The deepest well in the world. On the threshold of hell: Kola superdeep well

Kola over deep well WITH late XIX centuries it was believed that the Earth consists of a crust, mantle and core. At the same time, no one could really say where one layer ends and the next begins. Scientists did not even know what these layers actually consist of. Just 30 years ago, researchers were sure that the layer of granites begins at a depth of 50 meters and continues up to three kilometers, and then there are basalts. The mantle was assumed to be at a depth of 15-18 kilometers.

An ultra-deep well, which began to be drilled in the USSR on the Kola Peninsula, showed that scientists were wrong...

Three billion year dive

Projects for traveling deep into the Earth appeared in the early 1960s in several countries at once. The Americans were the first to start drilling ultra-deep wells, and they tried to do it in places where, according to seismic studies, the earth's crust should have been thinner. These places, according to calculations, were located at the bottom of the oceans, and the most promising area was considered to be the area near the island of Maui from the Hawaiian group, where ancient rocks lie under the very ocean floor and the earth's mantle is located approximately at a depth of five kilometers under four kilometers of water. Alas, both attempts to break through the earth’s crust in this place ended in failure at a depth of three kilometers.

The first domestic projects also involved underwater drilling - in the Caspian Sea or on Lake Baikal. But in 1963, drilling scientist Nikolai Timofeev convinced State Committee according to science and technology of the USSR is that it is necessary to create a well on the continent. Although it would take much longer to drill, he believed, the well would be much more valuable from a scientific point of view. The drilling site was chosen on the Kola Peninsula, which is located on the so-called Baltic shield, consisting of the most ancient known to mankind terrestrial rocks. The multi-kilometer section of the shield layers was supposed to show a picture of the history of the planet over the past three billion years.

Deeper and deeper and deeper...

The start of work after almost five years of preparation was timed to coincide with the 100th anniversary of the birth of V.I. Lenin in 1970. The project began in earnest. The well housed 16 research laboratories, each the size of an average factory; the project was personally supervised by the Minister of Geology of the USSR. Ordinary employees received triple salaries. Everyone was guaranteed an apartment in Moscow or Leningrad. It is not surprising that getting into the Kola Superdeep Station was much more difficult than joining the cosmonaut corps.

Appearance wells could disappoint an outside observer. No elevators or spiral staircases leading into the depths of the Earth. Only a drill with a diameter of a little more than 20 centimeters went underground. In general, the Kola superdeep can be imagined as a thin needle piercing the earth's thickness. A drill with numerous sensors located at the end of this needle, after several hours of work, was raised for almost a whole day for inspection, readings and repairs, and then lowered for a day. It couldn’t be faster: the strongest composite cable (drill string) could break under its own weight.

What was happening at depth at the time of drilling was not known for certain. Temperature environment, noise and other parameters were transmitted upward with a minute delay. Nevertheless, the drillers said that even such contact with the underground was sometimes seriously frightening. The sounds coming from below were similar to screams and howls. To this we can add a long list of accidents that plagued the Kola Superdeep when it reached a depth of 10 kilometers. Twice the drill was taken out melted, although the temperatures at which it could take this form are comparable to the temperature of the surface of the Sun. One day, it was as if the cable had been pulled from below and was torn off. Subsequently, when they drilled in the same place, no remains of the cable were found. What caused these and many other accidents still remains a mystery. However, they were not the reason for stopping drilling in the Baltic Shield.

In 1983, when the depth of the well reached 12,066 meters, work was temporarily stopped: it was decided to prepare materials on ultra-deep drilling for the International Geological Congress, which was planned to be held in 1984 in Moscow. It was there that foreign scientists first learned about the very existence of the Kola Superdeep, all information about which had been classified until then. Work resumed on September 27, 1984. However, during the first descent of the drill, an accident occurred - the drill string broke off again. Drilling had to continue from a depth of 7,000 meters, creating a new trunk, and by 1990 this new branch reached 12,262 meters, which was absolute record for ultra-deep wells, broken only in 2008. Drilling was stopped in 1992, this time, as it turned out, forever. On further work there were no funds.

