underground gas line pipe - three gas pump nozzles over a nature background

Everything That You Ever Wanted To Know About Natural Gas

Natural gas is a fossil fuel that is formed underground and contains many different compounds. The largest component of natural gas is methane (CH4), and it contains smaller quantities of ethane, propane, and butane. Natural gas can be extracted from the earth and transported via pipelines as an energy source for commercial and domestic use. 

Why does natural gas exist?

Like all fossil fuels, natural gas is the result of decaying organic matter such as the remains of plants and animals. This process began millions of years ago, and there are several theories as to the factors that contributed to the development of fossil fuels. 

According to National Geographic, the most prevalent theory is that the decomposing matter was gradually covered with layers of soil, sediment, and rock and became compressed deeper into the earth’s crust. This created chambers of material with highly concentrated levels of carbon and hydrogen. 

As the organic material was driven deeper underground, it was exposed to higher temperatures. Together with the intense pressure, this triggered molecular breakdown, which is key to the production of methane, the primary component of natural gas. Some of the organic matter was also converted into coal and oil.

Different types of natural gas

The type of natural gas that is extracted for commercial use is known as ‘conventional gas.’ It is found at accessible depths of a few thousand metres in the earth’s crust, and is relatively straightforward to extract. 

Other types of natural gas that are more difficult to extract are sometimes known as ‘unconventional gas.’ This includes deep natural gas that is at least 4,500 metres beneath the surface of the earth. As new techniques are developed, it has become possible to extract deep natural gas, but it is a more expensive, complex, and time consuming process.

Shale gas is another unconventional gas because it is particularly difficult to extract. It is deposited between thick layers of shale, which is an impermeable fine-grained rock. It can be accessed via hydraulic fracturing (known as fracking), which involves splitting the rock open with high-pressure water jets. It can also be accessed via horizontal drilling.

Tight gas is also an unconventional gas that is trapped under impermeable rock layers and is complicated to extract. It is sometimes accessed via fracking, or a similar process known as acidizing. This involves injecting an acid such as hydrochloric acid into the tight rock to dissolve it.

Biogas is a type of renewable gas that can be produced by decomposing organic matter without oxygen, a process known as anaerobic digestion. It can be used for vehicle fuel, or it can be refined into biomethane and used as an alternative to natural gas.

Where are natural gas reserves and how are they located?

About 40 per cent of the world’s natural gas reserves are located in the Middle East, and a further 17 per cent are located in Russia. There are also sizable reserves in North and South America, China, Nigeria, Australia and the North Sea. 

Natural gas is more likely to be found in certain rock formations that can be identified by geologists. They can also carry out seismic surveys to explore the structure of the underlying rock beds and work out where natural gas reserves are potentially located.

How is natural gas extracted from the earth and transported?

If a reserve of natural gas is found that is large enough to be financially viable and profitable to extract, then a well is drilled. In the case of conventional gas, the wells are usually drilled vertically. Unconventional gases are sometimes extracted by drilling vertically and then horizontally. 

At the wellhead, natural gas is known as wet natural gas because it contains water vapour and liquid gases such as propane and butane. It also contains non-hydrocarbons that need to be removed to render it usable as an energy source. The gas is sent to processing plants where the various compounds are removed or separated for other purposes. 

When the gas has been processed it is called dry natural gas, and this is what is transported via pipelines to storage sites or distribution companies. Before the gas is piped, a chemical called mercaptan is added to give it a distinctive rotten egg smell. This is to help detect leaks, because natural gas is colourless and odourless.

How is natural gas used?

Natural gas has many uses, including heating, cooking, transport, and for powering industrial machinery. It burns more cleanly than other fossil fuels, although it does produce some greenhouse gases.

No Comments

Sorry, the comment form is closed at this time.