Kola superdeep in section. The deepest well on earth - to hear the Earth's heartbeat

The famous abandoned well is located in the Murmansk region in the Pechenga ore region, which is known for copper-nickel deposits. The nearest settlement is the city of Zapolyarny, which is located 10 km from SG-3.

Kola superdeep - photo from space

To this day, the Kola well is the deepest in the world. Its depth is a record 12,262 m, the diameter at the surface is 92 cm, and at the maximum depth it is 21.5 cm. research activity.

Of course, the choice of this remote place with a harsh climate is not accidental. Previously, a special geological expedition was organized, which indicated exactly this point for the construction of the entire drilling structure and subsequent drilling of the well. The entire territory of the peninsula has many settlements with very strange names: New Titan, Nickel, Mica, Apatity, Magnetity, etc. But in fact, there is nothing strange in this, because the peninsula is just a huge warehouse of minerals. An important conclusion of the expedition was the fact that over the course of millions of years, the destructive effects of water, wind and ice, the surface of the Baltic Shield seemed to be more “bare” to the oldest terrestrial formations, which are usually hidden in other areas, due to a milder climate and less erosion. . Those. it was in this place that the drillers had an advantage of 5-8 km in comparison with a cut of the earth's crust on the continent. Therefore, if a well is drilled here with a depth of 15 km, then this is comparable to 20-23 km on the continent.

The surface layers of the earth's crust by that time were very well studied in the drilling of oil wells and oil production. And for the extraction of minerals, wells of about 2000-3000 m were enough. But the SG-3 had a completely different and very difficult task - to reach a depth of 15,000 m. It was not without reason that it was compared with the preparation and flight into space in terms of technical equipment. And as it turned out, the similarities are not only in this. Well, more on that later. It was not easy to get a job at the well at that time, only the best engineers and workers were selected there. Each of them received an apartment and a very decent salary, about eight times more than specialists in the central part of the union.

D. Guberman and academician Timofeev discuss drilling prospects

Since the 20th century, it has been accepted in science that the Earth consists of a crust, a mantle and a core. And the boundaries of all layers were established theoretically, i.e. it was assumed that the layer of granites has a depth of 3 km, and the layer of basalts begins from a depth of 3 km. Scientists expected to find the mantle at a depth of 15-18 km. But just the same, SG-3 destroyed all these ideas and gave different results, on which scientists are working to this day.

Drilling started on May 24, 1970. By the way, it is worth noting that the main condition of the government was to use only its own tools and equipment. Therefore, the drilling equipment was of the Soviet production of the Uralmash enterprise. The first stage of drilling was carried out by a typical drilling rig, the maximum depth limit of which was 5,000 m, but on SG-3 it was possible to break through with its help to a depth of 7,000 m. Which was a very good result. The drilling process itself up to the first point at 7,000 m took place without any emergency situations, the drill easily coped with homogeneous granites and all this work took 4 years.

To continue deep drilling, it was necessary to rebuild the tower for another more powerful installation and complete its installation. All this refurbishment work took about a year. For the next stage of drilling, the Uralmash-15000 was specially developed, which had cardinal differences in the device. Firstly, the lifting and immersion of the drill with the column was automated, and secondly, thanks to the new design, not the entire column rotated, but only the tool itself. Its rotation was carried out by supplying a specially designed solution. The crown itself has a special design, due to which the workers periodically removed rock samples in the form of cylinders, they are called core. The crushed rock in the process of drilling rises to the surface along with a special solution. Then the solution is cleaned and run in a new way. The entire string assembly with the bit and drilling fluid has a mass of about 200 tons. The pipes from which the string of the required length is assembled are made of aluminum alloys. Drilling at great depths is a very complex technological process, and even more so it was the conquest of new depths, so a lot of problems arose in the process, which were promptly and professionally solved by the best specialists at the station. It takes a very long time to lower and raise the drill string, about 18 hours, and the drilling process itself takes 4 hours. Therefore, work at the well was round-the-clock in three shifts.

