Ultra-deep well on the Kola Peninsula: history and secrets. Mysteries of the Kola superdeep
The largest mine in the world on the remote Kola Peninsula, in northern Russia. Against the backdrop of the rusting ruins of an abandoned research station lies the deepest hole in the world.
Now closed and sealed with a welded metal plate, the Kola Superdeep Well is a remnant of the human race's largely forgotten gambles, aimed not at the stars but at the depths of the Earth.
There were rumors that a deep well had been drilled into hell: screams and moans of people could be heard from the abyss - as if this was the reason for the closure of the station and the well. In fact, the reason was different.
The city of Mirny is known for its largest mine in the world: a deep well on the Kola Peninsula is the largest man-made hole in the world. 1722 m - deep, so deep that all flights over it were prohibited because too many helicopters crashed due to being sucked into the hole.
The deepest hole ever drilled in the name of science, evidence of Precambrian life has been found here. The human race knows about distant galaxies, but little does it know what lies beneath its very feet. Of course, the project produced a huge amount of geological data, most of which showed how little we know about our planet.
The US and USSR competed for spatial exploration supremacy in the space race, and another competition was between the two countries' greatest drillers: the American "Mohole Project" on the Pacific coast of Mexico - was interrupted in 1966 due to lack of funding; Councils, a project of the Interdepartmental Scientific Council for the Study of the Earth's Interior and Ultra-Deep Drilling, from 1970 to 1994 on the Kola Peninsula. The study of the Earth is limited to ground observations and seismic studies, but the Kola well provided a direct look at the structure of the Earth's crust.
Kola Super Deep Well Drilled to Hell
The drill on Kola never encountered a layer of basalt. Instead, the granite rock turned out to be beyond the twelfth kilometer. It is quite surprising that the rocks of many kilometers are saturated with water. Previously it was believed that free water should not exist at such great depths.
But the most intriguing discovery is the discovery of biological activity in rocks that are more than two billion years old. The most striking evidence of life came from microscopic fossils: the preserved remains of twenty-four species of single-celled marine plants, otherwise known as plankton.
Fossils are typically found in limestone rocks and silica deposits, but these "microfossils" were embedded in organic compounds that remained remarkably intact despite extreme environmental pressures and temperatures.
Kola drilling was forced to stop due to unexpectedly high temperatures encountered. While the temperature gradient in the bowels of the earth. At a depth of approximately 10,000 feet, the temperature increased at a rapid rate—reaching 180 °C (or 356 °F) at the bottom of the hole, as opposed to the expected 100 °C (212 °F). Also unexpected was the decrease in rock density.
Beyond this point, the rocks had greater porosity and permeability: combined with high temperatures, they began to behave like plastic. This is why drilling has become practically impossible.
A repository of core samples can be found in the nickel-mining town of Zapolyarny, about ten kilometers south of the hole. With its ambitious mission and contributions to geology and biology, the Kola Superdeep Well remains the most important relic of Soviet science.
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 to find out its internal structure is to 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 extract 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 see only the upper 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 15-kilometer depth 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 work resumed, the column drilled a hole 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 turbodrill 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 a new accident occurred, and since 1994, work on the well was 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 of cracks and low density, which could not be expected at all from many kilometers deep. Moreover, traces of underground water were found in the cracks - it was even suggested 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 instruments were not designed to operate in the harsh conditions of the lower levels 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 in the Indian Ocean, not far from Africa, as a new target. 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 that impressive compared to the scale of 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 significant part of the celestial bodies in the solar system, then for geologists the most interesting things are still ahead.
Vladimir Korolev
At a depth of 410-660 kilometers below the surface of the Earth, there is an ocean of the Archean period. Such discoveries would not have been possible without the ultra-deep drilling methods developed and used in the Soviet Union. One of the artifacts of those times is the Kola superdeep well (SG-3), which, even 24 years after the cessation of drilling, remains the deepest in the world. Why it was drilled and what discoveries it helped make, says Lenta.ru.
The Americans were the pioneers of ultra-deep drilling. True, in the vastness of the ocean: in the pilot project they used the Glomar Challenger vessel, designed precisely for these purposes. Meanwhile, the Soviet Union was actively developing an appropriate theoretical framework.
