Where does natural gas come from? Being in nature

There is a mixture of methane CH 4 with a small amount of nitrogen N 2 and carbon dioxide CO 2 - that is, that it is qualitatively identical in composition to the gas released from swamps.

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Chemical composition

The main part of natural gas is methane (CH 4) - from 70 to 98%. Natural gas may contain heavier hydrocarbons - homologues of methane:

ethane (C 2 H 6),
propane (C 3 H 8),
butane (C 4 H 10).

Natural gas also contains other substances that are not hydrocarbons:

helium (He) and other inert gases.

Pure natural gas is colorless and odorless. To facilitate the detection of gas leaks into it, large quantities add odorants - substances that have a pungent bad smell(rotten cabbage, rotten hay, rotten eggs). Most often, thiols (mercaptans) are used as an odorant, for example, ethyl mercaptan (16 g per 1000 m³ of natural gas).

Physical properties

Approximate physical characteristics(depend on the composition; with normal conditions, unless otherwise specified):

Natural gas fields

In the sedimentary shell earth's crust Huge deposits of natural gas are concentrated. According to the theory of the biogenic (organic) origin of oil, they are formed as a result of the decomposition of the remains of living organisms. Natural gas is believed to form in the sediment at higher temperatures and pressures than oil. Consistent with this is the fact that gas fields are often located deeper than oil fields.

Russia (Urengoy field), Iran, most of the Persian Gulf countries, the USA, and Canada have huge reserves of natural gas. From European countries It is worth noting Norway and the Netherlands. Among the former republics Soviet Union Turkmenistan, Azerbaijan, Uzbekistan, as well as Kazakhstan (Karachaganak field) have large gas reserves.

Methane and some other hydrocarbons are widespread in space. Methane is the third most abundant gas in the Universe, after hydrogen and helium. In the form of methane ice, it participates in the structure of many planets and asteroids far from the sun, but such accumulations, as a rule, are not classified as natural gas deposits, and they have not yet been found practical application. A significant amount of hydrocarbons is present in the Earth's mantle, but they are also not of interest.

Gas hydrates

In science for a long time It was believed that accumulations of hydrocarbons with a molecular weight of more than 60 reside in the earth’s crust in a liquid state, and lighter ones in a gaseous state. However, in the second half of the 20th century, a group of employees A. A. Trofimuk, N. V. Chersky, F. A. Trebin, Yu. F. Makogon, V. G. Vasiliev discovered the property of natural gas under certain thermodynamic conditions to transform in the earth’s crust into solid state and form gas hydrate deposits. It was later discovered that the reserves of natural gas in this state are enormous.

The gas turns into a solid state in the earth's crust, combining with formation water at hydrostatic pressures of up to 250 atm and relatively low temperatures(up to +22 °C). Gas hydrate deposits have an incomparably higher concentration of gas per unit volume of porous medium than in conventional gas fields, since one volume of water, when it passes into the hydrate state, binds up to 220 volumes of gas. Zones of gas hydrate deposits are concentrated mainly in areas of permafrost, as well as at shallow depths under ocean floor.

Natural gas reserves

Extraction and transportation

Natural gas is found in the ground at depths ranging from 1000 m to several kilometers. Ultra-deep well near the city of Novy Urengoy, an influx of gas was received from a depth of more than 6,000 meters. In the depths, gas is found in microscopic voids (pores). The pores are connected to each other by microscopic channels - cracks; through these channels gas flows from the pores with high pressure into pores with lower pressure until it ends up in the well. The movement of gas in the formation obeys certain laws.

Gas is extracted from the depths of the earth using wells. They try to place wells evenly throughout the entire territory of the field to ensure a uniform drop in reservoir pressure in the deposit. Otherwise, gas flows between areas of the field, as well as premature watering of the deposit, are possible.

Gas comes out of the depths due to the fact that the formation is under pressure many times greater than atmospheric pressure. Thus, driving force is the pressure difference between the reservoir and the collection system.

World natural gas production in 2014 was 3,460.6 billion m3. Russia and the USA occupy the leading positions in gas production.

