The Organisation of Petroleum Exporting Countries (OPEC) expects the current excess of crude supply responsible for plummeting oil prices to continue through 2015, despite a slight increase in global demand.
In its monthly report published Thursday in Vienna, OPEC said oil prices now at their lowest levels in nearly six years will continue dropping this year, as "bearish sentiment in the oil market persists as it faces an increasing overhang of at least" one million barrels per day.    
After a brief technical rally Wednesday, oil prices resumed their slide on European markets Thursday, driven by the combination of excessive production and flagging demand.
The 12-nation cartel -- which produces around a third of the world's crude oil -- says the slight rise in 2015 demand will come largely from reviving economic activity in North America and Asian countries other than China and Japan.
However, OPEC expects next year's jump in demand will be satisfied by production increases planned by non-cartel countries, while the appreciation of the dollar will accentuate the downward pressure on per-barrel prices denominated in US currency.     
During its last meeting in Vienna in November, OPEC voted to maintain production levels despite demands from some members to cut output as a means of reversing the slide in oil prices.