In May 1970, in the north of the Murmansk region, 10 kilometers from the city of Zapolyarny, drilling of the Kola superdeep well began. As expected, this was timed to coincide with the centenary of Lenin’s birth. Unlike other ultra-deep wells, SG-3 was drilled exclusively for scientific purposes and even organized a special geological exploration expedition.
The drilling location chosen was unique: it is on the Baltic Shield in the Kola Peninsula area that ancient rocks come to the surface. The age of many of them reaches three billion years (our planet itself is 4.5 billion years old). In addition, there is the Pechenga-Imandra-Varzuga rift trough - a cup-like structure pressed into ancient rocks, the origin of which is explained by a deep fault.
It took scientists four years to drill a well to a depth of 7263 meters. So far, nothing unusual has been done: the same installation was used as for oil and gas production. Then the well stood idle for a whole year: the installation was modified for turbine drilling. After the upgrade, it was possible to drill approximately 60 meters per month.
The depth of seven kilometers brought surprises: alternation of hard and not very dense rocks. Accidents became more frequent, and many cavities appeared in the wellbore. Drilling continued until 1983, when the depth of SG-3 reached 12 kilometers. After this, the scientists gathered a large conference and talked about their successes.
However, due to careless handling of the drill, a five-kilometer-long section remained in the mine. They tried to get her for several months, but were unsuccessful. It was decided to start drilling again from a depth of seven kilometers. Due to the complexity of the operation, not only the main trunk was drilled, but also four additional ones. It took six years to restore the lost meters: in 1990, the well reached a depth of 12,262 meters, becoming the deepest in the world.
Two years later, drilling was stopped, the well was subsequently mothballed, and in fact abandoned.
Nevertheless, many discoveries were made at the Kola superdeep well. Engineers have created an entire system of ultra-deep drilling. The difficulty lay not only in the depth, but also in the high temperatures (up to 200 degrees Celsius) due to the intensity of the drills.
Scientists not only moved deeper into the Earth, but also lifted rock samples and cores for analysis. By the way, it was they who studied the lunar soil and found that its composition almost completely corresponds to the rocks extracted from the Kola well from a depth of about three kilometers.
At a depth of over nine kilometers they came across deposits of minerals, including gold: in the olivine layer there is as much as 78 grams per ton. And this is not so little - gold mining is considered possible at 34 grams per ton. A pleasant surprise for scientists, as well as for the nearby plant, was the discovery of a new ore horizon of copper-nickel ores.
Among other things, the researchers learned that granites do not transform into a super-strong basalt layer: in fact, behind it were Archean gneisses, which are traditionally classified as fractured rocks. This produced a kind of revolution in geological and geophysical science and completely changed traditional ideas about the interior of the Earth.
Another pleasant surprise is the discovery at a depth of 9-12 kilometers of highly porous fractured rocks, saturated with highly mineralized waters. According to scientists, they are responsible for the formation of ores, but previously it was believed that this occurs only at much shallower depths.
Among other things, it turned out that the temperature of the subsoil was slightly higher than expected: at a depth of six kilometers, a temperature gradient of 20 degrees Celsius per kilometer was obtained instead of 16 expected. The radiogenic origin of the heat flow was established, which also did not agree with previous hypotheses.
In deep layers more than 2.8 billion years old, scientists have found 14 species of fossilized microorganisms. This made it possible to shift the time of the emergence of life on the planet one and a half billion years ago. The researchers also found that at depths there are no sedimentary rocks and there is methane, forever burying the theory of the biological origin of hydrocarbons.
The Kola superdeep well is the deepest borehole in the world (from 1979 to 2008). It is located in the Murmansk region, 10 kilometers west of the city of Zapolyarny, on the territory of the geological Baltic shield. Its depth is 12,262 meters. Unlike other ultra-deep wells that were made for oil production or geological exploration, SG-3 was drilled solely to study the lithosphere in the place where the Mohorovicic boundary is. (abbreviated Moho boundary) is the lower boundary of the earth’s crust, at which there is an abrupt increase in the velocities of longitudinal seismic waves.
