US Blockade Squeezes Iranian Oil Sales to China, Threatening Tehran’s War Chest and Global Energy Markets

US Blockade Squeezes Iranian Oil Sales to China, Threatening Tehran’s War Chest and Global Energy Markets The US naval blockade of Iran, re-imposed in mid-July after the collapse of a truce in the ongoing war, is now visibly choking Tehran’s most vital economic lifeline: crude oil exports to China. Trade sources report that offers of Iranian crude to Chinese buyers have dwindled sharply this week, with prices flipping to premiums as the blockade cuts off shipments at the source. The squeeze is hitting China’s independent “teapot” refiners hardest, forcing them to scramble for alternative supplies and raising the stakes in a conflict that began in February with US and Israeli strikes on Iranian targets. For Israel, the economic strangulation of Iran’s oil revenue is a central pillar of the war effort, undermining Tehran’s ability to fund its military, its proxies, and its nuclear program. The blockade has effectively halted visible supertanker crossings of the Strait of Hormuz carrying Iranian crude since mid-July, according to ship-tracking firm Kpler, though many vessels switch off their transponders to evade detection. As the US Treasury prepares to unveil what it calls “the toughest sanctions in history” on Monday, the ripple effects are already reaching the refining hubs of eastern China.

Iranian Crude Prices Flip to Premiums as Supply Dries Up

The most immediate sign of the blockade’s impact is the dramatic shift in pricing for Iranian crude in the Chinese market. Historically sold at a discount to international benchmarks to attract buyers despite sanctions, Iranian barrels are now being offered at a premium of roughly $2 per barrel to ICE Brent futures, according to one trade source. Just earlier this week, Iranian Light was still offered at a discount of about $3 per barrel, the same level as a month ago. Four trade sources told reporters that offers of Iranian crude to Chinese buyers have declined noticeably this week, with sellers holding back cargoes amid uncertainty about whether they can get them through the blockade. Iranian crude held on tankers outside the blockade zone has fallen to approximately 80 million barrels, down from about 105 million before the blockade was reinstated on July 13. Two sources estimated that only around 30 million barrels remain in Asian waters—roughly half the usual levels. Kpler Senior Crude Oil Analyst Muyu Xu noted that about 40 million barrels of Iranian oil are held on ships in Malaysian waters east of Singapore, most already promised to buyers. “Buyers could face virtually no new Iranian supplies available for late-September delivery onwards since no laden Iranian tankers have so far managed to break through the US blockade,” she wrote.

China’s Teapot Refiners Feel the Pinch

The brunt of the squeeze is being borne by China’s independent refiners, known as “teapots,” concentrated in the eastern province of Shandong. These smaller, privately owned facilities account for roughly a fifth of China’s refining capacity and are the top buyers of sanctioned oil. With Iranian supply drying up, they are being forced to look elsewhere—and fast. One teapot has already purchased Brazil’s Lapa crude this week, while others are evaluating Iraq’s Basrah crude as a substitute, according to two trade sources. Sun Jianan, senior oil analyst at Energy Aspects, said the shift is now structural: “Given the thin Iranian availability amid the US blockade, Chinese teapots are now looking beyond Russia and Iran.” The scramble comes at a cost, as these grades typically command higher prices than the discounted Iranian barrels the teapots have long relied on. The timing could hardly be worse. China’s imports of Iranian oil had already fallen to 785,000 barrels per day in June, the lowest level since February 2023, according to Kpler provisional data. July saw a modest recovery to 823,000 barrels per day, but August intake has plummeted to just 534,000 barrels per day—versus an average of 1.4 million barrels per day last year. China buys more than 80% of Iran’s shipped oil.

US Treasury Targets Hengli Petrochemical in ‘Economic Fury’ Campaign

This week, the US Treasury’s Office of Foreign Assets Control (OFAC) escalated its pressure campaign with a direct strike on one of Iran’s largest Chinese customers. OFAC sanctioned Hengli Petrochemical (Dalian) Refinery Co., Ltd., China’s second-largest teapot refinery, which has purchased billions of dollars’ worth of Iranian petroleum. The action, taken pursuant to Executive Order 13902 and National Security Presidential Memorandum 2, also targeted approximately 40 shipping firms and vessels operating as part of Iran’s shadow fleet. The campaign, dubbed “Economic Fury,” is designed to impose what Bessent called “a financial stranglehold on the Iranian regime, hampering its aggression in the Middle East, and helping to curtail its nuclear ambitions.” Since February 2025, OFAC has sanctioned over 1,000 Iran-related persons, vessels, and aircraft as part of the maximum pressure campaign. The targeting of Hengli is notable for its connections: the refinery received Iranian crude from shadow fleet vessels BIG MAG, GALE, and ARES, which alone delivered over five million barrels. Those shipments were overseen by Sepehr Energy Jahan Nama Pars Company, the oil sales arm of Iran’s Armed Forces General Staff, generating hundreds of millions of dollars for the Iranian military. The action follows Treasury’s earlier targeting of four other teapot refineries. Yet new sanctions are unlikely to significantly deter purchases—previously sanctioned refiners have continued processing Iranian oil through opaque trading networks.

