A U.S. naval blockade has effectively restricted the country’s oil exports by preventing fresh cargoes from leaving Iranian ports and exhausting overseas crude reserves. The blockade targets maritime infrastructure, preventing fresh cargoes from leaving Iranian ports and shifting severe pressure back onto domestic storage facilities and production fields.
The Collapse of Overseas Crude Reserves
For months following the onset of the conflict in February, Tehran sustained its crude exports to China using millions of barrels already sitting in Asian waters. That vital buffer is now almost entirely gone. Kpler analysts cited by The Wall Street Journal estimated that Iran held roughly 135 million barrels in overseas storage when the war began. By October 5, that figure had plummeted below 1 million barrels. Meanwhile, Vortexa estimated Iranian stocks sitting off Singapore at approximately 6 million barrels on October 9. While the tracking methods and storage locations differ between the two firms, both datasets confirm that the offshore supplies feeding the export trade have been largely exhausted.
China Finds Alternative Suppliers as Iranian Crude Flows Drop
Malaysia has long served as a crucial transfer point for Iranian crude heading to Chinese markets, utilizing ship-to-ship transfers off the Malaysian coast to obscure the oil’s origin. With no new Iranian crude available for transfer near Malaysia, cargo flows recorded under Malaysian origin in Chinese customs data have dropped sharply. Faced with these disruptions, China’s independent “teapot” refineries have lined up alternative suppliers to secure predictable deliveries. Reuters reported on October 6 that these refineries purchased at least 12 million barrels of Iraqi and Qatari crude for delivery across October and November, with traders projecting totals could reach 15 million to 20 million barrels. While Iranian oil previously attracted buyers through steep discounts, Iraqi and Qatari cargoes arrive through normal channels with significantly lower sanctions risk.
| Data Point / Metric | Reported Figure | Date / Timeframe | Source |
|---|---|---|---|
| Initial Overseas Storage | ~135 million barrels | February 2026 | Kpler / The Wall Street Journal |
| Offshore Stocks Near Singapore | ~6 million barrels | October 9, 2026 | Vortexa |
| Chinese Alternative Purchases | 12 to 20 million barrels | October and November 2026 deliveries | Reuters |
| Denied Oil Revenue | At least $25 billion | Blockade to date | CENTCOM / The Wall Street Journal |
Export Bottlenecks at Jask and Pressure on Domestic Storage
With traditional tanker routes blocked, alternative export outlets have failed to provide a viable workaround. The Goreh-Jask pipeline and terminal on the Gulf of Oman were engineered to bypass the Strait of Hormuz, but the International Energy Agency’s February 2026 factsheet described the facility as effectively out of regular service. Although S&P Global noted intermittent tanker activity between March and July, the terminal cannot support the volume of exports Iran requires, and its coastal position leaves it vulnerable to blockade enforcement. Overland options like rail and trucking remain economically unviable due to high costs, limited infrastructure, and severe sanctions risks.
Consequently, the inability to export oil forces the crisis directly onto Iran’s domestic infrastructure. Tehran must choose between sending excess crude to domestic refineries, utilizing available storage, or cutting production further. Kpler indicated earlier in the blockade that Iran had already begun curtailing output as inventories grew and usable storage space tightened. Total tank capacity does not equate to usable storage, as certain tanks contain condensate and cannot be easily repurposed for crude. Further production cuts threaten to diminish state revenue and complicate any future efforts to restart output, compounding the financial squeeze as the United States estimates the naval blockade has already denied Tehran at least $25 billion in oil revenue.
