Depth of the Kola. Where is the deepest oil well
Hundreds of thousands of wells have been drilled in 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 is inevitably associated with deep drilling. But among all these wells there is only one on the planet - the legendary Kola Superdeep (SG), the depth of which is still 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.
Today, no drilling is carried out at the Kola Superdeep, it was stopped in 1992. SG was not the first and not the only one in the program of studying the deep structure of the Earth. Of the foreign wells, three reached depths of 9.1 to 9.6 km. It was planned that one of them (in Germany) would surpass the Kola. However, drilling on all three, as well as on the SG, was stopped due to accidents and technical reasons until it can be continued.
It can be seen that it is not in vain that the tasks of drilling ultra-deep wells are compared in complexity with a flight into space, with a long-term 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 FORECAST
A special exploration expedition (Kola GRE) was created to drill the SG. The place of drilling was also, of course, not chosen by chance - the Baltic Shield in the area of the Kola Peninsula. Here, the oldest igneous rocks with an age of about 3 billion years come to the surface (and the Earth is only 4.5 billion years old). It was interesting to drill in the most ancient igneous rocks, because the sedimentary rocks to a depth of 8 km have already been well studied in oil production. And in igneous rocks during mining, they usually get only 1-2 km. The choice of a place 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 it is here that 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.
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 a granite sequence extends to a depth of 5 km, after which stronger and more ancient basalt rocks were expected.
So, the north-west of the Kola Peninsula, 10 km from the city of Zapolyarny, not far from our border with Norway, was chosen 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 the winds and snowstorms, there is a "square", each side of which is formed from seven five-story houses. 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 the ravine, the buildings and tall chimneys of the nickel plant are visible, behind it, along the mountain slope, waste rock dumps from the nearest quarry darken. Near the town there is a highway to the city of Nikel and to a small lake, on the other side of which is already Norway.
The land of those places in abundance keeps traces of the past war. When you travel by bus from Murmansk to Zapolyarny, about half 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, resting against the Barents Sea. Although there were fierce battles all the time and the losses on both sides were huge. The Germans tried unsuccessfully 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.
On this hook, a string of pipes was lowered and raised. On the left - in a basket - there are 33-meter pipes prepared for descent - "candles".
Kola superdeep well. In the figure on the right: A. Forecast of the geological section. B. Geological section constructed on the basis of SG drilling data (arrows from column A to column B indicate at what depth the predicted rocks are encountered). In this section, the upper part (up to 7 km) is a Proterozoic sequence with layers of volcanic (diabase) and sedimentary rocks (sandstones, dolomites). Below 7 km there is an Archean stratum with repeating rock units (mainly gneisses and amphibolites). Its age is 2.86 billion years. C. The borehole with many drilled and lost boreholes (below 7 km) is shaped like the branched roots of a giant plant. The well seems to meander, because the drill is constantly deviated towards less durable rocks.
From Zapolyarny to Superdeep - 10 km. The road goes past the plant, then along the edge of the quarry and then climbs uphill. A small basin opens from the pass, in which a drilling rig is installed. Its height is from a twenty-story building. "Shift workers" came here from Zapolyarny to 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 was heard around the clock from the drilling rig. Silence meant that for some reason there was a break in drilling. In winter, during the long polar night - and it lasts there from November 23 to January 23 - the entire drilling rig was lit up with lights. Often, the light of the aurora was added to them.
A little about the staff. A good, highly qualified team of workers gathered in the Kola geological exploration expedition, created for drilling. D. Huberman was almost always the head of the GRE, a talented leader who selected the team. Chief engineer I. Vasilchenko was responsible for drilling. The rig was commanded by A. Batishchev, whom everyone called simply Lekha. V. Laney was in charge of geology, and Yu. Kuznetsov was in charge of geophysics. Huge work on core processing and creation of the core storage was carried out by geologist Yu. Smirnov - the one who had the "cherished locker", which we will tell about later. More than 10 research institutes took part in the research on the SG. The team also had its own "kulibins" and "left-handers" (S. Tserikovsky was especially distinguished), who invented and manufactured various devices, sometimes allowing them 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
Drilling of the well began in 1970. Sinking to a depth of 7263 m took 4 years. It was driven by a serial installation, which is usually used in the extraction of oil and gas. Because of the constant winds and cold, the entire tower had to be sheathed to the top with wooden shields. Otherwise, it is simply impossible for someone who must stand at the top during the lifting of the pipe string to work.
Then there was a one-year 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 ultra-deep drilling was carried out. The new installation 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 column under pressure, which rotated the multi-stage turbine below. Its total length is 46 m. The turbine ends with a drilling head with a diameter of 214 mm (it is often called a crown), 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 along the well to the surface.
On the core samples on the right, oblique stripes are clearly visible, which means that here the well passed through the layers located obliquely.
The mass of the string immersed in the well with drilling fluid is about 200 tons. This despite the fact that specially designed pipes made of light alloys were used. If the column is made of ordinary steel pipes, it will break from its own weight.
