It suggests that crude oil could be entering a more stable trading range of $50-$70/barrel rather than falling back below $50 again for a significant period.

Iraq, which depends on oil sales for 95 percent of its public spending, appears set to continue boosting production, which currently stands at around 4.6 million barrels per day.

Iran sent a letter to members of the Organization of the Petroleum Exporting Countries saying it would attend the group’s informal talks in Algeria in September, OPEC delegates told The Wall Street Journal. An Iranian oil-ministry press official couldn’t confirm the letter had been sent late Tuesday.

Net income dropped 98 percent to 531 million yuan ($80 million), the state-run explorer said in a statement to the Hong Kong stock exchange on Wednesday. Revenue fell 15.8 percent to 739 billion yuan. The sale of a Central Asian pipeline network helped the company eke out a profit and recover from its first-ever quarterly loss earlier this year.

Saudi Arabia has traditionally accounted for most of the crude imports by Asia, the world's biggest oil-consuming region. But recently OPEC's top producer has lost ground in a number of major markets including Russia and China, and faces a further threat from Iran, which is ramping up exports after the removal of Western sanctions.

International Brent crude oil futures were trading at $48.86 per barrel at 0644 GMT (0244 ET), down 30 cents, or 0.61 percent, from their last close. U.S. West Texas Intermediate (WTI) crude was down 40 cents, or 0.84 percent, at $47.01 per barrel.

Brent crude futures LCOc1 were trading at $49.39 per barrel at 1028 GMT, down $1.49 from their last close. U.S. West Texas Intermediate (WTI) crude Clc1 was down $1.27 at $47.25 a barrel.

This summer the U.S. oil price has whipsawed from more than $50 a barrel in June to below $40 earlier this month. In the past two weeks it has risen more than 20%, to a recent $48.22 a barrel.

Brent ended the session up 2.09 percent at $50.89. The session high of $51.05 was its highest since June 23. U.S. crude settled at $48.22, up 3.06 percent after touching a session high of $48.38, the highest since July 5.

Prices have struggled to go much higher than $50 a barrel. After the longest run of gains since March, Brent crude, the international benchmark, traded 0.9 percent higher at $51.17 at 7:13 a.m. in London on Friday.