Discoveries and finds

The discoveries made at the Kola Superdeep Pole have made a real revolution in our knowledge about the structure earth's crust. Theorists promised that the temperature of the Baltic Shield would remain relatively low to a depth of at least 15 kilometers. This means that a well can be drilled up to almost 20 kilometers, right up to the mantle. But already at the fifth kilometer the temperature exceeded 700°C, at the seventh - over 1200°C, and at a depth of twelve it was hotter than 2200°C.

Kola drillers questioned the theory of the layered structure of the earth's crust - at least in the interval up to 12,262 meters. It was believed that there was a surface layer (young rocks), then there should be granites, basalts, the mantle and the core. But the granites turned out to be three kilometers lower than expected. The basalts that were supposed to lie underneath were not found at all. An incredible surprise for scientists was the abundance of cracks and voids at a depth of over 10 kilometers. In these voids, the drill swung like a pendulum, which led to serious difficulties in work due to its deviation from the vertical axis. In the voids, the presence of water vapor was recorded, which moved there with high speed, as if transported by some unknown pumps. These vapors created the very sounds that thrilled the drillers.

Quite unexpectedly for everyone, the hypothesis of the writer Alexei Tolstoy about the olivine belt, expressed in the novel “The Hyperboloid of Engineer Garin,” was confirmed. At a depth of over 9.5 kilometers, they discovered a real treasure trove of all kinds of minerals, in particular gold, which turned out to be 78 grams per ton. By the way, industrial production carried out at a concentration of 34 grams per ton.

Another surprise: life on Earth, it turns out, arose one and a half billion years earlier than expected. At depths where it was believed that no organic matter could exist, 14 species of fossilized microorganisms were discovered (the age of these layers exceeded 2.8 billion years). At even greater depths, where there are no longer sedimentary rocks, methane appeared in high concentrations, which finally disproved the theory biological origin hydrocarbons such as oil and gas.

It is impossible not to mention the discovery made by comparing lunar soil delivered by the Soviet space station in the late 70s from the surface of the Moon and samples taken at the Kola well from a depth of 3 kilometers. It turned out that these samples are as similar as two drops of water. Some astronomers saw this as evidence that the Moon had once broken away from the Earth as a result of a cataclysm (possibly a collision of the planet with a large asteroid). However, according to others, this similarity only indicates that the Moon was formed from the same gas and dust cloud as the Earth, and at the initial geological stages they “developed” in the same way.

The Kola Superdeep was ahead of its time

The Kola well showed that it is possible to go 14 or even 15 kilometers deep into the Earth. However, one such well is unlikely to provide fundamentally new knowledge about the earth’s crust. This requires a whole network of wells drilled at different points on the earth's surface. But the times when ultra-deep wells were drilled for purely scientific purposes seem to be gone. This pleasure is too expensive. Modern programs ultra-deep drilling is no longer as ambitious as before, and pursues practical goals.

Mainly it is the discovery and extraction of minerals. In the United States, oil and gas production from depths of 6-7 kilometers is already becoming commonplace. In the future, Russia will also begin pumping hydrocarbons from such levels. However, even those deep wells that are being drilled now bring a lot of valuable information, which geologists strive to generalize in order to obtain a holistic picture of at least the surface layers of the earth’s crust. But what lies below will remain a mystery for a long time to come. Only scientists working in ultra-deep wells like the Kola can reveal it using the most modern scientific equipment. In the future, such wells will become for humanity a kind of telescopes into the mysterious underground world of the planet, about which we know no more than about distant galaxies.

In one of the scientific programs they gave a simple example that allows you to realize how huge our planet is. Imagine big balloon. This is the whole planet. And the thinnest walls are the zone where there is life. But people have actually mastered only one layer of atoms surrounding this wall.

But humanity is constantly striving to expand its knowledge about the planet and the processes occurring on it. We are launching spaceships and satellites, we stand submarines, but the hardest thing is to find out what is under our feet, inside the earth.

Wells bring relative understanding. With their help, you can find out the composition of rocks, study changes in physical conditions, and also conduct mineral exploration. And the deepest well in the world will, of course, bring the most information. The only question is where exactly it is. This is what we will try to figure out today.

OR-11

It is not surprising that the longest well was made quite recently, in 2011. New, more advanced technologies, durable and reliable materials, and accurate calculation methods made it possible to achieve this result.

Surely you will be pleased to know that it is located in Russia, and was drilled as part of the Sakhalin-1 project. All work required only 60 days, which far exceeds the results of previous surveys.

