Where Natural Gas Comes From Natural gas consists mostly of a substance called methane. There's a fairly plentiful supply of natural gas on the North American continent, so it's cheaper than oil. And gas is the most environmentally benign of the fossil fuels.
Natural gas is found under the earth, often in oil fields.
It's brought to the surface at gas wells. Then the gas is purified and the odorant which allows gas leaks to be detected is added to the normally odorless gas. Surplus gas can be stored in underground reservoirs until needed.