Big encyclopedia of oil and gas. Combustible ice: how technologies for methane extraction from gas hydrates are developing in Russia

Methane hydrate on the ocean floor

Methane hydrate- the most mysterious mineral of the Earth, which became known only in recent decades. This mineral can only exist under specific conditions. For example, at earthly atmospheric pressure and temperature no higher than minus 80 degrees. If the air temperature is 0 degrees Celsius, then for the existence of this mineral it is necessary to create a high pressure of 25 bar. It cannot be in a liquid or gaseous state, it cannot be melted. Methane hydrate can only be solid.

What is this mysterious mineral?
Methane hydrate is ice that has a special structure in the form of clusters, inside which molecules of methane and other methane compounds (CH4, C2H6, C3H8, isobutane, etc.) are located. Water and methane are connected by weak molecular bonds, and as the temperature rises, the methane gas simply leaves the clusters and evaporates. If heating occurs quickly, methane release also occurs quickly, sometimes explosively.

Methane hydrate model

There are known cases of explosive release of methane from thawed permafrost and sedimentary strata of the seas. This leads to the saturation of water with methane bubbles and a decrease in its density. As a result, the ship or submarine may sink. There is an assumption that this phenomenon was the reason for the sudden sinking of ships in the famous Bermuda Triangle.

During strong earthquakes and movements of lithospheric plates, heating of rocks and explosive release of methane can also occur. If you lift methane hydrate from the bottom or extract it from the permafrost, gas will immediately begin to come out of it. This gas can be set on fire and you will see an amazing picture - flaming ice!

Where are methane hydrates found? and why did this amazing connection become known only in the second half of the twentieth century?
This mineral is found at the bottom of the oceans, on the shelf and in the rock strata of the ocean floor. But only at a certain depth, where heat from the bowels of the Earth does not yet heat sedimentary rocks. Under permafrost, again, to a certain depth. At the bottom of Lake Baikal. Natural reserves of this mineral are very large.

Methane hydrate is a source of energy, since its extraction can produce natural gas in large quantities. According to experts, this is 160 - 180 cubic centimeters of methane from 1 cubic meter. cm of ice. So the industrial development of accumulations of this mineral can bring a lot of blue fuel. The prospect of using methane hydrate as a source of gas reserves prompted extensive study of it in the late 20th and early 21st centuries.

But this mineral is also a source of great danger to life on Earth. Imagine that the temperature of sea water suddenly increased, and large numbers of volcanoes began to erupt at the bottom of the seas and oceans. Methane will immediately be released into the water and atmosphere. Methane is a greenhouse gas, just like CO2. The greenhouse effect created by methane is many times greater than that of carbon dioxide. The atmosphere and oceans will heat up. This will lead to global climate change on Earth, to the death of many species of animals and plants in the seas and on land. Perhaps even to the death of a person.

Geologists believe that something similar happened about 252 million years ago (the end of the Permian geological period), when a large asteroid fell in north-central Siberia and pierced the earth's crust. This led to the outpouring of basaltic lava over a large area, volcanic eruptions and earthquakes throughout the planet. As a result, not only volcanic ash, but also methane enters the atmosphere. As a result, 70 percent of land-dwelling species and 96% of sea and ocean species died. The world has changed... This cosmic and geological event is known as the “Permian catastrophe.” , erupted after the fall of the asteroid can be seen on geological maps, they are called “Siberian traps”.

Increased volcanic activity and the release of large amounts of methane into the atmosphere also occurred in the late Paleocene, which also led to changes in flora and fauna, and the death of thousands of species of living organisms.

It exists not only on Earth. Methane hydrates are most likely found on planets in the solar system that are covered in ice and have a methane atmosphere. These are Neptune and Uranus. Perhaps the ice of comets contains methane hydrates.

] expressed a hypothesis about the presence of gas hydrate deposits in the permafrost zone. In the 60s, the first deposits of gas hydrates were discovered in the north of the USSR. From this point on, gas hydrates begin to be considered as a potential source of fuel. Gradually, their widespread distribution in the oceans and instability with rising temperatures became clear.