The world's largest gas producers

A country	2010		2006
A country	Extraction, billion m³	Share of world market (%)	Extraction, billion m³	Share of world market (%)
Russia	647		673,46	18
USA	619		667	18
Canada	158
Iran	152		170	5
Norway	110		143	4
China	98
Netherlands	89		77,67	2,1
Indonesia	82		88,1	2,4
Saudi Arabia	77		85,7	2,3
Algeria	68		171,3	5
Uzbekistan	65
Turkmenistan			66,2	1,8
Egypt	63
Great Britain	60
Malaysia	59		69,9	1,9
India	53
UAE	52
Mexico	50
Azerbaijan			41	1,1
Other countries			1440,17	38,4
World gas production		100	3646	100

Preparation of natural gas for transportation

The gas coming from the wells must be prepared for transportation to the end user - the chemical plant, boiler house, thermal power plant, city gas networks. The need for gas preparation is caused by the presence in it, in addition to the target components (different components are target for different consumers), also impurities that cause difficulties during transportation or use. Thus, water vapor contained in gas, under certain conditions, can form hydrates or, condensing, accumulate in various places(for example, bending a pipeline), interfering with the flow of gas; Hydrogen sulfide causes severe corrosion of gas equipment (pipes, heat exchanger tanks, etc.). In addition to preparing the gas itself, it is also necessary to prepare the pipeline. Wide Application Nitrogen units are found here, which are used to create an inert environment in the pipeline.

Gas is prepared according to various schemes. According to one of them, in the immediate vicinity of the field, an integrated gas treatment unit (CGTU) is being built, which purifies and dehydrates gas in absorption columns. This scheme was implemented at the Urengoyskoye field. It is also advisable to prepare gas using membrane technology.

To prepare gas for transportation, they use technological solutions using membrane gas separation, with the help of which it is possible to isolate heavy hydrocarbons (C 3 H 8 and higher), nitrogen, carbon dioxide, hydrogen sulfide, and also significantly reduce the dew point temperature of water and hydrocarbons before feeding into the hydraulic structure.

If the gas contains a large amount of helium or hydrogen sulfide, then the gas is processed at a gas processing plant, where sulfur is separated in amine purification units and Claus units, and helium is separated in cryogenic helium units (CHU). This scheme has been implemented, for example, at the Orenburg field. If the gas contains less than 1.5% vol. hydrogen sulfide, then it is also advisable to consider membrane technology for the preparation of natural gas, since its use allows reducing capital and operating costs by 1.5-5

Transportation of natural gas

Currently, the main mode of transport is pipeline. Gas under a pressure of 75 atm is pumped through pipes with a diameter of up to 1.42 m. As the gas moves through the pipeline, it, overcoming frictional forces both between the gas and the pipe wall, and between layers of gas, loses potential energy, which is dissipated as heat. Therefore, at certain intervals it is necessary to build compressor stations (CS), in which the gas is usually pressurized to a pressure of 55 to 120 atm and then cooled. The construction and maintenance of the pipeline is very expensive, but nevertheless it is the cheapest method of transporting gas over short and medium distances in terms of initial investments and organization.

In addition to pipeline transport, special gas tankers are widely used. These are special ships on which gas is transported in a liquefied state in specialized isothermal containers at temperatures from −160 to −150 °C.

To liquefy the gas, it is cooled at high blood pressure. At the same time, the compression ratio reaches 600 times, depending on needs. Thus, to transport gas using this method, it is necessary to stretch a gas pipeline from the field to the nearest sea coast, build a terminal on the shore, which is much cheaper than a conventional port, for liquefying gas and pumping it onto tankers, and the tankers themselves. The typical capacity of modern tankers is between 150,000 and 250,000 m³. This method of transportation is significantly more economical than the pipeline one, starting from distances to the liquefied gas consumer of more than 2000-3000 km, since the main cost is not transportation, but loading and unloading operations, but it requires higher initial investments in infrastructure than the pipeline method. Its advantages also include the fact that liquefied gas is much safer during transportation and storage than compressed gas.

In 2004, international gas supplies through pipelines amounted to 502 billion m³, liquefied gas - 178 billion m³.

There are also other gas transportation technologies, for example using railway tanks.

Gas transportation projects using

How many people these days can immediately define natural gas? Do they know his history and chemical composition? Obviously not, because everything can be found on Google.

So.

Natural gas is a mixture of hydrocarbons that is something ephemeral, something that cannot be touched, seen and odorless. The basis of natural gas is methane (CH4) - the simplest hydrocarbon ( organic compound, consisting of carbon and hydrogen atoms). Typically, it also contains heavier hydrocarbons, homologues of methane: ethane (C2H6), propane (C3H8), butane (C4H10) and some non-hydrocarbon impurities.

In search of truth.

