The production commenced just eight months after obtaining the production permit, the company said.
Located at a water depth of 28m and close to existing plants, the Nené Marine field can produce from Djeno pre-salt formation 2.5km below the ground level.
The complete field development will be performed in several stages and will comprise the production platforms installation and the drilling of over 30 wells, with a plateau of over 140,000 barrels of oil equivalent per day (boepd).
The first phase production is anticipated at 7,500 boepd.
Eni CEO Claudio Descalzi said: "The startup of Nené Marine field achieved just eight months after obtaining the production permit is a great result for Eni, and confirms our strategy of rapid exploitation of exploration resources, thanks to the technical and planning capabilities of the company and the integration of exploration, operational and development efficiency."
Eni, through its own subsidiary Eni Congo SA, operates Marine XII with a 65% stake while the other partners include New Age with 25% stake and Société Nationale des Pétroles du Congo with 10% interest.
