Candidate of Technical Sciences A. OSADCHY
Hundreds of thousands of wells were drilled into the earth's crust over the last decades of the last century. And this is not surprising, because the search and extraction of minerals in our time inevitably involves deep drilling. But among all these wells there is only one on the planet - the legendary Kola Superdeep (SG), the depth of which still remains unsurpassed - more than twelve kilometers. In addition, SG is one of the few that was drilled not for the sake of exploration or mining, but for purely scientific purposes: to study the most ancient rocks of our planet and learn the secrets of the processes taking place in them.
Geologists V. Lanev (left) and Yu. Smirnov examine core samples.
Drill bits. Exactly the same, but it was the one that was used when drilling at a depth of 12 km, which became an exhibit at the 1984 International Geological Congress.
The pipe string was lowered and raised on this hook. On the left - in the basket - there are 33-meter pipes - "candles" - prepared for descent.
Kola superdeep well.
Selected core samples.
A unique core storage facility, where the cores of the entire twelve-kilometer well are laid out on shelves in boxes in strict order, numbered.
Such badges were proudly worn by everyone who worked for the SG.
Today there is no drilling on the Kola superdeep; it was stopped in 1992. SG was not the first and not the only one in the program for studying the deep structure of the Earth. Three of the foreign wells reached a depth of 9.1 to 9.6 km. It was planned that one of them (in Germany) would surpass the Kola one. However, drilling at all three, as well as at SG, was stopped due to accidents and for technical reasons cannot yet be continued.
Apparently, it is not for nothing that the complexity of drilling ultra-deep wells is compared with a flight into space, with a long space expedition to another planet. Rock samples extracted from the earth's interior are no less interesting than samples of lunar soil. The soil delivered by the Soviet lunar rover was studied at various institutes, including the Kola Science Center. It turned out that the composition of the lunar soil almost completely corresponds to the rocks extracted from the Kola well from a depth of about 3 km.
SITE SELECTION AND FORECASTA special geological exploration expedition (Kola Geological Exploration Expedition) was created to drill the SG. The drilling location was also, of course, not chosen by chance - the Baltic Shield in the Kola Peninsula area. Here, the oldest igneous rocks about 3 billion years old (and the Earth is only 4.5 billion years old) come to the surface. It was interesting to drill in the oldest igneous rocks, because sedimentary rocks down to a depth of 8 km have already been well studied for oil production. And during mining, they usually only penetrate 1-2 km into igneous rocks. The choice of location for the SG was also facilitated by the fact that the Pecheneg trough is located here - a huge bowl-like structure, as if pressed into ancient rocks. Its origin is associated with a deep fault. And this is where large copper-nickel deposits are located. And the tasks assigned to the Kola Geological Expedition included identifying a number of features of geological processes and phenomena, including ore formation, determining the nature of the boundaries separating layers in the continental crust, collecting data on the material composition and physical condition rocks.
Before drilling began, a section of the earth's crust was constructed based on seismological data. It served as a forecast for the appearance of those earth layers that the well intersected. It was assumed that a granite strata extends to a depth of 5 km, after which stronger and more ancient basaltic rocks were expected.
So, the drilling site was chosen in the north-west of the Kola Peninsula, 10 km from the city of Zapolyarny, not far from our border with Norway. Zapolyarny is a small town that grew up in the fifties next to a nickel plant. Among the hilly tundra on a hillock, blown by all the winds and snowstorms, there is a “square”, each side of which is formed from seven five-story buildings. Inside there are two streets, at their intersection there is a square where the House of Culture and the hotel stand. A kilometer from the town, behind a ravine, the buildings and tall chimneys of a nickel plant are visible; behind it, along the mountainside, are dark dumps of waste rock from a nearby quarry. Near the town there is a highway to the city of Nikel and to a small lake, on the other side of which is Norway.
The soil of those places contains abundant traces of the past war. When you take a bus from Murmansk to Zapolyarny, about halfway along the way you cross the small river Zapadnaya Litsa, on its bank there is a memorial obelisk. This is the only place in all of Russia where the front stood motionless during the war from 1941 to 1944, facing the Barents Sea. Although there were fierce battles all the time and losses on both sides were huge. The Germans unsuccessfully tried to break through to Murmansk - the only ice-free port in our North. In the winter of 1944, Soviet troops managed to break through the front.
From Zapolyarny to Superglubokaya - 10 km. The road goes past the plant, then along the edge of the quarry and then climbs up the mountain. From the pass a small basin opens, in which the drilling rig is installed. Its height is as high as a twenty-story building. “Shift workers” came here from Zapolyarny for each shift. In total, about 3,000 people worked on the expedition; they lived in the city in two houses. The grumbling of some mechanisms could be heard from the drilling rig around the clock. The silence meant that for some reason there was a break in the drilling. In winter, during the long polar night - and it lasts there from November 23 to January 23 - the entire drilling rig glowed with lights. Often the light of the aurora was added to them.
A little about the staff. The Kola geological exploration expedition created for drilling brought together a good, highly qualified team of workers. The head of the GRE, a talented leader who selected the team, was almost always D. Guberman. Chief Engineer I. Vasilchenko was responsible for drilling. The drilling rig was commanded by A. Batishchev, whom everyone simply called Lekha. Geology was in charge of V. Laney, and geophysics was in charge of Yu. Kuznetsov. A huge amount of work on processing the core and creating a core storage facility was carried out by geologist Yu. Smirnov - the same one who had the “treasured cabinet”, which we will tell you about later. More than 10 research institutes took part in conducting research on SG. The team also had its own “Kulibins” and “left-handers” (S. Tserikovsky was especially distinguished), who invented and manufactured various devices that sometimes made it possible to get out of the most difficult, seemingly hopeless situations. They themselves created many of the necessary mechanisms here in well-equipped workshops.
DRILLING HISTORYWell drilling began in 1970. Drilling to a depth of 7263 m took 4 years. It was carried out using a serial installation, which is usually used in oil and gas production. Due to constant winds and cold, the entire tower had to be covered to the top with wooden panels. Otherwise, it is simply impossible for someone who must stand at the top while lifting a pipe string to work.
