Brent North Sea crude steadied Monday while New York-traded oil fell as markets reacted to high supplies and sluggish demand.
US benchmark West Texas Intermediate (WTI) for September delivery fell 72 cents to $41.78 a barrel compared with Friday's close.
It slumped Friday to $41.35 -- the lowest level since March 2009 -- before finding some support ahead of Monday's renewed fall.
In afternoon London deals, Brent North Sea crude for October was unchanged at $49.03 a barrel.
WTI came under pressure after data revealed that the number of rigs drilling for US oil increased last week, the sixth rise in seven weeks, analysts said.
The news added to concerns regarding a prolonged global surplus as output from the Organization of the Petroleum Exporting Countries and the United States remains robust despite damp demand.
"The combination of elevated stockpiles in the US and increasing production from OPEC, sluggish demand growth, and a stronger US (dollar) would continue to pressure oil prices," said Bernard Aw, market strategist at IG Markets.