There are many difficulties, sometimes completely unexpected, in the process of drilling at great depths and with the selection of cores.
Penetration in one trip, determined by the wear of the drill head, is usually 7-10 m. (A trip, or a cycle, is the descent of a string with a turbine and a drilling tool, the actual drilling and a complete rise of the string.) The drilling itself takes 4 hours. And the descent and ascent of the 12-kilometer column takes 18 hours. When lifting, the string is automatically disassembled into sections (stands) 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. That's how worn they are.
Up to a depth of about 7 km, the well crossed strong, relatively homogeneous rocks, and therefore the wellbore was flat, almost corresponding to the diameter of the drill head. Work progressed, one might say, calmly. However, at a depth of 7 km, less strong fractured, interbedded with small very hard interlayers of rocks - gneisses, amphibolites - went. Drilling has become more difficult. The trunk took an oval shape, many cavities appeared. Accidents have become more frequent.
The figure shows the initial forecast of the geological section and the one made on the basis of drilling data. It is interesting to note (column B) that the formation inclination along the well is about 50 degrees. Thus, it is clear that the rocks intersected by the well come to the surface. It is here that one can recall the already mentioned "cherished locker" of the geologist Y. Smirnov. There, on one side, he had samples obtained from the well, and on the other, taken on the surface at that distance from the drilling rig, where the corresponding layer goes up. The coincidence of breeds is almost complete.
The year 1983 was marked by a hitherto unsurpassed record: the drilling depth exceeded 12 km. Work has been 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 congress participants the work in kind 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 a record depth. There were impressive graphs telling about the technique and technology of drilling, mined rock samples, photographs of equipment and the team at work. But the greatest attention of participants and guests of the congress was attracted by one non-traditional detail for an exhibition show: the most common and already slightly rusted drill head with worn 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 specialists. Probably, everyone involuntarily 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 drilling heads was assembled on the SG next to the drilling rig: after all, they had to be replaced with new ones for about every 7-8 meters drilled.
Many congress delegates wanted to see with their own eyes the unique drilling rig on the Kola Peninsula and make sure that a record drilling depth had indeed been achieved in the Union. Such a departure took place. There, a meeting of the congress section was held on the spot. The delegates were shown the drilling rig, while they were lifting a string from the well, disconnecting 33-meter sections from it. Photos and articles about the SG were published in newspapers and magazines in almost all countries of the world. A postage stamp was issued, special cancellation of envelopes was organized. I will not list the names of the winners of various awards and those awarded for their work ...
But the holidays were over, we had to continue drilling. And it began with the largest accident on the very first flight on September 27, 1984 - a "black date" in the history of the SG. The well does not forgive when it is left unattended for a long time. During the time until drilling was carried out, changes inevitably occurred in its walls, those that were not fixed with a cemented steel pipe.
At first everything went smoothly. 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 the drilling fluid supply pipe, turned on the pumps. We started drilling. The instruments on the console in front of the operator showed the normal mode of operation (the number of revolutions of the drill head, its pressure on the rock, the fluid flow rate for the rotation of the turbine, etc.).
Having drilled another 9-meter segment at a depth of more than 12 km, which took 4 hours, they reached a depth of 12.066 km. Prepare for the rise of the column. We tried. 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 jammed a little). To move the column from its place, a force exceeding its weight (about 200 tons) is required. So did this time, but the column did not move. We added a little effort, and the arrow of the device sharply slowed down the readings. The column became much lighter, there could not have been such a weight loss during the normal course of the operation. We began to rise: one by one, the sections were unscrewed one after the other. During the last ascent, a shortened piece of pipe with an uneven bottom edge hung on a hook. This meant that not only the turbodrill, but also 5 km of drill pipes remained in the well...
Seven months trying to get them. After all, we lost not just 5 km of pipes, but the results of five years of work.
Then all attempts to return the lost were stopped and they began to drill again from a depth of 7 km. I must say 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 - even more difficult. Drilling, operation of equipment and equipment are at the limit.
Therefore, accidents here have to be expected at any moment. They are preparing for them. Methods and means of their elimination are thought over in advance. A typical complex accident is a breakage of the drilling assembly along with part of the drill string. The main method of eliminating it is to create a ledge just above the lost part and from this place to drill a new bypass hole. A total of 12 such bypass holes were drilled in the well. Four of them are from 2200 to 5000 m long. The main cost of such accidents is years of lost labor.
Only in the everyday view, 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 ultra-deep and crosses inclined seams of various densities. Then it seems to meander, because the drill constantly deviates towards less durable rocks. After each measurement, showing that the inclination of the well exceeds the allowable one, it must be tried to "return to its place". To do this, together with the drilling tool, special "deflectors" are lowered, which help to reduce the angle of inclination of the well during drilling. Accidents often occur with the loss of drilling tools and parts of pipes. After that, a 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 approached a depth of 12 km only after 6 years. In 1990, a maximum was reached - 12,262 km. After a few more accidents, we were convinced that we couldn’t get deeper. All the possibilities of modern technology have been exhausted. It seemed as if the Earth no longer wanted to reveal its secrets. Drilling was stopped in 1992.
