We humans have always exploited nature and its resources for our benefit. It is, therefore, important for us to understand that it is high time to use them wisely and sustainably. In this article, let’s discuss one such natural resource, which is depleting with time, and answer the question of how is natural gas extracted.
1. What Is Natural Gas?
Natural gas is a fossil fuel that forms a deep earth crust. Natural gas contains a variety of compounds. The most abundant component of natural gas (CH4)is Methane, a compound composed of one carbon atom and four hydrogen atoms. Natural gas also contains trace amounts of natural gas liquids (NGLs) and nonhydrocarbon gases such as carbon dioxide and water vapor. Natural gas is used as a fuel and to manufacture materials and chemicals.
2. How Is Natural Gas Formed?
Natural gas is formed in warm, shallow oceans that existed on Earth millions of years ago. These oceans’ bottoms are covered with small dead organic matter decomposes known as plankton. These plankton consist of phytoplankton (plant remains) and zooplankton (animal remains). Plankton enters the ocean by river and lands on the ocean floor, mixing with the inorganic material. Over a long time, this sediment on the ocean floor forms oil and natural gas. Natural gas contains sunlight-derived energy that has been captured by decomposing plankton.
3. Formation Process
Natural gas is formed in the same process that creates oil and is generally the same around the globe. However, different types of plant and animal debris may fall to the ocean floor in slightly different conditions. The steps listed below are used to produce natural gas.
- Dead plankton, including phytoplankton (algae), zooplankton, and other soft and hard organic matter tissues (including microbes), sink to the bottom of an ancient ocean where they mix with inorganic, clay-like substances that enter these oceans from streams and rivers. This results in organically dense mud. The formation of mud takes place only in still water.
- If the mud is exposed to excess oxygen, the organic matter will decompose and disappear quickly by bacteria interaction. As a result, anoxic environments are those in which natural gas is formed. Before the disappearance of organic matter, it is buried by more sediments and becomes sedimentary rock (lithifies), creating organic shale.
- If the shale embed is between 2-4 km, the temperature rises as it is located in the earth’s interior. As the pressure and temperature increase, the shale transforms into a material known as kerogen. This substance-containing shale is referred to as oil shale.
- The kerogen will transform into oil and natural gas if the temperature of the kerogen rises more than 90°C but is lower than 160°C. Natural gas or graphite is formed if the temperature is greater than 90°C.
- Since natural gas and oil are lighter than water, they escape from the original oil shale, rise through rocks and pores, and replace the water. Reservoir rocks are rock masses that contain significant amounts of oil or natural gas. If the gas remains trapped in the reservoir due to some thick impermeable layers of rocks that seal the reservoir. If the seal is still present and oil gas and water are trapped, the oil is obtained using a drill.
4. Where Is Natural Gas Found?
Natural gas occasionally moved into wide cracks and gaps between the underlying rock layers. Conventional natural gas is natural gas found in these types of formations sometimes. In other regions, natural gas can be found in some shale, sandstone, and other sedimentary rock formations’ minute pores (spaces).
This natural gas is sometimes referred to as shale, tight, or unconventional natural gas. Associative natural gas is the term for natural gas that coexists with crude oil deposits. Natural deposits can be found in offshore deep underwater oceans and on land. Coalbed methane is a type of natural gas that can be discovered in coal deposits.
5. Types of Natural Gas
Biogas is a type of gas that is created when organic matter breaks down without the presence of oxygen. This is known as anaerobic decomposition. It occurs in landfills or other places where organic matter decomposes, such as animal waste, sewage, or industrial byproducts.
Biogas is a biological substance that originates from living or non-living plants or animals. This substance can be burned to produce a renewable energy source, such as forest residue.
Although biogas can be refined and used as an energy source, it does not have as much methane as natural gas.
5.2 Deep Natural Gas
Deep natural gas is an unconventional gas. Deep natural gas is found in deposits at least 4,500 meters (15,000 feet) below the Earth’s surface, as opposed to conventional gas, typically found at depths of just a few thousand meters. Although techniques to extract it have been developed and improved, drilling for deep natural gas is not always economically feasible.
Another example of an unconventional deposit is shale gas. Shale is a sedimentary rock with fine grains that do not break down in the water. Shale is allegedly so impermeable that marble is viewed as “spongy” in comparison, according to some scientists. A layer of natural gas can be “sandwiched” between thick sheets of this impermeable rock.
Because it requires horizontal drilling and hydraulic fracturing, also known as fracking, to access, shale gas is considered an unconventional source. A high-pressure water stream splits open rock during the fracking process, and then tiny grains of sand, glass, or silica are used to “prop” the rock open. Gas can now exit the well more easily as a result of this. Drilling horizontally means going straight down into the ground.
5.4 Tight gas
Tight gas is an unconventional natural gas impermeably trapped underground in a rock formation, making it very challenging to extract. Gas extraction from “tight” rock formations typically involves costly and difficult techniques like fracking and acidizing.
