Kola superdeep now. Superdeep well on the Kola Peninsula: history and secrets

An attempt to study the geological section and thickness of volcanic rocks that emerge on the earth's surface prompted research centers and, like them, research organizations to identify the origin of deep faults. The fact is that structural rock samples 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, close to the surface, sedimentary rocks were sufficiently explored in 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, was supposed to discover a section of granite and basalt layers. This did not happen. The drill bit pierced hard granite rocks up to 7000 meters. Further, the sinking proceeded along relatively soft soils, which caused the collapse of the barrel walls and the formation of caverns. The scattered soil jammed the tool head so much that when the pipe string was lifted, it broke off, leading to an accident. The Kola well was supposed to confirm or deny these long-established teachings. In addition, scientists did not dare to indicate the intervals where the boundaries between these three layers lie. The Kola well was intended for exploration and study of deposits of mineral resources, determination of the pattern and stage-by-stage formation of fields of occurrence of reserves of raw materials. 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 superdeep shaft sinking could provide reliable information about the geological structure of the subsoil.

Meanwhile, the long-term 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 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, all possible difficulties and obstacles were taken into account that could lead to a slowdown in the deepening process due to the loss of time for lowering and lifting of the drill, a decrease in the drilling speed due to a change in the category of rocks, and an increase in energy consumption for downhole movers.
The most difficult factor was considered to be the constant increase in the weight of the casing and drill pipe as it went deeper.

Technical developments in the field have become successful:
- increasing the carrying capacity, power and other characteristics of drilling equipment and equipment;
- heat resistance of rock cutting tools;
- automation of control of all stages of the drilling process;
- processing of information coming from the bottomhole zone;
- warnings about emergency situations with drill pipe or casing.

Drilling a super-deep shaft should have revealed the correctness or falsehood of a scientific hypothesis about the deep structure of the planet.

The purpose of this very costly construction included research:
1. Deep structure of the Pechenga nickel deposit and the crystalline base of the Baltic shield of the peninsula. Deciphering the contour of the polymetal deposit in Pechenga, coupled with the manifestations of ore bodies.
2. Study of the nature and forces causing the division of the stratal boundaries of the continental crust. Identification of zones of layers, motives and the nature of the formation of high temperature. Determination of the physical and chemical composition of water, gases formed in cracks, pores of rocks.
3. Obtaining comprehensive material on the material composition of rocks and information on the intervals of separation of granite and basalt "pads" of the crust. Comprehensive study of the physical and chemical properties of the recovered core.
4. Development of advanced technical means and new technologies for ultra-deep hole sinking. Possibility of using geophysical research methods in the zone of ore occurrences.
5. Development and creation of the latest equipment for observation, testing, research, monitoring the progress of the drilling process.

For the most part, the Kola well was for scientific purposes. The task included the study of the most ancient rocks, of which the planet is composed and the knowledge of the secrets of the processes occurring in them.

Geological substantiation of drilling on the Kola Peninsula

Exploration and production of deposits of useful ores is always predetermined by the drilling of deep wells. And why on the Kola Peninsula and precisely in the Murmansk region, and certainly on Pechenga. A prerequisite for this was the fact that this region was considered a real treasure of mineral resources, with the richest reserves of a wide variety of ore raw materials (nickel, magnetite, apatite, mica, titanium, copper).

However, the geological calculation, performed on the basis of the core from the well, revealed the absurdity of world scientific opinion. Seven kilometers depth turned out to be composed of volcanic and sedimentary rocks (tuffs, sandstones, dolomites, breccias). Below this interval, it was assumed that there should have been rocks separating the granite and basalt structures. But, alas, the basalts never appeared.

In geological terms, the Baltic shield of the peninsula, with partial coverage of the territories of Norway, Sweden, Finland and Karelia, has undergone erosion and evolution for millions of centuries. Natural outbursts, destructive processes of volcanism, phenomena of magmatism, metamorphic modifications of rocks, sedimentation are most clearly imprinted on the geological chronicle of Pechenga. This is the part of the Baltic fold shield, where the geological history of stratal and ore occurrences took shape for billions of years.

Especially, the northern and eastern parts of the shield surface were exposed to centuries-old corrosion. As a result, glaciers, wind, water and other natural disasters, as it were, ripped off (scraped) the upper layers of rocks.

The choice of the well location was based on the serious erosion of the upper layers and outcropping of the ancient Archean formations of the Earth. These outcrops significantly brought closer and facilitated access to the underground storehouses of nature.

Superdeep borehole design

Superdeep structures have a mandatory telescopic design. In our case, the initial orifice diameter was 92 cm, and the final diameter was 21.5.

