As Petrobras noted, a small amount of oil reached a stream that passes through the refinery internal grounds.
However, the leak is under control, while safety and emergency teams were immediately deployed, in order to contain and repair the affected area.
Petrobras has reported the incident to the relevant authorities, with its causes being examined.
Rnest is currently operating normally.
Before that leakage, an investigation at the external tanks of FPSO 'Cidade do Rio de Janeiro', at the Espadarte field in Brazil, revealed cracks at the hull, the Tokyo-based operator MODEC informed.
Over the weekend, 1.2 cubic meter of residual oil leaked from the unit, which was identified and recovered, the operator said.
On Monday, 26 August, in a new overflight, the presence of oil at sea was perceived, in an estimated amount of 6.6 cubic meters.
The FPSO 'Cidade do Rio de Janeiro' is located in the Campos Basin, 130 km off the coast of Brazil.