Then there was a year-long break associated with the construction of a new tower and the installation of a specially designed drilling rig - Uralmash-15000. It was with its help that all further ultra-deep drilling was carried out. The new installation has more powerful automated equipment. Turbine drilling was used - this is when not the entire column rotates, but only the drilling head. Drilling fluid was fed through the column under pressure, rotating a multi-stage turbine located below. Its total length is 46 m. The turbine ends with a drill head with a diameter of 214 mm (it is often called a crown), which has a ring shape, so an undrilled column of rock remains in the middle - a core with a diameter of 60 mm. A pipe passes through all sections of the turbine - a core receiver, where columns of mined rock are collected. The crushed rock along with the drilling fluid is carried down the well to the surface.
The mass of the column immersed in a well with drilling fluid is about 200 tons. This is despite the fact that specially designed light alloy pipes were used. If a column is made from ordinary steel pipes, it will burst from its own weight.
Many difficulties, sometimes completely unexpected, arise in the process of drilling at great depths and with core sampling.
The penetration in one trip, determined by the wear of the drill head, is usually 7-10 m. (A trip, or cycle, is the lowering of the string with the turbine and drilling tool, the actual drilling and the complete lifting of the string.) Drilling itself takes 4 hours. And the descent and ascent of the 12-kilometer column takes 18 hours. When lifted, the column is automatically disassembled into sections (candles) 33 m long. On average, 60 m were drilled per month. 50 km of pipes were used to drill the last 5 km of the well. This is the extent of their wear.
To a depth of approximately 7 km, the well intersected strong, relatively homogeneous rocks, and therefore the borehole was smooth, almost corresponding to the diameter of the drill bit. The work progressed, one might say, calmly. However, at a depth of 7 km, less durable fractured rocks appeared, interbedded with small very hard layers - gneisses, amphibolites. Drilling became more difficult. The trunk took on an oval shape, and many cavities appeared. Accidents have become more frequent.
The figure shows the initial forecast of the geological section and the one compiled on the basis of drilling data. It is interesting to note (column B) that the inclination angle of the formations along the well is about 50 degrees. Thus, it is clear that the rocks intersected by the well come to the surface. This is where we can remember the already mentioned “cherished cabinet” of geologist Yu. Smirnov. There, on one side, he had samples obtained from the well, and on the other, samples taken on the surface at the distance from the drilling site where the corresponding formation comes up. The match between the breeds is almost complete.
The year 1983 was marked by a hitherto unsurpassed record: the drilling depth exceeded 12 km. Work was suspended.
The International Geological Congress was approaching, which, according to plan, was held in Moscow. The Geoexpo exhibition was being prepared for it. It was decided not only to read reports on the results achieved at the SG, but also to show the participants of the congress the work in situ and the extracted rock samples. The monograph “Kola Superdeep” was published for the congress.
At the Geoexpo exhibition there was a large stand dedicated to the work of the SG and the most important thing - achieving record depth. There were impressive graphs telling about drilling techniques and technology, extracted rock samples, photographs of equipment and staff at work. But the greatest attention of the participants and guests of the congress was attracted by one detail that was unconventional for an exhibition display: the most ordinary and already slightly rusty drill head with worn-out carbide teeth. The label stated that it was exactly what was used when drilling at a depth of more than 12 km. This drill head amazed even specialists. Probably, everyone involuntarily expected to see some kind of miracle of technology, maybe with diamond equipment... And they still did not know that at the SG next to the drilling rig there was a large pile of exactly the same already rusted drill heads: after all, they had to be replaced with new ones approximately every drilled 7-8 m.
Many congress delegates wanted to see with their own eyes the unique drilling rig at Kola Peninsula and make sure that a record drilling depth has actually been achieved in the Union. Such a departure took place. A section of the congress held a meeting there on site. The delegates were shown the drilling rig, where they lifted the column from the well, disconnecting 33-meter sections from it. Photos and articles about SG circulated in newspapers and magazines in almost all countries of the world. A postage stamp was issued and special cancellation of envelopes was organized. I will not list the names of laureates of various prizes and those awarded for their work...
But the holidays were over, it was necessary to continue drilling. And it began with the biggest accident on the first flight on September 27, 1984 - a “black date” in the history of the SG. The well does not forgive when it is left without attention for a long time. During the time that drilling was not carried out, changes inevitably occurred in its walls, those that were not secured with a cemented steel pipe.
At first everything went casually. The drillers were doing their normal operations: sections of the drill string were lowered one after another, a drilling fluid supply pipe was connected to the last, upper one, and the pumps were turned on. We started drilling. The instruments on the console in front of the operator showed the normal operating mode (number of revolutions of the drill head, its pressure on the rock, fluid flow to rotate the turbine, etc.).
Having drilled another 9-meter section at a depth of more than 12 km, which took 4 hours, we reached a depth of 12.066 km. We got ready to lift the column. We tried it. Doesn't work. “Sticking” has been observed more than once at such depths. This is when some section of the column seems to stick to the walls (maybe something fell off from above and it jammed a little). To move a column, a force exceeding its weight (about 200 tons) is required. They did the same this time, but the column did not move. We increased the force a little, and the instrument needle sharply decreased the readings. The column became much lighter; such weight loss could not have happened during the normal course of the operation. We started lifting: we unscrewed the sections one by one. During the last lift, a shortened piece of pipe with an uneven bottom edge was hanging on a hook. This meant that not only the turbo drill remained in the well, but also 5 km of drill pipes...
They tried to get them for seven months. After all, they lost not just 5 km of pipes, but the results of five years of work.
Then all attempts to recover what was lost were stopped and drilling began again from a depth of 7 km. It must be said that it is after the seventh kilometer that the geological conditions here are especially difficult for work. The drilling technology of each step is worked out by trial and error. And starting from a depth of about 10 km it is even more difficult. Drilling, operation of equipment and equipment are carried out at maximum speed.
Therefore, accidents can be expected here at any moment. They are preparing for them. Methods and means of their elimination are thought out in advance. A typical complex accident is the breakage of the drilling assembly along with part of the drill pipe string. The main method of eliminating it is to create a bench just above the lost part and from this place drill a new bypass shaft. A total of 12 such bypass trunks were drilled in the well. Four of them range from 2200 to 5000 m in length. The main cost of such accidents is years of lost labor.
