Brazil's federal energy major Petrobras expects to add a gas injection well to its local ultra-deepwater operations by December, the company said in a statement.

The Rio de Janeiro-based firm said preparatory drilling of well LL-38D-RJS was completed 29 days ahead of schedule.

"The well will help recover oil through the injection of gas in the reservoir and in turn optimize production," Petrobras said.

More than 2Mm3/d of gas is expected to be injected into the well, which will be connected to the Cidade de Mangaratiba compression unit at a depth of 2.21km.

The well is located in the Santos basin's Lula and Iracema Sul accumulations, off Brazil's southeast coast.

Petrobras said the area is responsible for producing about 500,000boe/d, almost a quarter of the company's overall domestic output.