Oil prices were higher on Friday in a see-saw session, retreating from session highs and headed for weekly declines on lingering questions about whether OPEC will extend output cuts at its May meeting.
The market also questioned whether an extension would reduce a global crude glut enough to boost prices.
U.S. oil prices have lost ground in eight of the last 11 sessions. On Thursday, prices fell sharply on news that oilfields in Libya resumed production.
Most analysts polled by Reuters expect the deal between the Organization of the Petroleum Exporting Countries and non-OPEC producers struck in December 2016 to be extended to the end of this year.
U.S. light crude settled at $49.33 a barrel on Friday, up 36 cents, on the day, but posting a loss for both the week and the month.
Benchmark Brent crude futures were trading up 27 cents at $51.71 a barrel by 2:35 p.m. ET (1835 GMT), and was also headed for weekly and monthly losses.