Most of that was in the South - which gained its independence as the new country of South Sudan, and took 80% of the oil deposits with them.
They still have the infamous Darfur Region in the West though (itself larger than France), which was also the site of years of regime supported genocidal jihads against the local animists, by the islamist Jangaweed militia. Lots of slaves were taken, in addition to the land and general slaughter.
The old islamist dictator is now in jail facing a potential death sentence, and the new regime wants to chart a new path for the Nation, allied with the USA and Israel (perhaps with Saudi and Egyptian encouragement).