PetroChina Company Limited is an oil and gas producer and seller. The Company operates in four segments: Exploration and Production, Refining and Chemicals, Marketing, and Natural Gas and Pipeline. The Company's Exploration and Production segment is engaged in the exploration, development, production and marketing of crude oil and natural gas. The Company's Refining and Chemicals segment is engaged in the refining of crude oil and petroleum products, production and marketing of primary petrochemical products, and derivative petrochemical products and other chemical products. The Company's Marketing segment is engaged in the marketing of refined products and trading business. The Company's Natural Gas and Pipeline segment is engaged in the transmission of natural gas, crude oil and refined products and the sale of natural gas.