Oil prices suffered big losses Friday after data showed the U.S. oil drillers added seven rigs for the week.

Oilfield services company Baker Hughes said Friday that the number of rigs operating in U.S. fields rose by 7 to 414 this week, marking the 10th week of increase in the past 11 weeks.

On Thursday, oil prices surged, with both U.S. oil and Brent crude jumping over 4 percent, as official data showed a surprisingly large drawdown in U.S. oil stockpiles.

However, traders believed that the U.S. crude inventories will rebound strongly next week as the big draw was caused mainly by Tropical Storm Hermine in the Gulf Coast, whose influence is temporary.

Investor sentiment was also dented by a stronger U.S. dollar, which made the dollar-denominated oil less attractive for holders of other currencies.

The dollar index, which tracks the greenback against six major peers, was up 0.32 percent at 95.334 in late trading Friday.

The West Texas Intermediate for October delivery dropped 1.74 U.S. dollars to settle at 45.88 dollars a barrel on the New York Mercantile Exchange, while Brent crude for November delivery slumped 1.98 dollars to close at 48.01 dollars a barrel on the London ICE Futures Exchange. 

Source : XINHUA