The next stage of drilling from a depth of 7,000 meters was complicated due to loose uneven rocks, the tool constantly deviated towards softer rocks and the process slowed down significantly, but more unpleasant situations arose due to damage to the drill and breakage of the entire drill string. So, due to accidents and the loss of tools, it was necessary to cement this area and start drilling from the previous stages. By June 6, 1979, the record of 9583 meters, which belonged to the Bert Rogers oil well, was broken.

By 1983, the new drilling depth record was 12,066 meters. Work on the well had to be temporarily suspended due to preparations for the International Geological Congress, which was scheduled for 1984 in Moscow.

After a break on September 27, 1984, drilling work was resumed. But at the first stage, an accident occurred - a break in the column with a drill. The specialists lost 5 km of the string pipes. All attempts to get equipment out of the well ended in failure. Therefore, we had to start drilling from 7000 m. And in 6 years by 1990, the new well reached a record high of 12,262 m. All attempts to continue drilling ended in failure, so the project was frozen and after a while completely stopped due to lack of funding and the political situation in the country. But this depth remains a record!

Kola superdeep today

In the end, in 2008, everything was finally abandoned, the well was mothballed, some of the equipment was dismantled, the rest is destroyed from time to time and at the hands of marauders. According to some reports, it will take about 100 million rubles to restore all the equipment and continue research work, but most likely this is already unrealistic.
Below is a photo of the current state of the object

For more information, watch the short film

An attempt to study the geological section and the thickness of volcanic rocks emerging on the surface of the earth prompted scientific centers and, like them, research organizations to identify the origin of deep faults. The fact is that structural 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 point of laying the mouth fell on the existing huge bowl-like trough, the origin of which is associated with the presence of a deep fault in the area of ​​the Kola Peninsula.

It was believed that the Earth is a kind of sandwich, consisting of a crust, mantle and core. By this time, sedimentary rocks close to the surface had been sufficiently 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 find a section of granite and basalt layers. This did not happen. The drilling projectile pierced hard granite rocks up to the mark of 7000 meters. Further, the sinking went through relatively soft soils, which caused the collapse of the walls of the shaft and the formation of cavities. The crumbling soil jammed the tool head so much that when lifting the pipe string broke off, leading to an accident. The Kola well was supposed to confirm or refute these long-established teachings. In addition, scientists did not dare to indicate the intervals where exactly the boundaries between these three layers pass. The Kola well was intended for exploration and study of deposits of mineral resources, determination of patterns and gradual formation of fields of occurrence of raw material reserves. The basis was, first of all, the scientific validity of the theory of physical, hydrogeological and other parameters of the Earth's depths. And reliable information about the geological structure of the subsoil could only be provided by ultra-deep sinking of the shaft.

Meanwhile, the long-term preparation for the start of drilling operations included: the possibility of an increase in temperature as it deepens, an increase in the hydrostatic pressure of the formations, the unpredictability of the behavior of rocks, their stability due to the presence of rock and reservoir 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 loss of time for tripping the projectile, a decrease in drilling speed due to a change in the category of rocks, and an increase in energy costs for downhole thrusters.
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 of:
- increasing the carrying capacity, power and other characteristics of drilling equipment and equipment;
- thermal stability of the rock cutting tool;
- automation of management of all stages of the drilling process;
- processing of information coming from the bottomhole zone;
- warnings about emergencies with a drill pipe or casing string.

The sinking of an ultra-deep shaft was supposed to reveal the correctness or fallacy of the scientific hypothesis about the deep structure of the planet.