The total length of this record-breaking well is 12 kilometers 345 meters, which remains an unsurpassed record. Another achievement is the maximum length of the horizontal trunk, which is 11 kilometers 475 meters. So far no one has been able to surpass this result. But that's it for now.

BD-04A

This oil well in Qatar is famous for its record depth at that time. Its total length is 12 kilometers 289 meters, of which 10,902 meters is a horizontal trunk. By the way, it was built in 2008, and held the record for three whole years.

But this deep well is known not only for its impressive size, but also for a very sad fact. It was built next to an oil shelf for geological exploration, and in 2010 it suffered a serious accident.

This is what the well looks like now

Drilled during the USSR, Kola ultra-deep well in 2008 she lost her leadership title. But still, it remains one of the most famous objects of this type and continues to hold third place.

Preparatory work for drilling began back in 1970. It was planned that this well would become the deepest on Earth, reaching 15 kilometers. True, such a result was never achieved. In 1992, work was suspended when the depth reached an impressive 12 kilometers 262 meters. Further research had to be stopped due to lack of funding and government support.

With its help, it was possible to obtain a lot of interesting scientific data and gain a deeper understanding of the structure of the earth’s crust. This is not surprising, because the project was initially completely scientific, not related to geological exploration or the study of mineral deposits.

By the way, the popular legend about the “well to hell” is associated with the Kola superdeep well. They say that when they reached the 11-kilometer mark, scientists heard terrifying screams. And soon after that the drill broke. According to legend, this indicates the existence of hell underground, in which sinners are tormented. It was their screams that were heard by scientists.

True, the legend does not stand up to criticism. If only because no acoustic equipment could operate at pressure and temperature at these levels. But, on the other hand, it is quite interesting to speculate that the deepest borehole will be able to reach, if not hell, then some other legendary and mythical places.

For now, they just help scientists better understand how our planet lives. And although the journey to the center of the earth is still very far away, people are clearly striving for it.

Soil studies prove: the Moon came off Kola Peninsula

Kola superdeep section

Kola superdeep

Allegedly, on approaching the 13th kilometer, the instruments recorded a strange noise coming from the bowels of the planet - the yellow newspapers unanimously assured that only the cries of sinners from the underworld could sound like that. A few seconds after the terrible sound appeared, an explosion occurred...

Space under your feet

In the late 70s - early 80s, get a job at the Kola Superdeep Well, as residents of the village of Zapolyarny affectionately call the well Murmansk region, it was more difficult than getting into the cosmonaut corps. Out of hundreds of applicants, one or two were chosen. Along with the employment order, the lucky ones received a separate apartment and a salary equal to double or triple the salary of Moscow professors. There were 16 research laboratories operating at the well simultaneously, each the size of an average factory. Only the Germans dug the earth with such tenacity, but, as the Guinness Book of Records testifies, the deepest German well is almost half as long as ours.

Distant galaxies have been studied by humanity much better than what is located under the earth’s crust a few kilometers away from us. The Kola Superdeep is a kind of telescope into the mysterious inner world planets.

Since the beginning of the 20th century, it was believed that the Earth consists of a crust, mantle and core. At the same time, no one could really say where one layer ends and the next begins. Scientists did not even know what these layers actually consist of. Some 40 years ago they were sure that the granite layer begins at a depth of 50 meters and continues up to 3 kilometers, and then there are basalts. The mantle was expected to be encountered at a depth of 15–18 kilometers. In reality, everything turned out completely different. And although school textbooks still write that the Earth consists of three layers, scientists with the Kola Superdeep Site have proven that this is not so.

Baltic shield

Projects for traveling deep into the Earth appeared in the early 60s in several countries at once. They tried to drill wells in places where the crust should have been thinner - the goal was to reach the mantle. For example, the Americans drilled in the area of ​​the island of Maui, Hawaii, where, according to seismic studies, ancient rocks emerge under the ocean floor and the mantle is located at a depth of approximately 5 kilometers under a four-kilometer layer of water. Alas, not a single ocean drilling site has penetrated deeper than 3 kilometers. In general, almost all projects of ultra-deep wells mysteriously ended at a depth of three kilometers. It was at this moment that something strange began to happen to the drills: either they found themselves in unexpected super-hot areas, or as if they were being bitten off by some unprecedented monster. Only 5 wells broke through deeper than 3 kilometers, 4 of which were Soviet. And only the Kola Superdeep was destined to overcome the 7-kilometer mark.

