the painful and destructive wounds of WWII. The search and
development of natural gas gained momentum and expanded from the little village of
Caviaga, to the entire peninsula including Sicily and the offshore Adriatic. Italy’s gas
consumption soared rather quickly and the BP Statistical Review reports that in 2010 the
country’s gas consumption (76.1 bcm or 2,700 bcf) was third in Europe behind the United
Kingdom (93.8 bcm ore 3,300 bcf) and Germany (81.3 bcm or 2,870 bcf); ahead of France
(46.9 bcm or 1,650 bcf). Italy’s gas production in that year has been of 7.6 bcm (270 bcf).
In any case Italian gas industry has developed a good pipeline system with a grid of more
than 33,000 km (20,500 miles) and the natural gas trade movement in 2010 amounted to
75.34 billion cubic meters (2,660 bcf).
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Fig 3: Enrico Mattei (1906- 1962)
Fig. 4: North Italy and Caviaga Village
The Caviaga gas field was the first gas discovery by Agip (July 15, 1944) in the Po Valley
area while the WWII conflict was still being fought on the Italian peninsula. Agip’s
President, Enrico Mattei (1906 – 1962), promptly realized the value and significance of the
gas discovery that would be instrumental, in the years to follow, in allowing Italy to enter
the post industrial phase.
The discovery of the Caviaga gas field was not only the starting point for the development
of O&G in Italy; it also was the initial milestone that propelled Agip into the international
E&P arena where it evolved becoming a significant competitor
In 1944 Agip drilled the Caviaga gas discovery well, just a few kilometers south of Milan.
The open flow production testing carried out in the Pliocene reservoir section reached
100,000 cmd, which was highly encouraging. The testing results were indicative of a
potential of very high reserves which displayed along with the first large gas deposit in
Western Europe, an almost inexhaustible and then practically unknown source of power.
Today natural gas is among the most widely used energy sources, because it is more
environmentally friend than oil and also offers a higher yield, especially when employed
to produce electrical power.
The Caviaga gas field discovery was made a few decades before gas was found in the
Netherlands and in the Northern Sea: consequently Italy was able to break through the
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European gas market at least 30 years ahead of the other European countries. In the early
1970s Italy produced and consumed 14 bcm (almost 500 bcf) of natural gas a year, while
gas production and consumption were insignificant in other European countries.
3. The State of Exploration for Hydrocarbons in Italy in the Early Forties
To place all the facts in the proper context we should examine how hydrocarbon
exploration in Italy fared in the 1930s.
4
Fig. 5: Orso Mario
Corbino
….In Italy it was a few years after the
WWI that the country’s own petroleum
industry took its first tentative steps,
triggered by the Sinclair scandal. A row
had erupted after Mr. Orso Mario
Corbino (1876 – 1937), Italian Minister
for National Economy and Mr. Weach,
Vice President for Exploration of
Sinclair, a New York – based oil
company, signed an agreement on 29
April 1924, granting the American
company exclusive rights to
hydrocarbon exploration in almost the
whole Sicily and a good part of
Emilia/Romagna region. Following a
ferocious press campaign mounted
against the deal, Orso Mario Corbino
and his official had to resign and the
Sinclair agreement was revoked on
January 1925. Not long after in 1926, the Italian Government, well
aware of the difficulties in supplying gasoline and diesel to the
Italian market , founded the Azienda Generale Italiana Petroli,
AGIP, with the mission to explore, produce and purchase any sort of
hydrocarbon both in Italy and abroad in order to stock the domestic
market. But exploration in the Italian Peninsula, geologically
broken by so many orogenic movements, did not achieve very much
apart from finding a few accumulations of oil the northern
Apennines. It was therefore inevitable that the company would have either to look abroad. (di
Cesare - Guidi).
But domestic exploration activity was never abandoned and Agip geologists devoted the
search of drilling opportunities targeting the northern Apennines where many natural
gas shows and seeps had been mapped and exploited since the Middle Age.

Here many of these seeps are from the “Argilla Scagliose” unit, a sequence composed of argillites
and calcareous and sandy flysch with a complex and, in some places, a chaotic structure. This unit
overlies the Tertiary flysch of the Northern Apennines sequence and is overlain by Oligocene-
Miocene and Pliocene clastics. Most nineteenth century Italian geologists assumed that the Argille
Scagliose is itself the source of the petroleum seeps, while others favoured a deeper origin. Whatever
their origin, oil and gas accumulations in the Northern Apennines, as a rule, were small in size and
low in productivity, and their discovery was mainly due to chance.
