Oil slipped in New York, trimming its fourth straight weekly gain and longest winning streak since July, on concern that European plans to solve the region’s debt crisis may founder, threatening economic growth.

Futures reversed gains as the euro halted a two-day advance against the dollar on signs that an agreement to bail out Greece may be hindered by collateral requirements by some European countries. The 17 euro nations accounted for about 12 percent of global oil demand in 2010, according to Bloomberg calculations based on BP Plc’s Statistical Review of World Energy.

“Persistent concerns about the euro zone’s problems continue to dominate the markets,” said Myrto Sokou, an analyst at Sucden Financial Ltd. in London. “The current economic and political conditions look fairly tentative at the moment.”

Crude for October delivery on the New York Mercantile Exchange fell as much as 98 cents, or 1.1 percent, to $88.42 a barrel, and was 53 cents lower at $88.87 at 1:39 p.m. London time. Prices are still up 1.9 percent this week.

Brent oil for November settlement was up 50 cents at $112.80 a barrel on the London-based ICE Futures Europe Exchange. The October contract rose $2.94 to $115.34 yesterday, when it expired. Prices have risen 44 percent in the past year.

The euro fell 0.9 percent against the dollar, reducing the appeal of commodities priced in the U.S. currency, after Finland’s Finance Minister Jutta Urpilainen said an agreement on collateral is unlikely to be reached at today’s trans-Atlantic finance meeting in Wroclaw, Poland.

‘Coiled Spring’

Brent oil was at a premium of $23.74 to West Texas Intermediate November futures, compared with a record $26.87 on Sept. 6 based on front-month settlement prices. Brent, which is little changed this week, may be headed for $150 a barrel, according to chart analysis by Citigroup Inc.

“Crude oil looks to be a coiled spring,” Tom Fitzpatrick, the bank’s New York-based chief technical analyst, said in a research note dated yesterday. A weekly close above $117.60 a barrel “would suggest a breakout and the possibility of a move toward at least $150.”

Oil stockpiles in developed nations fell below their five- year average in July, the first time since the 2008 recession, and were expected to have fallen further in August, the International Energy Agency said on Sept. 13.

Supply Premium

The lack of supply from Libya and production outages in areas such as the North Sea caused inventories to fall in Europe and North America, while Asian companies held less crude than normal, the IEA said in its monthly report.

Libya will resume partial crude exports within three or four days, an official from the nation said in Doha yesterday. The country, holder of Africa’s largest oil reserves, will produce about 700,000 barrels a day by the end of this year and an estimated 1.6 million barrels a day by the end of 2012, Abdulla Saudi told reporters yesterday in the Qatari capital.

“Reports of Libya resuming partial crude exports next week could weigh on Brent, with some of the tight supply premium removed from prices,” Mark Pervan, head of commodity research at Australia & New Zealand Banking Group Ltd. in Melbourne, said in a note today.

Fighting in the African nation since February has reduced the availability of light, sweet crude, or oil with low density and sulfur content. The

country’s output fell to 45,000 barrels a day last month, according to Bloomberg estimates, compared with the 1.6 million barrels a day the nation pumped in January.

Ichimoku Cloud

U.S. crude inventories slid 6.7 million barrels to 346.4 million last week as Tropical Storm Lee closed platforms in the Gulf of Mexico, which accounts for 27 percent of U.S. supply, according to the Energy Department report. As much as 61 percent of production was shut, the Bureau of Ocean Energy Management, Regulation and Enforcement said on its website.

New York crude may fall next week on concern that Europe’s debt crisis will remain unresolved, a Bloomberg News survey showed. Eighteen of 40 analysts, or 45 percent, forecast oil will decline through Sept. 23, while 13 respondents, or 33 percent, predicted prices will increase.

The decline may be limited to around $85.60 a barrel, the second of two leading-span lines that define the boundaries of an “ichimoku cloud” on the weekly chart, according to data compiled by Bloomberg. The cloud is an area where buy orders may be clustered. Investors tend to sell contracts when prices breach technical-support levels.