)
Oil prices dived Friday as traders were worried that global supplies exceeded the demand.
US oil companies added more oil rigs this week despite the collapse in crude prices, Xinhua reported.
Data showed a weekly rise of five in the number of active US oil drilling rigs to 664, according to oil services company Baker Hughes' Friday report.
The downbeat earnings of US petroleum giants added woes to the industry.
ExxonMobil, the largest US oil company reported on Friday that its second-quarter profits fell by 52% to $4.2 billion.
Chevron reported about a 90% drop in profit, the worst quarterly result in several years.
Traders also anticipated more Iran crude would come to the already well-supplied oil market as the sanctions would be lifted.
The west Texas intermediate for September delivery moved down $1.4 to settle at $47.12 a barrel on the New York Mercantile Exchange, while Brent crude for September delivery decreased $1.1 to close at $52.21 a barrel on the London ICE Future Exchange.