RESEARCH WORK. OBJECTIVES AND METHODS
One of the very important goals of drilling was to obtain a core column of rock samples along the entire length of the borehole. And this task has been completed. The longest core in the world was marked out like a ruler in 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 it remains only to study the core, which is really 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 mud. Even if deep conditions are recreated in a special chamber, the parameters measured on the sample still differ from those in the array. And one more small "hack": for every 100 m of a drilled well, 100 m of core are not obtained. 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 individual plaques 2-3 cm thick, corresponding to the most durable interlayers.
So, the core taken from the well on the SG does not provide complete information about deep rocks.
The wells were drilled for scientific purposes, so the whole complex was used modern methods research. In addition to extracting the core, studies of the properties of rocks in their natural occurrence were necessarily carried out. The technical condition of the well was constantly monitored. The temperature was measured throughout the wellbore, natural radioactivity - gamma radiation, induced radioactivity after pulsed neutron irradiation, electrical and magnetic properties of rocks, elastic wave propagation velocity, and the composition of gases in the well fluid.
To a depth of 7 km, serial instruments were used. Work at great depths and at more high 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°C and the pressure exceeded 1000 atmospheres, the serial instruments could no longer work. The geophysical design bureaus and specialized laboratories of several research institutes came to the rescue, producing single copies of thermal pressure-resistant instruments. Thus, all the time they worked only on domestic equipment.
In a word, 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 after that, the reliability of the received materials was assessed. Appropriate calculations made it possible to determine the parameters of a particular breed. We discovered a certain alternation of layers and already knew what rocks the caverns are confined to and the partial loss of information associated with them. We learned to identify rocks literally by "crumbs" and on this basis to recreate a complete picture of what the well "hidden". In short, we managed 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 the measurements that I was entrusted with. The well at this time was usually washed out and provided for research for a month. The time of the planned stop was always known in advance. The telegram-call for work also came in advance. The equipment has been 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 downhole tool developer, a developer of new ground equipment, and I am 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 equipment. We are waiting for a call - a call from the well. Our turn to "dive" is the third, but if there is a refusal from the predecessors, the well will be provided to us. This time they are all right, they say that tomorrow morning they will finish. We are in the same team of geophysicists - operators who record the signals received from the equipment in the well and command all operations for lowering and raising the downhole tool, as well as mechanics on the lift, they control the winding from the drum and winding on it those same 12 km of cable on which the tool is lowered into the well. Drillers are also on duty.
Work has begun. The device is lowered into the well for 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. So 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 was faulty. He is being replaced. This takes more than a day. The new descent took 10 hours. Finally, the observer of the signal said: "Arrived at the eleventh kilometer." Command to operators: "Start recording". What and how is pre-scheduled 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 lift. We climbed up to 3 km, and suddenly the call of the winch (he is our man with humor): "The rope is over." How?! What?! Alas, the cable broke... The downhole tool and 8 km of cable were left lying at the bottom... Fortunately, a day later, the drillers managed to pick it all up, using the methodology and devices developed by local craftsmen to eliminate such emergencies.
RESULTS
The tasks set in the ultra-deep drilling project have been fulfilled. Special equipment and technology for ultra-deep drilling, as well as for the study of wells drilled to a great depth, 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 the core to a depth of 12,262 m.
The well gave out an excellent gift to the motherland at a shallow depth - in the range of 1.6-1.8 km. Industrial copper-nickel ores were discovered there - a new ore horizon was discovered. And very handy, because the local nickel plant is already running out of ore.
As noted above, the geological forecast of the well section did not come true (see the figure on page 39.). The picture that was expected during the first 5 km in the well stretched 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 most reflection in seismic sounding is the level where the granites pass into a more durable basalt layer. In reality, it turned out that less durable and less dense fractured rocks - Archean gneisses - are located there. This was not expected at all. And this is a fundamentally new geological and geophysical information that allows you to interpret the data of deep geophysical surveys 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 and fundamentally new. So, at depths of 9-12 km, highly porous fractured rocks saturated with underground highly mineralized waters were encountered. 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 that is considered suitable for industrial development). But will it ever be profitable to mine gold from such a depth?
The ideas about the thermal regime of the earth's interior, about the deep distribution of temperatures in the areas of basalt shields, have also changed. At a depth of more than 6 km, a temperature gradient of 20°C per 1 km was obtained instead of the expected (as in the upper part) 16°C per 1 km. It was revealed that half of the heat flux is of radiogenic origin.
Having drilled the unique Kola super-deep 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. OSADCHI.
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.
Sredao.ru cottage settlements from HABITAT
Sredao.ru townhouses from real estate agency HABITAT
In the USSR, they loved the scale, but more, and this applied to literally everything. So one well was dug in the Union, which today bears the title of the deepest on earth. It is noteworthy that the well was not drilled for oil production or geological exploration, but purely for scientific research.
