The U.S. West Texas Intermediate crude November contract was down 27 cents or about 0.53% at $51.03 a barrel by 03:45 a.m. ET (07:45 GMT), off Wednesday's more than one-week highs of $51.41.
Prices rose 2 percent the day before to back above $50 a barrel.
Oil prices slightly pared losses on Thursday after official government data showed USA crude stocks fell, contradicting an earlier industry report that weighed on prices. USA light crude was down 67 cents to $50.63 a barrel.
Elsewhere, were up 0.18% at $1.610 a gallon, while advanced 0.73% to $2.910 per million British thermal units.
Yesterday the EIA said it expects USA crude oil production in 2018 to rise by more than previously expected.
Carsten Fritsch, commodities analyst at Commerzbank in Frankfurt, said the tone of the IEA report was bearish because it suggested that demand for OPEC crude next year would not be sufficient to absorb all the available supplies. S. inventories and a falloff in weekly production on Thursday.
Gasoline stockpiles, on the other hand, unexpectedly increased by 2.5 million barrels, according to EIA data.
"Our forecast of global demand growth remains unchanged at 1.6 million barrels per day in 2017, or 1.6 percent, and 1.4 million barrels per day in 2018, or 1.4 percent", said the report.
Traders have expressed concerns of late that the United States will at some point reach its export capacity, though that has not been hit yet.
Meanwhile, the agency forecast that US oil demand for 2017 is set to grow by 230,000 bpd compared with previous forecast of 350,000 bpd.