The design guide string or the so-called conductor with a diameter of 720 mm provided for drilling to a depth of 39 running meters. The first technical string (stationary casing), 324 mm in diameter and 2000 meters long; removable casing 245 mm, metric area of 8770 meters. Further drilling was planned to be carried out with an open hole up to the design mark. Crystalline rocks made it possible to count on long-term stability of the uncased part of the walls. The second removable string, marked with magnetic tags, would allow for continuous coring along the entire length of the wellbore. The radioactive marks on the downhole pipe were set to record the temperature of the drilling environment.

Technical equipment of a drilling rig for drilling an ultra-deep well

The drilling was carried out from scratch with the Uralmash-4E rig, that is, serial equipment used for drilling deep oil and gas wells. Up to 2000 meters, the borehole was driven by steel drill pipes, with a turbodrill at the end. This 46-meter long turbine with a bit at the end was driven into rotation by mud, which was pumped into a pipe at 40 atmospheres pressure.

Further, the sinking was carried out from an interval of 7264 meters with the domestic installation "Uralmash-15000", from an innovative point of view, a more powerful structure, with a carrying 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 for implementation:

shaft sinking, lowering and lifting operations of the projectile and other auxiliary actions;
retention of the leading and the entire pipe string, both in weight and during the drilling process;
placement of sections (plugs) of drill pipes, including weighted pipes (drill collars), tackle system.

In the inner space of the tower were also placed means of joint venture (descent - ascent), tools. It also housed security equipment and a possible emergency evacuation of the horseman (assistant driller).

2. Power and technological equipment, power and pumping units.

3. Circulation and blowout prevention system, cementing equipment.

4. Automation, control, process control system.

5. Electrical support, mechanization means.

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 handed over 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 is working in which to this day they study the core extracted from a superdeep well.

The core itself was taken out to the city of Yaroslavl, where it is now kept.

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, which is 12,290 meters long, was drilled in the Al-Shahin oil basin at an acute angle to the earth's surface.

In January 2011, this record was also broken, and her oil well was drilled in the Northern Dome (Odoptu-more - a gas and oil field in Russia), this well was also drilled at an acute angle to the earth's surface, the length was 12 345 meters.

In June 2013, the Z-42 well of the Chayvo field again broke the depth record with a length of 12,700 meters.

Despite the fact that the 21st century is in the yard, the internal structure of our planet has been studied very little. We know quite well what is happening in distant space, at the same time, the degree of penetration into the secrets of the Earth can be compared with a light pin prick into the surface of the rind of a watermelon.
In the mid-1950s, when drillers learned how to drill wells more than 7 km deep, mankind approached a very ambitious task - to go through the earth's crust and see what is hidden under it. Our compatriots, who drilled the Kola superdeep well, came closest to this goal.
The Earth's solid shell is surprisingly thin in relation to its size - the thickness of the crust varies between 20-65 km on land and 3-8 km under the ocean, occupying less than 1% of the planet's volume. Behind it is a vast layer - the mantle - which accounts for the bulk of the Earth. Even below there is a dense core, consisting mainly of iron, as well as nickel, lead, uranium and other metals. Between the crust and the mantle, a boundary zone is distinguished, named after the Yugoslav scientist who discovered it, the surface (boundary) of Mohorovich, or in abbreviated form - Moho. In this zone, the speed of propagation of seismic waves increases sharply. There are a number of hypotheses designed to explain this phenomenon, but on the whole it remains unsolved.

The most important goal of the most serious deep drilling projects launched in the second half of the 20th century was precisely this mysterious layer. The researchers did not succeed in reaching it, but the data on the structure of the earth's crust obtained during the drilling of superdeep wells turned out to be so unexpected that the Mokhorovich boundary seemed to recede into the background. First, it was necessary to explain the riddles found in the higher layers.
The Americans were the first to start deep drilling of the earth's crust for scientific purposes. In the 1960s, they launched the Mohole scientific project, which envisaged the creation of submarines using special drilling vessels. Over the next thirty years, more than 800 wells appeared in the seas and oceans, many of which are located at depths of more than 4 km. The longest well was able to go only 800 m deep into the seabed, and yet the data obtained was of colossal importance for geology. In particular, they served as a weighty confirmation of the so-called. tectonic theory, according to which the continents are based on solid lithospheric plates, slowly floating, submerged in the liquid mantle.

