Where does natural gas come from?

Like oil, natural gas is believed to have formed from living organisms that died millions of years ago in shallow oceans and seas.

After drifting to the bottom, these organisms were covered by further layers of organic remains, sand and rocks. Scientists believe that as the remains were covered before they could decay, this allowed anaerobic bacteria, assisted by heat and pressure, to begin the process of turning them into gas and oil.

The natural gas resulting from these changes mostly consists of methane, which is lighter than air.

This gas collected in pockets between layers of rock where it was trapped underground. As the earth shifted and buckled over thousands of years, it flowed through fault lines into pockets under impermeable rock such as granite or marble, where it was trapped and could not escape into the air above the earth's surface.

To bring natural gas to the surface, a drilling rig drills a shaft deep into the ground. The gas travels up the shaft and is transported by truck or through a pipeline to a refinery to be processed.

The refinery removes impurities from the natural gas and compresses it for easier transportation.

From the refinery the gas travels through pipelines or is shipped by truck or ship to where it is needed. This can involve transporting the gas hundreds or even thousands of kilometres across sea and land.

At destination it is pumped into smaller gas pipes in cities and towns which connect to each home and business.