The purpose of this very costly construction was to study:
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 manifestations of ore bodies.
2. The study of the nature and forces that cause the separation of the sheet boundaries of the continental crust. Identification of reservoir zones, motives and nature of high temperature formation. Determination of the physical and chemical composition of water, gases formed in cracks, pores of rocks.
3. Obtaining exhaustive material on the material composition of rocks and information on the intervals between the granite and basalt "gaskets" of the crust. Comprehensive study of the physical and chemical properties of the extracted core.
4. Development of advanced technical means and new technologies for sinking super-deep shafts. Possibility of application of geophysical methods of research in the zone of ore manifestations.
5. Development and creation of the latest equipment for monitoring, testing, research, control of the drilling process.

The Kola well, for the most part, met scientific goals. 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 extraction of deposits of useful ores is always predetermined by the drilling of deep wells. And why on the Kola Peninsula and specifically in the Murmansk region, and definitely in Pechenga. The prerequisite for this was the fact that this region was considered a real pantry of mineral resources, with the richest reserves of a wide variety of ore raw materials (nickel, magnetites, apatites, mica, titanium, copper).

However, the geological calculation, made on the basis of a core from a well, revealed the absurdity of world scientific opinion. The seven-kilometer depth turned out to be composed of volcanic and sedimentary rocks (tuffs, sandstones, dolomites, breccias). Below this interval, as expected, there should have been rocks separating the granitic 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 been eroded and evolved 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 record of Pechenga. This is that part of the Baltic folded shield, where the geological history of stratal and ore manifestations has evolved over 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 (scrapers) the upper layers of rocks.

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

Superdeep well design

Ultra-deep structures have a mandatory telescopic design. In our case, the initial diameter of the mouth was 92 cm, and the final one was 21.5.

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

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

Drilling from scratch was carried out by the Uralmash-4E installation, that is, serial equipment used for drilling deep oil and gas wells. Up to 2000 meters, the shaft was drilled with steel drill pipes, with a turbodrill at the end. This turbine, 46 meters long, with a chisel at the end, was set in rotation under the action of a clay solution, which was pumped into the pipe at a pressure of 40 atmospheres.

Further, the sinking was carried out from an interval of 7264 meters by 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. Designed to implement:

• sinking of the barrel, operations of descent - lifting of the projectile and other auxiliary actions;
• retention of the leading and the entire pipe string, both on weight and during drilling;
• placement of sections (stands) of drill pipes, including collars, traveling system.

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

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

3. Circulation and blowout control system, cementing equipment.

4. Automation, control, process control system.

5. Electrical supply, means of mechanization.

6. A complex of measuring equipment, laboratory equipment and much more.

In 2008, the Kola super-deep well was completely abandoned, all valuable equipment was dismantled and removed (most of it was sold for scrap).

Until 2012, the main tower of the drilling rig was dismantled.

Now only the Kola Scientific Center of the Russian Academy of Sciences is operating, which to this day is studying core extracted from an ultra-deep well.

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

Documentary video about the Kola Superdeep Well

New ultra-deep well records

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 at an acute angle in the Al Shaheen oil basin.

In January 2011, this record was also broken, and it was broken by an oil well drilled in the Northern Dome (Odoptu-Sea - an oil and gas 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 Chayvinskoye field again broke the depth record with a length of 12,700 meters.

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 for technical reasons cannot be continued yet.

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, and collecting 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 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 the 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 drill 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, the sections of the drill string were lowered, the drilling fluid supply pipe was connected to the last, upper one, and the pumps were turned on. We started drilling. The instruments on the console in front of the operator showed the normal 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 range of modern research methods was used. 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 greater depths and at higher temperatures required the creation of special heat and pressure resistant instruments. 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. 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 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.

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The deepest wells in the world March 18th, 2015

The dream of penetrating into the bowels of our planet, along with plans to send a man into space, for many centuries seemed absolutely unrealizable. In the 13th century, the Chinese were already digging wells up to 1200 meters deep, and with the advent of drilling rigs in the 1930s, Europeans managed to penetrate to a depth of three kilometers, but these were only scratches on the body of the planet.