Only in everyday life is a well a vertical “hole” from the surface of the earth to the bottom. In reality this is far from the case. Especially if the well is super-deep and intersects inclined formations of varying densities. Then it seems to squirm, because the drill constantly deviates towards less durable rocks. After each measurement showing that the well’s inclination exceeds the permissible one, an attempt must be made to “put it back in place.” To do this, special “deflectors” are lowered along with the drilling tool, which help reduce the inclination angle of the well during drilling. Accidents often occur with the loss of drilling tools and parts of pipes. After this, the new trunk has to be made, as we have already said, by stepping aside. So imagine what a well looks like in the ground: something like the roots of a giant plant branching at depth.
This is the reason for the special duration of the last drilling phase.
After the largest accident - the "black date" of 1984 - they again approached a depth of 12 km only after 6 years. In 1990, the maximum was reached - 12,262 km. After several more accidents, we became convinced that we couldn’t get any deeper. All possibilities of modern technology have been exhausted. It seemed as if the Earth no longer wanted to reveal its secrets. Drilling stopped in 1992.
RESEARCH WORK. OBJECTIVES AND METHODSOne of the very important goals of drilling was to obtain a core column of rock samples along the entire length of the well. And this task is completed. The longest core in the world was marked like a ruler into meters and placed in the appropriate order in boxes. The box number and sample numbers are indicated at the top. There are almost 900 such boxes in stock.
Now all that remains is to study the core, which is truly indispensable in determining the structure of the rock, its composition, properties, and age.
But a rock sample raised to the surface has different properties than in the massif. Here, at the top, he is freed from the enormous mechanical stresses that exist at depth. During drilling, it cracked and became saturated with drilling fluid. Even if you recreate deep conditions in a special chamber, the parameters measured on the sample still differ from those in the array. And one more small “hiccup”: for every 100 m of a drilled well, 100 m of core is not obtained. In the SG, from depths of more than 5 km, the average core yield was only about 30%, and from depths of more than 9 km, these were sometimes only individual plaques 2-3 cm thick, corresponding to the most durable layers.
So, the core lifted from the well using SG does not give complete information about deep rocks.
The wells were drilled for scientific purposes, so the entire complex was used modern methods research. In addition to core extraction, studies of the properties of rocks in their natural occurrence were necessarily carried out. The technical condition of the well was constantly monitored. We measured the temperature along the entire wellbore, natural radioactivity - gamma radiation, induced radioactivity after pulsed neutron irradiation, electrical and magnetic properties of rocks, the speed of propagation of elastic waves, and studied the composition of gases in the well fluid.
Up to a depth of 7 km, serial devices were used. Working at greater depths and at higher temperatures required the creation of special heat- and pressure-resistant devices. Particular difficulties arose during the last stage of drilling; when the temperature in the well approached 200 o C, and the pressure exceeded 1000 atmospheres, serial devices could no longer work. Geophysical design bureaus and specialized laboratories of several research institutes came to the rescue, producing single copies of heat- and pressure-resistant instruments. Thus, all the time we worked only on domestic equipment.
In short, the well was explored in sufficient detail to its entire depth. Research was carried out in stages, approximately once a year, after deepening the well by 1 km. Each time after this, an assessment was made of the reliability of the materials received. The corresponding calculations made it possible to determine the parameters of a particular breed. They discovered a certain alternation of layers and already knew what rocks the caverns were associated with and the partial loss of information associated with them. We learned to literally identify rocks from “crumbs” and on this basis to recreate a complete picture of what the well “hidden.” In short, it was possible to construct a detailed lithological column - to show the alternation of rocks and their properties.
FROM OWN EXPERIENCEAbout once a year, when the next stage of drilling was completed - deepening the well by 1 km, I also went to the SG to take measurements that were entrusted to me. At this time, the well was usually washed out and made available for research for a month. The time of the planned stop was always known in advance. The telegram calling for the work also arrived in advance. The equipment has been checked and packaged. Formalities related to closed work in the border zone have been completed. Finally everything is settled. Let's go.
Our group is a small, friendly team: a borehole tool developer, a developer of new ground-based equipment, and I, a methodologist. We arrive 10 days before measurements. We get acquainted with the data on the technical condition of the well. We draw up and approve a detailed measurement program. We assemble and calibrate the equipment. We are waiting for a call - a call from the well. It’s our turn to “dive” third, but if our predecessors refuse, the well will be provided to us. This time everything is fine with them, they say that they will finish by tomorrow morning. With us in the same team are geophysicists - operators who record signals received from equipment in the well and command all operations for lowering and raising downhole equipment, as well as mechanics on the hoist, they control the unwinding of those same 12 km of cable from the drum and onto it. , on which the device is lowered into the well. Drillers are also on duty.
Work has begun. The device is lowered into the well several meters. Last check. Go. The descent is slow - about 1 km/h, with continuous monitoring of the signal coming from below. So far so good. But at the eighth kilometer the signal twitched and disappeared. This means something is wrong. Full lift. (Just in case, we have prepared a second set of equipment.) We begin checking all the details. This time the cable turned out to be faulty. He is being replaced. This takes more than a day. The new descent took 10 hours. Finally, the person observing the signal said: “We have arrived at the eleventh kilometer.” Command to operators: “Start recording.” What and how is planned in advance according to the program. Now you need to lower and raise the downhole tool several times at a given interval to take measurements. This time the equipment worked fine. Now it's a full rise. They raised it to 3 km, and suddenly the winchman called (he is a man with humor): “The rope is over.” How?! What?! Alas, the cable broke... The downhole tool and 8 km of cable remained lying at the bottom... Fortunately, a day later the drillers were able to pick it all up, using methods and devices developed by local craftsmen to eliminate such emergencies.
RESULTSThe 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 samples 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 km. 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 (see figure on page 39.). 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 o C per 1 km was obtained instead of the expected (as in the upper part) 16 o C per 1 km. It was revealed that half of the heat flow is of radiogenic origin.
Having drilled the unique Kola superdeep well, we learned a lot and at the same time realized how little we still know about the structure of our planet.
Candidate of Technical Sciences A. OSADCHY.LITERATURE
Kola superdeep. M.: Nedra, 1984.
