History's Biggest Reserve Release Fails as Iran Mines Hormuz and Oil Tops $100
Iran's IRGC attacked at least seven vessels in the Persian Gulf and Strait of Hormuz on 12 March, including strikes on two tankers — the Safesea Vishnu and Zefyros — in Iraqi waters that set both vessels ablaze and killed at least one crew member, per Al Jazeera as of 12 March 11:26 UTC. In a significant escalation of tactics, Iran is also deploying sea mines in the Strait of Hormuz, with KOMU 8 reporting Iran retains 80–90% of its small boats and minelayers operational.
The IEA characterised the conflict as producing "the largest supply disruption in the history of the global oil market," with Gulf states — Iraq, Qatar, Kuwait, UAE, and Saudi Arabia — cutting combined production by at least 10 million barrels per day, and Strait of Hormuz flows running at less than 10% of pre-war levels. Brent crude briefly surpassed $101.59 per barrel before retreating to approximately $96.50, while WTI climbed to $91.77, up $4.52 — both benchmarks moving higher despite the confirmed 400 million barrel IEA strategic reserve release.
Additional infrastructure damage has been reported across the Gulf: Iranian drones struck Saudi Arabia's Shaybah oilfield, Bahrain's fuel storage tanks sustained direct hits, and Oman's Mina Al Fahal terminal was evacuated, per Fortune as of 12 March 11:46 UTC. The U.S. confirmed it will not provide naval escorts through the Strait of Hormuz, while Iranian President Pezeshkian stated attacks will continue until Iran receives security guarantees, leaving no de-escalation pathway in sight.
The 400 million barrel IEA reserve release — the largest in the agency's history — has been decisively overwhelmed in real time, and markets are pricing it accordingly. CNN reported the entire reserve volume would be exhausted in just 26 days at current disruption levels, while Goldman Sachs modelled the release as offsetting only 50% of the supply disruption impact even under revised assumptions. The market's verdict was immediate: Brent spiked above $100 within hours of the IEA announcement, signalling that participants view the reserve release as a short-duration buffer against a structural supply hole — not a solution. Macquarie Group's energy strategist placed the residual daily supply deficit at 5–8 million barrels per day after accounting for both SPR releases and alternative routing capacity combined.
The forward risk profile has escalated materially on two distinct fronts since the previous brief. First, the introduction of sea mines into the Strait of Hormuz — a tactic with persistent, non-linear risk that survives any ceasefire — substantially raises the cost and timeline of restoring normal tanker transit well beyond the duration of active hostilities. Second, direct drone strikes on Saudi Arabia's Shaybah oilfield represent an expansion of the conflict into core Gulf Cooperation Council production infrastructure itself, not merely the transit routes that carry it; if those strikes cause sustained production damage, the supply disruption deepens independent of any Hormuz resolution. Analyst projections cited by Fortune range from $130 to $200 per barrel if the conflict extends to six months — a scenario that now appears increasingly plausible given Iran's stated refusal to stand down without security guarantees.