Initial domestic projects also involved underwater drilling - in the Caspian Sea or on Lake Baikal. But in 1963, drilling scientist Nikolai Timofeev convinced the USSR State Committee for Science and Technology that it was necessary to create a well on the continent. Although it would take much longer to drill, he believed, the well would be much more valuable from a scientific point of view, because it is in the thickness of the continental plates that prehistoric times the most significant movements of earth rocks occurred. The drilling point was not chosen on the Kola Peninsula by chance. The peninsula is located on the so-called Baltic Shield, which is composed of the most ancient rocks known to mankind.

A multi-kilometer section of the layers of the Baltic Shield is a visual history of the planet over the past 3 billion years.

Conqueror of the Depths

The appearance of the Kola drilling rig can disappoint the average person. The well is not like the mine that our imagination pictures. There are no descents underground, only a drill with a diameter of a little more than 20 centimeters goes into the thickness. The imaginary section of the Kola superdeep well looks like a tiny needle piercing the earth's thickness. A drill with numerous sensors, located at the end of a needle, is raised and lowered over several days. You can’t go faster: the strongest composite cable can break under its own weight.

What happens in the depths is not known for certain. Ambient temperature, noise and other parameters are transmitted upward with a minute delay. However, drillers say that even such contact with the underground can be seriously frightening. The sounds coming from below really look like screams and howls. To this we can add a long list of accidents that plagued the Kola Superdeep when it reached a depth of 10 kilometers. Twice the drill was taken out melted, although the temperatures at which it can melt are comparable to the temperature of the surface of the Sun. One day, it was as if the cable had been pulled from below and was torn off. Subsequently, when they drilled in the same place, no remains of the cable were found. What caused these and many other accidents still remains a mystery. However, they were not the reason for stopping drilling in the Baltic Shield.

12,000 meters of discoveries and a little devilry

“We have the deepest hole in the world - so we must use it!” — David Guberman, the permanent director of the Kola Superdeep Research and Production Center, exclaims bitterly. In the first 30 years of the Kola Superdeep, Soviet and then Russian scientists broke through to a depth of 12,262 meters. But since 1995, drilling has been stopped: there was no one to finance the project. What is allocated within the framework of UNESCO's scientific programs is only enough to maintain the drilling station in working condition and study previously extracted rock samples.

Huberman recalls with regret how many scientific discoveries took place on the Kola Superdeep. Literally every meter was a revelation. The well showed that almost all of our previous knowledge about the structure of the earth's crust is incorrect. It turned out that the Earth is not at all like a layer cake. “Up to 4 kilometers everything went according to theory, and then the end of the world began,” says Huberman. Theorists promised that the temperature of the Baltic Shield would remain relatively low to a depth of at least 15 kilometers. Accordingly, it will be possible to dig a well up to almost 20 kilometers, just up to the mantle. But already at 5 kilometers the ambient temperature exceeded 700C, at seven - over 1200C, and at a depth of 12 it was hotter than 2200C - 1000C higher than predicted. Kola drillers questioned the theory of the layered structure of the earth's crust - at least in the interval up to 12,262 meters. At school we were taught: there are young rocks, granites, basalts, mantle and core. But the granites turned out to be 3 kilometers lower than expected. Next there should have been basalts. They weren't found at all. All drilling took place in the granite layer. This is a very important discovery, because all our ideas about the origin and distribution of minerals are connected with the theory of the layered structure of the Earth.

Another surprise: life on planet Earth turns out to have arisen 1.5 billion years earlier than expected. At depths where it was believed that there was no organic matter, 14 species of fossilized microorganisms were discovered - the age of the deep layers exceeded 2.8 billion years. At even greater depths, where there are no longer sediments, methane appeared in huge concentrations. This completely and utterly destroyed the theory of the biological origin of hydrocarbons such as oil and gas.

