(MENAFN) State-owned Chinese oil giant CNOOC has signed a production-sharing deal with Somalia's transitional federal government in the east African country, which ranks as a high-risk frontier even in an industry well accustomed to dangerous environments, Reuters reported. Somalia's Interim Prime Minister said that ConocoPhillips, Chevron, BP, Royal Dutch Shell and Eni will be invited to return and change their concessions into production-sharing agreements under an oil law due to be published in the next two months. Range Resources estimates that Somalia has the potential to yield five billion to 10 billion barrels of oil. The US Energy Information Administration, however, says the country has no proved oil reserves.