Canada's second-largest oil producer said that it would now produce 740,000 to 750,000 barrels of oil equivalent per day (boepd), down from the earlier outlook of between 740,000 and 780,000 boepd.

Suncor said Syncrude's first coker returned to partial production in the second half of July, with a ramp up to full rates expected in September.

The Calgary, Alberta-based company said net income more than doubled to C$972 million ($745.6 million) or 60 Canadian cents per share in the second quarter ended June 30, from C$435 million or 26 Canadian cents per share a year earlier.

The company's operating profit, which excludes one-time items, jumped 22.4 percent to C$1.19 billion, or 73 Canadian cents per share in the quarter.

Analysts had predicted earnings of 67 Canadian cents per share, according to Thomson Reuters I/B/E/S.

Total upstream production rose 22.7 percent to 661,700 barrels of oil equivalent per day, helped by gains at its Fort Hills oil project which began production in January.

(Reporting by Karan Nagarkatti and Uday Sampath in Bengaluru; Editing by Sandra Maler and Lisa Shumaker)