* Enbridge Line 6A pipeline expected to restart on Friday
* Mixed U.S. economic data spurs negative sentiment
* Hurricane Karl seen sparing Mexico oil patch
* Coming Up: U.S. August CPI inflation Friday (Recasts, updates market activity, prices, adds analyst quote, changes byline and moves dateline from LONDON)
By Gene Ramos
NEW YORK, Sept 16 (Reuters) - Oil prices fell nearly 2 percent on Thursday, sliding for a third day, as U.S. Midwest supply anxieties eased further on news that a major Canadian pipeline carrying crude to the region would be back in service by Friday.
Prices were also pressured by mixed U.S. data showing weekly jobless benefit claims eased slightly and mid-Atlantic factory activity contracted more slowly, further reducing the chances of a feared double-dip recession, but confirming that the economy remained on a slow growth path. [
]U.S. benchmark crude futures for October delivery <CLc1> settled down $1.45 at $74.57 a barrel, after earlier dropping to a session low of $74.11.
Oil prices have now completely erased their surge to as high as $78.04 on Monday, following the closure of Enbridge Inc's 670,00-barrels-per-day Canada-U.S. crude oil pipeline last Thursday after a leak, halting up to a third of Canada's crude exports to the United States.
The line was set to resume operation on Friday after the company completed repairs and received regulatory clearance, Enbridge said.
In London, European benchmark ICE Brent crude for November delivery <LCOc1> traded down $1.07 at $78.35 a barrel, widening its premium against U.S. crude as traders unwound bets that the pipeline outage would drain inventories in the Midwest, and particularly in the key storage hub in Cushing, Oklahoma.
However, the latest data showed that crude stored at the hub rose by 93,496 barrels to 37.66 million barrels in the week to Sept. 14, according to a report from industry data provider Genscape on Thursday.
The U.S. Energy Information Administration's data on Wednesday showed that stocks at that delivery point fell 581,000 barrels to 34.95 million barrels in the week to Sept. 10. [
]"With the return of the Enbridge line shut last week now imminent, the crude oil market is looking at external financial markets, where there is negative economic sentiment today," said Gene McGillian, an analyst at Tradition Energy, in Stamford, Connecticut.
"That's the feeling, even though the weekly jobless claims dropped, but not too much," Mcgillian said.
Meanwhile, weather worries were easing.
Karl strengthened and became a Category 1 hurricane in the southern Gulf of Mexico on Thursday as it headed for the coast of eastern Mexico, but none of the country's dozens of offshore oil platforms reported damage due to Karl's passage, state oil firm Pemex said on Thursday.
Nonetheless, Mexico closed two of its three main oil export ports in the gulf, guarding against rough weather.
U.S. STOCKPILES DOWN, SUPPLIES STILL HIGH
Wednesday's U.S. government data showing crude and product inventories all fell last week did little to ease worries over a surplus of crude oil.
Total U.S. commercial crude and product inventories fell by just 2.9 million barrels to just above 1.14 billion barrels in the week to Sept. 10, easing from their highest weekly level since 1990, when the government began issuing weekly reports.
In Europe, suplies of crude from the North Sea have been restricted since mid-summer due to maintenance work, helping support Brent prices relative to U.S. crude, but those stocks are now rising gradually.
Crude oil output from nine of the main North Sea streams will increase by 9.9 percent in October, according to data compiled by Reuters on Thursday from trading sources. Output in October is set to average 2.017 million bpd, up from 1.836 million bpd planned in September. (Additional reporting by Robert Gibbons in New York; Christopher Johnson in London; Alejandro Barbajosa in Singapore; Editing by Walter Bagley)