Properties of hydrates

Gas hydrates resemble compressed snow in appearance, can burn, and easily break down into water and gas when the temperature rises. Due to its clathrate structure, a gas hydrate with a volume of 1 cm³ can contain up to 160-180 cm³ of pure gas.

Methane hydrate in nature

Phase diagram and stability field of methane hydrate in the seas and on continents. In the sea, the range of methane hydrate stability is determined by the temperature of the bottom water and the geothermal gradient. The water temperature at the bottom in the northern seas is +4 °C. Below, in sedimentary rocks, it increases in accordance with the geothermal gradient; at a certain temperature, methane hydrate becomes unstable and breaks down into water and methane. A similar picture is observed on the continents, but the depth of hydrate breakdown on them depends on the depth of permafrost development. As follows from the phase diagram of methane hydrate, its formation requires low temperatures and relatively high pressure, and the higher the pressure, the higher the temperature at which methane hydrate is stable. Thus, at 0 °C it is stable at pressures of the order of 25 bar and above. This pressure is achieved, for example, in the ocean at a depth of about 250 m. At atmospheric pressure, the stability of methane hydrate requires a temperature of about −80 °C. However, methane hydrates can still exist for quite a long time under conditions of low pressure and at a higher temperature, but always negative - in this case they are in a metastable state, their existence provides the effect of self-preservation - during decomposition, methane hydrates are covered with an ice crust, which prevents further decomposition.

As the thickness of sediments in the sea increases and the thickness of the permafrost sinks or decreases, methane hydrate will disintegrate and a gas reservoir will form at a shallow depth, from which gas can break through to the surface. Such explosions are actually observed in the tundra and sometimes in the seas.

The catastrophic breakdown of methane hydrate is considered to be the cause of the Late Paleocene Thermal Maximum, a geological event at the Paleocene–Eocene boundary that led to the extinction of many animal species, climate change and sedimentation.

The process of methane breakthrough from marine deposits of gas hydrates has been invoked to explain the disappearance of ships in the Bermuda Triangle and some other places. The fact is that when methane rises to the surface, the water is saturated with gas bubbles and the density of the mixture drops sharply. As a result, the ship loses buoyancy and sinks.

During gas production, hydrates can form in well bores, field communications and main gas pipelines. By depositing on the walls of pipes, hydrates sharply reduce their throughput. To combat the formation of hydrates in gas fields, various inhibitors are introduced into wells and pipelines (methyl alcohol, glycols, 30% CaCl 2 solution), and also maintain the gas flow temperature above the hydrate formation temperature using heaters, thermal insulation of pipelines and selection of operating modes, providing the maximum temperature of the gas flow. To prevent hydrate formation in main gas pipelines, gas drying is the most effective - cleaning gas from water vapor.