Of course, the USSR could not lag behind its overseas competitor, therefore, in the mid-1960s, we also launched numerous projects to study the earth's crust. Soviet scientists took a slightly different path, deciding to drill wells not in the sea, but on the ground. The most famous and successful project of this kind is the Kola Superdeep Borehole - the deepest "hole in the earth" ever made by man. The well is located at the northern end of the Kola Peninsula. This place was not chosen by chance - over hundreds of millions of years, natural erosion destroyed the surface of the Kola crystalline shield, tearing off the upper layers of the rock from it. As a result, ancient Archean layers appeared on the surface, corresponding to depths of 5-10 km for the average continental-type crustal section. The 15-kilometer design depth of the well allowed scientists to hope to reach the mysterious surface of Mohorovich.
Drilling of the Kola well began in 1970 and ended more than 20 years later - in 1994. At first, the drillers worked with quite traditional methods: a string of light-alloy pipes was lowered into the well, at the end of which a cylindrical metal drill with diamond teeth and sensors was attached. The column was rotated by an engine located on the surface. As the depth of the well increased, new sections were added to the pipes. Periodically, the entire column had to be lifted to the surface in order to extract the cut rock core and replace the blunt bit. Unfortunately, this proven technology becomes ineffective when the depth of the well exceeds a certain mark: the friction of the pipes against the walls of the well becomes too great for this entire huge shaft to be rotated. To overcome this difficulty, the engineers developed a scheme in which only the head of the drilling rig rotated. At the end of the string, turbines were reinforced, through which drilling mud was passed - a special fluid that acts as a lubricant and circulates through the pipes. These turbines made the drill rotate.

Samples brought to the surface while drilling have revolutionized geology. The existing ideas about the structure of the earth's crust turned out to be far from reality. The first surprise was the lack of a transition from granite to basalt, which scientists expected to see at a depth of about 6 km. Seismological studies indicate that in this area the speed of propagation of acoustic waves changes sharply, which was interpreted as the beginning of the basalt basement of the earth's crust. However, even after the transition zone, granites and gneisses continued to rise to the surface. From that point on, it became clear that the dominant model of a two-layer crust was wrong. Now the presence of a seismic transition is explained by changes in rock properties under conditions of increased pressure and temperature.
An even more surprising discovery was the fact that rocks located at depths of more than 9 km turned out to be extremely porous. Prior to that, it was believed that as the depth and pressure increased, on the contrary, they should become more and more dense. The miniature cracks were filled with an aqueous solution, whose origin remained completely unclear for a long time. Later, a theory was put forward, according to which the discovered water is formed from hydrogen and oxygen atoms, which are "squeezed" from the surrounding rock under the influence of colossal pressures.
Another surprise: life on planet Earth appeared, it turns out, 1.5 billion years earlier than expected. At a depth of 6.7 km, where it was believed that there was no organic matter, 14 species of fossilized microorganisms were found. They were found in highly uncharacteristic carbon-nitrogen deposits (instead of conventional limestone or silica) that were more than 2.8 billion years old. At even greater depths, where there are no longer sedimentary rocks, methane appeared in huge concentrations. This completely and completely destroyed the theory of the biological origin of hydrocarbons such as oil and gas.
Scientists were also extremely surprised by the rate at which the temperature increased as the well deepened. At the 7 km mark, it reached 120 ° C, and at a depth of 12 km - already 230 ° C, which was a third higher than the planned value: the temperature gradient of the crust was almost 20 degrees per 1 km, instead of the expected 16. It was also found that half of the heat flux is of radiogenic origin. The high temperature negatively affected the bit's performance, so the drilling fluid was cooled before being pumped into the well. This measure turned out to be quite effective, but after passing the 12 km mark, it was no longer able to provide sufficient heat removal. In addition, the compressed and heated rock acquired some properties of a liquid, as a result of which the well began to float with the next extraction of the drill string. Further progress was impossible without new technological solutions and significant cash costs, so in 1994 drilling was suspended. By that time, the well had managed to deepen to 12262 m.

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 superdeep wells, which were made for oil production or geological exploration, SG-3 was drilled exclusively for the study of the lithosphere in the place where the border of Mohorovichich. (abbreviated as the Moho boundary) - the lower boundary of the earth's crust, on 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 were well studied in 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. For mining, 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 basalt. On June 6, 1979, the well broke the record of 9583 meters, previously owned 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 there would be a pronounced boundary between granites and basalts, only granites were found in the core throughout the depth. However, due to the high pressure, the compacted granites greatly changed the physical and acoustic properties. As a rule, the raised core crumbled from active gas release into the cuttings, since it could not withstand a sharp change in pressure. It was possible to pull out a solid piece of core only with a very slow rise of the drill, when the "excess" gas, while still under pressure to a high pressure, had time to come out of the rock. The density of cracks at great depths, contrary to expectations, increased. There was also water at depth, filling the cracks.

It is interesting that when the International Geological Congress was held in Moscow in 1984, at which the first results of the well survey were presented, many scientists jokingly suggested that it be buried immediately, since it destroys all ideas about the structure of the earth's crust. Indeed, the oddities began in the early stages of penetration. For example, even before drilling began, theorists 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, by seven - over 120 degrees, and at a depth of 12 it was frying stronger than 220 degrees - 100 degrees higher than predicted. Kola drillers questioned the theory of the layer-by-layer structure of the earth's crust - at least in the interval up to 12,262 meters.

