Oil futures jumped 31 percent this year, climbing above $50 a barrel last week, as U.S. crude stockpiles declined, trimming a glut. Robust demand in India and other emerging nations led the International Energy Agency in May to reduce its estimate of the global oil surplus for the first half. Brent last traded above $60 in July.

Saudi Arabia has been fighting with fellow OPEC members since the oil rout started two years ago. For the first time next week, it can argue convincingly that its strategy of squeezing rival producers is succeeding.

The aggregate net debt of the 15 largest North American and European oil groups rose to $383bn at the end of March, up $97bn from 12 months ago.

Khelil expects prices to increase to $70 to $80 a barrel or more after oil majors abandoned or shelved projects. Still, that rebound risks reviving U.S. shale drillers, said the two-time president of OPEC.

Brent LCOc1 fell 1.3 percent, or 64 cents, to $48.95 a barrel by 1031 GMT, retreating from the previous session's $50.51 peak, its highest since early November. U.S. crude CLc1 dropped 45 cents to $49.03 a barrel after touching $50.21 on Thursday, its highest since early October.

Futures rose as much as 1.4 percent in New York after climbing 1.1 percent Tuesday. Inventories dropped by 5.14 million barrels last week, the American Petroleum Institute was said to report. Data from the Energy Information Administration Wednesday is forecast to show supplies fell. Canadian oil-sands producers that cut more than 1 million barrels a day from the market because of the threat of wildfires are starting the process of resuming operations.

With most companies indicating continued reductions in E&D budgets absent a meaningful increase in crude oil prices, proved reserves additions will likely continue to decline.

Brent futures rose 50 cents to $49.11 a barrel, having closed 26 cents up previously to snap a four-day slide.

Now, under the economic plan known as Vision 2030 promoted by the king’s powerful son, Deputy Crown Prince Mohammed bin Salman, the government is signaling it wants to wean the kingdom’s economy off oil revenue, lessening the need to manage prices.

Speaking from his high-rise office in the capital, Doha, Mohammed bin Saleh al-Sada said a minimum price of $65 a barrel is "badly needed at the moment." He cautioned that the security of future supplies is as risk because of the price slump that has squeezed oil producers since 2014.