The Calgary-based company (TSX:CNQ) had originally planned for first-steam at the 40,000-barrel-per-day project in November, but now it's looking like that will take place during the third quarter.
The company also said the Kirby project remains on budget.
Canadian Natural reported net earnings from operations were $401 million, or 37 cents per share, missing the average analyst estimate of 42 cents per share, according to Thomson Reuters. Last year, it brought in $300 million, or 27 cents per share.
Revenues were $3.8 billion, up from $3.5 billion in the same 2012 quarter.
Net earnings, which include one-time accounting items, were cut in half to $213 million, or 19 cents per share, from $427 million, or 39 cents per share, a year earlier.
Average company-wide production during the first three months of the year was 680,884 barrels per day, up three per cent from the previous year.
At its flagship Horizon oilsands mine, production of synthetic crude oil — a premium product that has been upgraded from tar-like oilsands bitumen — averaged 109,000 barrels per day, a 31 per cent increase from a year earlier.
For all of 2013, Horizon production is expected to range from 100,000 barrels to 108,000 barrels per day, including a 24-day maintenance outage currently underway.
Canadian Natural also said it has found a partner to help it drill exploratory wells in the choppy waters off the South African coast. The company won't provide further details about who the partner is until it receives regulatory approval.
Earlier this year, it said it was on the lookout for a deal that will unlock value from its vast shale holdings in northeastern B.C.
It's a departure for the company, which has resisted the sorts of joint-venture deals that have been all the rage among its oilpatch peers in recent years.
Canadian Natural is the largest player in the Montney formation, which stretches through parts of northeastern B.C. and northwestern Alberta.
It said it is looking to "monetize" about a quarter of the more than 400,000 hectares it controls in the Montney. The land being offered is in the Graham Kobes area of B.C., an area rich in valuable natural gas liquids and outside of what Canadian Natural considers to be its core position.