A seasonal maintenance program in Canada’s oil sands is set to reduce crude production by 300,000 barrels per day in September, tightening supply for U.S. refiners already operating at capacity to offset global fuel shortages.
The disruption arrives as replacement heavy crude remains scarce. Canadian inventories are at their lowest level in 12 months, according to Rystad Energy, limiting the usual buffer against seasonal declines. Venezuela’s crude output recovery has also fallen short of expectations, with exports rising only modestly to 1.16 million barrels per day in July, down slightly from 1.2 million in June as state producer PDVSA draws on inventories to meet commitments.
U.S. refiners typically receive 4 million barrels per day of heavy crude from Canada. The September reduction, combined with sustained global fuel demand, could further elevate refining margins—particularly for diesel, where the crack spread recently reached a record $100 per barrel.
The supply squeeze follows months of elevated refinery activity in the U.S., where facilities have run near full capacity to compensate for disruptions in the Middle East. Tanker-tracking data cited by the Wall Street Journal has not confirmed claims from Washington that shipping lanes have normalized, while Ukrainian drone strikes on Russian refineries continue to constrain gasoline and diesel output.
Pipeline operators have already reduced space rationing on key lines, signaling expectations of lower Canadian crude flows in September. Analysts warn that if the supply imbalance persists, demand destruction could spread from the most price-sensitive markets, with potential knock-on effects for inflation and economic growth.
The broader geopolitical backdrop—including the ongoing conflict in the Middle East and expanded U.S. sanctions on Iran—adds further pressure to global fuel markets, with no near-term resolution in sight.