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Literature

J. Carroll. Natural gas hydrates. - Technopress, 2007. - 316 p.
(Ukrainian)

Excerpt characterizing Methane Hydrate

The Cossack got off his horse, took the boy off and walked up to Denisov with him. Denisov, pointing to the French, asked what kind of troops they were. The boy, putting his chilled hands in his pockets and raising his eyebrows, looked at Denisov in fear and, despite the visible desire to say everything he knew, was confused in his answers and only confirmed what Denisov was asking. Denisov, frowning, turned away from him and turned to the esaul, telling him his thoughts.
Petya, turning his head with quick movements, looked back at the drummer, then at Denisov, then at the esaul, then at the French in the village and on the road, trying not to miss anything important.
“Pg” is coming, not “pg” Dolokhov is coming, we must bg”at!.. Eh? - said Denisov, his eyes flashing cheerfully.
“The place is convenient,” said the esaul.
“We’ll send the infantry down through the swamps,” Denisov continued, “they’ll crawl up to the garden; you will come with the Cossacks from there,” Denisov pointed to the forest behind the village, “and I will come from here, with my ganders. And along the road...
“It won’t be a hollow—it’s a quagmire,” said the esaul. - You’ll get stuck in your horses, you need to go around to the left...
While they were talking in a low voice in this way, below, in the ravine from the pond, one shot clicked, smoke turned white, then another, and a friendly, seemingly cheerful cry was heard from hundreds of French voices who were on the half-mountain. In the first minute, both Denisov and the esaul moved back. They were so close that it seemed to them that they were the cause of these shots and screams. But the shots and screams did not apply to them. Below, through the swamps, a man in something red was running. Apparently he was being shot at and shouted at by the French.
“After all, this is our Tikhon,” said the esaul.
- He! they are!
“What a rogue,” Denisov said.
- He will go away! - Esaul said, narrowing his eyes.
The man they called Tikhon, running up to the river, splashed into it so that splashes flew, and, hiding for a moment, all black from the water, he got out on all fours and ran on. The French running after him stopped.
“Well, he’s clever,” said the esaul.
- What a beast! – Denisov said with the same expression of annoyance. - And what has he been doing so far?
- Who is this? – Petya asked.
- This is our plastun. I sent him to take the tongue.
“Oh, yes,” Petya said from Denisov’s first word, nodding his head as if he understood everything, although he absolutely did not understand a single word.
Tikhon Shcherbaty was one of the most necessary people in the party. He was a man from Pokrovskoye near Gzhat. When, at the beginning of his actions, Denisov came to Pokrovskoye and, as always, calling the headman, asked what they knew about the French, the headman answered, as all the headmen answered, as if defending themselves, that they didn’t know anything, to know they don't know. But when Denisov explained to them that his goal was to beat the French, and when he asked if the French had wandered in, the headman said that there were definitely marauders, but that in their village only one Tishka Shcherbaty was involved in these matters. Denisov ordered Tikhon to be called to him and, praising him for his activities, said a few words in front of the headman about the loyalty to the Tsar and the Fatherland and the hatred of the French that the sons of the Fatherland should observe.
“We don’t do anything bad to the French,” said Tikhon, apparently timid at Denisov’s words. “That’s the only way we fooled around with the guys.” They must have beaten about two dozen Miroders, otherwise we didn’t do anything bad... - The next day, when Denisov, completely forgetting about this guy, left Pokrovsky, he was informed that Tikhon had attached himself to the party and asked to be left with it. Denisov ordered to leave him.
Tikhon, who at first corrected the menial work of laying fires, delivering water, skinning horses, etc., soon showed greater willingness and ability for guerrilla warfare. He went out at night to hunt for prey and each time brought with him French clothes and weapons, and when he was ordered, he also brought prisoners. Denisov dismissed Tikhon from work, began to take him with him on travels and enrolled him in the Cossacks.
Tikhon did not like to ride and always walked, never falling behind the cavalry. His weapons were a blunderbuss, which he wore more for fun, a pike and an ax, which he wielded like a wolf wields his teeth, equally easily picking out fleas from his fur and biting through thick bones. Tikhon equally faithfully, with all his might, split logs with an ax and, taking the ax by the butt, used it to cut out thin pegs and cut out spoons. In Denisov's party, Tikhon occupied his special, exclusive place. When it was necessary to do something especially difficult and disgusting - turn a cart over in the mud with your shoulder, pull a horse out of a swamp by the tail, skin it, climb into the very middle of the French, walk fifty miles a day - everyone pointed, laughing, at Tikhon.
“What the hell is he doing, you big gelding,” they said about him.
Once, the Frenchman whom Tikhon was taking shot at him with a pistol and hit him in the flesh of his back. This wound, for which Tikhon was treated only with vodka, internally and externally, was the subject of the funniest jokes in the entire detachment and jokes to which Tikhon willingly succumbed.
- What, brother, won’t you? Is Ali crooked? - the Cossacks laughed at him, and Tikhon, deliberately crouching and making faces, pretending that he was angry, scolded the French with the most ridiculous curses. This incident had only the influence on Tikhon that after his wound he rarely brought prisoners.
Tikhon was the most useful and brave man in the party. No one else discovered cases of attack, no one else took him and beat the French; and as a result of this, he was the jester of all the Cossacks and hussars and he himself willingly succumbed to this rank. Now Tikhon was sent by Denisov, at night, to Shamshevo in order to take the tongue. But, either because he was not satisfied with just the Frenchman, or because he slept through the night, during the day he climbed into the bushes, into the very middle of the French and, as Denisov saw from Mount Denisov, was discovered by them.