Tips used to drill a well.
The Kola super-deep well, or SG-3, is the deepest man-made well in the earth. It is located in the Murmansk region, 10 kilometers from the city of Zapolyarny, in a 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 SG-3 is that, unlike any other wells for oil production or geological work, this one was drilled solely for scientific purposes.
The well was laid in 1970, on the occasion of the 100th anniversary of the birth of Vladimir Lenin. The chosen location is remarkable in that the well was drilled in outcropping volcanic rocks more than 3 billion years old. By the way, the age of the Earth is about 4.5 billion years. When mining, wells are rarely drilled deeper than two thousand meters.
The work went on for days on end.
Drilling began on May 24, 1970. Up to the mark of 7,000 meters, drilling proceeded easily and calmly, but after the head hit the less dense rocks, problems began. The process has slowed down considerably. Only on June 6, 1979 a new record was set - 9583 meters. It was previously installed in the US 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 super-deep well was the real road to hell. One of these legends 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 a well at such a depth - but it did not record anything either. There have indeed been several accidents at the complex, including underground explosion during drilling, however, geologists definitely did not disturb any underground "demons".
The well itself is mothballed.
It is really important that 16 research laboratories worked at SG-3. At times Soviet Union domestic geologists were able to make many valuable discoveries and better understand how our planet works. The work at the site allowed to significantly improve the drilling technology. The scientists were also able to understand the local geological processes, received comprehensive data on the thermal regime of the bowels, underground gases and deep waters.
Unfortunately, today the Kola super-deep well is closed. The building of the complex has been deteriorating since the last laboratory was closed here in 2008, and all equipment was dismantled. The reason is simple - lack of funding. In 2010, the well was already mothballed. Now it is slowly but surely destroyed under the influence of natural processes.
I want to tell you about the famous super-deep well Kolskaya. It is unlikely that many people knew (like me, until my father told me) that the Kola SG-3 well is the deepest drilled well in the world (until 2008). While still studying at the institute, the teachers carried legends about the Kolskaya well from corner to corner, although many of our teachers had nothing to do with drilling, etc. at all.
General review:
Kola Superdeep Well ( SG-3) is the deepest borehole in the world. It is located in the Murmansk region, 10 kilometers west of the city of Zapolyarny, on the territory of the geological Baltic Shield. Its depth is 12,262 meters. Unlike other ultra-deep wells that were made for oil production or exploration, SG-3 was drilled exclusively for the study of the lithosphere in the place where the Mohorovichic boundary comes close to the Earth's surface.
It was also the deepest well until 2008 when it was bypassed by the 12,290 meter Maersk Oil BD-04A oil well drilled at an acute angle to the ground (located in the Al Shaheen Oil Basin, Qatar), after which in January 2011 this the well was also bypassed by the oil well of the Odoptu-Sea field of the Sakhalin-1 project, also drilled at an acute angle to the surface of the earth, with a length of 12,345 meters.
Well from the point of view of science:
When, at the end of the last century, the drilling of the famous Kola super-deep well was started, the media wrote that in the very thickness of the earth, the microphones of scientists recorded screams and groans ... Is the Hell really there? Like it or not, but what the researchers saw radically changed the traditional ideas about the structure of the upper layer of the Earth.
For a long time, people have tried to understand how the bowels of our planet are arranged. However, for a long time it was not possible to drill the earth's firmament more than a few hundred meters - there was no necessary equipment. Therefore, all ideas about internal structure Earths are based mainly on theoretical calculations, which have not yet been confirmed by experimental data.
According to the generally accepted point of view, the Earth consists of three large layers: the core, the mantle and the earth's crust. In the center is the core, divided into the inner hard area(with a radius of about 1300 km) and a liquid outer core with a radius of about 2200 km, between which a transition zone is sometimes distinguished. It is believed that this region of the planet is composed of an iron-nickel alloy.
Next is the mantle - a layer consisting of silicates of magnesium, iron, calcium and other metals. It extends from depths of 5-70 kilometers below the boundary with the earth's crust, to the boundary with the core at a depth of 2900 km. It is believed that the mantle is quite hot and in some of its layers the substance is in a molten state.
The upper layers of the mantle are in contact with the earth's crust - the very layer on which we, in fact, live. The thickness of this outer shell varies from several kilometers (in the oceanic regions) to several tens of kilometers (in the mountainous regions of the continents). The sphere of the earth's crust is very small, accounting for only about 0.5% of the total mass of the planet. The main composition of the crust is oxides of silicon, aluminum, iron and alkali metals.
It is believed that in the composition of the continental crust, which contains the upper (granite) and lower (basalt) layers under the sedimentary layer, there are the most ancient rocks of the Earth, whose age is estimated at more than 3 billion years. The oceanic crust is younger and thinner - under the accumulation of sediments (their age does not exceed 100-150 million years) there is only one layer, close in composition to basalt.
