•The nuclear accord reached in Vienna yesterday could eventually reshape global oil markets.
Iran has the world's fourth-biggest crude reserves and will benefit from an easing of international sanctions on exports.
How much more oil can Iran produce?
Iranian Oil Minister Bijan Namdar Zanganeh says the country can increase exports by 500,000 barrels a day as soon as sanctions are lifted, then an additional 500,000 a day in the following six months. Iran produced an average of 2.8 million barrels a day this year.
What's the timetable for oil exports?
Sanctions will remain in place at least until United Nations monitors report on Iran's compliance with the deal in December, diplomats involved in the talks said. The European Union will lift sanctions once Iran has met its nuclear obligations, according to the diplomats.
What does Iran's return mean for Opec?
The 12-nation Organisation of Petroleum Exporting Countries (Opec) has exceeded its self-imposed limit of 30 million barrels a day since June last year.
Saudi Arabia's focus on defending market share by increasing production rather than curtailing output to raise prices means all members are free to pump as much oil as they please. More Iranian crude could amplify Saudi Arabia's strategy of pressuring producers with the highest costs while increasing competition among Opec members for Asian customers.
Which markets will Iran target?
Iran's priorities are Asia and then Europe, Mr Zanganeh said in May. The one million barrels of daily sales lost following the 2012 sanctions were split between the two regions.