/. Russian mathematicians created a model for developing deposits of the richest source of natural gas on the planet - gas hydrates, the concentration of which is high in the Arctic zone, and Skoltech scientists proposed a technology for extracting methane from hydrates. Experts told TASS how the production of such methane will help reduce the greenhouse effect, what are the advantages of new research, and whether there are prospects for the industrial development of gas hydrates in Russia.

Against the greenhouse effect

Gas hydrates are solid crystalline compounds of ice and gas; they are also called “flammable ice.” In nature, they are found in the thickness of the ocean floor and in permafrost rocks, so extracting them is very difficult - wells must be drilled to a depth of several hundred meters, and then natural gas can be separated from the ice deposits and transported to the surface. Chinese oil workers managed to do this in the South China Sea in 2017, but to do this they had to go deeper into the seabed by more than 200 meters, despite the fact that the depth in the production area exceeded 1.2 km.

Researchers consider gas hydrates a promising source of energy, which can be in demand, in particular, by countries with limited other energy resources, for example, Japan and South Korea. Estimates of the content of methane, the combustion of which provides energy, in gas hydrates around the world vary: from 2.8 quadrillion tons according to the Ministry of Energy of the Russian Federation to 5 quadrillion tons according to the World Energy Agency (IEA). Even minimal estimates reflect huge reserves: for comparison, BP Corporation (British Petroleum) estimated global oil reserves at 240 billion tons in 2015.

“According to estimates of some organizations, primarily Gazprom VNIIGAZ, methane resources in gas hydrates on the territory of the Russian Federation range from 100 to 1000 trillion cubic meters, in the Arctic zone, including the seas, up to 600-700 trillion cubic meters, but this is very approximate,” - Evgeniy Chuvilin, leading researcher at the Center for Hydrocarbon Production at the Skolkovo Institute of Science and Technology (Skoltech), told TASS.

In addition to the actual source of energy, gas hydrates can become a salvation from greenhouse gases, which will help stop global warming. The voids emptied of methane can be filled with carbon dioxide.

"According to researchers, methane hydrates contain more than 50% of the carbon of the total known world hydrocarbon reserves. This is not only the richest source of hydrocarbon gas on our planet, but also a possible reservoir for carbon dioxide, which is considered a greenhouse gas. You can kill two birds with one stone - extract methane, burn it to produce energy and pump in its place carbon dioxide obtained during combustion, which will take the place of methane in the hydrate,” Nail Musakaev, deputy director for scientific work of the Tyumen branch of the Institute of Theoretical and Applied Mechanics of the Siberian Branch of the Russian Academy of Sciences, told TASS.

In permafrost conditions

Today, researchers identify three main promising methods for extracting gas hydrates.

“Before extracting gas from hydrates, it is necessary to decompose them into components - gas and water or gas and ice. The main methods of gas production can be distinguished - reducing pressure at the bottom of the well, heating the formation with hot water or steam, supplying inhibitors (substances) to the formation for the decomposition of gas hydrates - TASS note),” Musakaev explained.

Scientists from Tyumen and Sterlitamak have created a mathematical model for methane production in permafrost. It is noteworthy in that it takes into account the process of ice formation during field development.

“The formation of ice has pros and cons: it can clog equipment, but, on the other hand, the decomposition of gas hydrate into gas and ice requires three times less energy than when decomposing into gas and water,” Musakaev said.

The advantage of mathematical modeling is the ability to predict the development scenario for gas hydrate deposits, including assessing the economic efficiency of gas production methods from such deposits. The results may be of interest to design organizations involved in planning and exploration of gas hydrate fields, the scientist noted.

Skoltech is also developing technologies for extracting methane from hydrates. Together with colleagues from Heriot-Watt University in Edinburgh, Skoltech specialists proposed extracting methane from gas hydrates by pumping air into the rock layer. “This method is more economical than existing ones and has less impact on the environment,” Chuvilin explained.

This method assumes that carbon dioxide or nitrogen is injected into the formation, and gas hydrates are decomposed into components due to the difference in pressure. “We are currently conducting methodological research to test the method and its effectiveness. The creation of the technology is still far away, while we are creating the physical and chemical foundations of this technology,” the scientist emphasized.

