CNOOC Ltd. is an investment holding company, which engages in the exploration, development, production, and sale of crude oil, natural gas, and other petroleum products through its subsidiaries. It operates through the following segments: Exploration and Production, Trading Business, and Corporate. Its core operations areas is comprised of Bohai, Western South China Sea, Eastern South China Sea, East China Sea, Asia, Africa, South America, North America, Oceania, and Europe. The company was founded on August 20, 1999 and is headquartered in Hong Kong.