Kola superdeep. Scientific results and research experiences. M., 1998.
Kozlovsky E. A. World Forum of Geologists."Science and Life" No. 10, 1984.
Kozlovsky E. A. Kola superdeep."Science and Life" No. 11, 1985.
In the 50-70s of the last century, the world changed at incredible speed. Things have appeared that are difficult to imagine today’s world without: the Internet, computers, cellular communications, the conquest of space and the depths of the sea. Man was rapidly expanding the spheres of his presence in the Universe, but he still had rather rough ideas about the structure of his “home” - planet Earth. Although even then the idea of ultra-deep drilling was not new: back in 1958, the Americans launched the project "Mohole". Its name is formed from two words:
Moho– surface named after Andrija Mohorovicic– Croatian geophysicist and seismologist, who in 1909 identified the lower boundary of the earth’s crust, at which an abrupt increase in the speed of seismic waves occurs;
Hole- well, hole, opening. Based on assumptions that the thickness of the earth's crust under the oceans is much less than on land, 5 wells were drilled near the island of Guadelupe with a depth of about 180 meters (with an ocean depth of up to 3.5 km). Over five years, researchers drilled five wells, collected many samples from the basalt layer, but did not reach the mantle. As a result, the project was declared a failure and the work was stopped.
The CUSS vessel, which carried out the Mohole project
One of the main goals of the expedition “On the Roads of the Arctic” was the Kola superdeep well (or object SG-3) - the deepest in the world. I first learned about it back in 2004, while studying in my first year at the Geological Faculty of the Russian State University of Oil and Gas, at a lecture on general geology. And since then I hoped to see everything with my own eyes.
Times have changed and, once inaccessible, the territory of the SG-3 facility is now in close proximity to the mining and processing plant of the Kola Mining and Metallurgical Company. And the route to the well goes through technological roads.
If you follow the navigator, then after the town of Zapolyarny it will lead to the checkpoint of the mining and processing plant. Security, of course, won’t let you into the territory, and I supposedly haven’t heard anything about the Kola Superdeep.
The management of the plant, as expected, was tired of the constant pilgrimage to the Kola superdeep of various kinds of neo-stalkers, geology lovers and metal hunters, so the road to the well was dug up with excavators and sprinkled with cobblestones for good measure.
So we return to the place where last time The mobile Internet worked and we are looking for a well-established alternative road via satellite. Having found the treasured hole, we raise the hydropneumatic suspension of our Toyota Land Cruiser 200 Executive to the top position and crawl up the hills towards the well.
The road, as befits a real adventure, was replete with various kinds of obstacles - fords, stones, even lakes.
Having already returned to Murmansk and analyzing the GPS track (we wrote the entire route using the locme.ru service, I’ll talk about it later), I noticed that we were not driving to the well along the optimal route and somewhere lost our way, but back We've already gone as far as we should. Which I don’t regret one bit.
The track was recorded using the LocMe service
And now, having climbed another hill, we have a view of the once majestic research and production complex of the Kola superdeep well.
In an effort to take a leading position in all industries at once, in 1962 the USSR launched its ultra-deep drilling program.
It took 4 years to prepare the project: the main difficulty was that according to the geothermal gradient ( physical quantity, which describes the increase in temperature of rocks with depth), the temperature at a depth of 10 km should be about 300°C, and at 15 km - almost 500°C. Neither the drilling tool nor the measuring equipment were designed for such a temperature. By 1970, just in time for the 100th anniversary of Lenin’s birth, a drilling site was found - an ancient crystalline shield of the Kola Peninsula. According to a report from the Institute of Physics of the Earth, over billions of years the Kola Shield cooled; the temperature at a depth of 15 km should not have exceeded 150°C. According to the approximate section, the first 7 kilometers should be composed of granite strata of the upper part of the earth's crust, and basalts begin below. The drilling site was chosen on the northern tip of the Kola Peninsula near Lake Vilgiskoddeoaivinjärvi (in Finnish it means “Under the Wolf Mountain”). Drilling of the well, the design depth of which was 15 kilometers, began in May 1970.
Despite the non-trivial task, no special equipment was developed for the work - we worked with what we had. At the first stages, a Uralmash 4E drilling rig with a lifting capacity of 200 tons and light-alloy aluminum pipes were used. Expensive aluminum was used for a number of reasons: pipes made of “winged metal” have much less weight, and 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. When the well reached depth 7000 meters, a new drilling rig was installed on the site "Uralmash 15000"- one of the most modern at that time. Powerful, reliable, with an automatic hoisting mechanism, it could withstand a pipe string up to 15 km long. The drilling rig turned into a fully sheathed tower 68 m high, defying the strong winds raging in the Arctic. The weight of the drill string alone at a depth of 15 kilometers would reach 200 tons. And the installation itself could lift a load of up to 400 tons. A mechanical repair plant, scientific laboratories and a core storage facility grew nearby. : in the 70s, rotary drilling was most widespread, when the entire string of pipes was turned by a rotor located on the surface. This method was excellent for relatively shallow wells, but when the bore length approaches 7,000 or even 10,000 meters, rotary drilling becomes powerless. At SG-3, drilling was carried out using a turbodrill - a hydraulic motor, the rotation of which was provided by the energy of the circulating drilling fluid. The 46 meter sections installed at the lower end of the column rotated the drill bit. Neither in the USSR nor in the world at that time there was any experience in drilling in crystalline basement rocks at such depths, and in addition to purely technological problems, the work was complicated by 100% core sampling. The penetration in one trip, determined by the wear of the drill head, is usually 7-10 m (a trip, or cycle, is the lowering of a string with a turbine and drilling tool, the actual drilling and the complete lifting of the string.) The drilling itself takes 4 hours, and the lowering takes The ascent of the 12-kilometer column takes about 18 hours. When lifted, the column is automatically disassembled into sections (candles) 33 m long. On average, 60 m were drilled per month. 50 km of pipes were used to drill the last 5 km of the well. This is the extent of their wear.
