"We see that 2018 might not be quite so happy for OPEC producers, " the Paris-based organization said in its latest monthly report Thursday.

The IEA said that there were signs that the rise in U.S. crude oil supply was likely to continue into 2018 and upset rivals who are cutting back.

in order to boost global oil prices and rebalance markets put out of kilter in 2014 by a glut in supply and lackluster demand.

One of the main beneficiaries of these cuts is the producers' major competitor, U.S. shale oil. U.S. oil producers are staging a dramatic comeback amid a recovering oil price that has allowed many of them to restart operations.

The IEA forecast that non-OPEC supply — which includes the U.S. — was set to rise by 600,000 barrels a day in 2017, and 1.6 million barrels a day in 2018. It also noted that global oil supply rose 200,000 barrels a day in November to 97.8 million barrels a day (mb/d), adding that this was "the highest in a year, on the back of rising U.S. production."