Oil producers meet in Vienna on Saturday to see whether those outside the Organization of the Petroleum Exporting Countries will cut production to help erase a global supply glut that has depressed prices for more than two years.
Late in the morning, Brent flipped into negative territory while U.S. prices pared gains briefly after reports that Russia sees a risk that the meeting could be moved due to questions that have come up. A Russian energy ministry spokeswoman, however, said the meeting would continue as planned.
Speaking at a conference in New York, former OPEC Secretary General Abdalla El-Badri said that a non-OPEC production cut of about 600,000 barrels per day (bpd) was "a must."
OPEC has agreed to slash production by 1.2 million barrels per day (bpd) in the first half of 2017, a deal that bolstered crude futures despite doubts over whether the amount was enough and whether the cuts would be effectively implemented.
Given the rally to $50 a barrel, non-OPEC members may not be persuaded to cut output, said Tim Evans, energy futures specialist at Citigroup.
"Further effective cooperation between oil producers seems unlikely in our view, as OPEC and Russia have already agreed on policy, reducing the leverage they have with other countries in our view," he said in a note.
Non-OPEC Russia has signaled it was ready to cut production by 300,000 bpd and on Thursday Azerbaijan said it would come to Vienna armed with proposals for its own reduction.