Approaching the territory of SG-3, we saw the “Loaf” and people fussily putting pieces of iron inside. This picture has long become familiar to the once advanced scientific center - it was assumed that the Kola superdeep well, after completion of its excavation, would be turned into a unique natural laboratory for studying deep processes occurring in the earth's crust using special instruments. However, in 2008, the facility was finally abandoned, and all more or less valuable equipment was dismantled. From that moment on, a period of plundering of everything that was of any value began - primarily metal.
The metal thieves, however, turned out to be quite sociable guys; they were sincerely surprised why we came here from Moscow - “there was nothing left right there!” and showed the legendary well. Now it is mothballed, and its mouth is closed by a steel plate. Nobody knows what happens in the trunk itself.
On the basis of SG-3, in addition to the drilling site itself, there were several research institutes, its own design bureau, a turning shop, and a forge. The most daring technical solutions were born right on site, implemented on our own, and after a few days they were already tested in operation. All this required energy and the Kola Superdeep was served by its own substation. Now the power unit looks like this; at one time 48 people worked here.
Boxes with unique equipment are piled at the entrance. Everything valuable is torn out “with meat”:
And a little further away there are power line supports. All the wires, of course, had been cut off long ago.
According to the directive “from above,” only domestic equipment was used at SG-3, and it could not have been any other way: at first, the well was a top-secret security facility. Up to a depth of 7 km, serial devices were used. Working at greater depths and at higher temperatures required the creation of special heat- and pressure-resistant devices. Particular difficulties arose during the last stage of drilling; when the temperature in the well approached 200 o C, and the pressure exceeded 1000 atmospheres, serial devices could no longer work. Geophysical design bureaus and specialized laboratories of several research institutes came to the rescue, producing single copies of heat- and pressure-resistant equipment. The competition for employment consisted of dozens of people per position, and those who passed a rigorous selection process were immediately given an apartment. At a time when an ordinary Soviet engineer received 120 rubles a month, an engineer at the Kola Superdeep Well earned an incredible 850 rubles - three salaries and you can buy a car. In total, about 300 people worked at the Kola Superdeep.
The depth of 7000 meters turned out to be fatal for the Kola superdeep
Depth in 7000 meters turned out to be extremely fatal for Kola. Higher up the section, drilling proceeded relatively calmly; the drill passed through homogeneous, durable granites. But after this depth, the drill head entered less durable layered rocks, and the barrel could not be kept vertical. When the well passed the 12 km mark for the first time, the shaft deviated from the vertical by 21°. Although the drillers had already learned to work with the incredible curvature of the barrel, it was impossible to go any further. The well had to be drilled from the 7 km mark. To get a vertical shaft in hard rocks, you need a very rigid bottom of the drill string so that it goes into the subsurface like a knife into butter. But another problem arises - the well gradually expands, the drill dangles in it, like in a glass, the walls of the barrel begin to collapse and can crush the tool. The solution to this problem turned out to be original - pendulum technology was used. The drill was artificially rocked in the well and suppressed strong vibrations. Due to this, the trunk turned out vertical. June 6, 1979 the first historical event happened. The drillers reported reaching the mark at 9584 meters. The Kola well has become the most deep well in the world, surpassing the American oil record holder “Bertha Rogers” (9583 meters).
On June 6, 1979, drilling foreman Fedor Atarshchikov made a triumphant entry in the logbook: “Bottomhole - 9584 meters. “Bertha Rogers,” ciao, good bye.”
In the early 1980s a second historical event also occurred. The Kola superdeep has passed 11,022 meters, bypassing the Mariana Trench. Humanity has never reached such a depth inside its own cradle. One of the most common drilling accidents is stuck drilling tools, a situation when crumbling well walls block the string and prevent the tool from rotating. Often, attempts to pull out a stuck column end in its breakage. It is useless to look for a tool in a 10-kilometer well; such a shaft was abandoned and a new one was started, a little higher. Breakage and loss of pipes at SG-3 happened many times. As a result, in its lower part the well looks like the root system of a giant plant. The branching of the well upset the drillers, but turned out to be a blessing for geologists, who unexpectedly received a three-dimensional picture of an impressive stretch of ancient Archean rocks formed more than 2.5 billion years ago.
Walking through the deserted corridors of the complex, despite the general monstrous devastation, you feel the former grandeur of what happened here. In one of the offices, the floor is strewn with rare scientific literature - issues of the magazine "Defectoscopy" for several years and a manual for calculating drill strings for ultra-deep wells - uniqueness scientific work roughly comparable to the “instructions for flying to the moon for dummies”, if it existed.
In another - miraculously preserved workplace drilling foreman. The first well in Russia was drilled in 1864 in Kuban. From then to now, the foreman almost always works directly at the drilling site to see and control everything that is happening. But it wasn’t like that on the Kola Superdeep! The operator sat as much as 250 meters from the mouth and monitored everything remotely, including the drilling parameters. Space!
The walls are shabby, the glass is broken by the harsh northern wind, but you can’t leave the feeling that a laboratory assistant is about to enter the office and drive out the uninvited guests.
IN September 1984 depth was reached for the first time 12,066 meters, and then another break in the drill string occurred. This became a real tragedy for the drilling crew, because they had to start almost all over again, all from the same 7 kilometers, again and again passing through cracks and caverns of the lower layer of the earth's crust. At the same time, within the framework of the World Geological Congress, the work carried out in the Arctic was declassified. In the scientific world, the SG-3 well created a real sensation. A large delegation of geologists and journalists went to the village of Zapolyarny. Visitors were shown the drilling rig in action; 33-meter sections of pipes were removed and disconnected. Around there were dozens of drill bits exactly the same as the one lying on the stand in Moscow. The USSR confirmed its status as a leading power in the field of deep drilling.
IN June 1990 when SG-3 reached depth 12,262 m, have begun preparatory work to excavation up to 14 km, an accident occurred again. At 8,550 m, the pipe string broke. Continuing the work required a long and expensive update of equipment, so in 1994 drilling of the Kola superdeep was stopped. All possibilities of modern technology have been exhausted. After 3 years, she entered the Guinness Book of Records and remains unsurpassed to this day.
What did ultra-deep drilling on the Kola Peninsula give to humanity?
