The 15-mile-long dual pipeline, inaugurated Saturday, will carry oil from the Junin 5 field to a processing facility operated by Venezuela's state-owned energy company Petroleos de Venezuela, known as PDVSA.
PDVSA and Eni manage Junin-5 through a joint venture in which the Venezuelan company holds a 60 percent stake.
The field, located in Venezuela's offshore Orinoco oil belt, is expected to produce about 240,000 barrels of oil per day at its maximum. Production started in March.
Last year, Eni agreed to provide up to $1.5 billion to help Venezuela develop its share of the production phase of Junin 5.
The Italian energy company estimates it will drill about 1,500 wells in the area.