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

Guberman recalls with regret how many scientific discoveries took place on the Kola superdeep. Literally every meter was a revelation. The well showed that almost all of our previous knowledge about the structure of the earth's crust is wrong. It turned out that the Earth does not at all look like a layer cake.

Another surprise: life on planet Earth appeared, it turns out, 1.5 billion years earlier than expected. At depths where it was believed that there is no organic matter, 14 species of fossilized microorganisms were found - the age of the deep layers exceeded 2.8 billion years. At even greater depths, where there are no longer sedimentary rocks, 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 also almost fantastic sensations. When in the late 70s the Soviet automatic space station brought 124 grams of lunar soil to Earth, the researchers of the Kola Science Center found that it is like two drops of water similar 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 exactly where. By the way, the Americans, who brought half a ton of soil from the Moon, did nothing sensible with it. Placed in sealed containers and left for future generations to research.

Quite unexpectedly for everyone, the predictions of Alexei Tolstoy from the novel "The Hyperboloid of Engineer Garin" were confirmed. At a depth of over 9.5 kilometers, they discovered a real mine of all kinds of minerals, in particular gold. A real olivine layer, brilliantly predicted by the writer. Gold in it is 78 grams 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 any sedimentary rocks, natural gas methane was found in huge concentrations. This completely and completely 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 fictionalized by journalists when checked. 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 Finnish newspaper report. Allegedly, while drilling a well at a depth of 12 thousand meters, the microphones of scientists recorded screams and groans.) Journalists, without even thinking that it is simply not possible to push a microphone to such a depth (what sound recording device can work at temperatures above two hundred degrees?) wrote about the fact 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 each new kilometer drilled brought misfortune to the country. It was said that when the drillers were driving 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 stumbled upon unusual voids. Intrigued by this unexpected discovery, the drillers deployed a microphone capable of operating at extremely high temperatures and other sensors there. The temperature inside allegedly reached 1,100 ° C - there was the heat of the chambers of fire, in which, allegedly, one could hear human screams.

This legend still wanders across the vast expanses of the Internet, having survived the very culprit of these gossip - 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 the well - to "bury". The final abandonment of the well took place in the summer of 2011.
So, as you can see, this time the scientists failed to get to the mantle and examine it. However, this does not mean that the Kola well gave nothing to science - on the contrary, it turned all their ideas about the structure of the earth's crust upside down.

RESULTS

The tasks set in the superdeep drilling project have been completed. Special equipment and technology for ultra-deep drilling, as well as for the study of 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. 8 kilometers. Commercial copper-nickel ores were uncovered there - a new ore horizon was discovered. And very handy, because the local nickel plant is already short of ore.

As noted above, the geological forecast of the well section did not come true. The picture, which was expected during the first 5 km, stretched in the well 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 pass into the stronger basalt layer. In fact, it turned out that there are less strong and less dense fractured rocks - Archean gneisses. This was not supposed in any way. And this is a fundamentally new geological and geophysical information that allows you to interpret the data of deep geophysical research in a different way.

The data on the process of ore formation in the deep layers of the earth's crust also turned out to be unexpected, fundamentally new. Thus, at depths of 9-12 km, highly porous fractured rocks saturated with highly mineralized underground waters were encountered. These waters are one of the sources of ore formation. Previously, it was believed that this is 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 that is considered suitable for industrial development). But will it ever be profitable to mine gold from this depth?

The ideas about the thermal regime of the earth's interior, about the deep distribution of temperatures in the regions of basalt shields have also changed. At a depth of more than 6 km, a temperature gradient of 20оС per 1 km was obtained instead of the expected (as in the upper part) 16оС per 1 km. It was revealed that half of the heat flux is of radiogenic origin.

The bowels 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 a person still does not know exactly what exactly is under our feet deep underground. During the entire existence of earthly civilization, we were able to go deep into the planet a little more than 10 kilometers. This record was set back in 1990 and lasted until 2008, after which it was updated several times. In 2008, the Maersk Oil BD-04A deviated oil well, 12,290 meters long, was drilled (Al-Shahin oil basin in Qatar). In January 2011, an inclined oil well with a depth of 12,345 meters was drilled at the Odoptu-more field (Sakhalin-1 project). The record for drilling depth is currently held by the Z-42 well of the Chayvinskoye field, the depth of which is 12,700 meters.

