Natural gas is a fossil fuel that plays a significant role as an energy source. Its primary component is methane, a chemical compound made of one carbon and four hydrogen atoms (CH4). Additionally, natural gas contains small amounts of other compounds such as natural gas liquids (NGLs), which are hydrocarbons, and nonhydrocarbon gases like carbon dioxide and water vapour. This versatile fuel is commonly used for generating energy and as a base material in the production of chemicals.
Millions of years ago, natural gas began forming as the remains of plants and animals accumulated on the earth’s surface and ocean floors. Over time, these remains were buried under layers of rock, sand, and silt. The pressure and heat transformed this organic material into various energy sources—coal, oil, and natural gas. The process took millions of years and is the reason why these resources are considered non-renewable.
Natural gas can be found in various geological formations. It often accumulates in large cracks or spaces between layers of rock, known as conventional natural gas. Another type, shale gas or tight gas, is found in the tiny pores within shale and other sedimentary rocks, and is known as unconventional natural gas. Some natural gas is associated with crude oil deposits, and in coal beds, it is known as coalbed methane. These deposits are located both on land and offshore, deep beneath the ocean floor.
Geologists play a critical role in discovering natural gas by studying the earth’s geological structures. They use seismic surveys to locate formations that may contain gas deposits. On land, seismic waves are generated by machinery like thumper trucks or small explosives, while in the ocean, sound waves are used to map formations beneath the ocean floor. These seismic surveys give insight into whether an area is likely to yield natural gas. If the data suggests potential, exploratory wells are drilled to confirm the presence of natural gas and assess its quality and quantity.
If an exploratory well proves promising, production wells are drilled to tap into the gas. Natural gas often flows easily through wells in conventional deposits. In unconventional formations like shale, techniques such as hydraulic fracturing (fracking) are employed. This process involves injecting water, chemicals, and sand into the ground at high pressure to break apart the rock and release the trapped gas. The gas is then collected at the surface and transported via pipelines to processing facilities.
When natural gas is extracted from the ground, it contains more than just methane. Along with NGLs like ethane, propane, and butane, it may also have nonhydrocarbon gases such as sulfur, helium, and carbon dioxide. This wet natural gas needs to be processed before it can be sold. Processing plants remove water vapour and impurities, separating the NGLs from the gas. The result is dry, consumer-grade gas that is ready for distribution. Some natural gas is dry enough at the point of extraction and requires little to no processing. An odourant is added to the processed gas to make leaks detectable, and the gas is transported via pipelines to storage or distribution companies before reaching consumers.
In cases where natural gas pipelines are unavailable, such as offshore oil wells, the gas may be reinjected into the oil-bearing formation or burned off. Reinjecting the gas can also help maintain pressure in oil wells, enhancing oil recovery. Additionally, methane found in coal beds can be extracted either before or during coal mining and added to natural gas pipelines without requiring special treatment.
Most of the natural gas used in the United States is produced domestically. A portion is also imported from neighbouring countries like Canada and Mexico via pipelines, while a smaller amount arrives as liquefied natural gas (LNG). The availability of natural gas and its processing ensures a steady supply for various uses, making it a crucial component of the energy sector.
Natural gas, a fossil fuel formed over millions of years, is an essential energy source used globally. Its discovery, extraction, and processing involve advanced geological techniques and careful handling to ensure safe and efficient use. While the bulk of natural gas is produced locally in many regions, international trade ensures that even places with limited natural gas reserves can benefit from this valuable resource.
Touchstone Exploration Inc (LON:TXP) is a Canadian-based, international upstream oil and gas company currently active in the Republic of Trinidad and Tobago. Primera Oil and Gas is the Trinidadian subsidiary of Touchstone.
