Some analysts expect the loss in Canadian supply to offset more than half the increases next month planned by OPEC+. "Estimates suggest around 350,000 barrels per day have been affected and shut in," said SEB analyst Ole Hvalbye, referring to the impact of the wildfires.

Oil inventories have risen sharply across the world in recent weeks, a sign of the pressure that higher output from OPEC+ could place on the global crude market as the year progresses.