CALGARY, Alberta (Reuters) - Canadian Natural Resources Ltd's (CNQ.TO) Horizon oil sands plant in northern Alberta is shut down for unplanned repairs and could be off line for two to three weeks, a source with knowledge of the situation said on Tuesday.
The outage pushed up U.S. oil prices and pressured Canadian Natural shares, which fell as much as 5.2 percent. By early afternoon they were down C$1.69, or 4.2 percent, at C$38.59 on the Toronto Stock Exchange.
"It's off, and probably for two to three weeks," the source said.
The shutdown of the 110,000 barrel a day plant, the fourth-largest Canadian tar sands mining and crude processing venture, came as discounts for the synthetic oil had been deepening due to booming industry-wide supplies.
The work, which is said to be concentrated on one of the fractionation towers, follows weekend maintenance at the site. The plant was down for seven months in 2011 following a fire early that year.
Canadian Natural officials were not immediately available for comment.
Talk of the disruption helped prompt a spike in benchmark West Texas Intermediate of nearly $3, narrowing the Brent-WTI spread from a three-month low under $20 to around $18 a barrel.
Reporting by Jeffrey Jones and Scott Haggett; editing by Rob Wilson