* Canada to U.S. Keystone oil pipeline shutdown

* North Sea Buzzard oilfield restart delayed again

* Coming Up: U.S. CFTC commitment of traders data at 1930 GMT

(Recasts, adds fresh quotes, updates prices)

By Claire Milhench

LONDON, Oct 19 (Reuters) - Brent oil prices edged up towards $113 a barrel on Friday, retracing some of Thursday's losses after the shutdown of a key pipeline in the United States, and news of further delays in the restart of the UK's Buzzard oilfield.

At 1358 GMT December Brent crude oil futures LCOc1 were up

40 cents at $112.82 a barrel, but U.S. crude CLc1 was leading the way, up 71 cents at $92.81 a barrel.

Analysts and traders said oil was being supported by the shutdown at TransCanada Corp's TRP.TO Keystone pipeline, which moves Canadian crude from Alberta to the central United States.

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"The expectation is that the Keystone pipeline will only be shut for three days while a team is sent to investigate a 'small anomaly'," noted Olivier Jakob, an energy analyst at Petromatrix in Switzerland. However, there is a risk the situation could deteriorate over the weekend, he added.

The Brent-WTI spread also came under pressure, with traders taking the opportunity to try to close down what has been a persistent $20 a barrel premium for Brent by pushing U.S. crude higher.

"It's a classic Friday squeeze," said Bill Hubard, chief economist at Markets.com. "That pipeline is a critical issue for the upcoming U.S. elections - we've seen gasoline shortages in California in the last month."

Over in the North Sea, there was a further delay in the restart of the Buzzard oilfield, which is now expected to restart on Oct. 23 after a maintenance shutdown. ID:nL9E8GF04J

Nexen NXT.TO , operator of Buzzard, Britain's largest oilfield, had earlier said it would resume output on Oct. 21, increasing the supply of crude that underpins the Brent contract. ID:nL5E8LHCH2

Maintenance at the Buzzard field has tightened supply through late September and early October, strengthening prompt Brent prices and pushing the spread between the European marker and U.S. crude CL-LCO1=R to its widest in a year.

Tony Machacek, a broker at Jefferies Bache in London, said this was helping to support prices on Friday, with widespread deferrals of Forties crude cargoes for October loading.

Signs of progress in the euro zone debt crisis also created a relatively benign mood across the markets, with European leaders taking steps towards establishing a single banking supervisor. ID:nL5E8LI676

This opens the way for the bloc's rescue fund to inject capital directly into ailing banks. "It's difficult to see how the market will take this move as anything but a positive," said Gary Jenkins, an analyst at Swordfish.

Machacek also said that U.S. RBOB gasoline, which is often traded against Brent, had stabilised following a major sell-off.

This was triggered by the announcement that U.S. winter specification gasoline could be sold earlier than usual to ease extreme product shortages on the U.S. West Coast.

ID:nL1E8L8H2U "Maybe we are seeing some end-of-the-week short-covering in RBOB," he suggested.

Tensions between Syria and Turkey as well as Iran's nuclear ambitions are also keeping a floor under prices.

European Union governments imposed fresh sanctions this week against major Iranian state companies in the oil and gas industry and tightened curbs on the central bank, cranking up financial pressure on Tehran. ID:nL5E8LG1LB

BULLS VS BEARS

But analysts expect the market to come off once Buzzard is back, characterising the recent price direction as "rangebound" with numerous conflicting supply and demand factors offsetting each other.

"Bullish factors such as supply risks and the plentiful supply of liquidity by central banks are counterbalanced by bearish factors such as the supply surplus and subdued demand prospects," sa i d Carsten Fritsch, an energy analyst at Commerzbank in Frankfurt.

The market's lack of conviction in movements either way has led to some "flip-flopping" this week, he added.

Brent closed 80 cents down on Thursday after the dollar rose and Goldman Sachs GS.N revised its 2013 forecast for Brent down to $110 from $130 a barrel. ID:nL5E8LIHMN

"They went neutral after being one of the big bulls - that helped drive the market lower," said Ole Hansen, senior commodity strategist at Saxo Bank.

Dominick Chirichella of the Energy Management Institute, suggested that oil markets were entering the "election zone", when market participants start to neutralise their trading books because of uncertainty around the outcome of the U.S. presidential election.

(Additional reporting by Florence Tan; in Singapore; Editing by Jane Baird and Helen Massy-Beresford)

((claire.milhench@thomsonreuters.com)(+44)(0)(207 542 3571)(Reuters Messaging: claire.milhench.thomsonreuters.com@reuters.net))

Keywords: MARKETS OIL/