Scientists still cannot come to a consensus regarding the origin of natural gas, and in their dispute they split into two camps, trying to prove the occurrence of gas, they proposed two main theories.

Mineral theory

According to this theory, everything chemical elements, which make up natural gas and oil, were originally embedded in the Earth's mantle, representing mineral deposits. being deep in the layers rocks are part of the process of degassing the Earth. Due to the internal movements of the Earth, hydrocarbons located at great depths rise closer to the surface, where the least pressure is generated, thus resulting in oil and gas deposits.

Biogenic theory.

Proponents of this theory believe that natural gas was formed from the remains of plant and animal organisms that became extinct at the end of the Paleozoic era, which under the influence of bacteria, high pressure and temperature turned into a mixture of gaseous carbons. It was biochemical processes that provided the chemical cocktail of natural gas: 80-98% methane, 2-3% of its closest homologues - ethane, propane, butane, pentane, as well as a small amount of impurities - hydrogen sulfide, carbon dioxide, nitrogen.

Do you see gas? No. And he is.

Most people who are far from gas industry, imagine that the gas located underground is similar to valuable minerals, it occupies certain voids in the bowels of the earth, and is easily completely extracted. But this is not entirely true. Natural gas is indeed found deep underground, inside rocks that have a porous structure, but the pores are so microscopic that they naked eye almost impossible to see. Therefore, when you pick up a small piece of sandstone extracted from the depths of the earth, it is difficult to realize that natural gas is contained inside.

Sacred fire.

Ancient Zoroastrian temple Ateshgah

For many peoples, fire evoked awe. People worshiped fire, loved fire, hated fire.

Humanity has known about the existence of natural gas for a long time. And, although already in the 4th century BC. e. in China they learned to use it for heating and lighting; for a long time, a bright flame that leaves no ashes was the subject of a mystical and religious cult for some peoples. For example, on the Absheron Peninsula (modern territory of Azerbaijan) in the 7th century, the temple of fire worshipers Ateshgah, revered in different time Zoroastrians, Hindus and Sikhs. The temple arose on the site of “eternal” unquenchable fires - burning outlets of natural gas, due to which the temple is called “Ateshgah”, which means “House of Fire”. Services took place there until the 19th century. However, the Zoroastrians themselves say that they do not worship fire as such, but honor the Creator (Q’rt’), whose symbol is fire.

Get it and use it.

“Humanity is only about 200 thousand years old. But gas production began only in the last century.”

Man always and everywhere seeks profit. That's Persian king in the 1st century AD, seeing a fire that burned day and night and did not require additional fuel, he ordered the construction of a palace kitchen in the place where the gas came to the surface. Natural gas was first used in 1821 in Fredonia, New York.

On a note: The total length of gas pipelines in Russia is two times greater than the distance from the Earth to the Moon or 20 times greater than the length of the equator.

Scientists have been trying to find a clear answer to the question of how natural gas and oil are formed since the first mention of them in the 10th century. However, so far there are only hypotheses and theories.

The most “popular” is the so-called organic, or biogenic, theory of the origin of oil and gas. According to it, hydrocarbons are formed as a result of the decay of the remains of living organisms in the thickness of the earth, in conditions without access to oxygen. Hundreds of millions of years ago, when the ocean overflowed in place of the continents, its dead inhabitants sank to the bottom, turning into silt or sediment. Since there was no air or bacteria to promote decay, the remains did not decompose. The earth's crust moved, and this biological mass became denser and sank deeper and deeper, exposed to high temperatures and pressure, which contributed to the emergence chemical reactions, in which hydrocarbons (carbon + hydrogen) are formed.

There is also an inorganic (mineral) theory of the origin of hydrocarbons, based on the assumption of degassing of the earth's interior and the movement of gas contained in its mantle into the less dense layers of the planet, again, as a result of the displacement of the earth's plates.

This theory is based on Mendeleev's observations, stating the fact that hydrocarbons are widely distributed in space, including as components of the atmosphere of other cosmic bodies. Entire methane rivers even flow across the surface of some of them (example: Saturn’s moon Titan)! Consequently, the gas we are familiar with, although it belongs to organic substances, can also be formed through synthesis from inorganic compounds.

Regarding the planet Earth, Mendeleev justifies this as follows: when faults occur in the earth’s crust, water enters deep and, coming into contact with iron carbides, which presumably makes up the earth’s core, forms iron oxides and hydrocarbons, including ethane. In the conditions of modern realities, confirmation of this theory is most beneficial for our world, since it allows us to hope that if oil and gas reserves run out, it will be possible to synthesize them artificially until water supplies on earth run out. However, the organic theory of the origin of hydrocarbons has much more evidence.

