Sudan-South Sudan Conflict
The Sudan-South Sudan border is not clearly defined; the two states failed to finalize an agreement prior to South Sudan's independence. That the border region accounts for such a large percentage of the countries' combined oil production compounds the issue.
Oil blocks underneath South Kordofan and Unity states, as well as Upper Nile and Blue Nile states, yield about 80 percent of the countries' approximately 500,000 barrel-per-day capacity.
Since South Sudan's July 2011 declaration of independence from Sudan, the two countries have been engaged in negotiations -- and military skirmishes -- over their oil-rich borderlands, which have an estimated capacity of 460,000 barrels of crude oil per day. Sudan, which controls all export avenues for this oil but was left with only about one-fourth of the region's producing oil fields, has been attempting to seize southern oil fields to address what it views as an imbalance in oil wealth.
The core reason of the conflict is that each side wants to establish a border that places more oil reserves in its own territory. Sudan and South Sudan rely heavily on oil revenues for their respective national budgets -- indeed, oil revenues have constituted roughly 60 percent and 95 percent of Sudan and South Sudan's budgets, respectively. Khartoum (Capital of Sudan) and Juba (Capital of South Sudan) have sought to diversify their economies, but these efforts remain long-term goals.
In recent times, both Sudan and South Sudan have deployed the military forces to ensure territorial control. Sudan has military advantage: Between 20,000 and 50,000 SAF personnel are deployed to the border at any given time. South Sudan has a significantly smaller regular army -- only 5,000 or so troops are deployed to Unity state -- but Juba's strength lies in its proxy militias. Under the Sudan Revolutionary Front (SRF) alliance, which comprises the Justice and Equality Movement, two factions of the Sudanese Liberation Movement and forces under the SPLA-North grouping, as many as 20,000 militiamen with ethnic and political links to South Sudan are active in Sudanese territory.
This makes clear that South Sudan is not capable to the deter the Sudanese forces.
The border demarcation negotiations were in flux and result was that Sudan forcibly tried to control the territory, control the oil fields and eliminate South Sudan's ability to destabilize the border. But despite its superior numbers, Sudan cannot achieve these goals. In addition to SPLA units deployed to the border, pro-Juba rebels with knowledge of a region that contains no natural barriers for Khartoum can severely disrupt Sudan's military supply lines and exposed oil pipelines in the area.
Geopolitically, both the Government are under economic and political pressure from their oil sector partners, most notably China and India. As the major stakeholders in the cross-border oil blocks, both China and India want Juba and Khartoum to negotiate an agreement without any disruption to oil production.
The United States, a significant political supporter of South Sudan's independence bid, has also pressured South Sudan to rein in SRF militias and to refrain from provocative SPLA movements into Sudan.
Apart from that, the international groups keep watch along the border. A U.N. peacekeeping force that includes 4,000 Ethiopians is deployed to the contested Abyei region on the Sudan-South Sudan border. It has also been proposed that U.N. peacekeepers currently in Sudan's Darfur region redeploy to South Sudan to supplement border security measures.