The week ending in Aug. 11, OPEC's crude oil reserves decreased by 8.9 million barrels to to 465.5 million barrels, which is a greater decrease than was previously expected of only 3.4 million barrels.

The Organization of the Petroleum Exporting Countries is pleased by the drop as it means it should see a decline in stocks and market surpluses.

Twelve OPEC and 12 non-OPEC countries are trying to rebalance the market by cutting production by 1.8 million barrels a day. This plan has been implemented since January.

Unconventional oil extraction is anticipated to increase by 117,000 barrels per day in September in main regions of production.