US WTI crude futures were at $ 64.86 a barrel by 0201 GMT, down 39 cents, or 0.6 per cent, from their previous settlement.
Brent crude futures were at $ 69.75 per barrel, down 36 cents, or 0.5 per cent.
Traders said the dips came after the American Petroleum Institute (API) late on Tuesday reported a surprise 5.3 million barrels rise in crude sticks in the week to March 23, to 430.6 million barrels.
Official US inventory data will be published by the Energy Information Administration (EIA) late on Wednesday.
“We’ll see how the inventory data looks and whether these recent highs can be challenged again. For the moment it is looking like both WTI and Brent are stalling,” said Greg McKenna, chief market strategist at futures brokerage AxiTrader.
Wednesday’s price falls came despite top exporter Saudi Arabia saying it was working with top producer Russia on a historic long-term pact that could extend controls over world crude supplies by major exporters for many years.
Saudi Crown Prince Mohammed bin Salman told Reuters that Riyadh and Moscow were considering greatly extending a short-term alliance on oil curbs that began in January 2017 after a crash in crude prices.
“We are working to shift from a year-to-year agreement to a 10 to 20 year agreement,” the crown prince told Reuters in an interview in New York late on Monday.
AxiTrader’s McKenna said such an agreement between Russia and Saudi Arabia “effectively means an expansion” of the Organization of the Petroleum Exporting Countries (OPEC), of which Saudi Arabia is the de-facto leader but in which Russia is not a member.
In Asia, Shanghai crude oil futures saw their third day of trading continuing with high volume but also volatility.
Spot Shanghai crude futures were down by 4.4 per cent on Wednesday, to 407.5 yuan ($ 64.93)per barrel by 0201 GMT.
In dollar-terms, that puts Chinese crude prices significantly below Brent and only slightly above US WTI.
McKenna said he hoped Shanghai crude “gets a lot of traction and we end up with three established global benchmarks”, but he cautioned that “the first couple of days have been volatile.” ($ 1 = 6.2760 Chinese yuan renminbi)