What Is Natural Gas and How Is It Formed?

13th January 2013 written by Richard Hearne in the category Gas Articles

Natural GasNatural gas is a fossil fuel that we rely heavily on in the industrialised western world and UK. We’re going to look at where gas comes from, how it was formed, more about it’s chemical breakdown, and what benefits it has.
Where Does Natural Gas Come From and How Was It Formed?
Gas has been formed over many millions of years and is found deep in the earths crust where oil is usally found too. It is believed that whether gas or oil is formed, depends on the pressure and temperature at which they are subjected.

There are different theories, but the mos popular is that fossil fuels were created by dead plants and organisms which were buried and then subjected to increased temperatures, compressed over time, and then the chemical bonds were broken down to form a reservoir of energy. Fossil fuels in terms of the history of the earth have only very recently been discovered and harnessed. It’s well documented that since the industrial revolution, our demand for energy has become and continues to be insatiable and the next one hundred years could see most fossil fuel reserves dry up. We use fossil fuels everywhere from keeping ourselves warm to producing food. This has sparked a demand to look at other fuel sources such as nuclear and green energy (wind, tidal, solar, hydroelectric, biomass and more).

Gas can be found both under the sea and on land. It is low density and rises to become trapped under rock formations below ground, and can then be drilled to release the gas. Shale Gas can also be found inside porous rocks. Fracturing rocks using hydraulic machinery is then used to induce pressure so as to fracture rocks and access the gas. Recently the UK government authorised shale gas extraction from a site near Blackpool, Lancashire.

Typically natural gas is found one to two miles below our feet or the sea bed. Deep wells and drills penetrate the the earths top layer to access the valuable resources we rely on. Once the gas is brought to the surface, unwanted impurities are removed which include sand, water and other gases.  After cleaning of the gas, it is pumped into our transporation networks for delivery to our homes and businesses for use in cooking, heating, and manufacturing.

The worlds biggest producers of gas include Norway, The United States, Iran and Russia which has huge reserves of gas. Gazprom is 51% state owned by the Russian Government and is the world’s largest gas company and one of the largest companies in the world. The United Kingdom is in the top 20 gas producing companies in the world thanks to gas sites in the North Sea and Morecambe Bay.

Chemical Formula MethaneWhat Elements Does Gas Consist Of?
In it’s natural state, gas predominantly consists of methane (CH4) which makes up 70-90%. In case you can’t remember your chemistry lessons from school, CH4 means for every one carbon atom, there are four hydrogen atoms attached.

The other main elements which make up gas are ethane (C2H6), propane (C3H8), and butane (C4H10) and provide typically around 0-20% of the total. Gas is also comprised of much smaller levels of Hydrogen Sulpide, Nitrogen, Oxygen, Helium, and Carbon Dioxide but not usually more than 0.5%-5% composition each..

What Properties Do Gas Have and What Are The Benefits Over Other Fossil Fuels?
Natural gas has no odour, no colour and no shape. It is easily burnt, very combustable and leaves no residue or ash which means it is very clean in terms of emissions. It produces less carbon dioxide than other fossil fuels and is often viewed as a ‘greener’ choice of energy. However due to the overall demand of gas worldwide, it actually makes up a large percentage of the total contributions to carbon dioxide emissions and the green house effect / global warming. Compared to oil or coal, which create smoke and air pollution, gas is often a favourable choice. Gas is not a liquid or solid which means it easy to transport by pipeline and doesn’t need to be moved by ship or truck.

What Steps Are Taken To Make Gas Safe?
Gas has no smell. Therefore to reduce the safety risks of gas leaks, an odour is added to gas before it is introduced into the network. This process is known as odourisation. The smell is typicall that of sulphur and not very pleasant to the human nose. This makes it much easier to quickly identify sites where gas is leaking so authorities and engineers can be informed and make safe.

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