How are oil and gas formed?
Oil and gas, as well as coal, are types of hydrocarbons. Hydrocarbons are formed from dead plant and animal (organic) matter. Much of the hydrocarbons being recovered today were the result of decaying plants and animals millions of years ago. As plants and animals died, they were covered by layers of mud and rocks. The layers of mud and rocks prevented oxygen from reaching the organic material and thus, the organic material couldn’t rot in the same way it does at the surface. As the layers of rocks and mud grew in thickness, they pushed down on the organic material with increasing pressure. The temperature of the organic material also increased. Under high temperatures, pressure, and lack of oxygen the organic matter slowly turned into hydrocarbons. As oil and gas molecules form, they migrate through the pores of sedimentary rocks. Because oil and gas are less dense than water, when they encounter water, they rise through the water and settle as a layer on its surface. The hydrocarbons
