The state-run oil company confirmed the incident aboard the P-48 FPSO on Friday, saying that the unit is no longer producing and there is no estimate on when it may restart again.
The fire broke out at about 1:45 p.m. local time on Thursday and was quickly brought under control, Petrobras said. One fire fighter suffered minor injuries while battling the blaze. No other injuries were reported.
Photos of smoke billowing from the FPSO began circulating online shortly after the fire broke out.
The P-48 floating production, storage and offloading ship (FPSO) is moored in about 1,000 meters of water at the Barracuda-Caratinga fields.