The price of Brent crude oil held steady on Friday after registering the largest monthly gains for six years in April.
Reuters reported that Brent dropped five cents to $66.73 a barrel, while US crude rose eight cents to $59.69.
The two worldwide benchmarks for crude increased between 20% and 25% in April due a weak US dollar and concerns of a supply glut.
ANZ bank said: "Prices (are) now looking to have firmly broken out of the trading range of the past 14 weeks."
Prices were stable even after a survey by Reuters revealed that OPEC oil supply increased to its highest in over two years, to 31.04 million barrels a day in April.
Higher exports from Nigeria and an additional small gain in Libyan output have also supported the prices.
Sources in the survey said Saudi Arabia’s production was at a record high in April.
Internal reshuffles in Saudi Arabia frequently change oil prices, as stability in the country plays an important role to worldwide supplies.
Earlier this week, King Salman of Saudi Arabia stripped his younger half-brother of the title of crown prince, and appointed his nephew, deputy crown prince Mohammed bin Nayef, as the new heir.
Prince Mohammed bin Salman has been appointed as deputy crown prince, and various other new ministers were also hired.