First of all, she refuted the simple two-layer structure of the Earth. The geological section compiled on the basis of the SG-3 core turned out to be exactly the opposite of what scientists had previously imagined. The first 7 kilometers were composed of volcanic and sedimentary rocks: tuffs, basalts, breccias, sandstones, dolomites. Deeper lay the so-called Conrad section, after which the speed of seismic waves in the rocks sharply increased, which was interpreted as the boundary between granites and basalts. This section was passed a long time ago, but the basalts of the lower layer of the earth’s crust never appeared anywhere. On the contrary, granites and gneisses began to appear. 
One of the most important goals of drilling was to obtain a core (a cylindrical column of rock) along the entire length of the well. The longest core in the world was marked like a ruler into meters and placed in the appropriate order in boxes. The box number and sample numbers are indicated at the top. There are almost 900 such boxes in stock.
Seismic sections in the subsurface, as it turned out, are not the boundaries of rock layers different composition. Rather, they indicate changes in the petrophysical properties of rocks with depth. At high pressure and temperature, the properties change so much that granites in their physical characteristics become similar to basalts, and vice versa. It was believed that with depth and increasing pressure, the porosity and fracturing of rocks decreases. However, starting from the 9-kilometer mark, the strata turned out to be abnormally porous and fractured. Aqueous solutions circulated through a dense system of cracks. This fact was later confirmed by other ultra-deep wells on the continents. It turned out to be much hotter at depth than expected: as much as 80°! At the 7 km mark the temperature in the face was 120°C, at 12 km it had already reached 230°C. Scientists discovered gold mineralization in samples from the Kola well. Insertion of the precious metal was found in ancient rocks at a depth of 9.5-10.5 km. However, the concentration of gold was too low to declare a deposit - an average of 37.7 mg per ton of rock, but sufficient to expect it in other similar places. The Kola superdeep well aged the Earth by as much as 1.5 billion years: life appeared on the planet earlier than expected. At depths where it was believed that there was no organic matter, more than 17 species of fossilized microorganisms - microfossils - were discovered, and the age of these deep layers exceeded 2.8 billion years. And more than a dozen more narrowly focused discoveries.
In total, about 30 ultra-deep wells were drilled on the territory of the USSR
Few people know, but in the territory former USSR more than 30 ultra-deep wells were drilled (today, all or almost all of them have been destroyed). They were connected to each other using special transects (measurement lines), obtaining regional geological profiles many thousands of kilometers long. Special geophysical equipment was placed along the transects, which recorded all the processes occurring in the subsoil at a single time. Until 1991, underground nuclear explosions were used as sources of excitation (a pulse that was recorded in wells).
This fundamentally new technical and methodological approach to solving the regional deep structure of the earth's crust and upper mantle was based on integrating data from ultra-deep and deep drilling, as well as seismic deep sounding and other geophysical and geochemical methods. For the territory of the USSR, a system of mutual correlation of geophysical profile data based on reference ultra-deep wells was developed. All this made it possible to carry out a fairly detailed zoning, primarily of promising zones from the point of view of oil, gas and ore deposits, on a national scale. 
The cost of restoration is 100 million rubles?
In his interviews, the director of the Geological Institute of the Kola Scientific Center of the Russian Academy of Sciences claims that for 100 million rubles it is possible even now to restore the complex of the Kola superdeep well, open a scientific and technical center on its basis and train specialists in offshore drilling. It is quite obvious to me that this is not the case. And the issue, unfortunately, is not about money. A unique object, comparable in scale and significance to humanity only with human space flight, has been lost. And lost forever.
After SG-3, many attempts have been and are being made around the world to look into the deep horizons of the Earth’s interior, but unfortunately, not a single project has come close in importance to the work carried out in the Arctic.
- What is the most important thing the Kola well showed?
- Gentlemen! The main thing is that it showed that we know nothing about the continental crust
How to get to the Kola superdeep well? Points, coordinates, etc.
- From Murmansk by road A138 moving towards the city of Nikel;
- At the point 69.479533, 31.824395 there will be a checkpoint where documents will be checked;
- Let's go further to 69.440422, 30.594060 where we turn left;
- We continue along the technological road until 69.416088, 30.684387 ;
- The filled road should be on the right hand at the point 69.408826, 30.661051 ;
- We go further and carefully look at the lapel on the left hand. I went here: 69.414850, 30.613894 ;
- Next we move along the well-worn path, but at the point 69.411232, 30.608956 you need to stay to the right.
- Coordinates of the well itself 69.396326, 30.609513 .
In the second half of the 20th century, the world became sick with ultra-deep drilling. In the United States, they were preparing a new program for studying the ocean floor (Deep Sea Drilling Project). The Glomar Challenger, built specifically for this project, spent several years in the waters of various oceans and seas, drilling almost 800 wells in their bottoms, reaching a maximum depth of 760 m. By the mid-1980s, the results of offshore drilling confirmed the theory of plate tectonics. Geology as a science was born again. Meanwhile, Russia went its own way. Interest in the problem, awakened by the successes of the United States, resulted in the program “Study of the Earth's interior and ultra-deep drilling,” but not in the ocean, but on the continent. Despite its centuries-old history, continental drilling seemed to be a completely new matter. After all, we were talking about previously unattainable depths - more than 7 kilometers. In 1962, Nikita Khrushchev approved this program, although he was guided more by political motives than by scientific ones. He did not want to fall behind the United States.
The newly created laboratory at the Institute of Drilling Technology was headed by the famous oil worker, Doctor of Technical Sciences Nikolai Timofeev. He was tasked with justifying the possibility of ultra-deep drilling in crystalline rocks - granites and gneisses. The research took 4 years, and in 1966 the experts made a verdict - it is possible to drill, and not necessarily with the technology of tomorrow, the equipment that already exists is sufficient. The main problem is the heat at depth. According to calculations, as it penetrates into the rocks that make up the earth's crust, the temperature should increase by 1 degree every 33 meters. This means that at a depth of 10 km we should expect about 300°C, and at 15 km - almost 500°C. Drilling tools and instruments will not withstand such heat. It was necessary to look for a place where the depths are not so hot...
