Iran's dispute with the West over its nuclear work is not scaring foreign investors from the country's prized oil, which Tehran vows to keep exporting no matter what.
Iran stands accused of seeking to develop nuclear weapons and may face United Nations sanctions if it does not stop enriching uranium. Iran says it only wants to produce electricity.
"The idea of having other sources of energy was recommended to Iran 15 years before the (Islamic) revolution," Oil Minister Kazem Vaziri said on Sunday.
"The Americans at that time were supporting this idea that we have to have another source of energy because of our population and for Iran to stay a stable producer and supplier of oil." But oil remains the top attraction for foreign money.
Foreign oil executives are hopeful Vaziri can end years of commercial paralysis brought on by vicious infighting and layers of bureaucracy in Iran's oil sector, stagnant since the 1979 Revolution.
Iran's oil and gas fields have been open to outsiders since 1995 - with European firms Royal Dutch Shell, Total and Eni investing billions to help lift output capacity by 500,000 barrels per day (bpd).
Shell's Chief Executive Jeroen van der Veer, also at the Doha forum, said Iran remains a prime investment target.
"I think one has to realise that Iran has huge oil and gas reserves," he said. "This is all about energy for the future of the world that can be developed, contracts which last for decades and that's a completely different time horizon." Despite the slow pace of Iranian decision-making and the absence of US technology and firms due to Washington's unilateral sanctions, Iran has managed to boost production capacity to 4.2 million bpd.