Iran does not rely completely on selling oil and it does not sell 10 million barrels of oil a day. The Saudi's are coward, they will not fight, they just supply Al-Qaeda recruits to fight in other countries and they pay others to fight wars for them like Israel and France. I remember watching Saudi troop leaving all their equipments and running away when Saddam's forces attacked Saudi borders. I do not think they can operate most of the stuffs they buy.
EU's Mogherini in Tehran to talk nuclear deal, regional issues (Reuters)