Kazakh oil producer Tengizchevroil, led by Chevron, said on Monday that it had temporarily halted production at the Tengiz and Korolev oilfields after an issue affected power distribution systems.
The statement came a day after Kazakhstan's state-owned KazMunayGas reported a fire at a power station at the Tengiz field, which was extinguished.
Oil production at Tengiz averaged about 860,000 barrels per day in 2025, according to Reuters calculations.
"Tengizchevroil (TCO) confirms that, as a precautionary measure, it has temporarily shut in production at its Tengiz and Korolev oil fields," TCO said in a statement.
"This is due to an issue which has affected some of the site power distribution systems. There have been no injuries, and the safety of personnel remains the highest priority," the company said.
It added that TCO was working closely with the government authorities to mitigate the impact of this situation.
The Tengiz field and facilities remain safe and secure, it added.
The suspension of oil production at Kazakhstan's largest oilfields further complicates output for the producer, which has already faced export bottlenecks and drone attacks on energy infrastructure and vessels.
KazMunayGas said on Sunday that the staff had been evacuated to a safe place and that nobody had been hurt. The fire had erupted at a turbine's transformer, it said, adding that the causes of the fire were being investigated.
An industry source told Reuters last week that oil production at Tengiz more than halved from January 1-12, leading to Kazakhstan's oil and gas condensate output plunging by 35% for the period. That was mainly due to export constraints via a Black Sea terminal.
(Reuters - Reporting by Reuters in Moscow, Shadia Nasralla in London;Editing by Andrew Osborn, Guy Faulconbridge and Louise Heavens)