Gas can accumulate in the form of “gas caps” in places where oil accumulates. Natural gas is almost always present in oil fields, because it is the same hydrocarbon, only high-molecular, unlike low-molecular oil, and its formation requires exposure to higher pressure.

What holds gas in the thickness of the earth's crust, preventing it from dissolving in the atmosphere?

Gas is also contained in gas-bearing rock layers, or reservoirs. Most often this is sandstone, but there are also reservoirs made of limestone or carbonate. These rocks are porous, and the gas would easily be released if it were not for the layer of clay covering the reservoir.

If the biogenic theory of natural gas formation is confirmed, and it will be confirmed with a 90% probability, someday the earth's treasures will exhaust themselves, and we will have to look for an alternative way to obtain fuel. Fortunately, the impressive deposits of gas and oil on the territory of Russia, according to some calculations, will allow us to use this benefit for about 70 years, and this is a very realistic period for finding a solution to the problem of exhaustible resources.

Natural gas is a mineral resource. Gas, just like oil and coal,

formed in the bowels of the earth from organic matter animal origin

(that is, deposits of long-lived organisms) under the influence of high pressures and

temperatures

Living organisms that died and sank to the seabed fell into such

conditions where they could not decompose as a result of oxidation (after all, in the sea

there is no air or oxygen at the bottom), nor can it be destroyed by microbes (they simply weren’t there).

The deposits of these organisms formed silty sediments. As a result

geological movements, these sediments penetrated to great depths. There under

influence of pressure and high temperature passed for millions of years

the process by which carbon contained in sediments is converted into compounds

called hydrocarbons. They got their name because they

molecules are made of carbon and hydrogen. Hydrocarbons with large molecules

(high molecular weight) are liquid substances from which oil was formed. A

low molecular weight hydrocarbons (which have small molecules) are gases. They-

then they formed natural gas. But only the gas was formed under the influence of more

higher temperatures and pressures than oil.

This is why oil fields always contain natural gas.

Over time, these deposits went deep down - they were covered by layers of sedimentary rocks.

Natural gas is not a homogeneous substance. It consists of a mixture of gases.

The main part of natural gas (98%) is methane gas. In addition to methane,

natural gas composition includes ethane, propane, butane, and also some

non-hydrocarbon substances - hydrogen, nitrogen, carbon dioxide, hydrogen sulfide.

Natural gas is found in the ground at a depth of 1 to several kilometers. IN

In the depths of the earth, gas is found in microscopic voids - pores. Pores

connected to each other by microscopic channels - cracks. According to these

channels, gas flows from pores with high pressure to pores with lower pressure

pressure.

Gas is extracted from the depths of the earth using wells. Gas comes out of the depths through

wells outward due to the fact that the formation is under pressure, repeatedly

exceeding atmospheric. Thus, the driving force behind gas production is

depth is the pressure difference between the reservoir and the collection system.

Currently, natural gas is widely used in the fuel, energy and chemical industry.

Natural gas is widely used as a cheap fuel in residential and private apartment buildings for heating, water heating and cooking. It is used as fuel for cars, boiler houses, and thermal power plants. This is one of best views fuels for domestic and industrial needs. The value of natural gas

fuel also lies in the fact that it is an environmentally friendly mineral fuel. When burned, much less harmful substances are formed compared to other types of fuel. Therefore, natural gas is one of the main sources of energy in human activity.

In the chemical industry, natural gas is used as a raw material for the production of various organic substances, for example, plastics, rubber, alcohol, and organic acids. It was the use of natural gas that helped synthesize many chemical substances that do not exist in nature, for example, polyethylene.

At first people had no idea about beneficial properties gas During oil production, it is often an associated gas. Previously, such associated gas was simply burned right at the production site. At that time, it was unprofitable to transport and sell natural gas, but over time they developed effective methods transportation of natural gas to the consumer, the main of which is pipeline. With this method, gas from wells, previously purified, enters the pipes under enormous pressure - 75 atmospheres. In addition, a method is used to transport liquefied gas in special tankers - gas carriers. Liquefied gas is safer during transportation and storage than compressed gas.

And the burning of natural gas is prohibited by law in a number of countries, but in some countries it is still practiced today...

Did you know that...