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Fig. 6: Cesare Porro 1865-1940 (Porro)
In 1921, Cesare Porro, an Italian petroleum
geologist of wide international experience (was
one of the most eminent petroleum geologists of
his generation. His experience spanned the
world from the East Indies to the United States
where he discovered the Salt Creek field in
Wyoming) summarized the status of
exploration in Northern Italy. In his opinion,
the Argille Scagliose could be the source of
petroleum but accumulations in economic
quantities require a reservoir rock sealed in a
trap; reservoirs, seals, and traps are all
lacking in the Northern Apennine area ,but he
thought these elements possibly could be
present in the external part of the Apennine
chain where tectonism was presumably less
intense and where Pliocene clays could provide
an effective cap rock. This “external Apennine”
could be buried under the alluvial cover of the
southern Po Plain where geophysical surveys
could be used to identify possible traps.
Encouraged by this geological model, regional
gravimetric surveys were carried out by Agip,
during the years 1927 to 1935 and later by SPI
(a subsidiary of the Standard Oil Company of
New Jersey). Several tests were drilled on
positive anomalies, but results were disappointing. The sedimentary sequence of the Po Plain
subsurface was found to be different in thickness and facies from the sequence exposed in the
Apennines: tectonism was found to have been greater than predicted and structural conditions
could not be reliably interpreted from the gravimetric survey. Furthermore, gas and oil shows were
scanty. (Pieri)
4. Gas Seeps in Caviaga
Agip’s geological interest focused on areas where oil and gas seeps were detected:
Attention of the Agip Geologists were addressed, as mentioned before, to oil and gas
seeps and in Caviaga, a small town in the Cavenago d’Adda district, near Lodi, was highly
graded for that reason. In this area the natural gas seeps had been noticed in the outskirts
of town by local resident for a very long time: the methane, seeping from the subsurface,
polluted the air so much that the area was called “Via Gas” (Gas road).

Fig. 7: Caviaga and “Via Gas” (Gas road)
Fig. 8: Caviaga, Via Gas (Gas road)
5. Agip In Italy
Agip had been set in 1926 by the Italian Government to help Italy to enter the field of oil
and gas exploration/development: In fact the Italian economy could not find enough
private capital to finance oil research. While Agip had attained some significant results in
Romania, Albania and Iraq, achievements in Italy had been scanty. In the Thirties Agip
produced just 1,000 tons of oil per year (7,000 barrels/year) in Italy, against a consumption
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of some million tons and about ten million cubic meters of gas per year (35 million cubic
feet).
Such meagre results in spite of a remarkable commitment with the drilling of 15 wells per
year, on average, were due to Italy’s complex geology and the lack, at this time, of
adequate technique capable of defining the subsurface pattern. At this moment Agip
geologists decided to utilize a new geophysical methodology i.e. the seismic reflection
which had been proved to be very effective in the United States.
6. Seismic in Po Valley
However, these were years when German technology dominated Continental Europe and Agip
geophysicists were used to receiving information about the efficiency of German seismic
methodology. Agip first decided to send a technical mission to Germany, which lasted from 20 to 30
July 1938 during which time the Italian scientists had access to top German technology. Yet the
final report, despite the political ties between Italy and Germany did not contain any enthusiastic
recommendations, It was probably for this reason that Agip management did not make any
contracts with German companies and instead decided to compare the status of the German seismic
technology with the United States’.
Agip management succeeded in convincing the Italian Prime minister Benito Mussolini to approve
a visit to the USA. The mission set off in December 193, and after having met all the geophysical
companies and some petroleum companies active in the Unite States, the final recommendation was
decidedly in favour of Western Geophysical. The final report of the mission was subject to
considerable debate and not finalised until March 1939.
In the meantime dark clouds were looming on the horizon. The declarations of Adolf Hitler were
threatening everything and a ruinous fury was affecting the minds and souls of the nations.
Despite impending gloom, Agip succeeded in signing a contract with Western for a seismic crew to
be utilized in the Po Plain…On June 10, 1940 the day Italy entered WWII, already underway
without the US, the first American seismic crew from Western Geophysical started acquisition
work near Lodi, a few km south of Milan. Four years later, after the seismic surveys had been
completed, Agip’s Caviaga well, near Lodi, found what potentially was the first large European gas
field. (di Cesare – Guidi).
Following letter from Agip, Mr. Egidio Castelli, the Caviaga Podestà (The Chief Magistrate
in a Commune, Collins), authorized to perform seismic surveys in the area, i.e. to explode
mines in the territory of this community. The mines will be made up of dynamite or other explosive
of the second category, in the amount of 1 to 50 kg per charge and they will be exploded in depth
(Pallavera).
