Oil rose slightly on Friday on increased buying ahead of the weekend, but a strong U.S. dollar and lingering doubts that not all OPEC producers would cut output in line with an agreement, pressured prices, Reuters reported.
End of week position-squaring combined with relatively low volumes during the first trading week of the year led to the market being choppy, traders said.
Brent crude futures LCOc1 were trading 19 cents higher at $57.08 per barrel at 11:34 a.m. EST, after moving in a $56.28-to-$57.47 range.
U.S. West Texas Intermediate (WTI) crude futures CLc1 rose 24 cents at $54.00 a barrel, after trading between $53.32 and $54.32.
The contracts were on track for a slight gain on the week.
"There's a lot of volatility, or at least changes in direction," ABN Amro senior energy economist Hans van Cleef said. "People think the long-term trend is up, but after a gain of a few dollars, they take profit."