Pure natural gas is colorless and odorless. To be able to detect a household gas leak by smell, a small amount of substances that have a strong unpleasant odor are added to it. Most often, ethyl mercaptan is used for this purpose.

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History of natural gas use

19.06.2014

The Dutch physician and chemist Van Helmont at the beginning of the 17th century in the laboratory managed to decompose air into two component parts, calling these parts gases. By gas was meant a substance capable of spreading throughout the entire available volume. The word gas became widely known after the publication of the “Elementary Textbook of Chemistry” by the French chemist Lavoisier in 1789.

History in ancient times

ABOUT flammable gases has been known since ancient times. Burning gas torches were called “eternal fire”, they were worshiped, temples and sanctuaries were built next to them. "Sacred fires" existed in many countries ancient world– in Iran, the Caucasus, in North America, India, China, etc. Marco Polo also described the use of natural gas in China, where it was used for lighting, heating, and for evaporating salt.

What is natural gas

Natural gas is considered a mixture of gases formed as a result of the decomposition of organic substances in the bowels of the Earth. Typically, natural gas is collected at depths of one to several kilometers, although there are wells deeper than 6 km.
Under standard conditions this is gaseous substance as:

individual accumulations (gas deposits);
gas cap of oil and gas fields.

Russia, Iran, Turkmenistan, Azerbaijan, the Persian Gulf countries, and the USA have large reserves.

Use of natural gas

Practical uses of flammable gas, began in the mid-19th century after the invention German chemist Robert Bunsen gas burner. Bunsen burners operated on artificial “illuminating gas” obtained during the processing of coal or oil shale. Very quickly, gas burners illuminated the streets and residential buildings of many capitals and large cities around the world. IN Russian Empire At the same time as St. Petersburg, gas burners appeared in Lvov, Warsaw, Moscow, Odessa, Kharkov and Kyiv.

Some types of natural gas

A distinction is made between natural gas and “associated” or “petroleum” gas. The difference between them is the amount of heavy hydrocarbons they contain. In natural, heavy hydrocarbon (methane) makes up more than 80% of the total composition of gas, in “associated” gas – no more than 40%, and the rest is ethane, propane, butane, and others.

"Associated" gas is contained in oil reservoirs on top of the oil, forming a gas cap that collects in porous rock covered by shale. Shale prevents gas from escaping. Sometimes during drilling operations, as a result of a sudden change in pressure, gas separates from the oil and may leak. The disadvantage of “associated” gas is the need to purify it from impurities, while natural gas does not need purification.

Approximate composition of natural gas

Gas from different fields may have different compositions. On average, the content of the components is as follows:

methane 80-99%
ethane 0.5-0.4%
propane 0.2-1.5%
butane 0.1-1%
pentane 0-1%
noble gases (helium, argon) - hundredths and thousandths of a percent.

Deposits of flammable substances with a helium content of 5-8% are extremely rare. Helium is very valuable and has pronounced chemical passivity. In its liquefied state, helium is used for cooling nuclear reactors. High purity metals are smelted in a helium atmosphere. Natural gas is the only source of helium. The composition may include hydrogen sulfide, from which sulfur used in industry is obtained. Other substances can range from 2% to 13% of the total volume. Every fifth oil field is an oil and gas field, and often this field contains not associated, but natural gas, which has the same value as oil.

Gas industry of Russia

IN pre-revolutionary Russia natural gas was not used, although its presence was noted. Only after October revolution In 1917, the Soviet government set the task of using gas produced along with oil. Until the end of the 30s of the 20th century Soviet Russia did not have an independent gas industry, it was an accompanying oil industry, and gas fields were discovered exclusively in the process of oil exploration and production.

Exploration of gas fields began in 1939 in Saratov region: gas was found in 1940, and the first working well was installed in 1941. Fuel shortages that arose at the beginning of the Great Patriotic War 1941-1945 (the coal deposits of Donbass and oil fields North Caucasus), forced us to engage in exploration and production of natural gas with maximum intensity. Already in 1941, in the Saratov and Kuibyshev regions, industrial production natural gas. The daily productivity of one gas well was 800 thousand cubic meters. gas The exploitation of these fields marked the beginning of the gas industry. Initially, gas was used to operate the Saratov State District Power Plant, and in 1942, construction of the Saratov-Moscow gas pipeline began. Construction was supervised by Lavrentiy Beria and was completed in July 1946. More than 30 thousand people worked on the gas pipeline every day. From Saratov to Moscow, 840 km of gas pipeline was manually laid through 487 barriers. Was built: