Oil prices were down much of Monday on worries of oversupply and a strong dollar, but bets the market had hit bottom after a seven-month selloff limited the downside, traders said.
The weekly decline in the number of U.S. rigs drilling for oil slowed last week as crude prices rebounded from January lows, raising worries about oil inventories that were already at record highs.
The largest U.S. refinery strike in 35 years, involving workers at 12 refineries that account for one-fifth of the national production capacity, has also been a negative for crude.
U.S. East Coast refineries have also been hit by cold weather, sending up heating oil futures on fears of tight supplies.
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But a smaller-than-expected build in the Cushing, Oklahoma delivery point for U.S. crude reported on Monday by oil services firm Genscape helped prices pare some initial losses. Genscape reported a build of 2.2 million barrels for Feb. 13 to 20, versus trade expectations for 4 million barrels or more, according to a market source who saw the data.
The market has also been seeing quick "buying on dips," evidence that bulls were in more control than a few months ago, traders said. After percentage losses of between 9 and 18 percent each month from October to December, prices consolidated in January and in February rebounded as much as 11 percent month-to-date.
"There is the notion that a bottom has been set at $55 for Brent and $45 for WTI, and there are enough buyers out there each time the market tests those levels," said John Kilduff, partner at New York energy hedge fund Again Capital.