According to Chuvilin, Russia does not yet have fully ready-made technologies for the effective extraction of methane from hydrates, since there are no targeted programs to support this scientific area. But development is still underway. “Gas hydrates may not become the main energy resource of the future, but their use will certainly require the development of new knowledge,” Musakaev added.

Economic expediency

The forecast for the development of the Russian fuel and energy complex for the period up to 2035 takes into account the exploration and development of gas hydrate fields among the long-term prospects for gas production. The document notes that gas hydrates can become “a factor in global energy only in 30-40 years,” but a breakthrough scenario is not ruled out. In any case, the development of hydrates will entail a global redistribution in the world market of fuel resources - gas prices will decline, and mining corporations will be able to maintain their income only by capturing new markets and increasing sales volumes. For the massive development of such deposits, it is necessary to create new technologies, improve and reduce the cost of existing ones, the strategy notes.

Considering the inaccessibility of hydrates and the complexity of their extraction, experts call them a promising source of energy, but note that this is not a trend in the coming years - hydrates require new technologies that are still being developed. And in conditions of established natural gas production, methane from hydrates is not in the most advantageous position. In the future, everything will depend on the energy market conditions.

“The timing of industrial production depends both on the economically available technology for searching, localizing and producing gas, and on market factors. Gas producing companies have sufficient reserves of traditional gas, so they consider gas production technologies from gas hydrates as a basis for the long term. In my opinion, industrial production in the Russian Federation will begin no earlier than in 10 years,” the expert said.

According to Chuvilin, there are fields in Russia where methane from gas hydrates can begin to be produced in the next 10 years, and this will be quite promising. “In some gas fields in the north of Western Siberia, when traditional gas reservoirs are depleted, it is possible to develop overlying horizons where gas may be in hydrate form. This is possible in the next decade, everything will depend on the cost of energy resources,” summed up the agency’s interlocutor.

Despite the development of alternative energy sources, fossil fuels still retain and, in the foreseeable future, will retain a major role in the fuel balance of the planet. According to ExxonMobil experts, energy consumption on the planet will increase by half in the next 30 years. As the productivity of known hydrocarbon deposits declines, new large deposits are being discovered less and less often, and the use of coal is detrimental to the environment. However, dwindling reserves of conventional hydrocarbons can be compensated for.

The same ExxonMobil experts are not inclined to dramatize the situation. Firstly, Oil and gas production technologies are developing. Today in the Gulf of Mexico, for example, oil is extracted from a depth of 2.5-3 km below the surface of the water, such depths were unimaginable 15 years ago. Secondly, technologies for processing complex types of hydrocarbons (heavy and high-sulfur oils) and oil surrogates (bitumen, oil sands) are being developed. This makes it possible to return to and resume work in traditional mining areas, as well as to begin mining in new areas. For example, in Tatarstan, with the support of Shell, production of so-called “heavy oil” begins. In Kuzbass, projects are being developed to extract methane from coal seams.

Third the direction of maintaining the level of hydrocarbon production is associated with the search for ways to use non-traditional types. Among promising new types of hydrocarbon raw materials, scientists highlight methane hydrate, the reserves of which on the planet, according to rough estimates, amount to at least 250 trillion cubic meters (in terms of energy value, this is 2 times more than the value of all oil, coal and gas reserves on the planet combined) .

Methane hydrate is a supramolecular compound of methane and water. Below is model methane hydrate at the molecular level. A lattice of water (ice) molecules forms around the methane molecule. The compound is stable at low temperatures and high pressure. For example, methane hydrate is stable at a temperature of 0 °C and a pressure of about 25 bar and above. This pressure occurs at an ocean depth of about 250 m. At atmospheric pressure, methane hydrate remains stable at a temperature of −80 °C.

If methane hydrate heats up or the pressure increases, the compound breaks down into water and natural gas (methane). One cubic meter of methane hydrate at normal atmospheric pressure can produce 164 cubic meters of natural gas.

According to the US Department of Energy, stocks methane hydrate are huge on the planet. However, until now this compound has been practically not used as an energy resource. The department has developed and is implementing an entire program (R&D program) for the search, evaluation and commercialization of methane hydrate production.