Acidizing and fracking are similar processes. The natural gas well is injected with an acid, preferably hydrochloric acid. The thick rock that is blocking the flow is dissolved in acid
5.5 Gas in Geopressurized Zones
Another source of unconventional natural gas is Geopressurized zones. Below the Earth’s surface, geo-pressurized zones develop at depths of 3,007–7,600 meters (10,000–25,000 feet).
These zones are developed when clay layers quickly build up and compact on top of porous materials like sand or silt. Natural gas is deposited under extremely high pressure into the sand, silt, or other absorbent material below due to the compressed clay being forced to release its natural gas.
5.6 Methane Hydrates
Another variation of unconventional natural gas is methane hydrates. This unconventional natural gas was discovered recently in ocean sediments and the polar ice area of artic. Low temperatures (around 0°C, or 32°F) and high pressure are the conditions in which methane hydrates form. Methane hydrates are discharged into the atmosphere when the environment changes.
6. Natural Gas Extraction
Collecting this fossilized material may involve different methods depending on the type of natural gas. Following are a few methods used to extract natural gas.
- Vertical drilling
- Horizontal drilling
- Hydraulic Fracturing / Fracking
6.1 Vertical Drilling
Vertical drilling is the most popular technique. Until 1980, this method of extracting natural gas served as the sole production method. Vertical drilling is effective at liberating conventional natural gas when the natural gas is close to the surface.
Vertical wells only reach the natural gas deposit at an average depth of 300–800 meters, at which point the gas can begin to flow to the surface. Since vertical drilling can only access gas reserves found above ground, it is occasionally the ideal method.
6.2 Horizontal Drilling
A flexible and economical way to increase the drilling possibilities is through horizontal drilling. Due to the drill’s ability to change direction horizontally after reaching the necessary depth, drilling companies can install fewer drilling sites. It is more productive and possible to drill through the natural gas deposits horizontally with the steerable drill bit.
6.3 Fracking/Hydraulic Fracturing
Unconventional natural gas is extracted using hydraulic fracturing, or fracking.
The most exciting aspect of gas production is hydraulic fracturing. Drilling begins with a simulated micro-earthquake.’ The formation of rocks is broken up using high-pressure streams of water, sand, and chemicals. After that, natural gas can rise to the surface and flow into wells and gathering gas pipelines.
However, this practice is prohibited in some locations because. It requires a lot of water, which could harm the environment.
It is highly toxic or radioactive wastewater that, if handled improperly, could harm the environment.
It is a side-operation to all drilling techniques, primarily fracking. Natural gas can flow up to the well by dissolving any rocks in its path using acid.
7. Advantages of Natural Gas
- Natural gas is a widely available energy source. The International Energy Agency (IEA) calculates enough recoverable resources to last about 230 years if consumption stays current.
- It is adaptable. When compared to other energy sources, such as coal-fired facilities, a gas-fired power plant starts and stops much faster. Its flexibility complements renewable energy sources like solar and wind, which are only usable when the sun is out, and the wind blows.
- Natural gas is the cleanest-burning hydrocarbon energy source. When burned to produce electricity, releasing about half as much carbon dioxide (CO2) and only one-tenth as many air pollutants as coal.
- Utilizing gas instead of coal can significantly lower CO2 emissions and air pollution.
- The availability of gas through LNG is now so widespread that it can assist nations in coping with supply disruptions that only last a short time. Japan shut down its nuclear reactors in the wake of the Fukushima disaster and relied heavily on LNG to replace a large portion of its lost electricity supply.
- Natural gas is less expensive than producing coal. According to the IEA, the most efficient coal mining plant has investment costs of $3,700 per kilowatt, while the most efficient gas-fired plant has costs of $1,100 per kilowatt.
- When long-term costs related to global warming and the effects of air pollution on people and the environment are taken into account, gas-fired power becomes competitive again.
A growing number of other gas applications exist, such as using LNG in transportation as a lower-emission substitute for diesel and heavy fuel oil.
8. Disadvantages of Natural Gas
- Limited supplies: The issue in nations like India is that they don’t have significant natural gas reserves, meaning that most of the natural gas consumed must be imported. This makes it a rather costly venture over time.
- Natural gas is very flammable: Although natural gas is lighter than air, its high combustibility cannot be disputed. Leaks in natural gas are challenging to find because they have no smell.
- Storage: Although it is simpler to transport, the volume is four times greater than that of gasoline, adding to the cost of a larger storage area.
9. Uses of Natural Gas
- Since the 19th and 20th centuries, this gas has been extensively used to light homes and streets. It has many uses in these industries today and is also widely used for solar and wind energy.
- It is used to turn the turbines to capture wind and solar energy. It is used to make ammonia, which is then converted into fertilizers in agricultural fields. It also has domestic uses because heaters, ovens, and even boilers use them.
- Natural gas that has been compressed and kept at high pressure can occasionally be used in homes for cooking and heating. CNG is an inexpensive and environmentally friendly alternative to other transportation fuels that are bad for the environment. Heavy vehicles like off-road trucks and trains are propelled by liquefied natural gas.
