The decision comes a month after oil production started at the field, which is located deep offshore, 180km off the coast of Rio de Janeiro, in the pre-salt area of the Santos Basin in Brazil.

Total said that the new phase includes floating production storage and offloading (FPSO), which has a capacity for 150,000 barrels per day from 17 wells.

Total exploration and production president Arnaud Breuillac said: “We have worked with Petrobras, the operator, and our partners to secure technical costs below 20 dollars per barrel.

“Following startup of the Early Production System in November, this investment decision further strengthens our portfolio of projects under construction and feeds our production growth post-2020.”

The partners produced first oil from the Libra field using the Pioneiro de Libra, a 50,000-barrel-per-day FPSO.

In November, Petrobras has submitted the declaration of commerciality to the Brazil’s National Petroleum, Natural Gas and Biofuels Agency (ANP) for the oil accumulation discovered in the northwestern portion of Libra block.

The field, which has been named Mero, is estimated to have total recoverable volume of 3.3 billion barrels of oil.

As a next step in the Libra field development, the new “Mero 1” FPSO is planned to be commissioned in 2021.

As part of this work, the Libra consortium, which is led by Petrobras, has awarded a contract to Modec to charter the FPSO, the first definitive production system of Mero field.

Petrobras holds a stake of 40% in the Libra field, while Shell and Total have 20% stake each. CNPC and CNOOC also hold 10% stake each.

The Libra consortium plans to deploy three other FPSO to fully exploit the potential of the field, which is expected to reach production capacity of more than 600,000 barrels per day.