It is no coincidence that it is the United States that is ready to allocate significant funds for technology development production methane hydrate. Natural gas accounts for almost 23% of the country's fuel balance. Most of the US natural gas is obtained through pipelines from Canada. In 2007, natural gas consumption in the country amounted to 623 billion cubic meters. m. By 2030 it could grow by 18-20%. Using conventional natural gas deposits in the USA, Canada and on the shelf it is not possible to ensure such a level of production.

Just a few years ago, the theory of “hydrocarbon depletion” was popular among economists, that is, people far from technology. Many publications that make up the color of the global financial elite discussed: what will the world be like if the planet soon runs out of oil, for example? And what will the prices for it be when the process of “exhaustion” enters, so to speak, into the active phase?

However, the “shale revolution”, which is happening right now literally before our eyes, has removed this topic to at least the background. It became clear to everyone what only a few experts had previously said: there are still enough hydrocarbons on the planet. It is clearly too early to talk about their physical exhaustion.

The real issue is the development of new production technologies that make it possible to extract hydrocarbons from sources previously considered inaccessible, as well as the cost of the resources obtained with their help. You can get almost anything, it will just be more expensive.

All this forces humanity to look for new “unconventional sources of traditional fuel.” One of them is the shale gas mentioned above. GAZTechnology has written more than once about various aspects related to its production.

However, there are other such sources. Among them are the “heroes” of our today’s material – gas hydrates.

What it is? In the most general sense, gas hydrates are crystalline compounds formed from gas and water at a certain temperature (quite low) and pressure (quite high).

Note: a variety of chemicals can take part in their formation. We are not necessarily talking specifically about hydrocarbons. The first gas hydrates that scientists ever observed consisted of chlorine and sulfur dioxide. This happened, by the way, at the end of the 18th century.

However, since we are interested in the practical aspects associated with natural gas production, we will talk here primarily about hydrocarbons. Moreover, in real conditions, methane hydrates predominate among all hydrates.

According to theoretical estimates, the reserves of such crystals are literally amazing. According to the most conservative estimates, we are talking about 180 trillion cubic meters. More optimistic estimates give a figure that is 40 thousand times higher. Given such indicators, you will agree that it is somehow inconvenient to talk about the exhaustibility of hydrocarbons on Earth.

It must be said that the hypothesis about the presence of huge deposits of gas hydrates in the Siberian permafrost was put forward by Soviet scientists back in the terrible 40s of the last century. A couple of decades later it found its confirmation. And in the late 60s, the development of one of the deposits even began.

Subsequently, scientists calculated: the zone in which methane hydrates are able to remain in a stable state covers 90 percent of the entire sea and ocean floor of the Earth and plus 20 percent of the land. It turns out that we are talking about a potentially widespread mineral resource.

The idea of extracting “solid gas” really looks attractive. Moreover, a unit volume of hydrate contains about 170 volumes of the gas itself. That is, it would seem that it is enough to get just a few crystals to get a large yield of hydrocarbons. From a physical point of view, they are in a solid state and represent something like loose snow or ice.

The problem, however, is that gas hydrates are usually located in very hard-to-reach places. “Intra-permafrost deposits contain only a small part of the gas resources that are associated with natural gas hydrates. The main part of the resources is confined to the gas hydrate stability zone - that depth interval (usually the first hundreds of meters) where the thermodynamic conditions for hydrate formation occur. In the north of Western Siberia this is a depth interval of 250-800 m, in the seas - from the bottom surface to 300-400 m, in especially deep-water areas of the shelf and continental slope up to 500-600 m below the bottom. It was in these intervals that the bulk of natural gas hydrates were discovered,” Wikipedia reports. Thus, we are talking, as a rule, about working in extreme deep-sea conditions, under high pressure.

The extraction of gas hydrates may present other difficulties. Such compounds are capable, for example, of detonating even with minor shocks. They very quickly turn into a gas state, which in a limited volume can cause sudden pressure surges. According to specialized sources, it is precisely these properties of gas hydrates that have become the source of serious problems for production platforms in the Caspian Sea.

In addition, methane is one of the gases that can create a greenhouse effect. If industrial production causes massive emissions into the atmosphere, this could worsen the problem of global warming. But even if this does not happen in practice, the close and unfriendly attention of the “greens” to such projects is practically guaranteed. And their positions in the political spectrum of many states today are very, very strong.

