CNOOC Limited, an investment holding company, engages in the exploration, development, production, and sale of crude oil and natural gas. It operates through, E&P and Trading Business segments. The company produces offshore crude oil and natural gas primarily in Bohai, the Western South China Sea, the Eastern South China Sea, and the East China Sea in offshore China. It also holds interests in various oil and gas assets in Asia, Africa, North America, South America, Oceania, and Europe. In addition, the company is involved in the sales and trading of petroleum and natural gas; oil sands exploration, development, and production; and exploration, development, and production of unconventional natural gas resources in onshore China, as well as shale gas exploration activities in the People's Republic of China. CNOOC Limited operates in China, Indonesia, Iraq, Russia, Canada, the United States, the United Kingdom, Nigeria, Uganda, Argentina, Brazil, Guyana, Australia, and internationally. The company was incorporated in 1999 and is based in Central, Hong Kong. CNOOC Limited is a subsidiary of China National Offshore Oil Corporation.