Oil prices rose more than 1 percent on Thursday in volatile trade, drawing support from signs that Saudi Arabia is cutting crude output but pressured by concerns that slowing global economic growth could dent demand.
Prices traded in a wide range, with Brent hitting a session high of $56.30 a barrel and a low of $53.93 a barrel. WTI posted a session high of $47.49 a barrel and a low of $45.35 a barrel.
Supporting futures were signs of reduced supply from members of the Organization of the Petroleum Exporting Countries. OPEC oil supply fell in December by the largest amount in almost two years, a Reuters survey found, as top exporter Saudi Arabia made an early start to a supply-limiting accord while Iran and Libya posted involuntary declines.
"The Saudis are still spearheading a significant production cut that became official this week. Thus far, strong adherence to adjusted quotas appears a high probability," Jim Ritterbusch, president of Ritterbusch and Associates, said in a note.
But oil price gains were capped by concerns about a faltering global economy.
Weaker-than-expected US factory data also added to economic worries.
"Oil is flip-flopping on concerns of supply and demand," said Phil Flynn, an analyst at Price Futures Group in Chicago. "It's really a battle between the supply situation, which looks to be tightening, versus the possibility that demand will drop off."
US oil and gas executives' outlook turned negative for the first time since the low point of the last oil bust, according to results of a survey released on Thursday by the Federal Reserve Bank of Dallas.
US crude stocks fell last week, while gasoline and distillate inventories built, data from industry group the American Petroleum Institute showed on Thursday.
Crude inventories fell by 4.5 million barrels in the week ended Dec. 28 to 443.7 million, compared with analysts' expectations for a decrease of 3.1 million barrels.
Gasoline stocks rose by 8 million barrels, compared with analysts' expectations in a Reuters poll for a 2 million-barrel gain. Distillate fuels stockpiles rose by 4 million barrels, compared with expectations for a 1.6 million-barrel gain, the API data showed.
Official US government data is due to be released on Friday.
Riyadh was expected to cut February prices for heavier crude grades sold to Asia due to weaker fuel oil margins while reducing prices for light grades to keep Saudi oil competitive against rising US shale oil supplies, a Reuters survey showed on Thursday.