Petroleum gas, also known as natural gas, is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but also including varying amounts of other higher alkanes and cycloalkanes, depending on the geological formation. It is found in natural gas fields, as well as associated with oil deposits. Petroleum gas is used as a fuel for heating, cooking, and electricity generation. It is also a feedstock for the production of fertilizers, plastics, and other petrochemical products.