US West Texas Intermediate (WTI) crude futures fell $1.15 to settle at $68.72 a barrel, a 1.65 percent loss.
Brent crude futures fell 90 cents to settle at $77.27 a barrel, a 1.15 percent loss. The global benchmark had climbed in the previous session to $79.72 a barrel, its highest since May.
Crude jumped on Tuesday as oil companies shut dozens of offshore platforms in anticipation of damage from Tropical Storm Gordon. The storm, however, never became a hurricane and by Wednesday energy companies and port operators along the US Gulf Coast took steps to resume operations.
"Prices yesterday rose in anticipation that the storm could inflict some damage on the production and refining sector, but after all was said and done we lost a little bit of production and the refineries in Mississippi and Louisiana continued to run as Gordon made landfall," said Andrew Lipow, president of Lipow Oil Associates.
In all, companies halted 156,907 barrels per day of oil production, according to estimates Tuesday by the US Bureau of Safety and Environmental Enforcement.
Oil also weakened as the United States-China trade dispute raised demand worries. Trump could impose levies on $200 billion more of Chinese imports after a public comment period on the new tariffs ends on Thursday.
OPEC Secretary-General Mohammad Barkindo said global trade disputes could hurt energy demand in the future.
Also weighing on crude futures was a currency crisis in Turkey. The lira has fallen more than 40 percent this year .
"Fears of Turkey's currency crisis spreading to other emerging markets have prompted demand-side concerns," said Abhishek Kumar, senior energy analyst at Interfax Energy.
Oil could draw some support if weekly reports on US inventories show a drop in crude inventories, as expected. Analysts estimate, on average, that stocks fell by about 1.9 million barrels last week.
The American Petroleum Institute, an industry group, releases its supply report at 4:30 p.m. EDT (2030 GMT) on Wednesday, a day later than usual because of the US Labor Day holiday on Monday. Official government figures were also delayed to Thursday.
US sanctions targeting Iran's oil sector from November are already reducing exports from OPEC's third-largest producer and counteracting the impact of an agreement by OPEC and its allies to pump more oil.
"With the anticipation of up to 1.5 million barrels per day affected by the US sanctions on Iran, one would expect prices to move higher in the weeks ahead," said Stephen Innes, of futures brokerage OANDA.
US President Donald Trump said on Wednesday he could not predict what would happen with Iran and it did not matter to him if Iran's leaders wanted to talk to him or not.