Opec earned more than US$1 trillion (Dh3.67tn) last year as oil prices hovered at an average of $112 a barrel - the highest in history, according to the International Energy Agency (IEA), the industrialised nation's watchdog.
The director general of the Opec Fund for International Development (Ofid), a charity voluntarily funded by Opec members, defended the scale of the revenues and said that the money was sorely need for improvements at home as well as in developing nations.
"This is our resource. We are selling it," said Suleiman Al Herbishat the World Future Energy Summit. "But we are dividing this money between ourselves and others." Established in 1976, Ofid's contributions go to 120 countries including for the provision of solar cookers to remote villages in Nepal and funding highways in Bolivia.
"There is a philosophy behind creating Ofid, to help the poor, to share our resources with others," said Mr Al Herbish, a former Opec governor for Saudi Arabia. "The best way to display or demonstrate dialogue is to share your resources with others, not to talk to them. So we're sharing our resources."
In 2011, the last year with Ofid data, members pledged $3.4 billion. Ofid gave out $8.8bn, mostly in the form of loans.
Western countries benefit more per barrel than Opec countries, said Mr Al Herbish.
"The final price of the barrel of oil is divided between the producing countries, the consuming countries, and the industry," he said.
"Now most of the revenues from the barrel of oil goes to the industrialised countries, not us, through taxation."