NEW YORK (Reuters) - Calgary-based Enbridge Inc said on Friday it has shut its 670,000 barrel-per-day (bpd) Line 6A, a main artery for Canadian oil exports to the United States, after finding an unspecified problem with the line in Wisconsin during maintenance.
No oil leak was found on 6A, which runs from Northern Wisconsin to Griffith, Indiana, but during maintenance a crew found a "feature on the pipeline that we thought it would be prudent to fix," said company spokesman Larry Springer.
Springer didn't offer more detail, but said the line was shut pending a "typical repair," possibly requiring a sleeve to be placed over the suspected weak-point on the line.
He offered no time or date for restarting the line, which is a main conduit of Canadian crude into the U.S. Midwest.
A repair could probably be completed in less than two days, assuming Enbridge has the right equipment on hand, said analyst Tim Evans of Citi Futures in New York.
"It doesn't sound like anything where they would need a lot of interaction with regulators to get a restart. We're a long way from a shortage of crude oil in the Midwest."
The outage follows a series of mishaps on Enbridge pipelines this year. Line 6A had earlier been shut down between September 9-17 after it leaked more than 6,000 barrels of oil in Illinois. That leak helped to set off a rally of nearly $4 a barrel in U.S. crude prices in subsequent days, on concern that crude supplies to Midwest refineries would drop sharply.
The line forms part of the Enbridge Lakehead pipeline system, a 59 year-old, 1,900 mile (3,060-km) network that delivers mostly Canadian crude throughout the Midwest, and ships some oil back up into Ontario, Canada.
U.S. crude futures rose after the bell on Friday. They settled up by 99 cents on the day, but later jumped another 18 cents a barrel to $82.84.
In late trade, cash gasoline prices along the Gulf Coast rose more than a penny per gallon, and the outage could have been a minor contributing factor to that rise, a trader said. There was no price reaction in Midwest region products, where trade is often thinner.
Springer said the pipeline anomaly was found near Owen, a town in northwestern Wisconsin. A spokeswoman at Wisconsin's Department of Natural Resources declined to comment on the latest 6A outage. The U.S. Department of Transportation wasn't immediately available for comment.
At more than 91 million barrels as of last week, commercial crude inventories in PADD II, the Midwest region, were still well above five-year average levels, although they are down from over two-decade highs near 98 million barrels reached in July.
Apart from recent troubles on Line 6A, Enbridge had one of the largest U.S. pipeline spills of the last decade on its Line 6B in July, where a leak spewed more than 19,000 barrels into a Michigan waterway. That line wasn't restarted until nine weeks later.
(Reporting by Joshua Schneyer, Robert Campbell, Robert Gibbons, Kristen Hays and Selam Gebrekidan)
Additional reporting by Tom Doggett in Washington; Editing by Lisa Shumaker