Exxon said Phase I developments at the Kizomba satellites in Angola include development of 18 wells that would tie into existing floating, production, storage and offloading vessels.
The initial phase of the project is expected to produce as much as 100,000 barrels of oil per day from the deepwater complex.
Neil Duffin, president of Exxon's development company, said production was started ahead of schedule.
"This project combines ExxonMobil's project management expertise with local suppliers and businesses to maximize the value of Angola's significant petroleum resources," he said in a statement.
Major international oil companies expressed optimism after securing rights to explore the deep waters off Angola's coast following a licensing round in late 2011.
Advocacy group Global Witness said Angola has a history of corruption, though it has opened the books on crude oil revenue. The country produces around 1.8 million bpd and ranks 168th out of 182 rankings in a transparency index.