It turns out that for the entire time of their existence, people have not really been able to explore even the earth's crust, and for many years none of the scientists even dared to dream of "feeling" the mantle or the core. However, in the middle of the 20th century, the equipment necessary for such research was finally developed, and the dream began to turn into reality.
Projects for traveling deep into the Earth appeared in the early 60s of the last century in several countries at once. They tried to drill wells in those places where the earth's crust should have been thinner, since the purpose of such drilling was to reach the mantle, which, in fact, they were going to explore in detail.
For example, the Americans drilled in the area of the island of Maui, Hawaii, where, according to seismic studies, ancient rocks go under the ocean floor and the mantle is located at a depth of about five kilometers (under a four-kilometer water column). Nevertheless, not a single ocean drilling rig deeper than 3 kilometers could break through.
In general, almost all ultra-deep well projects mysteriously ended at a depth of three kilometers. It was at this moment that something strange began to happen to the Boers: either they fell into unexpected areas with high temperatures, or they seemed to be bitten off by some mysterious underground demon. So in most cases it was not even possible to study the composition of the deep layers of the earth's crust, not to mention the mantle, the study of which, in fact, was the real goal of such studies.
Start drilling:
Kolskaya drilling. Residential town and auxiliary workshops
And so, in 1970, drilling of the famous Kola well began on the Kola Peninsula. The drilling point was chosen in this place of the peninsula not by chance - the peninsula is located on the so-called Baltic Shield, which is composed of the most ancient rocks known to mankind. Work on this object was carried out from 1970 to 1992, during which time it was possible to "pierce" the earth's crust by 12,262 meters.
Interestingly, when the International Geological Congress was held in Moscow in 1984, at which the first results of the well research were presented, many scientists jokingly suggested that it be immediately buried, since it destroys all ideas about the structure of the earth's crust. Indeed, oddities began even at the first stages of penetration. So, for example, theorists had promised even before drilling began that the temperature of the Baltic Shield would remain relatively low to a depth of at least 15 kilometers. Accordingly, it will be possible to dig a well up to almost 20 kilometers, just up to the mantle.
However, already at a depth of five kilometers, the ambient temperature exceeded 700C, at seven - over 1200C, and at a depth of 12 kilometers, the sensors recorded as much as 2200C - 1000C higher than predicted. Scientists have not yet found an explanation for this phenomenon.
The well also did not confirm the idea of the structure of the earth's crust in the likeness of a layer cake - first sedimentary rocks, then granites, and basalts at the bottom. However, according to the drillers, the granites turned out to be 3 kilometers lower than the scientists expected. And there was no basalt layer at all - the last 6 kilometers made their way exclusively through granite. Scientists believe that the Kola drillers, without realizing it, made a discovery that is extremely important for all mankind.
The Kola superdeep well gave the researchers another surprise: life on planet Earth arose, it turns out, 1.5 billion years earlier than expected. At depths where it was believed that there was no organic matter, 14 types of fossilized microorganisms were found, and in fact the age of these deep layers exceeded 2.8 billion years. But, most surprisingly, at even greater depths, where there are no sedimentary rocks, natural gas methane was found in huge concentrations. This completely and utterly destroyed the theory of the biological origin of hydrocarbons such as oil and gas.
Not only scientific sensations were also associated with the Kola well, but also mysterious legends, most of which turned out to be fiction of journalists during verification. According to one of them (born by the authors of the reports of a Finnish newspaper), in the very thickness of the earth, at a depth of over 12 thousand meters, the microphones of scientists recorded cries and groans.
Myths or reality:
The journalists, without even thinking about the fact that it is simply not possible to stick a microphone to such a depth (what sound recording device can operate at temperatures above two hundred degrees?), wrote that the drillers heard a "voice from the underworld." After these publications, the Kola super-deep well began to be called the "road to hell", arguing that each new kilometer drilled brought misfortune to the country.
It was said that when the drillers were drilling the thirteenth thousand meters, the USSR collapsed. Well, when the well was drilled to a depth of 14.5 km (which actually did not happen), they suddenly stumbled upon unusual voids. Intrigued by this unexpected discovery, the drillers lowered a microphone capable of operating at extremely high temperatures and other sensors into it. The temperature inside allegedly reached 1,100 ° C - there was the heat of the fiery chambers, in which, allegedly, human screams could be heard.
This legend still roams 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. And two years ago, the final decision was made to abandon the continuation of research and dismantle the entire research complex, and "bury" the well. The final liquidation of the well took place this summer.
So, as you can see, this time the scientists were not able to get to the mantle and explore it. However, this does not mean that the Kola well did not give anything to science - on the contrary, it turned all their ideas about the structure of the earth's crust upside down. It is possible that the researchers of the current Maersk Oil oil well (12,290 meters deep - which is 28 meters deeper than the Kola), which is located in the Al Shahin oil basin, in Qatar, will be able to climb even deeper.
