What do you think the reason is? Sudan seems to have plenty of oil.
The Sudanese government uses oil revenues to fund a military capacity that is in turn, used to conduct war in Darfur. Oil revenues collected from companies around the world fund the civil war as well as violations of international human rights and humanitarian law. Sudanís oil wealth has played a major part in enabling an otherwise poor government to fund the expensive bombers, helicopters and arms supplies which have allowed the Sudanese government to launch aerial attacks on towns and villages and fund militias to fight its proxy war in Darfur.
War in Darfur - Wikipedia, the free encyclopedia