Petro-Canada Inc. said Thursday its production in the third quarter slipped, but one-time gains helped its overall bottom line.

The Calgary-based company told investors Thursday that it made $678 million ($1.36 a share) in the third quarter, compared with $614 million ($1.19 a share) in the same period of 2005.

The most recent results were boosted by $114 million in gains on foreign-currency translation, asset sales, and derivative contracts.

The company's earnings from continuing operations after factoring out unusual items came in at $564 million ($1.13 a share), down from $638 million ($1.23 a share) a year earlier.

Petro-Canada's third quarter production from continuing operations averaged 333,000 barrels of oil equivalent a day, down from353,000 barrels in the same quarter of 2005.

The company said the shutdown of the Terra Nova offshore field and natural declines in the North Sea and in North American natural gas were partially offset by the addition of White Rose oil production and higher oil sands volumes.

"Our downstream and oil sands businesses had their strongest quarters ever,"company president and CEO Ron Brenneman said.

"At the same time, our upstream production is building with Terra Nova about to restart, the Syncrude expansion up and running, and new production coming on-stream from the North Sea."

Suncor earnings more than double

Another oil and gas player, Suncor Energy Inc., said its earnings grew to $682 million in the third quarter, from $315 million a year earlier.

The company credited higher oilsands production and higher commodity prices.

Suncor's oil and natural gas production jumped to an average of 277,400 barrels of oil equivalent perday, from 184,500 in Q3 of last year.