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Materials: Alexey Voskoboynik (alex_oil), Wikipedia and Internet sources about Kola well
"Dr. Huberman, what the hell did you dig down there?" - a remark from the audience interrupted the report of the Russian scientist at the UNESCO meeting in Australia. A couple of weeks earlier, in April 1995, a wave of reports swept the world about a mysterious accident at the Kola superdeep well.
Allegedly, on the approach to the 13th kilometer, the instruments recorded a strange noise coming from the bowels of the planet - the yellow newspapers unanimously assured that only the cries of sinners from the underworld could sound like this. A few seconds after the appearance of a terrible sound, an explosion thundered ...
Space under your feet
In the late 70s and early 80s, getting a job at the Kola Superdeep, as the inhabitants of the village of Zapolyarny in the Murmansk region call the well familiarly, was more difficult than getting into the cosmonaut corps. From hundreds of applicants, one or two were chosen. Together with the order for employment, the lucky ones received a separate apartment and a salary equal to double or triple the salary of Moscow professors. There were 16 research laboratories working at the well at the same time, each the size of an average plant. Only the Germans dug the earth with such persistence, but, as the Guinness Book of Records testifies, the deepest German well is almost half as long as ours.
Distant galaxies have been studied by mankind much better than what is under the earth's crust a few kilometers from us. Kola Superdeep - a kind of telescope in the mysterious inner world planets.
Since the beginning of the 20th century, it has been believed that the Earth consists of a crust, a mantle, and a core. At the same time, no one really could tell where one layer ends and the next one begins. Scientists did not even know what, in fact, these layers consist of. Some 40 years ago, they were sure that the layer of granites starts at a depth of 50 meters and continues up to 3 kilometers, and then basalts come. It was expected to meet the mantle at a depth of 15–18 kilometers. In reality, everything turned out to be completely different. And although school textbooks still write that the Earth consists of three layers, scientists from the Kola Superdeep proved that this is not so.
Baltic shield
Projects for traveling deep into the Earth appeared in the early 60s in several countries at once. They tried to drill wells in those places where the crust should have been thinner - the goal was to reach the mantle. For example, the Americans drilled in the area of the island of Maui, Hawaii, where, according to seismic studies, ancient rocks go under the ocean floor and the mantle is located at a depth of about 5 kilometers under a four-kilometer water column. Alas, not a single ocean drilling rig has penetrated deeper than 3 kilometers.
In general, almost all ultra-deep well projects mysteriously ended at a depth of three kilometers. It was at this moment that something strange began to happen to the Boers: either they fell into unexpected super-hot areas, or they seemed to be bitten off by some unprecedented monster. Deeper than 3 kilometers, only 5 wells broke through, 4 of them were Soviet. And only the Kola Superdeep was destined to overcome the mark of 7 kilometers.
Initial domestic projects also involved underwater drilling - in the Caspian Sea or on Baikal. But in 1963, drilling scientist Nikolai Timofeev convinced the State Committee for Science and Technology of the USSR that a well should be created on the continent. Although drilling would take incomparably longer, he believed, the well would be much more valuable from a scientific point of view, because it was in the thickness of the continental plates in prehistoric times that the most significant movements of terrestrial rocks took place. The drilling point was chosen on the Kola Peninsula not by chance. The peninsula is located on the so-called Baltic Shield, which is composed of the most ancient rocks known to mankind.
A multi-kilometer section of the Baltic Shield layers is a clear history of the planet over the past 3 billion years.
Conqueror of the Deep
The appearance of the Kola drilling rig is capable of disappointing the layman. The well does not look like a mine that our imagination draws for us. There are no descents underground, only a drill with a diameter of a little more than 20 centimeters goes into the thickness. An imaginary section of the Kola super-deep well looks like a thin needle that has pierced the earth's thickness. A drill with numerous sensors, located at the end of the needle, is raised and lowered over several days. Faster is impossible: the strongest composite cable can break under its own weight.
What happens in the depths is not known for certain. Temperature environment, noise and other parameters are transmitted upward with a minute delay. However, drillers say that even such contact with the dungeon can be seriously frightening. The sounds coming from below are indeed like screams and howls. To this we can add a long list of accidents that haunted the Kola superdeep when it reached a depth of 10 kilometers. Twice the drill was taken out melted, although the temperatures from which it can melt are comparable to the temperature of the surface of the Sun. Once the cable seemed to be pulled from below - and cut off. Subsequently, when drilling in the same place, no remnants of the cable were found. What caused these and many other accidents is still a mystery. However, they were not at all the reason for stopping the drilling of the bowels of the Baltic Shield.
12,226 meters of discoveries and some hell
“We have the deepest hole in the world - this is how you should use it!” - bitterly exclaims the permanent director of the research and production center "Kola Superdeep" David Huberman. In the first 30 years of the existence of the Kola Superdeep, Soviet and then Russian scientists broke through to a depth of 12,226 meters. But since 1995, drilling has been stopped: there was no one to finance the project. What is allocated within the framework of UNESCO's scientific programs is only enough to maintain the drilling station in working order and study previously extracted rock samples.
