Oil prices rose modestly on Monday, but rising drilling activity in the United States and uncertainty over Libyan and Nigerian production cuts clouded the future supply outlook.
Brent crude futures, the international benchmark for oil prices, rose 22 cents to $46.93 per barrel at 2:39 p.m. ET (1839 GMT). U.S. West Texas Intermediate (WTI) crude futures ended Monday's session 17 cents higher at $44.40 per barrel.
"The market is in trouble and looks very vulnerable to lower numbers," PVM brokerage said in a note.
The Organization of the Petroleum Exporting Countries has agreed with some non-OPEC members to curtail production until March 2018, but the move has failed to eliminate a global glut of crude.
Several key OPEC ministers will meet non-OPEC Russia on July 24 in St Petersburg, Russia, to discuss the current situation in oil markets.