Demons

There were almost fantastic sensations. When in the late 70s the Soviet automatic space station brought 124 grams of lunar soil to Earth, Kola researchers scientific center They found that it is exactly like samples from a depth of 3 kilometers. And a hypothesis arose: the Moon broke away from the Kola Peninsula. Now they are looking for where exactly. By the way, the Americans, who brought half a ton of soil from the Moon, did nothing meaningful with it. They were placed in airtight containers and left for research by future generations.

The history of the Kola Superdeep is not without mysticism. Officially, as already mentioned, the well stopped due to lack of funds. Coincidence or not, it was precisely in 1995 that a powerful explosion of unknown origin was heard in the depths of the mine. Journalists from a Finnish newspaper broke through to the residents of Zapolyarny - and the world was shocked by the story of a demon flying out of the bowels of the planet.

"When I talk about this mysterious story They started asking questions at UNESCO, I didn’t know what to answer. On the one hand, it's bullshit. On the other hand, I, as an honest scientist, could not say that I know what exactly happened to us. A very strange noise was recorded, then there was an explosion... A few days later, nothing like that was found at the same depth,” recalls academician David Guberman.

Quite unexpectedly for everyone, Alexei Tolstoy’s predictions from the novel “Engineer Garin’s Hyperboloid” were confirmed. At a depth of over 9.5 kilometers, a real treasure trove of all kinds of minerals, in particular gold, was discovered. A real olivine layer, brilliantly predicted by the writer. It contains 78 grams of gold per ton. By the way, industrial production is possible at a concentration of 34 grams per ton. Perhaps in the near future humanity will be able to take advantage of this wealth.

You know that people have been unraveling the mysteries of the planet for centuries? They tried to find answers under their feet. TravelAsk will tell you about the largest wells in the world.

What history says

They tried to descend to the depths of the Earth many times. The Chinese were among the first. In the 13th century, they dug a well 1200 meters deep.

In 1930, this record was broken by Europeans: they drilled earth's surface to a depth of three kilometers.

Time passed, and this figure kept growing. So, at the end of the 1950s, the wells already reached 7 kilometers.

The deepest well in the world

In fact, most wells are made during mining. Today the record belongs to the well of the Chayvinskoye field Z-42. It took a lot of money to build it short terms: just over 70 days. It belongs to the Sakhalin-1 project and is an oil project.

Its depth is 12,700 meters. Just imagine, the most high mountain on Earth - Everest. It goes almost 9 kilometers into the sky. And the deepest trench is the Mariana Trench. It is about 11 kilometers. That is, well Z-42 surpassed all indicators of Mother Nature.

Well in the Murmansk region

But we want to tell you in more detail about one special well. It is located in the Murmansk region, about 10 kilometers from the city of Zapolyarny. It is called the Kola superdeep well. Its depth is 12,262 meters. It is interesting because it was originally created not for mining, but for studying the lithosphere.

The diameter of the well at the surface of the earth is 92 centimeters, and the diameter of the lower part is 21.5 centimeters.

The temperature during drilling at a depth of 5 kilometers was 70 degrees, at a depth of 7 kilometers - 120 degrees, and at a depth of 12 kilometers - 220 degrees.

The Kola superdeep well was laid in 1970 on the 100th anniversary of the birth of Vladimir Lenin. The main goal was to study volcanic rocks, which are rarely drilled for mining. More than 15 research laboratories operated here.

They curtailed their activities in 1990, as many accidents occurred here: drill strings often broke off.

Today the facility is abandoned, and the well itself is mothballed and begins to collapse.

Naturally, all the equipment was dismantled, and the building, which long time not used, slowly turning into ruins.

To resume work, a considerable amount is needed - about 100 million rubles, so no one knows whether the well will ever be opened.

Research results

Scientists believed that at a certain depth they would find a clearly defined boundary between granites and basalts. But, alas, all the works did not provide a clear understanding of the nature of the earth’s mantle. And then the researchers even stated that the place to start work was not the most successful.

Road to Hell

That's what they call it Kola well. Moreover, there are still many rumors about her related to the other world. So, there are stories that at a depth of 12 kilometers, scientists’ equipment recorded screams and moans coming from the bowels of the Earth.

