One day ahead of a key OPEC meeting in Vienna, crude oil prices were in negative territory amid early Wednesday signs of static production levels.

Iranian Oil Minister Bijan Zanganeh, who arrived early in Vienna, said his country was already producing below its capacity, so further cuts would be unfavorable for a country struggling to cope with sanctions targeting its energy sector.

Members of the Organization of Petroleum Exporting Countries are working to shore up a market share in an era when U.S. dependence is plummeting because of the glut of oil from shale. Low prices mean less revenue for countries like Iran that rely heavily on export revenue.

"We need to speak to other [member states] and exchange views with them on how to deal with the situation," the Iranian minister said. "The most important thing for all of us is the unity and solidarity of OPEC."

The price for Brent crude oil, the global benchmark, shed more than 75 cents per barrel for the January contract to trade at $77.56 early Wednesday. That's down from the monthly average of $112 per barrel in July.

For non-OPEC members like Russia, oil prices could put pressure on an economy already reeling from sanctions pressure on its energy sector. But Russian Energy Minister Alexander Novak said he too didn't foresee a production cut from OPEC, saying such issues should be decided by the market.

Some analysts have said keeping prices low by keeping production levels static would squeeze U.S. shale output, where production is more expensive than elsewhere in the world. Last week, Jim Burkhard, vice president at IHS Energy, said in a statement to UPI oil production from the United States still increases in 2015 if oil prices drop below the $70 per barrel mark.

West Texas Intermediate, the U.S. benchmark, was down more than 50 cents per barrel to trade at $73.53 for the January contract.