Kids Research Express

Most natural gas is formed from plankton—tiny water-dwelling organisms, including algae and protozoans—that accumulated on the ocean floor as they died. These organisms were slowly buried and compressed under layers of sediment. Over millions of years, the pressure and heat generated by overlying sediments converted this organic material into natural gas. Natural gas is composed primarily of methane and other light hydrocarbons. As discussed previously, natural gas frequently migrates through porous and fractured reservoir rock with petroleum and subsequently accumulates in underground reservoirs. Because of its light density relative to petroleum, natural gas forms a layer over the petroleum. Natural gas may also form in coal deposits, where it is often found dispersed throughout the pores and fractures of the coal bed.

. Natural Gas, flammable gaseous mixture consisting mostly of hydrocarbons (chemical compounds that contain carbon and hydrogen). Along with coal and petroleum, natural gas is a fossil fuel . Natural gas may contain as much as 85 percent methane and about 10 percent ethane, and also contains smaller amounts of propane , butane , pentane, and other alkanes. Natural gas, which is usually found together with petroleum deposits in Earth’s crust, is extracted and refined into fuels that provide approximately 25 percent of the world energy supply. Natural gas contains small amounts of impurities, including carbon dioxide , hydrogen sulfide, and nitrogen . Because these impurities can detract from the heating value and properties of natural gas, they are often removed during the refining process and used as commercial by-products. USES Natural gas is used both as a fuel and as a raw material in the manufacture of chemicals. As a residential fuel, it is burned in furnaces, water heaters, co