As a global project, the idea to drill into the upper shell of the Earth appeared in the 1960s. Hypotheses about the structure of the mantle were based on indirect data, such as seismic activity. And the only way to literally look into the bowels of the earth was to drill ultra-deep wells. Hundreds of wells on the surface and in the depths of the ocean provided answers to some of the scientists' questions, but the days when they were used to test a variety of hypotheses are long gone.

Let's remember the list of the deepest wells on earth ...

Siljan Ring (Sweden, 6800 m)

In the late 80s, a well of the same name was drilled in Sweden in the Siljan Ring crater. According to the hypothesis of scientists, it was in that place that it was supposed to find deposits of natural gas of non-biological origin. The result of the drilling disappointed both investors and scientists. Hydrocarbons have not been found on an industrial scale.

Zistersdorf UT2A (Austria, 8553 m)

In 1977, the Zistersdorf UT1A well was drilled in the area of ​​the Vienna oil and gas basin, where several small oil fields were hidden. When unrecoverable gas reserves were discovered at a depth of 7544 m, the first well collapsed unexpectedly and OMV had to drill a second one. However, this time the miners did not find any deep hydrocarbon resources.

Hauptbohrung (Germany, 9101 m)

The famous Kola well made an indelible impression on the European public. Many countries have begun to prepare their ultra-deep well projects, but the Hauptborung well, developed from 1990 to 1994 in Germany, deserves special mention. Reaching just 9 km, it has become one of the most famous ultra-deep wells due to the openness of drilling data and scientific work.

Baden Unit (USA, 9159 m)

A well drilled by Lone Star near Anadarko. Its development began in 1970 and lasted for 545 days. In total, this well took 1,700 tons of cement and 150 diamond bits. And its full cost cost the company $ 6 million.

Bertha Rogers (USA, 9583 m)

Another ultra-deep well created in the Anadarko oil and gas basin in Oklahoma in 1974. The entire drilling process took Lone Star workers 502 days. The work had to be stopped when the miners came across a molten sulfur deposit at a depth of 9.5 kilometers.

Kola Superdeep (USSR, 12,262 m)

Listed in the Guinness Book of Records as "the deepest human invasion of the earth's crust." When drilling began in May 1970 near the lake with the unpronounceable name Vilgiskoddeoaivinjärvi, it was assumed that the well would reach a depth of 15 kilometers. But due to high (up to 230 ° C) temperatures, the work had to be curtailed. At the moment, the Kola well is mothballed.

I already told you about the history of this well -

BD-04A (Qatar, 12,289 m)

Exploration well BD-04A was drilled 7 years ago in the Al-Shaheen oil field in Qatar. It is noteworthy that the Maersk drilling platform was able to reach the mark of 12 kilometers in a record 36 days!

OP-11 (Russia, 12,345 m)

January 2011 was marked by a message from Exxon Neftegas that the drilling of the longest extended reach well is close to completion. OR-11, located in the Odoptu field, also set a record for the length of the horizontal well - 11,475 meters. The tunnelers were able to complete the work in just 60 days.

The total length of the OP-11 well in the Odoptu field was 12,345 meters (7.67 miles), setting a new world record for drilling extended reach (ERD) wells. The OP-11 also ranked first in the world in terms of the distance between the bottomhole and the horizontal point of the drilling - 11,475 meters (7.13 miles). ENL completed a record-breaking well in just 60 days using ExxonMobil's high-speed drilling and TQM technologies, achieving top performance in drilling every foot of the OP-11 well.

“The Sakhalin-1 project continues to contribute to Russia's leadership in the global oil and gas industry,” said James Taylor, President of ENL. — To date, 6 of the 10 longest ERD wells, including the OP-11 well, have been drilled as part of the Sakhalin-1 project using ExxonMobil's drilling technologies. The specially designed Yastreb drilling rig was used throughout the life of the project, setting numerous industry records for hole length, drilling speed and directional drilling performance. We also set a new record while maintaining excellent performance in the field of safety, health and environment.”

