Iran easily beat expectations with its speed in boosting oil exports after the lifting of sanctions. Without an injection of cash and the easing of remaining trade barriers, the recovery may have run its course. When restrictions on Iran’s oil exports were relieved in January following a nuclear pact with world powers, analysts from Goldman Sachs Group Inc. to Barclays Plc doubted it could return to previous levels this year. The Persian Gulf state defied the skeptics with a 25 percent surge in production and aims to reach an eight-year high of 4 million barrels a day by year-end. “They have surprised most market participants with the speed they’ve been able to resume production,” said Antoine Halff, a senior fellow at the Center on Global Energy Policy at Columbia University in New York. “But to exceed pre-sanctions levels would require investment and technology and that’s a much longer-term proposition.” […]