The Kola superdeep well was laid in honor of the 100th anniversary of Lenin’s birth, in 1970. Sedimentary rock strata by that time had been well studied during oil production. It was more interesting to drill where volcanic rocks about 3 billion years old (for comparison: the age of the Earth is estimated at 4.5 billion years) come to the surface. To extract minerals, such rocks are rarely drilled deeper than 1-2 km. It was assumed that already at a depth of 5 km the granite layer would be replaced by a basalt one. On June 6, 1979, the well broke the record of 9583 meters, previously held by the Bertha-Rogers well (an oil well in Oklahoma). In the best years, 16 research laboratories worked at the Kola superdeep well, they were personally supervised by the Minister of Geology of the USSR.
Although it was expected that a clear boundary between granites and basalts would be discovered, only granites were found in the core throughout the entire depth. However, due to high pressure compressed granites greatly changed their physical and acoustic properties. As a rule, the lifted core crumbled from active gas release into slurry, since it could not withstand a sharp change in pressure. It was possible to remove a strong piece of core only with a very slow lifting of the drill, when the “excess” gas, still pressed to high pressure, managed to escape from the rock. The density of cracks at great depths, contrary to expectations, increased. There was also water at depth that filled the cracks.
It is interesting that when the International Geological Congress was held in Moscow in 1984, at which the first results of research on the well were presented, many scientists jokingly suggested that it should be buried immediately, since it would destroy all ideas about the structure of the earth’s crust. Indeed, strange things began even in the first stages of penetration. For example, theorists, even before the start of drilling, promised that the temperature of the Baltic shield would remain relatively low to a depth of at least 5 kilometers, the ambient temperature exceeded 70 degrees Celsius, at seven - over 120 degrees, and at a depth of 12 it was hot stronger than 220 degrees - 100 degrees 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.
“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 at 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.
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 completely destroyed the theory of the biological origin of hydrocarbons such as oil and gas. There were almost fantastic sensations. When, in the late 70s, the Soviet automatic space station brought 124 grams of lunar soil to Earth, researchers at the Kola Science Center found that it was like two peas in a pod to 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.
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. But, what is most surprising, at even greater depths, where there are no longer sedimentary rocks, natural methane gas was found in huge concentrations. This completely and utterly destroyed the theory of the biological origin of hydrocarbons such as oil and gas
Not only scientific sensations were also associated with the Kola well, but also mysterious legends, most of which turned out to be fictions of journalists when verified. According to one of them, the primary source of information (1989) was the American television company Trinity Broadcasting Network, which, in turn, took the story from a report by a Finnish newspaper. Allegedly, when drilling a well, at a depth of 12 thousand meters, the scientists' microphones recorded screams and moans.) Journalists, without even thinking that it was simply impossible to insert a microphone to such a depth (what kind of sound recording device can work at temperatures above two hundred degrees?) wrote that the drillers heard a “voice from the underworld.”
After these publications, the Kola superdeep well began to be called “the road to hell,” claiming that every new kilometer drilled brought misfortune to the country. They said that when the drillers were drilling the thirteenth thousand meters, the USSR collapsed. Well, when the well was drilled to a depth of 14.5 km (which actually did not happen), they suddenly came across unusual voids. Intrigued by this unexpected discovery, the drillers sent down a microphone capable of operating at extremely high temperatures and other sensors. The temperature inside allegedly reached 1,100 °C - there was the heat of fiery chambers, in which human screams could allegedly be heard.
This legend still roams the vast expanses of the Internet, having outlived the very culprit of these gossips - the Kola well. Work on it was stopped back in 1992 due to lack of funding. Until 2008, it was in a mothballed state. A year later, the final decision was made to abandon the continuation of research and to dismantle the entire research complex and “bury” the well. The final abandonment of the well occurred in the summer of 2011.
So, as you can see, this time scientists were not able to get to the mantle and examine it. However, this does not mean that the Kola well did not give anything to science - on the contrary, it turned all their ideas about the structure of the earth’s crust upside down.