All this makes it extremely difficult for projects to develop technologies for the extraction of methane hydrates. In fact, there are no truly industrial methods for developing such resources on the planet yet. However, relevant developments are underway. There are even patents issued to the inventors of such methods. Their description is sometimes so futuristic that it seems copied from a science fiction book.

For example, “A method for extracting gas hydrate hydrocarbons from the bottom of water basins and a device for its implementation (RF patent No. 2431042)”, set out on the website http://www.freepatent.ru/: “The invention relates to the field of mining minerals located on seabed. The technical result is to increase the production of gas hydrate hydrocarbons. The method consists in destroying the bottom layer with the sharp edges of buckets mounted on a vertical conveyor belt moving along the bottom of the pool using a caterpillar mover, relative to which the conveyor belt moves vertically, with the possibility of being buried in the bottom. In this case, the gas hydrate is lifted into an area isolated from water by the surface of an overturned funnel, where it is heated, and the released gas is transported to the surface using a hose attached to the top of the funnel, subjecting it to additional heating. A device for implementing the method is also proposed.” Note: all this must happen in sea water, at a depth of several hundred meters. It’s hard to even imagine how complex this engineering task is and how much methane produced in this way could cost.

There are, however, other ways. Here is a description of another method: “There is a known method for extracting gases (methane, its homologues, etc.) from solid gas hydrates in the bottom sediments of seas and oceans, in which two columns of pipes are immersed in a well drilled to the bottom of the identified gas hydrate layer - an injection and a pump-out. Natural water at natural temperature or heated water enters through the injection pipe and decomposes gas hydrates into a “gas-water” system, which accumulates in a spherical trap formed at the bottom of the gas hydrate formation. Through another pipe column, the released gases are pumped out of this trap... The disadvantage of the known method is the need for underwater drilling, which is technically burdensome, costly and sometimes introduces irreparable disturbances into the existing underwater environment of the reservoir” (http://www.findpatent.ru).

Other descriptions of this kind can be given. But from what has already been listed it is clear: the industrial production of methane from gas hydrates is still a matter of the future. It will require the most complex technological solutions. And the economics of such projects are not yet obvious.

However, work in this direction is underway, and quite actively. They are especially interested in countries located in the fastest growing region of the world, which means that it is presenting ever new demand for gas fuel. We are, of course, talking about Southeast Asia. One of the states working in this direction is China. Thus, according to the People's Daily newspaper, in 2014, marine geologists conducted large-scale studies of one of the sites located near its coast. Drilling has shown that it contains gas hydrates of high purity. A total of 23 wells were made. This made it possible to establish that the distribution area of gas hydrates in the area is 55 square kilometers. And its reserves, according to Chinese experts, amount to 100-150 trillion cubic meters. The given figure, frankly speaking, is so large that it makes one wonder whether it is too optimistic, and whether such resources can really be extracted (Chinese statistics in general often raise questions among experts). Nevertheless, it is obvious: Chinese scientists are actively working in this direction, looking for ways to provide their rapidly growing economy with much-needed hydrocarbons.

The situation in Japan is, of course, very different from that in China. However, supplying fuel to the Land of the Rising Sun even in calmer times was by no means a trivial task. After all, Japan is deprived of traditional resources. And after the tragedy at the Fukushima nuclear power plant in March 2011, which forced the country’s authorities, under pressure from public opinion, to reduce nuclear energy programs, this problem worsened almost to the limit.

That is why in 2012, one of the Japanese corporations began test drilling under the ocean floor at a distance of only a few tens of kilometers from the islands. The depth of the wells themselves is several hundred meters. Plus the depth of the ocean, which in that place is about a kilometer.

It must be admitted that a year later Japanese specialists managed to obtain the first gas in this place. However, it is not yet possible to talk about complete success. Industrial production in this area, according to the Japanese themselves, may begin no earlier than 2018. And most importantly, it is difficult to estimate what the final cost of fuel will be.

Nevertheless, it can be stated: humanity is still slowly getting closer to gas hydrate deposits. And it is possible that the day will come when it will extract methane from them on a truly industrial scale.