Saudi energy minister Khalid al-Falih on June 14 expressed confidence that OPEC and its non-OPEC partners will reach an agreement on gradually increasing output and loosening quotas when they meet next week in Vienna.

"I think it's inevitable," Falih told reporters after he met with Russian counterpart Alexander Novak ahead of the Russia-Saudi Arabia World Cup opener in Moscow. "I think it will be a reasonable, moderate agreement. It's not going to be anything outlandish. We will be easing our ceilings back."

But he declined to reveal any specific proposals that are being considered.

"We will see where we go, but I think we'll come to an agreement," Falih said. "As usual, we'll do the right thing."

OPEC meets June 22 in Vienna to decide on the future of its production cut agreement, which committed the bloc, along with 10 non-OPEC countries led by Russia, to a 1.8 million-barrel-per-day supply cut.

Saudi Arabia and Russia have been keen to pump more barrels to moderate oil prices and prevent a supply gap from continued production declines in Venezuela and the potential impact of U.S. sanctions on Iran, which snap back Nov. 5.

But Iran, Venezuela and Iraq have vowed to oppose any moves to raise production, saying the market remains amply supplied.

This article was written by Herman Wang and Nadia Rodova, who are reporters for S&P Global Platts, which, like S&P Global Market Intelligence, is owned by S&P Global Inc.