refineries.

Western Canadian Select jumped as much as $12.20 a barrel to $13.80 below the U.S. benchmark Monday, the narrowest spread since May 16. Canadian crudes have weakened to historically low levels in recent weeks as growing oil rig flanges gulf coast production overwhelms available pipeline capacity to transport Alberta’s supplies south of the border.

Canada’s biggest crude-export pipeline operator told shippers Monday that it won’t proceed with recently announced rules setting an allowance for the amount of crude companies could nominate for transport on its mainline. The move came after discussions with shippers, Enbridge said.

"Producers have a strong say in how the buy Wellhead market is going to be participated in,” Tim Pickering, chief investment officer at Auspice Capital Advisors Ltd., said in a phone interview from Calgary. The Enbridge turnabout shows that "the pipelines can’t just do changes that aren’t fair and are not conducive” to its customers.

The National Energy Board, Canada’s pipeline regulator, didn’t intervene on the Enbridge matter and received no complaints, spokeswoman Chantal Macleod said in an email.

In a notice last month, the BOP Blow Out Preventer repair company gulf coast informed shippers that their volumes would be based on a 12-month rolling average, plus 15 percent for heavy crude and 40 percent for light crude and that the new rules applied to July shipments onward. Shippers who wished to send more than their allotted amount would have had to show physical proof of the volumes.

"Enbridge’s mainline system continues to be oversubscribed," Enbridge said in a statement. "We have been engaged with our customers to improve the nomination process and will continue to work directly with them on this issue."

With assistance from Catherine Ngai. To contact the reporters on this story: Sheela Tobben in New York at This email address is being protected from spambots. You need JavaScript enabled to view it.; Robert Tuttle in Calgary at This email address is being protected from spambots. You need JavaScript enabled to view it.. To contact the editors responsible for this story: David Marino at This email address is being protected from spambots. You need JavaScript enabled to view it. Catherine Traywick.