The as called permanent court of arbitation ruled in 2009 that the Heglig oil field no longer belongs to south Sudan, though other reports say it straddles the north south border, possibly drawn by Britain as Sudan was said to have been governed by a British -Egyptian condominium from 1899 to 1956. Reportedly in practice Britain ensured control. They administered the north and south separately and were said to have discouraged trade between the two. Pressure to unite Sudan is said to have lead in 1946 to northerners holding positions in the south, Arabic becoming the language of administration and the southern elite being kept out of government.
The first Sudanese war broke out in 1955. Reportedly half a million people died. It ended in 1972 with the Addis Ababa agreement which gave religious and cultural autonomy to the south. The second Sudanese war lasted from 1983 to 2005. Both wars were said to be due to inequality, especially with regard to oil resources: An estimated two million people died as a result of the second Sudanese war and a reported four million were displaced in south Sudan.
The two states came into conflict over the greater Nile oil pipeline which begins in the Unity oil field, south Sudan, is 1,600 km long and commenced operation in 1999. Reports are that northern Sudan who have eastern influences own 5% of the Greater Nile Oil pipeline company. Other listed stakeholders are chinese, malaysian and indian nationals.
The Unity oil field in the Rueng district, said to be home to the Dinka people and the Heglig, north of Bientu were reportedly the most productive oil fields in Sudan. Also noted is the Tarjath of the upper Nile region, known to oil companies as block 5 a. Tarjath is situated 60 km south of Bientu and estimated to contain 250 million barrels of oil. Reports were that as in Nigeria, south Sudanese oil revenue was privatised to western interests. Oil exploration has resulted in major displacement of local populations. Tarjath was the scene of extensive fighting during the second Sudanese war. Out of an original population of 240,000, 12,000 people were said to have been killed or died of starvation and 160,000 displaced. Hunger may have been the reason. As called Block 5 A is home to the Nuer people. Other oil fields in the area are Mala, said to contain 24 million barrels of oil, and the Jarayan oil field.
An oil field as yet in the early stages of development is Adar which is estimated to contain 276 million barrels of oil. President Al-Bashir of Sudan was said to have commenced work on the Adar sight in 1997 though Adar is in south Sudan. The Palogue oil field is said to be currently producing 160,000 barrels of oil per day. South Sudan ranks 185/189 in the human development index.