<Table> <Tr> <Td> </Td> <Td> This article needs to be updated . Please update this article to reflect recent events or newly available information . (October 2017) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs to be updated . Please update this article to reflect recent events or newly available information . (October 2017) </Td> </Tr> <P> Petroleum (from Ancient Greek: petra: "rock" + oleum: "oil") is a naturally occurring, yellow - to - black liquid found in geological formations beneath the Earth's surface . It is commonly refined into various types of fuels . Components of petroleum are separated using a technique called fractional distillation i.e. separation of a liquid mixture into fractions differing in boiling point by means of distillation, typically using a fractionating column . </P> <P> It consists of hydrocarbons of various molecular weights and other organic compounds . The name petroleum covers both naturally occurring unprocessed crude oil and petroleum products that are made up of refined crude oil . A fossil fuel, petroleum is formed when large quantities of dead organisms, usually zooplankton and algae, are buried underneath sedimentary rock and subjected to both intense heat and pressure . </P>

What is the name of the process used to separate the components of petroleum