LONDON (Nov 14): Oil sank to a four-year low below $77 a barrel on Friday, pressured by excess supply and scepticism that OPEC would cut output at a meeting in two weeks.

The International Energy Agency, which typically refrains from predicting oil prices, said in its monthly report that prices could fall further in 2015 and pressure was building on OPEC to cut supply.

"Barring any new supply disruption, downward price pressures could build further in the first half of 2015," the IEA, adviser to the United States and other industrialised countries, said.

Brent was up 64 cents at $78.13 a barrel as of 0946 GMT, having hit an intra-day low of $76.76 earlier in the session. U.S. crude was unchanged at $74.21.

Global benchmark Brent is down from $115 in June and has dropped for eight weeks in a row, its longest weekly losing streak since records began in 1988, based on Reuters data.

Oil supply and demand balances of the IEA and other forecasters point to a rising supply surplus in 2015 because of increasing production from the United States and other countries outside OPEC.

The Organization of the Petroleum Exporting Countries meets on Nov. 27 to discuss its response to falling prices. While some members such as Venezuela want OPEC to reduce output, top exporter Saudi Arabia has yet to say if it supports a cut.

Saudi Oil Minister Ali al-Naimi broke months of silence this week to reaffirm the kingdom's longstanding policy of seeking stable global markets, but offered no insight on his response to tumbling oil prices.

"Prices are in free fall. The market is saying OPEC won't do anything," said Jonathan Barratt, chief investment officer at Sydney's Ayers Alliance.

Supply disruptions have the potential to support prices. In Libya, the Hariga oil port reopened after a protest ended, but an oilfield, El Sharara, remains shut.