At least a quarter of Iran’s oil rigs are out of action as U.S. sanctions strangle the Islamic Republic’s vital oil industry, according to a Reuters review of financial documents and industry sources, dealing a potentially long-term blow to its oil industry. The lack of rig activity could damage the OPEC member’s capacity to produce oil from older fields, which require continuous pumping to maintain pressure and output. That would make it difficult for Iran to raise production back to pre-sanction levels if tensions ease with the United States. The U.S. […]