I hope not. That'd be the result of a multitude of insane atrocities and genocidal acts that would either spark UN intervention or go down in history as something along the lines of the Rwandan Genocide, permanently leaving a stain on Egypt's global reputation and causing untold damage to a region that is known for being in a poor state today.
It isn't like you couldn't find locals willing to do it, Hutu vs Tutsi style. Except in this case, it's more of a Nuer vs. Dinka thing. Considering the current South Sudan conflict, creating a situation where you could get/assist one of the groups to mass murder the other seems plausible. I guess since the Dinka are the majority near the main oil areas, you would ally with the Nuer to butcher, slaughter, and drive out their enemies.
You do need to get the situation so you don't have both the Dinka and Nuer more or less allied against you as an enemy of my enemy sort of thing. Also, man-made famines (like the current one in South Sudan is to some degree or another) help in driving down the population numbers.
Your settlers would probably be Sudanese Arabs from the north.
Also, forced migration in the oil fields
already happened OTL.
But let's be honest, you're probably gonna get a major secession movement in the South. See the Jonglei Canal project, for instance, which Egypt in this case would definitely try and do. Some suggest that it would utterly wreck the ecosystem of the Sudd which in turn wrecks the livelihoods of millions of South Sudanese. If Egypt TTL can go ahead with it, then they're setting themselves up for one hell of a conflict. And that's just one example of how Egypt might spark a major secession war in South Sudan.