Such a place was found - an ancient crystalline shield of the Kola Peninsula. A report prepared at the Institute of Physics of the Earth stated: over the billions of years of its existence, the Kola Shield has cooled, the temperature at a depth of 15 km does not exceed 150 ° C. And geophysicists have prepared an approximate section of the subsoil of the Kola Peninsula. According to them, the first 7 kilometers are granite strata of the upper part of the earth’s crust, then the basalt layer begins. At that time, the idea of a two-layer structure of the earth's crust was generally accepted. But as it turned out later, both physicists and geophysicists were wrong. The drilling site was chosen at the northern tip of the Kola Peninsula near Lake Vilgiskoddeoaivinjärvi. In Finnish it means “Under the Wolf Mountain,” although there are neither mountains nor wolves in that place. Drilling of the well, the design depth of which was 15 kilometers, began in May 1970.
But
Here you can listen to the hellish sounds from the well.
Film: Kola Superdeep: The Last Fireworks
An attempt to study the geological section and thickness of volcanic rocks exposed on the surface of the earth prompted scientific centers and, like them, research organizations to identify the origin of deep faults. The fact is that structural samples of rocks previously extracted from the bowels of the Earth and the Moon were then of equal interest for study. And the choice of the location of the mouth fell on the existing huge bowl-like trough, the origin of which is associated with the presence of a deep fault in the area of the Kola Peninsula.
It was believed that the Earth is a kind of sandwich consisting of a crust, mantle and core. By this time, sedimentary rocks close to the surface had been sufficiently studied during the development of oil fields. Exploration for non-ferrous metals was rarely accompanied by drilling below the 2000-meter mark.
The Kola SG (superdeep), below a depth of 5000 meters, expected to detect a separation of granite and basalt layers. This did not happen. The drill pierced hard granite rocks up to 7000 meters. Further, the excavation proceeded through relatively soft soils, which caused the collapse of the shaft walls and the formation of cavities. The crumbled soil jammed the tool head so much that during lifting the pipe string broke off, leading to an accident. The Kola well was supposed to confirm or refute these long-established teachings. In addition, scientists did not risk indicating the intervals where exactly the boundaries between these three layers lie. The Kola well was intended for exploration and study of deposits of mineral resources, determination of patterns and gradual formation of fields of occurrence of raw material reserves. The basis was, first of all, the scientific validity of the theory of physical, hydrogeological and other parameters of the depths of the Earth. And only ultra-deep shaft excavation could provide reliable information about the geological structure of the subsoil.
Meanwhile, many years of preparation for the start of drilling operations provided for: the possibility of an increase in temperature with deepening, an increase in the hydrostatic pressure of the formations, the unpredictability of the behavior of rocks, their stability due to the presence of rock and formation pressures.
From a technical point of view, everything was taken into account possible difficulties and obstacles that could lead to a slowdown in the deepening process due to loss of time for lowering and raising the projectile, a decrease in drilling speed due to a change in the category of rocks, and an increase in energy costs for downhole movers.
The most difficult factor was considered to be the constant increase in the weight of the casing and drill pipe as they deepened.
Technical developments in the field have become successful:
- increasing the carrying capacity, power and other characteristics of drilling rigs and equipment;
- heat resistance of rock cutting tools;
- automation of management of all stages of the drilling process;
- processing information coming from the bottomhole zone;
- warnings about emergency situations with the drill pipe or casing.
Drilling an ultra-deep shaft was supposed to reveal the correctness or fallacy of the scientific hypothesis about the deep structure of the planet.
The purpose of this very expensive construction included research:
1.
The deep structure of the Pechenga nickel deposit and the crystalline base of the Baltic shield of the peninsula. Deciphering the contour of the polymetallic deposit at Pechenga, coupled with the manifestations of ore bodies.
2.
Study of the nature and forces causing the separation of the strata boundaries of the continental crust. Identification of formation zones, motives and nature of high temperature formation. Determination of the physical and chemical composition of water, gases formed in cracks and pores of rocks.
3.
Obtaining comprehensive material on the material composition of rocks and information on the intervals between the granite and basalt “gaskets” of the crust. A comprehensive study of the physicochemical properties of the extracted core.
4.
Development of advanced technical means and new technologies for sinking ultra-deep shafts. Possibility of using geophysical research methods in the zone of ore occurrences.
5.
Development and creation of the latest equipment for monitoring, testing, research, and monitoring the progress of the drilling process.
The Kola well mostly met scientific purposes. The task was to study ancient breeds, of which the planet is composed and knowledge of the secrets of the processes occurring in them.
Geological justification for drilling on the Kola Peninsula
Exploration and extraction of useful ore deposits is always predetermined by drilling deep wells. And why on the Kola Peninsula and specifically in the Murmansk region, and certainly in Pechenga. The prerequisite for this was the fact that this region was considered a real storehouse of mineral resources, with rich reserves of a wide variety of ore raw materials (nickel, magnetites, apatites, mica, titanium, copper).
However, a geological calculation made on the basis of a core from a well revealed the absurdity of the world scientific opinion. The seven-kilometer depth turned out to be composed of volcanic and sedimentary rocks (tuffs, sandstones, dolomites, breccias). Below this interval, it was assumed, there should have been rocks separating the granitic and basaltic structures. But, alas, the basalts never appeared.
In geological terms, the Baltic Shield of the peninsula, which partially covers the territories of Norway, Sweden, Finland and Karelia, has been subject to erosion and evolution for millions of centuries. Natural outbursts, destructive processes of volcanism, magmatism phenomena, metamorphic modifications of rocks, and sedimentation are most clearly imprinted on the geological record of Pechenga. This is that part of the Baltic folded shield, where the geological history of formation and ore manifestations took shape over billions of years.
Especially, the northern and eastern parts of the shield surface were subjected to centuries of corrosion. As a result, glaciers, wind, water and other natural disasters seemed to tear off (scrape) the upper layers of rocks.
The basis for choosing the location for the well was the serious erosion of the upper layers and the exposure of ancient Archean formations of the Earth. These outcrops significantly brought closer and easier access to the underground storehouses of nature.
Ultra-deep well design
Ultra-deep structures have a mandatory telescopic design. In our case, the initial diameter of the mouth was 92 cm, and the final diameter was 21.5.
