Suncor said Stage 3 of the facility went online in August and has since exceeded initial expectations. First oil from a fourth stage of the facility is expected by the end of the year, there months ahead of schedule and 10 percent under budget.
The company said production at the Firebag complex reached an average capacity of 113,000 bpd during the third quarter of this year.
"Quarterly production was up over 100 percent from last year's third quarter production of approximately 55,000 bpd," the company said in a statement.
Steve Williams, president and chief executive officer at Suncor, said the Firebag facility was a "crucial component" of its oil sands portfolio.
The first two stages of the Firebag production facility have been in operation for more than five years. Combined production was estimated at around 60,000 bpd.