Brent crude oil slipped to $79 a barrel on Tuesday, falling for the sixth session in seven as traders tested OPEC's willingness to agree a coordinated output cut at next week's meeting to prop up tumbling prices.
Talk about OPEC's response to a 30-percent drop in global oil prices since June intensified this week after Venezuela called for increased cooperation within the cartel, as well as with non-members including top producer Russia.
A special global meeting is being planned "very soon," Venezuelan President Nicolas Maduro said on Monday. The head of Russia's state-backed oil giant Rosneft will fly to Vienna on Nov. 25, two days before OPEC members meet in the city.
"We are getting closer to 50:50 on whether there is going to be an OPEC cut or not," said Michael Poulsen, an oil analyst at A/S Global Risk Management in Copenhagen.
"The travel itineraries of several of the members suggests there is a lot of background work going on, so that the meeting itself goes more smoothly."
Brent for January delivery was down 28 cents at $79.03 a barrel by 1317 GMT, reversing a brief rally in early London trading that failed to break above the key $80 mark, peaking at $79.95. The front-month contract settled 10 cents lower on Monday and has dropped from a year high of $115.71 in June, touching a four-year low of $76.76 last week.
U.S. crude was down 11 cents at $75.53 a barrel. The contract settled 18 cents lower on Monday.
Russian Energy Minister Alexander Novak on Monday met Venezuela's foreign minister, Rafael Ramirez, to discuss "the need to coordinate actions in defense" of oil prices. Previous overtures between OPEC and Russia have not produced results.
Goldman Sachs said in a research note dated Nov. 17 that Brent prices may need to fall as low as $60 a barrel to slow production if OPEC cannot agree a cut in Vienna, but maintained their forecast for prices to average more than $80 next year.
"With prices below $80, the market should not rule out an OPEC cut," London-based consultancy Energy Aspects said.
Speculation about the OPEC meeting is expected to overshadow the usually closely watched weekly oil inventory data published by the U.S. Energy Information Administration (EIA).
U.S. commercial crude oil stockpiles are forecast to have fallen by 1.2 million barrels in the week ended Nov. 14, a preliminary Reuters survey showed.
Data from the American Petroleum Institute (API) is due at 2130 GMT, while the EIA will publish its report on Wednesday. (Additional reporting by Jacob Gronholt-Peterson; Editing by Jane Baird, Keiron Henderson and David Clarke)