* IEA says OPEC has increased output as prices have risen
* IEA revises up slightly 2011 oil demand growth view
* Restarted Alaska pipeline expects 500,000-bpd throughput
(Recasts, updates prices and market activity, changes byline and moves dateline from previous LONDON)
By Robert Gibbons
NEW YORK, Jan 18 (Reuters) - U.S. oil prices slipped on Tuesday in choppy trading on pressure from Alaska's pipeline restart and the International Energy Agency saying OPEC has been quietly raising output.
Brent crude futures were higher, also in choppy trading, as the euro's strength, a weaker dollar and a higher IEA demand growth forecast helped offset the bearish supply factors.
The IEA revised higher its 2011 world oil demand growth forecast in its monthly report. [
] But the agency also said some OPEC members appeared to have boosted production and that the group's output may quietly increase. [ ]U.S. crude oil for February delivery <CLc1> fell 13 cents, or 0.14 percent, to $91.41 a barrel at 12:23 p.m. EST (1723 GMT). The February contract expires on Thursday.
In London, ICE Brent crude for March <LCOc1> rose 36 cents, to $97.79 a barrel. Before expiring on Friday, the Brent February contract reached $99.20 intraday, which was the highest front-month price since Brent hit $100.31 intraday on Oct. 1, 2008.
The euro rose against the dollar on Tuesday on buying by sovereign funds and strong German data. The dollar index <.DXY> weakened. [
] Germany's ZEW headline economic sentiment indicator surged to its highest reading in six months. [ ]A weaker dollar can lift dollar-denominated oil prices because it lowers the value of currency paid to producers and the price of oil for consumers using other currencies.
Along with the dollar's weakness, oil received some support from Wall Street equities hovering near unchanged after a weaker open, though the closely watched S&P 500 index seesawed near flat at midday in New York. [
]ALASKA PIPELINE RESTART
Last week's major supply disruption in the United States was drawing to a close after Alaska's crude oil pipeline resumed operations on Monday. The pipeline was expected to boost throughput to 500,000 barrels per day within 24 hours. [
]"The Alaska pipeline is running and that resumption is being priced in and is the major factor pulling prices lower. No one was surprised by the IEA and OPEC reports or that OPEC might be producing above quota," said Phil Flynn, analyst at PFGBest Research in Chicago.
While Alaska's pipeline was restarted, Royal Dutch Shell <RDSa.L> said on Tuesday it was unclear when four Brent North Sea oil and gas platforms shut on Saturday would restart. Oil output from the platforms is only 20,000 bpd. [
]Investors will be eyeing weekly oil inventory reports to see the effect of the Alaska pipeline outage.
The weekly reports will be delayed a day following the Martin Luther King public holiday in the United States on Monday.
The report from the industry group the American Petroleum Institute will arrive at 4:30 p.m. EST (2130 GMT) on Wednesday, while the U.S. Energy Information Administration's oil inventory report will arrive on Thursday at 11 a.m. EST (1600 GMT).
Also on Thursday, China is due to release inflation, industrial output and retail sales reports for December, and economic growth figures for the fourth quarter. (Additional reporting by Jessica Donati and Barbara Lewis in London and Alejandro Barbajosa in Singapore;editing by Sofina Mirza-Reid)