"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."
In November at a meeting in Vienna, OPEC and non-OPEC members agreed to extend their oil output cuts until the end of 2018, giving markets a further boost. At the same time, U.S. crude oil output was rising, the IEA noted.
"Just as the OPEC oil ministers were sitting down in Vienna, our colleagues at the U.S. Energy Information Administration released data showing that for September U.S. crude oil output increased month-on-month by 290,000 b/d to reach 9.48 million barrels a day, the highest monthly average since April 2015 and 928,000 b/d above a year ago," the IEA said.
"Preliminary weekly . Recently, U.S. drilling activity and well completion rates have picked up again, suggesting higher production to come in a few months … Consequently, we have raised our annual growth forecast for total U.S. crude oil to 390,000 b/d this year and 870,000 b/d for 2018," the IEA added.
Looking at next year, it believes that total global supply growth could exceed demand growth, predicting there could be a surplus of 200,000 b/d in the first half of 2018. It then estimates that it could revert to a deficit of about 200,000 b/d in the second half of next year, leaving 2018 as a whole showing a "closely balanced market."
"A lot could change in the next few months but it looks as if the producers' hopes for a happy New Year with de-stocking continuing into 2018 at the same 500,000 b/d pace we have seen in 2017 may not be fulfilled," it said.