Crude oil prices were down on Friday and failed to recover from their lowest level in three months on Thursday.

Crude oil prices were slightly up at opening on Tuesday as the U.S. and China's restart of trade talks provided optimism for investors who expect poor global economic growth and low overall oil demand next year.

Qatar in a surprise announcement says it will leave the Organization of the Petroleum Exporting Countries (OPEC) next month in a move that appears to have been meant to take a swipe at the group’s de factor leader Saudi Arabia.