Iran’s oil exports have been slashed by over 80 per cent, with analysts saying only “around 4 million barrels” have made it out. OSLO: A US naval blockade of Iranian ports has shrunk Tehran's oil exports , stranding a growing stockpile of crude on tankers as Iranian storage sites run out of space, shipping data showed and analysts said. With some vessels switching off tracking systems and US forces turning back Iranian tankers, how much crude Iran is delivering to c us tomers, particularly main