Institutions Reveal Changes in Oil Supply Pattern: US Sanctions Force Iran's Maritime Crude Exports to "Zero", Russian Exports Up 6% MoM

The US blockade against Iran is directly cutting off its seaborne crude oil exports. According to energy intelligence firm Vortexa, Iran's seaborne crude exports dropped to zero in the second week of September and had not recovered as of October 5; meanwhile, Russia’s crude exports defied the trend and rose 6% month-on-month in September to 3.79 million barrels per day. The diverging export trends of Iran and Russia are reshaping the supply dynamics of sanctioned crude oil.

Vortexa data shows that at the start of September, Iran’s 14-day average seaborne crude export was still 230,000 barrels per day, which then quickly plummeted to zero. Claire Jungman, Head of Maritime Risk and Intelligence at Vortexa, said that the US blockade has physically prevented Iranian crude from leaving the Persian Gulf, achieving an effect that years of sanctions had failed to accomplish.

Meanwhile, Russian crude oil exports remain on the rise. Vortexa statistics indicate that, excluding CPC and KEBCO crude oil, Russia’s crude oil exports increased by 6% month-on-month in September to 3.79 million barrels per day. The combination of blocked Iranian exports and increased Russian exports highlights how Middle Eastern conflict and US sanctions are jointly altering the flow of international crude oil trade.

Iran’s seaborne exports drop to zero, with 43 million barrels of crude stranded west of the Strait

According to Vortexa, the total amount of Iranian crude stranded on offshore tankers has dropped to about 83 million barrels, of which approximately 43 million barrels are trapped west of the Strait of Hormuz, affected by the US blockade and difficult to export.

The export bottleneck affects not only Iranian crude. Vortexa reports that Iran’s LPG exports fell 48% month-on-month in September, dropping to their lowest level since at least January 2023. This indicates that the blockade’s impact has extended from crude oil to other energy products.

However, a zero export flow does not mean that Iran’s crude oil inventory has disappeared. The millions of tons of crude oil still stranded on tankers means part of the supply has yet to enter the international market. Whether this can be re-shipped in the future and through which channels remains dependent on how long the blockade persists and the regional shipping security situation.

Russian exports rise month-on-month, while Chinese demand pressure for Iranian oil eases

As Iranian crude exports are impeded, Russian oil is filling part of the supply gap. Jungman of Vortexa noted that Chinese buyers’ urgent demand for Iranian crude has declined, as Russian crude fills some of the void.

Vortexa data shows that combined crude exports from Iran, Russia, and Venezuela totaled 4.73 million barrels per day in September, down from 6.39 million barrels per day a year ago. As Iranian exports fell sharply, Russia’s share in what Vortexa terms “high-risk crude exports” rose to 80%.

This set of data also illustrates that Russia’s export growth does not mean total crude supply from the three countries has recovered. On the contrary, combined exports remain significantly below last year's level, and the export structure is shifting further toward Russia.

It is important to note that Vortexa’s figure of 3.79 million barrels per day excludes CPC and KEBCO crude, so it is not directly comparable to Russian crude oil export data using different metrics.

Other Gulf states resume exports, but supply improvement still faces shipping risks

As Iran’s exports drop to zero, other oil-producing countries in the Gulf region are resuming exports. Vortexa data shows that, excluding Iran, Gulf crude oil flows in September have rebounded to more than 81% of pre-war levels, mainly driven by the resumption of Saudi exports.

However, the rebound in export volumes does not mean energy supply risks have been eliminated. The Strait of Hormuz remains under the shadow of regional conflict, and tanker passage, insurance costs, and transportation arrangements may all affect actual delivery. Even as some oil producers resume exports, whether crude can be delivered safely and steadily to buyers remains a concern for the international energy market.

Overall, the US blockade has caused a substantial interruption in Iran’s crude oil exports, while Russia has gained some space amid the shifting export structure; meanwhile, the resumption of exports by other Gulf states has provided some buffer for global supply. Going forward, the market will continue to watch for whether the US blockade can be sustained, whether Iran’s stranded crude can re-enter the market, and whether Russia’s export growth will be sufficient to offset the loss of Iranian supply.