Candidate of Technical Sciences A. OSADCHIY

Hundreds of thousands of wells have been drilled in the earth's crust in the last decades of the last century. And this is not surprising, because the search and extraction of minerals in our time is inevitably associated with deep drilling. But among all these wells there is one and only one on the planet - the legendary Kola Superdeep (SG), the depth of which still remains unsurpassed - more than twelve kilometers. In addition, the 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 going on in them.

Geologists V. Lanev (left) and Yu. Smirnov examine core samples.

Drill bits. Exactly the same, but exactly the one that was used when drilling at a depth of 12 km, became an exhibit at the 1984 International Geological Congress.

On this hook, a string of pipes was lowered and raised. On the left - in a basket - there are 33-meter pipes - "candles" prepared for descent.

Kola superdeep well.

Selected core samples.

A unique core storage, where cores of the entire twelve-kilometer well are laid out in strict order, numbered, on shelves in boxes.

Such badges were proudly worn by everyone who worked for the SG.

Drilling is not carried out on the Kola superdeep today; 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. From foreign wells, three have reached a depth of 9.1 to 9.6 km. It was planned that one of them (in Germany) would surpass the Kola. However, drilling at all three, as well as at the SG, was stopped due to accidents and cannot be continued for technical reasons.

It can be seen that it is not for nothing that the task of drilling superdeep wells is compared in complexity to a flight into space, with a long space expedition to another planet. Samples of rocks extracted from the earth's interior are of no less interest than samples of lunar soil. The soil delivered by the Soviet lunar rover was examined 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 borehole from a depth of about 3 km.

SELECTING A LOCATION AND FORECAST

A special exploration expedition (Kola GRE) was set up to drill the SG. The drilling site, of course, was also not chosen by chance - the Baltic Shield in the Kola Peninsula region. Here, the oldest igneous rocks, about 3 billion years old, come to the surface (while the Earth is only 4.5 billion years old). It was interesting to drill in the most ancient igneous rocks, because sedimentary rocks up to a depth of 8 km have already been studied quite well in oil production. And in the extraction of minerals, they usually take only 1-2 km into igneous rocks. The choice of the site for the SG was also facilitated by the fact that the Pecheneg trough is located here - a huge bowl-like structure, as it were, pressed into the ancient rocks. Its origin is associated with a deep fault. And it is here that there are large copper-nickel deposits. And the tasks set for the Kola Geological Expedition were to identify a number of features of geological processes and phenomena, including ore formation, to determine the nature of the boundaries separating the layers in the continental crust, to collect data on the material composition and physical state of rocks.

Prior to drilling, a section of the earth's crust was built on the basis of seismological data. It served as a forecast for the appearance of those earth layers that the well crossed. It was assumed that there is a granite stratum to a depth of 5 km, after which stronger and more ancient basalt rocks were expected.

So, we chose the north-west of the Kola Peninsula, 10 km from the town of Zapolyarny, not far from our border with Norway, as the drilling site. 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 winds and blizzards, there is a "square", each side of which is formed of seven five-storey buildings. Inside there are two streets, at their intersection is the square where the House of Culture and the hotel are. A kilometer from the town, behind a ravine, one can see the buildings and tall pipes of a nickel plant; behind it, along the slope of the mountain, waste rock heaps from the nearest quarry darken. Near the town there is a highway to the town of Nikel and to a small lake, on the other side of which there is already Norway.

The land of those places keeps the traces of the past war in abundance. When you go by bus from Murmansk to Zapolyarny, about half 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 during the war from 1941 to 1944 stood motionless, abutting against the Barents Sea. Although there were fierce battles all the time and losses on both sides were huge. The Germans unsuccessfully tried to get 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 further climbs up the hill. A small hollow opens from the pass, in which the drilling is installed. Its height is about a twenty-story building. For each shift, "shift workers" came here from Zapolyarny. In total, about 3,000 people worked on the expedition; they lived in the city in two houses. From the drilling rig, the grumbling of some mechanisms could be heard around the clock. Silence meant that for some reason there was a break in drilling. In winter, on the long polar night - and it lasts there from 23 November to 23 January - the entire rig was lit with lights. Often the light of the aurora was added to them.

A little about the staff. The Kola exploration expedition, created for drilling, has gathered a good, highly qualified team of workers. D. Guberman was almost always the head of the GRE, a talented leader who had selected the team. Chief engineer I. Vasilchenko was in charge of drilling. The drilling rig was commanded by A. Batishchev, whom everyone simply called Lehoy. V. Lanei was in charge of geology, and Yu. Kuznetsov was in charge of geophysics. Geologist Yu. Smirnov, the one who had the "cherished locker", which we will talk about later, carried out a huge amount of work on processing the core and creating the core storage. More than 10 research institutes took part in the research at the SG. The team also had their own "kulibins" and "left-handers" (S. Tserikovsky was especially distinguished), who invented and manufactured various devices, sometimes allowing to get out of the most difficult, seemingly hopeless situations. They themselves created many of the necessary mechanisms here in well-equipped workshops.

