Brent crude oil slipped below $112 per barrel on Wednesday as Hurricane Isaac, which hit land in Louisiana, left U.S. Gulf Coast oil production facilities without significant damage.
U.S. energy companies have shut most facilities in the Gulf of Mexico, cutting the region's oil output by more than 90 percent. Most shutdowns were precautionary.
An unexpected rise in U.S. crude inventories and data showing weakening U.S. consumer confidence added to bearishness, although lingering tensions in the Middle East supported prices.
By 0952 GMT, Brent crude oil futures for October were down $1 per barrel at $111.58 after hitting an intra-day low of $111.50. U.S. light crude oil was down 80 cents at $95.53.
"It is expected that oil production in the Gulf of Mexico will quickly return to normal," said Carsten Fritsch, an oil analyst at Commerzbank in Frankfurt. "What is more, inventory data from the United States were disappointing."
"In the short term, prices are likely to fall moderately as U.S. oil production normalises."
Worries about supply disruptions resulting from the hurricane on Monday pushed Brent to a high of $115.50 per barrel, while Nymex futures hit a peak of $97.72. Brent has risen around 6.5 percent so far this month while U.S. oil has gained 8.5 percent, its biggest monthly rise since February.
Isaac has brought high winds and soaking rains to southern U.S. states, posing the first test for multibillion-dollar flood defences put in place in New Orleans after Hurricane Katrina devastated the U.S. Gulf Coast seven years ago.
Concerns over the global economy and uncertainty about the U.S. Federal Reserve's monetary policy were also muddying the outlook for oil demand, adding to pressure on prices.
While data showed U.S. home prices rose in June for a fifth straight month, another measure of U.S. consumer confidence slipped to a nine-month low in August as Americans were more pessimistic about business and labour market prospects.
Clues to whether the Fed is leaning towards more stimulus are expected from Chairman Ben Bernanke's speech on Friday at an annual meeting at Jackson Hole, Wyoming. Bernanke has used the event in the past to indicate the Fed's policy intentions.
Inventories
A poll of 61 economists gave a 45 percent chance of the Fed announcing a third round of quantitative easing, or QE3, after its policy meeting on September 12-13.
Oil prices were also pressured by an unexpected rise in U.S. crude oil inventories as indicated by a report from the American Petroleum Institute (API).
U.S. crude oil stocks rose 5.5 million barrels last week, against expectations for a 1.5 million-barrel drop. The market will now await inventory data from the U.S. Energy Information Administration due out later in the day.
Violence in the Middle East, the world's biggest oil-producing region, has prevented a sharper drop in prices.
Syria's refugee exodus is accelerating, and up to 200,000 people could settle in Turkey alone if the conflict worsens, the United Nations warned on Tuesday, increasing pressure for the creation of a buffer zone inside Syria.
Iran, in dispute with Western nations over its nuclear programme, said it had no plans to show its nuclear sites to diplomats visiting Tehran for this week's Non-Aligned Movement summit, despite an earlier offer by a deputy foreign minister.
Adding to investor uncertainty are mixed signals from policymakers on a White House plan to release some U.S. strategic reserves to rein in rising prices.
Sources told Reuters this month that the White House was considering a possible release of oil reserves. Analysts say it could use the disruption of Gulf of Mexico production as an excuse to release some oil into markets.
But such a move would be controversial. The head of the International Energy Agency has voiced strong opposition to any use of emergency oil stocks unless there is a supply shortage.
