Opec is expecting oil prices to remain below $100 a barrel for the next decade, according to an internal report seen by the Wall Street Journal.
In its high-price forecast, the oil producer group forecast that prices would be about $76 a barrel in 2025.
Under Opecs low-price scenario, it forecast that prices would be about $40 a barrel.
The group has refused to cut output in the wake of a collapse in oil prices that saw the Opec basket price drop from $108 a barrel to $44 a barrel in January.
On 12 May, WTI crude was trading at $59 a barrel, while Brent traded at $65 a barrel.