There are three steps to make petroleum. Step 1: separation: the crude oil that was taken out of the ground is piped through hot furnaces. This separates the different parts of crude oil. Step 2: conversion: Thick-walled, bullet shaped reactors, and a network of furnaces and heat exchangers make the crude oil into gasoline, diesel, jet fuels, etc. Step 3: treatment: The finishing touches occur here. Refinery technicians use a variety of steams to make special considerations such as whether the product will be used at high altitudes.