The discount on heavy crude narrowed versus the West Texas Intermediate (WTI) benchmark on Monday as the new monthly trade cycle got underway.
Western Canada Select heavy blend crude for June delivery in Hardisty, Alberta, last traded at $12.60 a barrel below WTI, according to NE2 Canada Inc, narrowing 15 cents from the previous settlement.
Light synthetic crude from the oil sands for June delivery last traded at $5.50 a barrel over WTI, strengthening 50 cents from the previous trading day.
One industry source said Alberta oil inventories were likely to draw down throughout the month of June as maintenance in the oil sands restricts supply, lending support to prices.
Global oil prices reversed course to settle in positive territory, helped by a rally in the diesel market and fears that supply might be crimped by a potential European Union ban on Russian crude.