The US Department of Energy on Wednesday reported another rise in US commercial crude stockpiles last week, by 2.3 million barrels.
While the increase was lower than analysts' estimates of about three million barrels, it still pushed inventories to fresh record highs, in a market already brimming with supplies.
At around 0715 GMT (1245 IST), US benchmark West Texas Intermediate for delivery in May was down 39 cents to USD 37.93 while Brent crude was trading 25 cents lower at USD 39.01.
Traders have been moving back into oil thanks to a weaker dollar and hopes about an April 17 meeting in Doha of major oil producers led by Russia and Saudi Arabia to discuss measures to stabilise prices, including a possible output freeze.
"Strangely, crude oil was not moving up despite the fact that the dollar index has collapsed over the last three days," said CMC Markets analyst Margaret Yang.
"On the other hand, oil inventories are still building and demand is weak," she added.
