A natural gas pipeline rupture on TransCanada’s 1.6 Bcf/d North Central Corridor pipe in northern Alberta that serves Canada’s prime oil sands production area has caused at least two major oil producers to curtail production.

“We understand the outage is on one of the lines that brings in a large part of our gas supply,” said a spokesperson for Canadian Oil Sands Ltd., operator of the giant Syncrude project near Fort McMurray. “They are still assessing the situation and we’re not shipping any volumes. The Syncrude operation normally may ship as much as 300,000 b/d, or enough to meet about 15% of Canada’s daily energy needs. The natural gas is used to heat the heavy oil so it can be extracted.

Canadian Natural Resources Ltd. also said Thursday afternoon that it has cut production in the area.

“We are aware of a TCPL fuel gas supply interruption in the Fort McMurray area,” Canadian Natural Resources told NGI. “As a result, we have safely ramped down production at Horizon as well as production at our heavy oil operations at Woodenhouse. We understand that TCPL is at the site investigating the incident and are developing plans and alternatives on how to move forward with getting gas to the Fort McMurray region.”

According to Canadian Natural Resources reports, the company’s normal Horizon production capacity is approximately 110,000 b/d of synthetic crude oil, while Woodenhouse volumes are normally at approximately 15,000 b/d of heavy crude oil.

TransCanada Gas Control said it was alerted to the incident early Thursday on a section of pipe in the vicinity of the company’s Woodenhouse and Buffalo Creek North compressor stations affecting pressures in the Fort McMurray oil sands area.

“Our regional field staff is currently in the process of confirming the exact location and isolating the affected section if required,” TransCanada said in a notice Thursday.

The NGTL system gathers gas for use within the province of Alberta. It also delivers to provincial boundary points for connection with the company’s Canadian Mainline and Foothills natural gas pipelines and with the natural gas pipelines of other companies.