American television even officially announced this legend: in 1989, the Trinity Broadcasting Network television company told this story to its viewers. Well, then there’s more: in the tabloid newspapers of that time one could also find interesting stories. For example, that scientists heard screams and moans, but did not stop the research. And every kilometer was imprinted with misfortune on the country. So, when the drillers reached the 13-kilometer mark, the USSR collapsed. And at a depth of 14.5 kilometers, they generally discovered voids. Intrigued by this unexpected discovery, the researchers lowered a microphone there that could operate at extremely high temperatures. high temperatures, and other sensors. The temperature inside reached 1,100 degrees - well, a real hellfire. And they heard human screams.

In fact, acoustic methods for studying wells do not record the actual sound and not on a microphone. They record on seismic receivers the wave pattern of reflected elastic vibrations excited by the emitter device with a frequency of 10 - 20 kHz and 20 kHz - 2 MHz. Well, we already wrote about the depth: no one reached the 13-kilometer mark.

However, one of the authors of the project D.M. Huberman later said: “When people ask me about this mysterious story, I don’t know what to answer. On the one hand, stories about the “demon” are bullshit. On the other hand, as an honest scientist, I cannot say that I know what exactly happened here. Indeed, a very strange noise was recorded, then there was an explosion... A few days later, nothing similar was found at the same depth.”.

Perhaps we will end the story on such a mysterious note. Think for yourself, decide for yourself whether this is really the road to hell.

Today, humankind's scientific research has reached the boundaries of the solar system: we have landed spacecraft on planets, their satellites, asteroids, comets, sent missions to the Kuiper belt and crossed the heliopause boundary. With the help of telescopes, we see events that took place 13 billion years ago - when the Universe was only a few hundred million years old. Against this background, it is interesting to evaluate how well we know our Earth. The best way get to know her internal structure- drill a well: the deeper, the better. The deepest well on Earth is the Kola Superdeep Well, or SG-3. In 1990, its depth reached 12 kilometers 262 meters. If we compare this figure with the radius of our planet, it turns out that this is only 0.2 percent of the way to the center of the Earth. But even this was enough to change ideas about the structure of the earth’s crust.

If you imagine a well as a shaft through which you can descend by elevator into the very depths of the earth, or at least a couple of kilometers, then this is not at all the case. The diameter of the drilling tool with which engineers created the well was only 21.4 centimeters. The upper two-kilometer section of the well is a little wider - it was expanded to 39.4 centimeters, but still there is no way for a person to get there. To imagine the proportions of the well, the best analogy would be a 57-meter sewing needle with a diameter of 1 millimeter, slightly thicker at one end.

Well diagram

But this representation will also be simplified. During drilling, several accidents occurred at the well - part of the drill string ended up underground without the ability to remove it. Therefore, the well was started anew several times, from marks of seven and nine kilometers. There are four large branches and about a dozen small ones. The main branches have different maximum depths: two of them cross the 12-kilometer mark, two more do not reach it by only 200-400 meters. Note that the depth of the Mariana Trench is one kilometer less - 10,994 meters relative to sea level.

Horizontal (left) and vertical projections of SG-3 trajectories

Yu.N. Yakovlev et al. / Bulletin of the Kola Scientific Center of the Russian Academy of Sciences, 2014

Moreover, it would be a mistake to perceive the well as a plumb line. Due to the fact that rocks have different mechanical properties at different depths, the drill deviated towards less dense areas during the work. Therefore, on a large scale, the profile of the Kola Superdeep looks like a slightly curved wire with several branches.

Approaching the well today, we will only see top part- a metal hatch, screwed to the mouth with twelve massive bolts. The inscription on it was made with an error, the correct depth is 12,262 meters.

How was a super-deep well drilled?

To begin with, it should be noted that the SG-3 was originally conceived specifically for scientific purposes. The researchers chose for drilling a place where ancient rocks - up to three billion years old - came to the surface of the earth. One of the arguments during exploration was that young sedimentary rocks were well studied during oil production, and no one had ever drilled deep into ancient layers. In addition, there were large copper-nickel deposits, the exploration of which would be a useful addition to the scientific mission of the well.

Drilling began in 1970. The first part of the well was drilled with a serial Uralmash-4E rig - it was usually used for drilling oil wells. Modification of the installation made it possible to reach a depth of 7 kilometers 263 meters. It took four years. Then the installation was changed to Uralmash-15000, named after the planned depth of the well - 15 kilometers. The new drilling rig was designed specifically for the Kola superdeep: drilling at such great depths required serious modification of equipment and materials. For example, the weight of the drill string alone at a depth of 15 kilometers reached 200 tons. The installation itself could lift loads of up to 400 tons.

