Oil prices fell Wednesday after a US government report showed an unexpected rise in gasoline inventories and an increase in oil production amid global oversupply worries.

US benchmark West Texas Intermediate (WTI) for September delivery fell 59 cents to $45.15 a barrel on the New York Mercantile Exchange.

Brent North Sea crude for September closed at $49.59 a barrel, down 40 cents from Tuesday's settlement on the Intercontinental Exchange in London.

Prices had skidded for three consecutive sessions before rising modestly on Tuesday, the eve of the US Department of Energy's weekly petroleum report.

WTI soon reversed into the red as traders digested the DoE numbers and found them less bullish than initially thought.

"First there was an increase in gasoline and that weighed on the market. There was a pretty good increase in domestic production and that was bearish. I think a lot of people were expecting to see a smaller number," said Bob Yawger of Mizuho Securities.

As investors remain worried about global oversupply, with OPEC and the United States crude oil production rising, the DoE said that US production rebounded last week from the prior week's dip, increasing by 52,000 barrels per day to 9.5 million bpd.

The global supply glut, coupled with slowing economic growth, has helped to push oil prices into a nosedive from their mid-2014 peak above $100 a barrel.