DRILLING HISTORY

Well drilling began in 1970. It took 4 years to drill to a depth of 7263 m. It was run by a serial installation, which is usually used in oil and gas production. Due to the constant winds and cold, the entire tower had to be sheathed up to the top with wooden shields. Otherwise, it is simply impossible for someone who has to stand at the top while lifting the pipe string.

Then there was a year-long break associated with the construction of a new derrick and the installation of a specially designed drilling rig - "Uralmash-15000". It was with her help that all further superdeep drilling was carried out. The new plant has more powerful automated equipment. Turbine drilling was used - this is when not the entire string rotates, but only the drill head. Drilling fluid was fed through the string under pressure to rotate a multistage turbine at the bottom. Its total length is 46 m. The turbine ends with a drill head with a diameter of 214 mm (it is often called a bit), which has an annular 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 together with the drilling fluid is carried through the well to the surface.

The mass of the string, immersed in the borehole with drilling fluid, is about 200 tons. This is despite the fact that specially designed pipes made of light alloys were used. If the column is made of ordinary steel pipes, it will burst from its own weight.

Difficulties, sometimes completely unexpected, arise in the process of drilling at great depths and with coring.

Driving in one trip, determined by the wear of the drill head, is usually 7-10 m. (A trip, or cycle, is the descent of a string with a turbine and a drilling tool, the actual drilling and full lift of the string.) The drilling itself takes 4 hours. And the descent and ascent of a 12-kilometer column takes 18 hours. When lifting, the string is automatically disassembled into sections (plugs) 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 degree of their wear.

To a depth of approximately 7 km, the borehole intersected solid, relatively homogeneous formations, and therefore the borehole was flat, almost corresponding to the diameter of the drill head. The work progressed, one might say, calmly. However, at a depth of 7 km, less strong fractured rocks, interbedded with small very hard interlayers of rocks - gneisses, amphibolites, appeared. Drilling has become difficult. The barrel 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 based on the drilling data. It is interesting to note (column B) that the inclination of the formations along the well is about 50 degrees. Thus, it is clear that the rocks traversed by the borehole come to the surface. It is here that one can recall the already mentioned "cherished locker" of the geologist Yu. Smirnov. There, on one side, he had samples obtained from the borehole, and on the other, samples taken from the surface at the distance from the drilling site, where the corresponding layer exited. The coincidence of the breeds is almost complete.

1983 was marked by an unrivaled record so far: the drilling depth exceeded 12 km. The work was suspended.

The International Geological Congress was approaching, which, according to the plan, was held in Moscow. The Geoexpo exhibition was being prepared for it. It was decided not only to read the reports on the results achieved at the SG, but also to show the participants of the congress the work in nature and the samples of rock obtained. 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 - reaching a record depth. There were impressive graphics describing drilling techniques and technologies, rock samples extracted, photographs of equipment and the team at work. But the greatest attention of the participants and guests of the congress was attracted by one unconventional detail for the exhibition: the most common and already slightly rusted drill head with worn out carbide teeth. The label said that it was she who was used when drilling at a depth of more than 12 km. This drill head amazed even the experts. Probably, everyone unwittingly expected to see some kind of miracle of technology, maybe with diamond equipment ... And they still did not know that a large pile of exactly the same already rusted drill heads was assembled on the SG next to the drilling rig: 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 facility on the Kola Peninsula and make sure that a record drilling depth has really been achieved in the Union. This departure took place. There, a meeting of the section of the congress was held on the spot. The delegates were shown the rig, with them lifting the string from the well, disconnecting the 33-meter sections from it. Photos and articles about the SG have made it to 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 the 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 largest accident on the first flight on September 27, 1984 - the "black date" in the history of the SG. A well does not forgive when it is left unattended for a long time. During the time that drilling was not carried out, changes in its walls, those that were not fixed by a cemented steel pipe, inevitably occurred.

At first everything went casually. The drillers carried out their usual operations: one by one they lowered the sections of the drill string, to the last, upper one, they connected a pipe for supplying drilling fluid, and turned on the pumps. Drilling started. The instruments on the control panel in front of the operator showed the normal operating mode (the number of revolutions of the drill head, its pressure on the rock, the flow rate of fluid for the rotation of 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. Prepared for the rise of the column. We tried it. Doesn't go. At such depths, "sticking" has been observed more than once. This is when some section of the column seems to stick to the walls (maybe something crumbled from above, and it got a little jammed). To move the column from its place, an effort is required in excess of its weight (about 200 tons). So they did this time, but the column did not move. The effort was added a little, and the needle of the device sharply slowed down the readings. The column has greatly improved, such a loss of weight during the normal course of the operation could not be. We started lifting: one by one, the sections were unscrewed one after the other. On the last climb, a shortened piece of pipe with an uneven bottom edge hung from the hook. This meant that not only the turbodrill was left in the well, but also 5 km of drill pipes ...

