PetroChina Co. Ltd. engages in the petroleum related products, services and activities. It operates through the following business segments: Exploration and Production; Refining and Chemicals; Marketing; Natural Gas and Pipeline; and Head Office and Other. The Exploration and Production segment involves exploration, development, production, and marketing of crude oil and natural gas. The Refining and Chemicals segment focuses on the refining of crude oil and petroleum products, production and marketing of primary petrochemical products, derivative petrochemical products, and other chemical products. The Marketing segment includes marketing of refined products and the trading business. The Natural Gas and Pipeline segment comprises transmission of natural gas, crude oil, and refined products and the sale of natural gas. The Head Office and Other segment relates to cash management and financing activities, the corporate center, research and development, and other business services supporting the operating business segments of the Group. The company was founded on November 5, 1999 and is headquartered in Beijing, China.