RESULTS
The objectives set in the ultra-deep drilling project have been completed. Special equipment and technology for ultra-deep drilling, as well as for studying wells drilled to great depths, have been developed and created. We received information, one might say, “first-hand” about the physical state, properties and composition of rocks in their natural occurrence and from core to a depth of 12,262 m. The well gave an excellent gift to the homeland at shallow depths - in the range of 1.6-1. 8 kilometers. Industrial copper-nickel ores were opened there - a new ore horizon was discovered. And it comes in handy, because the local nickel plant is already running short of ore.
As noted above, the geological forecast of the well section did not come true. The picture that was expected during the first 5 km in the well extended for 7 km, and then completely unexpected rocks appeared. The basalts predicted at a depth of 7 km were not found, even when they dropped to 12 km. It was expected that the boundary that gives the greatest reflection during seismic sounding is the level where the granites transform into a more durable basalt layer. In reality, it turned out that less strong and less dense fractured rocks are located there - Archean gneisses. This was never expected. And this is fundamentally new geological and geophysical information, which allows us to interpret the data of deep geophysical research differently.
The data on the process of ore formation in the deep layers of the earth’s crust also turned out to be unexpected and fundamentally new. Thus, at depths of 9-12 km, highly porous fractured rocks were encountered, saturated with highly mineralized underground waters. These waters are one of the sources of ore formation. Previously, it was believed that this was possible only at much shallower depths. It was in this interval that an increased gold content was found in the core - up to 1 g per 1 ton of rock (a concentration considered suitable for industrial development). But will it ever be profitable to mine gold from such depths?
Ideas about the thermal regime of the earth's interior and the deep distribution of temperatures in areas of basalt shields have also changed. At a depth of more than 6 km, a temperature gradient of 20°C per 1 km was obtained instead of the expected (as in the upper part) 16°C per 1 km. It was revealed that half of the heat flow is of radiogenic origin.
The depths of the earth contain as many mysteries as the vast expanses of the Universe. This is exactly what some scientists think, and they are partly right, because people still don’t know exactly what is under our feet, deep underground. Over the entire existence of earthly civilization, we have been able to go a little more than 10 kilometers into the interior of the planet. This record was set back in 1990 and lasted until 2008, after which it was updated several times. In 2008, Maersk Oil BD-04A, a 12,290 meter long inclined oil well, was drilled (Al Shaheen oil basin in Qatar). In January 2011, an inclined oil well with a depth of 12,345 meters was drilled at the Odoptu-Sea field (Sakhalin-1 project). The record for drilling depth currently belongs to the Z-42 well of the Chayvinskoye field, the depth of which is 12,700 meters.
In 1970, right on Lenin’s 100th anniversary, Soviet scientists began one of the most ambitious projects of our time. On the Kola Peninsula, ten kilometers from the village of Zapolyarny, drilling of a well began, which as a result turned out to be the deepest in the world and entered the Guinness Book of Records.
The grandiose scientific project has been going on for more than twenty years. It brought a lot of interesting discoveries, went down in the history of science, and in the end acquired so many legends, rumors and gossip that it would be enough for more than one horror film.
USSR. Kola Peninsula. October 1, 1980. Advanced well drillers that reached a record depth of 10,500 meters
Entrance to hell
During its heyday, the drilling site on the Kola Peninsula was a cyclopean structure the height of a 20-story building. Up to three thousand people worked here per shift. The team was led by the country's leading geologists. The drilling rig was built in the tundra ten kilometers from the village of Zapolyarny, and in the polar night it shone with lights like a spaceship.
When all this splendor suddenly closed and the lights went out, rumors immediately began to spread. By any measure, the drilling was extraordinarily successful. No one in the world has ever managed to reach such a depth - Soviet geologists lowered the drill more than 12 kilometers.
The sudden end of a successful project seemed as absurd as the fact that the Americans closed the program of flights to the Moon. Aliens were blamed for the collapse of the lunar project. There are devils and demons in the problems of the Kola Superdeep.
A popular legend says that the drill was repeatedly pulled out from great depths melted. There were no physical reasons for this - the temperature underground did not exceed 200 degrees Celsius, and the drill was designed for a thousand degrees. Then the audio sensors allegedly began to pick up some moans, screams and sighs. Dispatchers monitoring instrument readings complained of feelings of panic and anxiety.
According to legend, it turned out that geologists had drilled to hell. The groans of sinners, extremely high temperatures, the atmosphere of horror at the drilling rig - all this explained why all work on the Kola superdeep was suddenly curtailed.