The design guide column or so-called conductor with a diameter of 720 mm provided for penetration to a depth of 39 linear meters. The first technical column (stationary casing), with a diameter of 324 mm and a length of 2000 meters; removable casing 245 mm, with a footage of 8770 meters. Further drilling was planned to be carried out with an open hole to the design level. Crystalline rocks made it possible to count on long-term stability of the uncased part of the walls. A second removable column, marked with magnetic markers, would allow for continuous core sampling along the entire length of the barrel. Radioactive tags on the downhole pipe were configured to record the temperature of the drilling environment.
Technical equipment of a drilling rig for drilling an ultra-deep well
Drilling from scratch was carried out using a Uralmash-4E installation, that is, serial equipment used for drilling deep oil and gas wells. Up to 2000 meters, the trunk was driven through steel drill pipes with a turbo drill at the end. This 46-meter-long turbine with a bit at the end was driven into rotation by the action of a clay solution that was pumped into the pipe at a pressure of 40 atmospheres.
Further, the excavation was carried out at an interval of 7264 meters using the domestic Uralmash-15000 installation, from an innovative point of view, a more powerful structure with a lifting capacity of 400 tons. The complex was equipped with many technical, technological, electronic and other advanced developments.
The Kola well was equipped with a high-tech and automated structure:
1.
Exploration, with a powerful base on which the sectional tower itself is mounted, 68 meters high. Intended to implement:
- shaft sinking, projectile lowering and lifting operations and other auxiliary actions;
- holding the leading and entire pipe string, both in weight and during the drilling process;
- placement of sections (candles) of drill pipes, including weighted drill pipes (drill collars), and the traveling system.
The internal space of the tower also housed SP (descent-ascend) equipment and tools. Safety equipment and possible emergency evacuation of the horseman (assistant driller) were also located here.
2. Power and technological equipment, power and pumping units.
3. Circulation and blowout control system, cementing equipment.
4. Automation, management, process control system.
5. Electrical equipment, mechanization equipment.
6. A set of measuring equipment, laboratory equipment and much more.
In 2008, the Kola superdeep well was completely abandoned, all valuable equipment was dismantled and removed (most of it was sold for scrap).
Until 2012, the main tower of the drilling rig was dismantled.
Now only the Kola Scientific Center of the Russian Academy of Sciences operates, where to this day they study core extracted from an ultra-deep well.
The core itself has been removed to the city of Yaroslavl, where it is now stored.
Documentary video about the Kola superdeep well
New records for ultra-deep wells
The Kola superdeep well was considered the deepest well in the world until 2008.
In 2008, the Maersk Oil BD-04A oil well, whose length is 12,290 meters, was drilled at an acute angle to the surface of the earth in the Al Shaheen oil basin.
In January 2011, this record was broken, and it was broken by an oil well drilled in the Northern Dome (Odoptu-sea - a gas-oil field in Russia), this well was also drilled at an acute angle to the surface of the earth, the length was 12,345 meters.
In June 2013, well Z-42 of the Chayvinskoye field again broke the depth record, with a length of 12,700 meters.
Back in 1990, in the southern part of Germany, a group of scientists decided to look into the depths of our planet at the junction of two tectonic plates that collided more than 300 million years ago, when the continent was formed. The final goal of the scientists was to drill one of the deepest wells in the world, up to 10 km.
Initially, it was assumed that the well would become a kind of “telescope”, which would make it possible to learn more about the depths of our planet and try to learn about the Earth’s core. The drilling process took place as part of the Continental Deep Drilling program and lasted until October 1994, when the program had to be curtailed due to financial problems.
The well was named Kontinentales Tiefbohrprogramm der Bundesrepublik, abbreviated KTB, and by the time the program was closed it had been drilled to more than 9 km, which did not add enthusiasm to the scientists. The drilling process itself was not easy. For 4 years, scientists, engineers and workers had to face a whole bunch of difficult situations and quite complex tasks. For example, the drill had to pass through rocks heated to a temperature of about 300 degrees Celsius, but even under such conditions, the drillers still managed to cool the hole with liquid hydrogen.
However, despite the fact that the program was curtailed, scientific experiments did not stop and were carried out until the end of 1995, and it is worth noting that they were not carried out in vain. During this time, it was possible to discover new, rather unexpected facts about the structure of our planet, new temperature distribution maps were compiled and data on the distribution of seismic pressure were obtained, which made it possible to create models of the layered structure of the upper part of the Earth's surface.
However, scientists saved the most interesting for last. Dutch scientist Lott Given, who, together with acoustic engineers and scientists from the Geophysical Research Center (Germany), did what many had dreamed of - almost in the literal sense of the word, he “heard the heartbeat” of the Earth. To do this, he and his team needed to carry out acoustic measurements, with which the research team recreated the sounds that we could hear at a depth of 9 kilometers. However, now you can hear these sounds too.
Despite the fact that KTB is currently considered the deepest well in the world, there are several similar wells, which, however, have already been sealed. And among them, a well stands out, which during its existence has managed to acquire legends; this is the Kola super-deep well-well, better known as the “Road to Hell”. Unlike other competitors of KTB, the Kola well reached 12.2 km in depth and was considered the deepest well in the world.
Its drilling began in 1970 in the Murmansk region (Soviet Union, now the Russian Federation), 10 kilometers west of the city of Zapolyarny. During drilling, the well experienced several accidents, as a result of which workers had to concrete the well and start drilling from a much shallower depth and at a different angle. It is interesting that it is with a series of accidents and failures that haunt the group that the reason for the emergence of the legend that the well was drilled all the way to the real Hell is associated.
As the text of the legend says, after passing the 12 km mark, scientists were able to hear the sounds of screams using microphones. However, they decided to continue drilling and while passing the next mark (14 km), they suddenly came across voids. After the scientists lowered the microphones, they heard the screams and moans of men and women. And after some time, an accident occurred, after which it was decided to stop drilling work
And, despite the fact that the accident really happened, scientists did not hear any screams of people, and all the talk about demons was nothing more than fiction, said David Mironovich Guberman, one of the authors of the project, under whose leadership the well was drilled.
After another accident in 1990, upon reaching a depth of 12,262 meters, drilling was completed, and in 2008, the project was abandoned and the equipment was dismantled. Two years later, in 2010, the well was mothballed.
Let us note that projects such as drilling wells such as the KTV and Kola wells are currently the only way and opportunity for geologists to study the interior of the planet.
