OPEC members have tentatively agreed to cut oil production, but the exact figure is still being debated.
This led to Thursday's talks in Vienna concluding without a press conference.
There is a consensus, however, on the need to curb production to stabilize falling oil prices.
But OPEC's ally Russia is reportedly refusing to commit to a huge cut proposed by Saudi Arabia.
Riyadh's Energy Minister Khalid Al-Falih said he isn't confident a deal can be agreed when OPEC meets Russia and other allies on Friday.
Benchmark crude prices have plummeted 30 percent in the past two months as global supplies have started to outstrip demand.
Market analysts say a cut of around one million barrels per day would not be enough to balance the market in the first half of next year.
