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How Do You Gather and Harvest Natural Gas?

Gas and Oil Pipeline | KB Delta

Natural gas is something that we are all familiar with in the modern world. Like coal and oil, it is a type of fossil fuel. These fossil fuels are formed from the remains of animals, microorganisms and plants that will all have lived millions of years ago. To know how to gather and harvest natural gas, you also have to know how it forms.


How does natural gas form?

Before you can gather and harvest natural gas, it must form. A number of different theories exist that suggest how natural gas is formed, but the most prevalent theory suggests that natural gas forms underground as long as a string of specific and intense conditions is present. As the remains of animals, microorganisms and plants begin to decompose, they are gradually covered by layers of other materials. These materials can include everything from sediment to rock, depending on a number of factors.

Over the course of millions of years, a combination of compression due to the layers that are present above the organic matter and the temperature rising as the organic matter moves deeper into the Earth creates a reaction. The carbon bonds that were present in the original organic matter begin to break down. This process produces something called thermogenic methane, but we call it natural gas.


Where can deposits of natural gas be found?

Most of the time, deposits of natural gas are found relatively close to deposits of oil. These deposits of natural gas are usually incredibly small when compared to their neighbors. However, this is only the case near the surface of the Earth. As we go deeper, deposits of natural gas become more and more lucrative.


Can natural gas be found anywhere else?

Natural gas can also be found on the surface of the Earth itself. A specific type of microorganism known as a methanogen is capable of creating it. This microorganism can be found in the intestines of a number of different living animals, including humans.

Methanogens can also be found thriving in environments that feature a relatively low level of oxygen, like landfills. A landfill is the perfect environment for methanogens due to the amount of decomposing matter that can be found there. The microorganisms can break the decomposing matter down, producing a type of methane that is known as biogenic methane through the process of methanogenesis.

Most of the biogenic methane that is created during the process of methanogenesis escapes up into the atmosphere of the Earth, where it dissipates. Luckily, scientists are constantly developing new technology and techniques that could one day teach us how to contain and harvest natural gas as biogenic methane, so it could one day become a reliable source of energy.


Is natural gas trapped underground?

Not all of the thermogenic methane that has been created over millions of years is actually trapped underground. Some of the natural gas is more than capable of escaping into the atmosphere. Most of the time, this occurs due to the ability that thermogenic methane has to rise through matter that is permeable, like a porous rock that can be found underground.

This process leads to the thermogenic methane dissipating in the same way that biogenic methane can. Luckily, this also leads to a lot of thermogenic matter rising to the point where it comes into contact with a geological formation that is completely impermeable. The thermogenic methane then cannot rise further, creating a reservoir of natural gas. These reservoirs are where we then gather and harvest natural gas.

It is really easy for people to access these reservoirs. The easiest way to access them involves drilling a hole straight down through the impermeable matter, accessing the reservoir directly. This allows gas to escape through the hole, so that we can harvest natural gas. Most of the time these holes are referred to as wells.


How is natural gas harvested?

There are a few different methods that are utilized in order to harvest natural gas that is trapped deep underground. New methods are also being developed frequently to make certain types of gas more accessible and more economical to access. New methods are also being developed with the hope of one day harvesting natural gas that is found on the surface of the Earth itself.

It is worth noting that the United States Energy Information Administration believe that there are only 6,289 trillion cubic feet of natural gas left. This number is an estimate based on the amount of proven reserves that can be found across the world. This makes it sound like we can harvest natural gas abundantly, until you realize that the amount of gas that we use rises on an annual basis. We used 112,920 billion cubic feet in 2010 alone.

Thermogenic methane is frequently extracted from deep inside of the Earth itself by drilling a hold vertically into the surface of the Earth. A single drill has the ability to access a reservoir of gas, but the reservoir that it accesses is limited. Other techniques need to be utilized in order to increase the productivity of a single well.

Additional Techniques

The only problem is that most of the additional techniques that can be utilized have a knock-on effect on the environment, creating a number of consequences. For example, hydraulic fracturing (fracking) has the ability to split open giant rock formations that might be stopping the gas from rising. This is done using either chemicals, water, or sand. The sand itself props the newly separated rocks open, enabling the gas to escape. We then can harvest natural gas that escaped.

This process requires an awful lot of water and can dramatically reduce the amount of water that can be found in the area. This can affect aquatic habitats around the area. The process itself can also produce waste water that is both toxic and radioactive. If a problem were to occur, it could potentially result in the underground water sources that we use becoming contaminated.

Horizontal drilling is a relatively safe alternative, as it can be used to increase the area that a well covers without the need to create multiple vertical holes. After drilling vertically, the drill can be directed to drill horizontally. This directly broadens the amount of productivity of a single well and allows us to harvest natural gas more effectively.


What happens after?

After the natural gas has been extracted from an underground reservoir, it has to be transported to its destination. This is usually done utilising a system of pipelines. These transfer pipelines can range from 5” in diameter to more than 50” in diameter.

The longer the pipeline, the more compressor stations will be required. These compressor stations are important as they make sure that the natural gas continues in the right direction. Most companies also use a series of underground storage facilities along the way. The natural gas has to be delivered to numerous different locations, and it can be received from numerous different locations, so the pipelines can be maze-like.

Another method of transporting natural gas to a final destination involves cooling it down a lot. By cooling it, it converts it into liquefied natural gas (LNG). The liquefied state of natural gas takes up a lot less space, enabling the gas to be easily stored and transported to a variety of locations.

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