How are oil and gas formed?
Oil and gas are formed from the decomposition and pressurisation of algae, plankton and other organisms.
When such organisms die, they sink to the bottom of the sea, lakes, as well as rivers that wash them into seas and lakes.
These low-lying areas are filled up over millions of years by fragmented material that hardens into rock layers – including sandstones, shales and coal seams.
Organic material in these rock layers breaks down to hydrocarbons (oil and gas) that are trapped in the rocks.