Even after the downgrade, OPEC still expects demand growth to be stronger this year and next than the International Energy Agency, which issues its latest forecasts on Thursday.
Next year, OPEC sees oil demand rising by 2.34 million bpd, 360,000 bpd less than previously forecast, to 102.02 million bpd.
OPEC cut its 2022 global economic growth forecast to 2.7% from 3.1%, trimmed next year's figure to 2.5% and said there was potential for further weakness.
The report showed OPEC output rose by 146,000 bpd to 29.77 million bpd in September, led by Saudi Arabia and Nigeria.
Still, the OPEC+ output cut agreed last week runs for all of 2023 and is much larger, at 2 million bpd.