Huberman recalls with regret how many scientific discoveries took place at the Kola Superdeep. Literally every meter was a revelation. The well showed that almost all of our previous knowledge about the structure of the earth's crust is incorrect. It turned out that the Earth is not at all like a layer cake. “Up to 4 kilometers, everything went according to theory, and then the doomsday began,” says Guberman. Theorists have promised that the temperature of the Baltic Shield will remain relatively low to a depth of at least 15 kilometers.
Accordingly, it will be possible to dig a well up to almost 20 kilometers, just up to the mantle. But already at 5 kilometers, the ambient temperature exceeded 70 ºC, at seven - over 120 ºC, and at a depth of 12 it was roasting more than 220 ºC - 100 ºC higher than predicted. The Kola drillers questioned the theory of the layered structure of the earth's crust - at least in the range up to 12,262 meters.
We were taught at school: there are young rocks, granites, basalts, a mantle and a core. But the granites turned out to be 3 kilometers lower than expected. Next were the basalts. They weren't found at all. All drilling took place in the granite layer. This is an extremely important discovery, because all our ideas about the origin and distribution of minerals are connected with the theory of the layered structure of the Earth.
Another surprise: life on planet Earth arose, it turns out, 1.5 billion years earlier than expected. At depths where it was believed that there was no organic matter, 14 types 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.
Demons
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 was 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.
In the history of the Kola Superdeep, it was not without mysticism. Officially, as already mentioned, the well stopped due to lack of funds. Coincidence or not - but it was in that 1995 that a powerful explosion of an unknown nature was heard in the depths of the mine. The journalists of a Finnish newspaper broke through to the inhabitants of Zapolyarny - and the world was shocked by the story of a demon flying out of the bowels of the planet.
“When I was asked about this mysterious story at UNESCO, I did not know what to answer. On the one hand, it's bullshit. On the other hand, I, as an honest scientist, could not say that I know what exactly happened here. A very strange noise was recorded, then there was an explosion ... A few days later, nothing of the kind was found at the same depth, ”recalls Academician David Huberman.
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 storehouse of all kinds of minerals, in particular gold. A real olivine belt, 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. Perhaps in the near future humanity will be able to take advantage of this wealth.
Kola Superdeep Well Since the end of the 19th century, it has been believed that the Earth consists of a crust, a mantle, and a core. At the same time, no one really could tell where one layer ends and the next one begins. Scientists did not even know what, in fact, these layers consist of. Some 30 years ago, researchers were sure that the layer of granites begins at a depth of 50 meters and continues up to three kilometers, and then basalts come. The mantle was supposed to be at a depth of 15-18 kilometers.
An ultra-deep well, which began to be drilled in the USSR on the Kola Peninsula, showed that scientists were wrong ...
Dive for three billion years
Projects for traveling deep into the Earth appeared in the early 1960s in several countries at once. The Americans were the first to drill ultra-deep wells, and they tried to do this in places where, according to seismic studies, the earth's crust should have been thinner. These places, according to calculations, were at the bottom of the oceans, and the area near the island of Maui from the Hawaiian group was considered the most promising, where ancient rocks lie under the very ocean floor and the earth's mantle is located approximately at a depth of five kilometers under a four-kilometer water column. Alas, both attempts to break through the earth's crust in this place ended in failure at a depth of three kilometers.
The first domestic projects also involved underwater drilling - in the Caspian Sea or on Baikal. But in 1963, drilling scientist Nikolai Timofeev convinced the State Committee for Science and Technology of the USSR that a well should be created on the continent. Although it would take an incomparably longer time to drill, he thought, the well would be far more scientifically valuable. The drilling site was chosen on the Kola Peninsula, which is located on the so-called Baltic Shield, which consists of the most ancient terrestrial rocks known to mankind. The multi-kilometer section of the shield layers, as conceived by scientists, was supposed to show a picture of the history of the planet over the past three billion years.
Deeper, and deeper, and deeper...
The start of work after almost five years of preparation was timed to coincide with the 100th anniversary of the birth of V.I. Lenin in 1970. The project was started in earnest. The well operated 16 research laboratories, each the size of an average plant; the project was personally supervised by the Minister of Geology of the USSR. Ordinary employees received a triple salary. Everyone was guaranteed an apartment in Moscow or Leningrad. It is not surprising that getting to the Kola Superdeep was much more difficult than getting into the cosmonaut corps.
The appearance of the well was capable of disappointing an outside observer. No elevators and spiral staircases leading deep into the Earth. Only a drill with a diameter of a little more than 20 centimeters went underground. In general, the Kola super-deep can be imagined as a thin needle piercing the earth's thickness. The drill located at the end of this needle with numerous sensors, after several hours of work, was raised for almost a whole day for inspection, reading and repair, and then lowered for a day. Faster is impossible: the strongest composite cable (drill string) could break under its own weight.
