The commercial viability of over 500 million barrels of crude oil reserves stranded in the Nigeria–São Tomé and Príncipe Joint Development Zone (JDZ) has been called to question, as the region is yet to produce its first oil 17 years after discovery.

China signed an agreement to restore diplomatic relations with Sao Tome and Principe Monday, just days after the small African nation announced it had cut ties with Taiwan.

China on Wednesday welcomed Sao Tome and Principe's decision to sever ties with Taiwan, a move that comes after President-elect Donald Trump questioned long-standing US policy towards the self-ruled island.