The drill string consists of pipes connected to each other. With its help, engineers lower the drilling tool to the bottom of the well, and it also ensures its operation. At the end of the column, special 46-meter turbodrills were installed, driven by the flow of water from the surface. They made it possible to rotate the rock crushing tool separately from the entire column.

The bits with which the drill string bit into the granite evoke futuristic parts from a robot - several rotating spiked disks connected to a turbine on top. One such bit was enough for only four hours of work - this approximately corresponds to a passage of 7-10 meters, after which the entire drill string must be lifted, disassembled and then lowered again. Constant descents and ascents themselves took up to 8 hours.

Even the pipes for the column in the Kola Superdeep Pipe had to be used in unusual ways. At depth, temperature and pressure gradually increase, and, as engineers say, at temperatures above 150-160 degrees, the steel of serial pipes softens and is less able to withstand multi-ton loads - because of this, the likelihood of dangerous deformations and column breakage increases. Therefore, the developers chose lighter and heat-resistant aluminum alloys. Each of the pipes had a length of about 33 meters and a diameter of about 20 centimeters - slightly narrower than the well itself.

However, even specially developed materials could not withstand drilling conditions. After the first seven-kilometer section, further drilling to the 12,000-meter mark took almost ten years and more than 50 kilometers of pipes. Engineers were faced with the fact that below seven kilometers the rocks became less dense and fractured - viscous for the drill. In addition, the wellbore itself distorted its shape and became elliptical. As a result, the column broke several times, and, unable to lift it back, the engineers were forced to concrete the branch of the well and drill the shaft again, losing years of work.

One of these major accidents forced drillers in 1984 to concrete a branch of the well that reached a depth of 12,066 meters. Drilling had to start again from the 7-kilometer mark. This was preceded by a pause in work with the well - at that moment the existence of SG-3 was declassified, and the international geological congress Geoexpo was held in Moscow, whose delegates visited the site.

According to eyewitnesses of the accident, after the resumption of work, the column drilled a well another nine meters down. After four hours of drilling, the workers prepared to lift the column back, but it “didn’t work.” The drillers decided that the pipe was “stuck” somewhere to the walls of the well, and increased the lifting power. The load has decreased sharply. Gradually dismantling the column into 33-meter candles, the workers reached the next section, ending with an uneven lower edge: the turbo drill and another five kilometers of pipes remained in the well; they could not be lifted.

The drillers managed to reach the 12-kilometer mark again only in 1990, at which time the diving record was set - 12,262 meters. Then it happened new accident, and since 1994, work on the well has been stopped.

Superdeep Scientific Mission

Picture of seismic tests at SG-3

“Kola Superdeep” Ministry of Geology of the USSR, Nedra Publishing House, 1984

The well was studied using a whole range of geological and geophysical methods, ranging from core collection (a column of rocks corresponding to given depths) to radiation and seismological measurements. For example, the core was taken using core receivers with special drills - they look like pipes with jagged edges. In the center of these pipes there are 6-7 centimeter holes where the rock falls.

But even with this seemingly simple (except for the need to lift this core from many kilometers deep) difficulties arose. Because of the drilling fluid, the same one that set the drill in motion, the core became saturated with liquid and changed its properties. In addition, conditions in the depths and on the surface of the earth are very different - the samples cracked due to pressure changes.

At different depths, the core yield varied greatly. If at five kilometers from a 100-meter segment one could count on 30 centimeters of core, then at depths of more than nine kilometers, instead of a rock column, geologists received a set of washers made of dense rock.

Microphotograph of rocks recovered from a depth of 8028 meters

“Kola Superdeep” Ministry of Geology of the USSR, Nedra Publishing House, 1984

Studies of material recovered from the well have led to several important conclusions. Firstly, the structure of the earth's crust cannot be simplified to a composition of several layers. This was previously indicated by seismological data - geophysicists saw waves that seemed to be reflected from a smooth boundary. Studies at SG-3 have shown that such visibility can also occur with a complex distribution of rocks.