We 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 return what was lost were stopped and they began to drill 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 tested by trial and error. And starting from a depth of about 10 km is even more difficult. Drilling, equipment and instrumentation are operating at their maximum conditions.

Therefore, accidents here have to wait any minute. They are preparing for them. They think over the methods and means of their elimination in advance. A typical complex accident is a breakage of a drilling assembly along with a part of the drill string. The main method of its elimination is to create a ledge just above the lost part and from this place drill a new bypass hole. A total of 12 such by-pass bores were drilled in the well. Four of them are from 2,200 to 5,000 meters long. The main cost of such accidents is the years of lost labor.

Only in everyday life, a well is 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 crosses inclined formations of various densities. Then it seems to wriggle, because the drill is constantly deviating in the direction of less durable rocks. After each measurement, showing that the inclination of the well exceeds the permissible one, it is necessary to try to "put it back in place". To do this, together with the drilling tool, special "diverters" are lowered, which help to reduce the angle of inclination of the well during drilling. Accidents with the loss of drilling tools and pipe parts are not uncommon. After that, the new trunk has to be done, as we have already said, stepping aside. So imagine what a well looks like in the ground: something like the roots of a giant plant branched at a depth.

This is the reason for the special duration of the last phase of drilling.

After the largest accident - the "black date" of 1984 - they again came to a depth of 12 km only 6 years later. In 1990, the maximum was reached - 12,262 km. After several more accidents, we made sure that we could not penetrate deeper. All the possibilities of modern technology have been exhausted. It seemed as if the Earth no longer wants to reveal its secrets. Drilling was stopped in 1992.

RESEARCH. OBJECTIVES AND METHODS

One of the very important drilling goals was to obtain a core core of the rock samples along the entire length of the borehole. And this task has been accomplished. The world's longest core was marked out like a ruler by meters and laid in the appropriate order in boxes. Above are the box number and sample numbers. There are almost 900 such boxes in stock.

Now it remains only to study the core, which is really irreplaceable in determining the structure of the rock, its composition, properties, age.

But a rock sample raised to the surface has different properties than in the massif. Here, above, he is freed from the enormous mechanical stresses that exist at depth. During drilling, it cracked and was saturated with drilling fluid. Even if the deep conditions are recreated in a special chamber, the parameters measured on the sample are still different from those in the array. And one more little "catch": for every 100 m of the drilled well, 100 m of core is not received. On the SG, from depths of more than 5 km, the average core recovery was only about 30%, and from depths of more than 9 km, these were sometimes only separate plaques 2-3 cm thick, corresponding to the most durable interlayers.

So, the core raised on the SG from the well does not provide complete information about the deep rocks.

Wells were drilled for scientific purposes, therefore, the whole range of modern research methods was used. In addition to core extraction, studies of the properties of rocks in their natural occurrence were necessarily carried out. We constantly monitored the technical condition of the well. 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.

Serial instruments were used to a depth of 7 km. Work at great depths and at higher temperatures required the creation of special heat-resistant devices. Particular difficulties arose during the last stage of drilling; when the temperature in the well approached 200 ° C, and the pressure exceeded 1000 atmospheres, the serial devices could no longer work. Geophysical design bureaus and specialized laboratories of several research institutes came to the rescue, which produced single copies of heat-and-pressure-resistant instruments. Thus, all the time they worked only on domestic equipment.

In short, the well was investigated in sufficient detail to its entire depth. The studies were carried out in stages, approximately once a year, after deepening the well by 1 km. Each time thereafter, an assessment was made of the reliability of the materials obtained. Corresponding calculations made it possible to determine the parameters of a particular breed. We discovered a certain alternation of layers and already knew to which rocks the caverns and the associated partial loss of information are confined. We learned how to identify rocks literally by "crumbs" and, on this basis, recreate a complete picture of what the well "hid". In short, it was possible to build a detailed lithological column - to show the alternation of rocks and their properties.

FROM OWN EXPERIENCE

Approximately 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. The well was usually flushed out at this time and allowed for research for a month. The scheduled stop time was always known in advance. The telegram-call for work also came in advance. The equipment is checked and packaged. The 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 developer of a downhole tool, a developer of new ground equipment, and I am a methodologist. We arrive 10 days before the measurements. We are getting acquainted with the data on the technical condition of the well. We draw up and approve a detailed measurement program. We collect and calibrate the equipment. We are waiting for a call - a call from the well. Our turn to "dive" is the third, but if the predecessors refuse, the well will be provided to us. This time they are all right, they say that they will finish by tomorrow morning. With us, in the same team of geophysicists, operators who register the signals received from the equipment in the well, and command all operations for lowering and lifting the downhole tool, as well as mechanics on the hoist, they control the unwinding and winding of the same 12 km of cable from the drum , on which the tool is lowered into the well. Drillers are also on duty.

