The discount on benchmark heavy Canadian crude versus West Texas Intermediate widened on Thursday.
Western Canada Select heavy blend crude for October delivery traded at $20.50 a barrel under WTI, according to NE2 Canada, widening 20 cents from the previous day.
WCS has traded around $20 a barrel below U.S. futures for much of the summer, pressured by the release of oil from the U.S. Strategic Petroleum Reserve and strong demand for lighter, rather than heavier, crudes globally due to high refined product prices.
Global oil prices edged up about 1% after dropping to a seven-month low in the prior session as some technical traders bought the dip and Russia threatened to halt oil and gas exports to some buyers.