Why reserves stayed at 300 billion

When people think of oil rich nations their mind generally goes to Saudi Arabia, Iraq and the US.

But according to international statistics, the country with the largest oil reserves is Venezuela, with 300 billion barrels worth.

At their peak they produced over 3.5 million barrels of the stuff per day. However, due to lack of investment, sanctions and mismanagement that peak is long gone.

Following their military intervention, the US administration claims they can get Venezuela's oil production up and running at full capacity within 18 months.

But can they, and why is it that estimates for other countries oil reserves have fluctuated but Venezuela’s has stayed at 300 billion barrels for over two decades?

Presenter: Tim Harford Producer: Lizzy McNeill Series Producer: Tom Colls Editor: Richard Vadon Production Co-Ordinator: Brenda Brown Sound Mix: Dave O’Neill