Angola’s offshore oil production is likely to be double that of Nigeria by 2020, according to oil major Shell.

Nigeria, which rivals Angola as Africa’s biggest producer, could miss out if changes to its terms make it less profitable to develop deepwater reserves, reports Reuters.

Since 2005, Nigeria’s oil and gas production has fallen by 30% and could continue to decline in the coming years.

In 2009, the country produced an average of 1.6mbpd out of a total capacity of 3.2mbpd, while Angola produced 1.6mbpd out of a total capacity of 2.1mbpd.