European oil companies are in fierce competition for the best oil and gas fields in Iran when Western sanctions are lifted, while U.S. energy firms watch from the sidelines. The contest has been evident this week at the first major oil-and-gas conference in Iran since world powers agreed in July to lift sanctions in exchange for curbs on the Persian Gulf nation’s nuclear program. The European Union and the U.S. on Sunday formally adopted the nuclear agreement. Iran is looking for Western help to ramp up its oil-and-gas industry after sanctions shaved more than one million barrels off its average daily production. At the conference in Iran, European executives pitched their company’s prowess. Total SA TOT -2.14 % of France cited its long history of working with Iran before it left the country in 2010 because of sanctions. Italy’s Eni E -2.25 % SpA played an animated video showing […]