In the old days, oilmen didn't know what to do with natural gas. They knew it could be used as a fuel, but it was too expensive to transport, so they usually wound up just burning it. This is called flaring. In Vurner Valley, in 1936, so much natural gas was flared that it was called Hell's Half Acre. Today the oil companies must conserve their natural gas.
Natural gas is almost all methane.
It's a light gas, but heavier than air. It is invisible, and has no smell. It burns very easily. Also, gas pipelines are expensive to build. Methane has no smell .