Oil prices dropped on Friday to $US98.06 in London - their lowest in 17 months on fears of waning economic growth in China.
The West Texas Intermediate price in the United States was also lower, falling to 1.4% to $US82 in early trade before recovering to $US84.10.
Brent crude bounced back in later trading to $US99.47, but is still more than 25% below its peak in March.
The BBC reports Saudi Arabia started to reduce its shipments in June. The world's biggest exporter of crude oil was previously pumping more than 9.5 million barrels of oil per day for the past year.