Prime Minister Ali al-Zaidi ordered security crackdowns and border closures after investigators traced long-range drone strikes on Saudi Arabia's East-West pipeline to Maysan province.
The precautionary shutdown of Saudi Arabia's Petroline removes the kingdom's primary energy safety valve, exposing global markets to vulnerabilities in the Strait of Hormuz.
Twin blows to energy infrastructure and maritime security have pushed crude prices above $100 a barrel while displacing over 46,000 people in Yemen.
Joint US and Saudi airstrikes in Iraq have triggered a sweeping regional escalation, with Iran launching retaliatory ballistic missiles at Jordan.
The US military intercepted an Iranian ballistic missile barrage and struck sites in Iraq used by Tehran-backed militias, shattering a brief pause in fighting.
Chevron is negotiating agreements with the Iraqi government to invest in major oil fields and explore a pipeline project to bypass the Strait of Hormuz.