Chinese and other Asian oil firms operating in newly-independent South Sudan on Friday signed new contracts with the government to replace existing deals with north Sudan.
South Sudan became independent in July under a 2005 peace agreement with Khartoum that ended decades of civil war.
The government of Africa's newest nation has been renegotiating contracts with foreign firms operating under pre-independence deals.
China National Petroleum Corp (CNPC) and China Petroleum and Chemical Corp (Sinopec) as well as Malaysia's Petronas and India's Oil and Natural Gas Corp (ONGC) signed new contracts with the oil ministry, officials said.
No details of the contracts were immediately available.
South Sudan produces around 350,000 barrels a day, officials have said.
The landlocked country needs to export its oil through Sudan which owns the only pipeline and export port but the two sides have failed to agree on how much Juba should pay for this.