Bessent Threatens ‘Toughest Sanctions in History’

On Thursday, Treasury Secretary Bessent escalated the rhetoric, threatening Iran with “the toughest sanctions in history,” with details to be announced on Monday. The goal, he said, is to pressure Tehran to reopen the Strait of Hormuz and end the war. Bessent described the strategy as a “one-two punch. We have the blockade, and we are going to have the toughest sanctions in history. It is going to work in Iran and we are going to collapse this regime.” Bessent argued that maximum economic pressure makes a renewed military escalation less likely, saying the approach means “likely not a kinetic restart.” He also sought to bring China onside, noting that “the Chinese get 50% (of their) energy from inside the Gulf. So it would do them a big service to get with the programme.” On the shadow trade network, Bessent was blunt: “Oil smuggling, swap lines, cash transfers, exchange houses, ship registries, front companies—It all needs to stop NOW.” For Tehran, the combination of a naval blockade and financial isolation threatens to cut off the revenue that funds its war effort, its proxies in Lebanon, Syria, and Yemen, and its nuclear program. For China, the choice is stark: continue buying Iranian oil and risk secondary sanctions, or pivot to alternative suppliers and absorb higher costs.

China Rejects Sanctions, Calls for Diplomacy

Beijing’s response has been predictably defiant. A Chinese foreign ministry spokesperson said on Thursday that sanctions will not solve the conflict, stating: “Sanctions and pressure do not help resolve the problem. China calls on the relevant parties to take responsible actions and resolve the issue through political and diplomatic means.” Beijing has long rejected unilateral sanctions. Yet China’s practical options are limited. While it could theoretically increase purchases from Russia, Saudi Arabia, or other Gulf producers, those barrels come at market prices, eroding the cost advantage that Iranian crude has long provided. The teapots operate on thin margins and are highly sensitive to input costs; a sustained loss of discounted Iranian supply could force consolidation in the sector. For now, Chinese buyers appear to be hedging their bets—stockpiling what Iranian crude they can still access while seeking alternative grades. The floating storage drawdown, from 105 million to 80 million barrels, suggests buyers are pulling whatever they can from tankers already outside the blockade zone. But as Kpler’s Xu warned, those stocks are finite.

Strategic Implications for Israel and the Region

For Israel, the economic campaign against Iran is not merely an American project—it is a core component of the war effort that began in February. Iran’s oil revenue is the financial engine that powers its armed forces, its regional proxies, and its nuclear ambitions. Every barrel of Iranian crude that fails to reach China is a barrel that cannot fund Hezbollah’s rockets, the Houthis’ missiles, or the centrifuges at Fordow and Natanz. The blockade also has direct implications for Israel’s home front. Sustained pressure on Iranian crude exports affects global energy prices, which in turn influence the cost of living in Israel—higher oil prices mean more expensive fuel, transportation, and goods. A weakened Iran, starved of revenue, is less able to project power across the region, but it may also become more desperate, raising the risk of unpredictable escalation. The reopening of the Strait of Hormuz, which Iran has threatened to close in retaliation, remains a critical flashpoint. Bessent expressed confidence that “everyone wants the Strait reopened, and for energy prices to come back down,” but Tehran has shown little willingness to back down. The coming days, with new sanctions due on Monday, will be pivotal in determining whether economic pressure can achieve what military strikes have not: forcing Iran to the negotiating table.

What Comes Next: A Test of Will and Resolve

The blockade and the impending sanctions represent a high-stakes gamble by Washington and its allies, including Israel. The bet is that economic strangulation will collapse the Iranian regime’s ability to wage war without triggering a broader military conflagration. But Bessent’s confidence in a “one-two punch” is premised on the assumption that Iran’s leadership will prioritize survival over aggression—an assumption that has yet to be tested. For China, the coming weeks will reveal whether it is willing to absorb the costs of defying US sanctions or whether it will quietly reduce its purchases of Iranian crude. The teapots, already squeezed by thin margins and now facing a supply vacuum, may have little choice but to pivot. For Israel, the outcome of this economic campaign will shape the strategic landscape for years to come. This article was produced with AI-assisted research and editorial support. Sources: The Jerusalem Post, Reuters, Bloomberg, US Department of the Treasury, Times of India. By Hannah Berg, Staff Writer