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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 63 (1979)

Issue: 3. (March)

First Page: 446

Last Page: 447

Title: Malossa Field, Deep Discovery in Po Valley, Italy: ABSTRACT

Author(s): G. Errico, G. Groppi, S. Savelli, G. C. Vaghi

Article Type: Meeting abstract

Abstract:

The discovery of the Malossa gas and condensate field 15 mi (24 km) east of Milan is one of the more recent results of the exploration activities carried out by AGIP in the Po Valley since the 1950s.

The structure was recognized by a seismic reflection survey. Since 1967-68, with the introduction of digital techniques in geophysical prospecting, the reflection seismic method has allowed better information at a greater depth with a vast improvement in quality of the reflecting horizons. The Malossa field structure is a faulted, southward-overthrust block. The top of the hydrocarbon-bearing formation is at about 5,400 m. Hydrocarbons are present in the Dolomia Principale Formation of Noric (Mesozoic) age. Even though the formation has low porosity values it is the main reservoir.

The caprocks are a marly limestone of Cretaceous

End_Page 446------------------------------

age and Oligocene marlstones. The source rock is considered to be the Rhaetic black shale, which was deposited in an euxinic environment.

Drilling activities have to overcome unusual difficulties owing to high pressure gradient. New methods to forecast and study overpressured zones have been developed. The hydrocarbons in the reservoir are in a gas phase. Reservoir pressure is 15,000 psi (103,425 kPa), temperature is 300°F (149°C), a minimum amount of carbon dioxide is present, and serious problems of corrosion have to be faced in the completion operations. Estimated original reserves are 50 × 109 cu m of gas and 40 × 106 tons of crude oil.

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Copyright 1997 American Association of Petroleum Geologists