This assumption affected the design of the well - scientists expected that at a depth of seven kilometers the shaft would enter basalt rocks, but they did not meet even at the 12-kilometer mark. But instead of basalt, geologists discovered rocks that had a large number cracks and low density, which was not at all expected from a depth of many kilometers. Moreover, in the cracks there were traces groundwater- there were even suggestions that they were formed by a direct reaction of oxygen and hydrogen in the thickness of the Earth.

Among the scientific results there were also applied ones - for example, at shallow depths, geologists found a horizon of copper-nickel ores suitable for mining. And at a depth of 9.5 kilometers, a layer of geochemical gold anomaly was discovered - micrometer-sized grains of native gold were present in the rock. Concentrations reached up to a gram per ton of rock. However, it is unlikely that mining from such depths will ever be profitable. But the very existence and properties of the gold-bearing layer made it possible to clarify the models of mineral evolution - petrogenesis.

Separately, we should talk about studies of temperature gradients and radiation. For this kind of experiments, downhole instruments are used, lowered on wire ropes. The big problem was to ensure their synchronization with ground-based equipment, as well as to ensure operation at great depths. For example, difficulties arose with the fact that the cables, with a length of 12 kilometers, stretched by about 20 meters, which could greatly reduce the accuracy of the data. To avoid this, geophysicists had to create new methods for marking distances.

Most commercial devices were not designed to operate in harsh conditions lower tiers of the well. Therefore, for research at great depths, scientists used equipment developed specifically for the Kola Superdeep.

The most important result of geothermal research is much higher temperature gradients than expected. Near the surface, the rate of temperature increase was 11 degrees per kilometer, to a depth of two kilometers - 14 degrees per kilometer. In the interval from 2.2 to 7.5 kilometers, the temperature increased at a rate approaching 24 degrees per kilometer, although existing models predicted a value one and a half times lower. As a result, already at a depth of five kilometers, the instruments recorded a temperature of 70 degrees Celsius, and by 12 kilometers this value reached 220 degrees Celsius.

The Kola superdeep well turned out to be unlike other wells - for example, when analyzing the heat release of rocks of the Ukrainian crystalline shield and Sierra Nevada batholiths, geologists showed that heat release decreases with depth. In SG-3, on the contrary, it grew. Moreover, measurements have shown that the main source of heat, providing 45-55 percent of the heat flow, is the decay of radioactive elements.

Despite the fact that the depth of the well seems colossal, it does not reach even a third of the thickness of the earth’s crust in the Baltic Shield. Geologists estimate that the base of the earth's crust in this area runs approximately 40 kilometers underground. Therefore, even if SG-3 reached the planned 15-kilometer cutoff, we still would not have reached the mantle.

This is the ambitious task that American scientists set for themselves when developing the Mohol project. Geologists planned to reach the border of Mohorovicic - an underground region where there is a sharp change in the speed of propagation of sound waves. It is believed to be associated with the boundary between the crust and the mantle. It is worth noting that the drillers chose the ocean floor near the island of Guadalupe as the location for the well - the distance to the border was only a few kilometers. However, the depth of the ocean itself reached 3.5 kilometers here, which significantly complicated drilling operations. The first tests in the 1960s allowed geologists to drill wells only to 183 meters.

Recently it became known about plans to resurrect the deep ocean drilling project with the help of the research drilling vessel JOIDES Resolution. Geologists chose a point at Indian Ocean, near Africa. The depth of the Mohorovicic boundary there is only about 2.5 kilometers. In December 2015 - January 2016, geologists managed to drill a well 789 meters deep - the fifth largest underwater well in the world. But this value is only half of what was required at the first stage. However, the team plans to return and finish what they started.

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0.2 percent of the path to the center of the Earth is not such an impressive value compared to the scale space travel. However, it should be taken into account that the border of the Solar system does not pass along the orbit of Neptune (or even the Kuiper belt). The Sun's gravity prevails over stellar gravity up to distances of two light years from the star. So if you carefully calculate everything, it turns out that Voyager 2 flew only a tenth of a percent of the path to the outskirts of our system.

Therefore, we should not be upset by how poorly we know the “insides” of our own planet. Geologists have their own telescopes - seismic research - and their own ambitious plans to conquer the subsoil. And if astronomers have already managed to touch a solid part celestial bodies V solar system, then for geologists the most interesting things are still ahead.

Vladimir Korolev