Many were skeptical about these rumors. However, in 1995, after work had stopped, a powerful explosion occurred at the drilling rig. No one understood what could explode there, not even the leader of the entire project, the prominent geologist David Guberman.
Today, excursions are taken to the abandoned drilling rig and tourists are told a fascinating story about how scientists drilled a hole into the underground kingdom of the dead. It’s as if moaning ghosts roam around the installation, and in the evening demons crawl to the surface and strive to whisk the unwary extreme sportsman into the abyss.
Underground Moon
In fact, the whole “well to hell” story was invented by Finnish journalists by April 1st. Their comic article was republished by American newspapers, and the duck flew to the masses. The long-term drilling of the Kola superdeep mine proceeded without any mysticism. But what happened there in reality was more interesting than any legends.
To begin with, ultra-deep drilling was doomed to numerous accidents. Under the yoke of enormous pressure (up to 1000 atmospheres) and high temperatures, the drills could not withstand, the well became clogged, and the pipes used to strengthen the vent broke. Countless times the narrow well was bent so that more and more branches had to be drilled.
The worst accident occurred shortly after the main triumph of geologists. In 1982, they were able to overcome the 12 kilometer mark. These results were solemnly announced in Moscow at the International Geological Congress. Geologists from all over the world were brought to the Kola Peninsula, they were shown a drilling rig and rock samples mined at fantastic depths that humanity had never reached before.
After the celebration, drilling continued. However, the break in work turned out to be fatal. In 1984, the worst drilling accident occurred. As many as five kilometers of pipes came loose and clogged the well. It was impossible to continue drilling. Five years of work were lost overnight.
We had to resume drilling from the 7-kilometer mark. Only in 1990, geologists again managed to cross 12 kilometers. 12,262 meters - this is the final depth of the Kola well.
But parallel to the terrible accidents, there were also incredible discoveries. Deep drilling is analogous to a time machine. On the Kola Peninsula, the oldest rocks approach the surface, their age exceeding 3 billion years. By going deeper, scientists have gained a clear understanding of what happened on our planet during its youth.
First of all, it turned out that the traditional diagram of the geological section compiled by scientists does not correspond to reality. “Up to 4 kilometers everything went according to theory, and then the end of the world began,” Huberman later said
According to calculations, by drilling through a layer of granite, it was supposed to get to even harder, basaltic rocks. But there was no basalt. After the granite came loose layered rocks, which constantly crumbled and made it difficult to move deeper.
But among rocks 2.8 billion years old, fossilized microorganisms were found. This made it possible to clarify the time of the origin of life on Earth. At even greater depths, huge deposits of methane were found. This clarified the issue of the emergence of hydrocarbons - oil and gas.
And at a depth of over 9 kilometers, scientists discovered a gold-bearing olivine layer, so vividly described by Alexei Tolstoy in “The Hyperboloid of Engineer Garin.”
But the most fantastic discovery occurred in the late 1970s, when the Soviet lunar station brought back samples of lunar soil. Geologists were amazed to see that its composition completely coincided with the composition of the rocks they mined at a depth of 3 kilometers. How was this possible?
The fact is that one of the hypotheses for the origin of the Moon suggests that several billion years ago the Earth collided with some celestial body. As a result of the collision, a piece broke off from our planet and turned into a satellite. Perhaps this piece came off in the area of the current Kola Peninsula.
Final
So why did they close the Kola superdeep pipeline?
Firstly, the main objectives of the scientific expedition were completed. Unique equipment for drilling at great depths was created, tested under extreme conditions and significantly improved. The collected rock samples were examined and described in detail. The Kola well helped to better understand the structure of the earth's crust and the history of our planet.
Secondly, time itself was not conducive to such ambitious projects. In 1992, funding for the scientific expedition was cut off. The employees quit and went home. But even today the grandiose building of the drilling rig and the mysterious well are impressive in their scale.
Sometimes it seems that the Kola Superdeep has not yet exhausted the entire supply of its wonders. The head of the famous project was also sure of this. “We have the deepest hole in the world - so we must use it!” - exclaimed David Huberman.