And the Western Geophysical seismic survey started on June 10, 1940 (deep shooting).
Two were the American technicians who had even the commitment to train the Italian
technicians from Agip. In October 1940, i.e. 4 months after the seismic crew had arrived in
Italy, following pressures from the American Embassy in Rome, which considered the US
entry in war as near (On 11 December 1941, Germany and Italy declared war on the
United States). Works went on and a structure was quickly traced out at Caviaga, being
the first structure detected in the Po Valley. The reports of the time describe the Caviaga
structure as a wide anticline stretching toward East-West for about 8 km (5 miles).
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7. Exploration in the Caviaga Structure
The wild cat produced the first positive result on 15 July 1944, following a producing test
in Lower Pliocene formation (prevailing sands with thin shale intervals) in the interval
1.374 – 1403.5 m (4,508’ – 4,605’). War events prevented intensive and regular tests which,
on the contrary were made in Caviaga 2 wells, on 1946.
60 wells for production were drilled which disclosed an average pay of more than 300
meters (1,000’) of sands with an average permeability of 750 md.
Produced reserves amount to 14 billion cubic meters (495 billion cubic feet). The ensuing
exploration activity has made evident Caviaga being part of a number of structures laying
in the Po Valley where they took their shapes and energy . (fig 13)
Fig. 9: Caviaga gas field, top Miocene Unconformity
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Fig. 10: Caviaga Gas Field: top Lower Pliocene producing sands
Fig. 11: Caviaga Gas Field: Longitudinal depth Section
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Fig. 12: Caviaga Gas Field
Caviaga 2 Well
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Fig. 13: Pliocene Structures in Western part of Po Plain
8. Present Gas Exploration and Production in Italy
Natural Gas in Italy has been mostly produced in Po Valley and Adriatic offshore. Total
production is summarized in the enclosed diagram, prepared by Jerà, utilizing data as
provided by Assomineraria (Association of Petroleum Companies operating in Italy) and
by DGRIME (Department for Energy of the Ministry for Economic Development).
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25000
20000
15000
10000
5000
Million cm produced per year
0
1951 1956 1961 1966 1971 1976 1981 1986 1991 1996 2001 2006 2010
It is clear that there has been a sharp decrease in production from 1994 to 2010, passing
from 20.6 billion to 7.9 billion.
The recent Macondo blowout in Gulf of Mexico (April 2010) has had a very negative
impact on the offshore petroleum exploration in Italy, notably in Adriatic Sea where the
Legislative Decree No. 128, of June 29, 2010 has practically blocked all the activity. In the
central and northern part of this Adriatic Sea, Agip in the years 1992 and 1994 had
acquired two large regional seismic 3D surveys for approximately 13,000 sq km (5,000 sq
miles). The largest in the world at that time. The interpretation of the data had indicated
the possible presence of many gas prospects.
9. Bibliography:
1. Assomineraria: L’Italia, Paese di Idrocarburi, 1999BP Energy Outlook 2030,
London, January 2011
2. BP Statistical Review of World Energy, June 2011
3. BP Energy Outlook 2030, London, January 2011
4. di Cesare, Franco; Guidi, Francesco: A story of two men and the beginning of
the Italian oil Industry, First Break, February 2003, Volume 21
5. Guidi, Francesco: Il Gigante della Val Padana (The Po Valley Giant) Eni’s
Way, 1994
6. Guidi, Francesco; di Cesare Franco: Caviaga a Sessant’anni dalla scoperta.
Industria Mineraria 1-2, 2004
7. Guidi, Francesco; di Cesare, Franco: The Birth of Agip in the Oil World
Landscape, SPE Technical Bulletin 3/2008
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8. Guidi, Francesco; di Cesare Franco: Alfredo Giarratana a Technician at the
Helm of Agip; SPE Technical Bulletin Special Issue 2009
9. Guidi, Francesco; di Cesare, Franco: Twenty First Century: a Natural Gas
Economy, SPE Technical bulletin 3/2010
10. I Giacimenti Gassiferi dell’Europa Occidentale, Roma Accademia dei Lincei,
1959
11. Pallavera, Ferruccio: Storia di Cavenago D’Adda, 1989
12. Paoloni, Carlo: Storia del Metano, 1976
13. Pieri, Marco: Cortemaggiore Field – Italy Po Plain, Northern Apennines,
AAPG Special Volumes. Volume TR: Structural Traps VII, Pages 99 -1118 (1992)
14. Pizzigallo, Matteo: L’Agip degli Anni Ruggenti (1926-1932), 1984
15. Porro, Anna; Porro, Pietro: Vita di Cesare Porro, Geologo. 1985
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