This came after the U.S. slashed its 2020 oil-production forecast by more than 1 million barrels a day on Tuesday, a move that could be enough to satisfy Riyadh and Moscow.

"Many oil producers around the world are now increasingly forced to reduce or close production basically because pipelines and local storage facilities are full," said Bjarne Schieldrop, chief commodities strategist at SEB AB.

"Natural declines or forced production cuts will thus likely be counted as deliberate cuts" when OPEC and other producers thrash out a deal in talks on Thursday.