What was happening at depth at the time of drilling was not known for certain. Ambient temperature, noise and other parameters were transmitted upward with a minute delay. Nevertheless, the drillers said that even such contact with the dungeon was sometimes frightening in earnest. The sounds coming from below were like shrieks and howls. To this we can add a long list of accidents that haunted the Kola superdeep when it reached a depth of 10 kilometers. Twice the drill was taken out melted, although the temperatures from which it could take on this form are comparable to the temperature of the surface of the Sun. Once the cable seemed to be pulled from below - and cut off. Subsequently, when drilling in the same place, no remnants of the cable were found. What caused these and many other accidents is still a mystery. However, they were not at all the reason for stopping the drilling of the bowels of the Baltic Shield.
In 1983, when the depth of the well reached 12,066 meters, work was temporarily stopped: it was decided to prepare materials on ultra-deep drilling for the International Geological Congress, which was planned to be held in 1984 in Moscow. On it, foreign scientists first learned about the very existence of the Kola Superdeep, all information about which had been classified until then. Work resumed on September 27, 1984. However, during the first descent of the drill, an accident occurred - the drill string broke again. It was necessary to continue drilling from a depth of 7000 meters, creating a new trunk, and by 1990 this new branch had reached 12,262 meters, which was an absolute record for ultra-deep wells, broken only in 2008. Drilling was stopped in 1992, this time, as it turned out, forever. There were no funds for further work.
Discoveries and finds
The discoveries made at the Kola Superdeep have made a real revolution in our knowledge of the structure of the earth's crust. Theorists have promised that the temperature of the Baltic Shield will remain relatively low to a depth of at least 15 kilometers. This means that a well can be drilled almost up to 20 kilometers, just up to the mantle. But already at the fifth kilometer the temperature exceeded 700°C, at the seventh - over 1200°C, and at a depth of twelve it was roasting more than 2200°C.
The Kola drillers questioned the theory of the layered structure of the earth's crust - at least in the range up to 12,262 meters. It was believed that there is a surface layer (young rocks), then granites, basalts, a mantle and a core should go. But the granites turned out to be three kilometers lower than expected. The basalts that were supposed to lie under them were not found at all. An incredible surprise for scientists was the abundance of cracks and voids at a depth of more than 10 kilometers. In these voids, the drill swayed like a pendulum, which led to serious difficulties in work due to its deviation from the vertical axis. In the voids, the presence of water vapor was recorded, which moved there at high speed, as if carried by some unknown pumps. These pairs created the very sounds that thrilled the drillers.
Quite unexpectedly for everyone, the hypothesis of the writer Alexei Tolstoy about the olivine belt, expressed in the novel The Hyperboloid of Engineer Garin, was confirmed. At a depth of more than 9.5 kilometers, they discovered a real storehouse of all kinds of minerals, in particular gold, which turned out to be 78 grams per ton. By the way, industrial production is carried out at a concentration of 34 grams per ton.
Another surprise: life on Earth arose, it turns out, one and a half billion years earlier than expected. At depths where, as it was believed, there could be no organic matter, 14 species of fossilized microorganisms were found (the age of these layers exceeded 2.8 billion years). At even greater depths, where there are no longer sedimentary rocks, methane appeared in high concentrations, which finally disproved the theory of the biological origin of hydrocarbons such as oil and gas.
It is impossible not to mention the discovery made when comparing the lunar soil delivered by the Soviet space station in the late 70s from the surface of the Moon, and samples taken at the Kola well from a depth of 3 kilometers. It turned out that these samples are like two peas in a pod. Some astronomers saw this as evidence that the Moon had once broken away from the Earth as a result of a cataclysm (possibly a collision of the planet with a large asteroid). However, according to others, this similarity only indicates that the Moon was formed from the same gas and dust cloud as the Earth, and at the initial geological stages they “evolved” in the same way.
Kola Superdeep was ahead of its time
The Kola well showed that it is possible to go deep into the Earth for 14, and even 15 kilometers. However, one such well is hardly capable of providing fundamentally new knowledge about the earth's crust. This requires a whole network of wells drilled at different points on the earth's surface. But the times when ultra-deep wells were drilled for purely scientific purposes seem to have passed. Too expensive this pleasure. Modern ultra-deep drilling programs are no longer as ambitious as they used to be, and pursue practical goals.
This is mainly the discovery and extraction of minerals. In the United States, oil and gas production from depths of 6-7 kilometers is already becoming commonplace. In the future, Russia will also start pumping hydrocarbon raw materials from such levels. However, even those deep wells that are being drilled now bring a lot of valuable information that geologists seek to generalize in order to obtain a complete picture of at least the surface layers of the earth's crust. But what lies below will remain a mystery for a long time to come. Only scientists working on ultra-deep wells like the Kola can reveal it with the help of the most modern scientific equipment. In the future, such wells will become for mankind a kind of telescopes into the mysterious underworld of the planet, about which we know no more than about distant galaxies.
