Sinopec Group, a leading Chinese oil and gas producer, announced Friday that it will buy a 33-percent stake in Apache Corporation's oil and gas business in Egypt for $3.1 billion.

The deal, still subject to government approval, was signed by Apache Corporation and Sinopec International Petroleum Exploration and Production Corporation, a wholly owned subsidiary of Sinopec Group.

If the deal goes through, it will enable Sinopec to expand output by an estimated 6.5 million tons of oil equivalent each year. It will also mark Sinopec's debut in the Egyptian oil and gas market, the company said.

Founded in 1954, US company Apache is one of the world's leading independent oil and gas exploration and production firms.

Data showed that as of Dec 31, 2012, Apache's Egypt assets had oil reserves equal to 641 million barrels available for exploration. Meanwhile, gas reserves eligible for exploration totalled 3.79 trillion cubic feet, equal to 632 million barrels of oil equivalent.