U.S. crude was up 18 cents at $41.88 a barrel at 0047 GMT after falling more than 3 percent on Friday. The contract is heading for a 10 percent fall in November.
Brent crude was up 4 cents at $44.90 a barrel following a decline of 1.3 percent on Friday. The global benchmark is on track for a 9.4 percent decline this month.
OPEC officials have called into question an upbeat forecast from the group's researchers last week before the gathering of oil ministers on Dec. 4, with some sceptical there will be a quick easing of the supply glut in 2016.
The research team expects higher demand for OPEC oil next year as supply from producers such as the United States declines, potentially reducing the glut, with world oil demand seen rising by 1.25 million barrels a day. Prices have slumped by more than half since the middle of last year because of the overhang.
OPEC last year made a historic decision to refuse to prop up prices by cutting supply and focussed on defending market share. The shift was led by Saudi Arabia, supported by other Gulf OPEC members, but doubts about the policy among less wealthy members are growing.
Still, officials told Reuters last week it is unlikely the group will change that policy.
(Reporting by Aaron Sheldrick; Editing by Richard Pullin)