Before departure, the last job the Indian executives did was to shut down the oilfields on Sunday.
ONGC Videsh, the overseas arm of state-owned Oil and Natural Gas (ONGC), had deputed 11 employees at Greater Nile Oil Project and Block 5A in Sudan.
The company made all arrangements to evacuate its personnel as rebel forces loyal to deposed South Sudanese vice-president Riek Machar captured Unity state, which housed most of the fields it was operating in.
OVL owns 25% stake in the Greater Nile Oil Project, which produces about 40,000 barrels of oil per day and 24.125% in Block 5A, that produced 5,000 bpd.
Other partners in the blocks Chinas CNPC and Petronas of Malaysia too, have decided to evacuate their officials from South Sudan, the source said.
Fighting in South Sudan, which broke out on December 15, has already claimed as many as 500 lives, including Indian soldiers working as United Nations peacekeepers. The source said rebels so far have not captured any of OVLs oil wells, but as a precaution all of them were shut before officials left the country.
Rebel forces last week captured Bor, the capital of Jonglei state, and are said to have taken control of most of the country.
The US has evacuated its 380 officials and private citizens to Nairobi and other locations, along with about 300 others. South Sudan seceded from neighbouring Sudan in July 2011.