- Domestic uses for natural gas, including cleaning cleaner energy, can benefit from residential electricity. Heating water at home is cheaper and heats faster than electricity. It is more practical and effective to have a controllable burner in a heating structure.
- Natural gas cooking is more cost-effective than an electric oven because it consumes less energy. Natural gas clothes dryers can save up to 50% more energy than their electric counterparts, making them more energy-efficient for drying cloth.
- Industrial applications for natural gas Chemicals, fertilizers, and hydrogen are produced using natural gas as raw material and a heating source. Glass, steel, brick, and other materials are heated there in the manufacturing sector.
- Acetic acid, ammonia, methanol, butane, propane, and ethane are just a few chemicals produced using natural gas. Glass, steel, cement, bricks, ceramics, tile, paper, food products, and other materials are all heated with natural gas. It is also burned at a lot of industrial facilities.
- Natural gas’s application in transportation is less expensive than comparable products, such as vehicle fuel.
10. Environmental Impacts of Natural Gas
Before being used, natural gas typically needs to be processed. Natural gas can contain a wide range of substances besides methane when it is extracted. A natural gas well might contain water, ethane, butane, propane, pentanes, hydrogen sulfide, carbon dioxide, water vapor, and occasionally helium and nitrogen. Methane must be processed and isolated from the other components to be used as energy. The almost pure form of methene is used in our home.
Natural gas is a fossil fuel that can be burned to produce energy. In fact, it burns the cleanest of all fuels and produces the least byproducts.
When fossil fuels are burned, various substances, compounds, and solid particles may be released (or emitted). Coal and oil are examples of fossil fuels with extremely complex molecular structures and high concentrations of carbon, nitrogen, and sulfur. They produce a lot of harmful emissions when burned, such as sulfur dioxide, nitrogen oxides, and air-polluting particles that float into the atmosphere.
Contrarily, the CH4 molecular structure of methane in natural gas makes it easy to identify. It only releases water vapor and carbon dioxide when burned. Every time a person breathes, they exhale the same two elements.
Other gases like ozone and nitrous oxide are also categorized as greenhouse gases, carbon dioxide, and water vapor. Global warming results from the atmosphere’s rising concentration of greenhouse gases, which could have catastrophic environmental effects.
Burning natural gas still produces greenhouse gases, but it does so at nearly 30% and 45% lower rates than coal and oil, respectively.
Drilling for natural gas can leak, as with any extractive activity. The leak could be dangerous immediately if the drill strikes an unanticipated high-pressure pocket of natural gas or if the well is harmed or ruptured.
Natural gas does not always cause an explosion or burn because it dissipates into the air so quickly. But the leaks also threaten the environment because they let mud and oil into the neighborhood.
The chemicals used in hydraulic fracturing have the potential to contaminate nearby drinking water supplies and aquatic habitats with highly radioactive materials. People may need to temporarily leave the area due to the uncontrolled methane released into the air.
12. World Distribution of Natural Gas
When gas generation and migration are considered, the shallow biogenic gas, the middle dissolved gas of the oil window, and the deeper thermal gas are all included in the extensive vertical gas-generation zone.
The fact that there is a lot of source material available in addition to the large vertical habitat for gas suggests that a lot of gas has formed but has not yet been found. In fact, according to estimates, 45 percent of the world’s recoverable gas is still undiscovered and based on energy content, natural gas’s final recoverable resources will be comparable to those of oil.
The world’s gas supply is anticipated to last longer than oil because gas isn’t used as frequently as oil, which means that it has a larger global stock.
In the long run, leaks can also develop gradually. Until the 1950s, cast iron was a common material for distribution pipelines, allowing a significant amount of natural gas to escape.
After years of freeze-thaw cycles, heavy overhead traffic, and strains from the soil’s settling naturally, the cast iron pipes start to leak. These days, various metals and plastics are used to construct pipelines to minimize leakage.
However, gas will lose its prominence as a major energy source if its consumption equals that of oil.
Flaring-associated gas has long been a method used in the oil industry. Approximately 141 billion cubic meters (bcm), or 5 trillion cubic feet (tcf), of the world’s annual gas production was lost at the wellhead as recently as 2017, according to a World Bank report. The United States’ annual gas consumption, or 75% of Russia’s annual gas exports, would be the equivalent of this rate, which, despite being lower than in previous years, represents a decline in flaring.
Most gas has historically been flared in Russia, the Middle East, and African oil-producing nations. Due to the expensive recovery of gas and the remote location of many oil wells, most of the gas produced is reinjected but frequently flared what cannot. However, as gas prices have increased, conservation efforts have grown, and gas flaring has decreased.
13. How Is Natural Gas Extracted: Frequently Asked Questions
13.1 How Does Natural Gas Smell?
Pure natural gas has no smell. Natural gas is given a synthetic odor by the companies that supply it so that people will be aware of any potential leaks. Most people identify this as the gas stove or oven’s “rotten egg” smell.
13.2 Who Are the Highest Consumer of Natural Gas?
These countries consumed the most natural gas in 2010, the latest year for which the U.S. Energy Information Administration provides data.
- The United States