The previous session's gain was wiping out of the crude futures market, which fell 94 cents or 0.9 per cent, to $99.60 a barrel at 0020 GMT.
West Texas Intermediate WTI crude futures were down 68 cents, or 0.7 per cent, at $93.74 a barrel, after climbing 53 cents on Tuesday.
Russia and the Organization of the Petroleum Exporting Countries are known as the OPEC, together known as the Organization of the Petroleum Exporting Countries. OPEC sources told Reuters last week that the group will likely keep output unchanged in September or raise it slightly.
Analysts are expecting nothing change due to a weak outlook for demand, and top producer Saudi Arabia may be reluctant to beef up output due to the weak outlook for demand due to the Ukraine conflict, which has hurt the OPEC partner Russia.
Ahead of the meeting, OPEC trimmed its forecast for an oil market surplus by 200,000 barrels per day bpd to 800,000 barrels per day, three delegates told Reuters.
The likelihood that they announce an increase in output remains low, due to the uncertain economic backdrop and signs of weakness in demand, ANZ Research analysts said in a note.
The demand outlook is weighed down by several factors, including rising fears of an economic slump in the United States and Europe, debt distress in emerging market economies, and China's COVID-zero policy curbing activity in the world's top oil importer, according to Commonwealth Bank analyst Vivek Dhar, and China's COVID-zero policy curbing activity in the world's top oil importer.
In a note, Dhar said there were growing downside risks to our forecast of US 100 bbl in Q 4th, 2022, as global demand concerns continue to grow.
A stronger dollar, boosted by comments from U.S. Federal Reserve officials hinting on more interest rate hikes to cool inflation, weighed on oil prices as a firmer dollar makes oil more expensive for holders of other currencies.
The American Petroleum Institute, an industry group, shows that the U.S. crude stocks rose by 2.2 million barrels for the week ended July 29 against analysts' expectations of a decline of around 600,000 barrels.
The drawdown on gasoline inventories fell by 200,000 barrels, which was smaller than expected, but distillate stocks fell by 350,000 barrels against analysts' forecasts for a build.
The market will look to see if official data from the U.S. Energy Information Administration EIA at 1430 GMT confirms the inventory view.