The work has begun. The tool is lowered into the well for several meters. The 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. So something is wrong. Full rise. (Just in case, we have prepared the second set of equipment.) We start checking all the details. This time the cable was faulty. It is being replaced. This takes more than a day. The new descent took 10 hours. Finally, the observer of the signal reported: "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 in a given interval in order to take measurements. This time the equipment worked fine. Now full recovery. We went up 3 km, and suddenly a call from the swan (he is a man with humor): "The rope is over." How?! What?! Alas, the cable was broken ... The downhole tool and 8 km of cable were left lying at the bottom ... Fortunately, a day later the drillers managed to lift all this, using the techniques and devices developed by local craftsmen to eliminate such emergencies.

RESULTS

The well gave an excellent gift to the homeland at a shallow depth - in the interval of 1.6-1.8 km. Commercial copper-nickel ores were uncovered there - a new ore horizon was discovered. And very handy, because the local nickel plant is already short of ore.

As noted above, the geological forecast of the well section did not come true (see figure on page 39.). The picture, which was expected during the first 5 km, stretched in the well 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 pass into the stronger basalt layer. In fact, it turned out that there are less strong and less dense fractured rocks - Archean gneisses. This was not supposed in any way. And this is a fundamentally new geological and geophysical information that allows you to interpret the data of deep geophysical research in a different way.

The ideas about the thermal regime of the earth's interior, about the deep distribution of temperatures in the regions of basalt shields have also changed. At a depth of more than 6 km, a temperature gradient of 20 о С per 1 km was obtained instead of the expected (as in the upper part) 16 о С per 1 km. It was revealed that half of the heat flux 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.

A. OSADCHIY, Candidate of Technical Sciences.

LITERATURE

Kola superdeep. Moscow: 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 USSR, they loved the scale, but more, and this extended to literally everything. So one well was dug in the Union, which even today bears the title of the deepest on earth. It is noteworthy that the well was drilled not for oil production or geological exploration, but purely for scientific research.

The tips with which the well was drilled.

The Kola Superdeep Borehole, or SG-3, is the deepest man-made borehole in the earth. Located in the Murmansk region, 10 kilometers from the city of Zapolyarny, in the western direction. The depth of the hole is 12,262 meters. Its diameter at the top is 92 centimeters. At the bottom - 21.5 centimeters. An important feature of SG-3 is that, unlike any other wells for oil production or geological work, this one was drilled exclusively for scientific purposes.

The well was laid in 1970, on the occasion of the 100th anniversary of the birth of Vladimir Lenin. The site chosen is notable for the fact that the well was drilled in over 3 billion years old volcanic rocks that surface. By the way, the age of the Earth is about 4.5 billion years. In the extraction of minerals, wells are rarely drilled deeper than two thousand meters.

The work went on day and night.

Drilling began on May 24, 1970. Up to 7 thousand meters, drilling was easy and calm, but after hitting the head in less dense rocks, problems began. The process has slowed down significantly. Only on June 6, 1979, a new record was set - 9583 meters. It was previously installed in the United States by oil producers. The mark of 12,066 meters was passed in 1983. The result was achieved by the International Geological Congress, which was held in Moscow. Subsequently, two accidents occurred at the complex.

Now the complex looks like this.

In 1997, several legends were circulated in the media at once that the Kola superdeep well is the real road to hell. In one of these legends, it was said that when the team lowered the microphone to a depth of several thousand meters, human screams, groans and screams were heard there.

Of course, there was nothing of the kind. If only because special equipment is used to record sound in the borehole at such a depth, but it did not record anything either. There were indeed several accidents at the complex, including an underground explosion during drilling, but the geologists did not disturb any underground "demons" for sure.

The well itself has been mothballed.

What is really important is that 16 research laboratories operated on SG-3. During the Soviet era, Russian geologists were able to make many valuable discoveries and better understand how our planet works. The work on the site has significantly improved the drilling technology. Scientists were also able to understand local geological processes, received comprehensive data on the thermal regime of the subsoil, underground gases and deep waters.

Unfortunately, today the Kola superdeep well is closed. The building of the complex has been dilapidated since the last laboratory was closed here in 2008 and all equipment has been dismantled. The reason is simple - lack of funding. In 2010, the well was already suspended. Now it is slowly but surely collapsing under the influence of natural processes.