The Odoptu field, one of the three fields of the Sakhalin-1 project, is located offshore, 5-7 miles (8-11 km) off the northeast coast of Sakhalin Island. ERD technology makes it possible to successfully drill wells from the shore under the seabed to reach offshore oil and gas deposits, without violating the principles of safety and environmental protection, in one of the most difficult subarctic regions of the world to develop.

P.S. And here is what they write in the comments: tim_o_fay: let's separate the flies from the cutlets :) Long well ≠ deep. The same BD-04A out of its 12,289 m has 10,902 m of horizontal shaft. http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x150185 Accordingly, there is a kilometer and a tail of the vertical. What does it mean? This means low (comparatively) bottom hole pressure and temperature, soft formations (with good ROP), etc. etc. OP-11 from the same opera. I won’t say that horizontal drilling is easy (I’ve been doing this for the eighth year), but it’s still much easier than ultra-deep ones. Bertha Rogers, SG-3 (Kola), Baden Unit and others with a large true vertical depth (literal translation from English True Vertical Depth, TVD) - this is really something beyond. In 1985, for the fiftieth anniversary of the SOGRT, former graduates from all over the Union came together with stories and gifts for the museum of the technical school. Then I was honored to feel a piece of granite-gneiss from a depth of more than 11.5 km :)

Despite the fact that the 21st century is in the yard, very little has been studied about the internal structure of our planet. We know quite well about what is happening in deep space, at the same time, the degree of penetration into the secrets of the Earth can be compared with a light pin prick in the surface of a watermelon peel.
In the mid-1950s, when drillers learned how to make wells more than 7 km deep, humanity approached the implementation of a very ambitious task - to penetrate the earth's crust and see what is hidden under it. Our compatriots, who drilled the Kola super-deep well, came closest to this goal.
The solid shell of the Earth 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 lower 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 stands out, named after the Yugoslav scientist who discovered it, the surface (border) of Mohorovich, or in short - Moho. In this zone, the propagation velocity of seismic waves increases sharply. There are a number of hypotheses designed to explain this phenomenon, but in general it remains unsolved.

The most important target of the most serious deep drilling projects launched in the second half of the 20th century was precisely this mysterious layer. The researchers failed to reach it, however, the data on the structure of the earth's crust, obtained during the drilling of ultra-deep wells, turned out to be so unexpected that the Mokhorovich boundary, as it were, faded 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 involved the creation of underwater drilling ships using special drilling ships. 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 borehole was able to penetrate only 800 m into the seabed, and yet the data obtained were of tremendous significance 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, immersed in a liquid mantle.

Of course, the USSR could not lag behind its overseas competitor, so in the mid-1960s we 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 land. The most famous and successful project of this kind is the Kola Superdeep Well, the deepest “hole in the ground” ever made by man. The well is located at the northern tip of the Kola Peninsula. This place was not chosen by chance - for hundreds of millions of years, natural erosion destroyed the surface of the Kola crystalline shield, ripping off the upper layers of rock from it. As a result, ancient Archean layers appeared on the surface, corresponding to depths of 5-10 km for the average section of the earth's crust of the continental type. 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 it ended more than 20 years later - in 1994. At first, the drillers worked using 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 fixed. 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 core of the rock and replace the blunt bit. Unfortunately, this proven technology becomes ineffective when the depth of the well exceeds a certain point: the friction of the pipes against the walls of the well becomes too great to turn this whole huge shaft. To overcome this difficulty, the engineers developed a scheme in which only the head of the drilling rig rotated. At the end of the column, turbines were strengthened, through which drilling fluid was passed - a special liquid that acts as a lubricant and circulates through the pipes. These turbines made the drill rotate.

The samples brought to the surface during the drilling process 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 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 dramatically, 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 moment it became clear that the prevailing model of a two-layered earth's crust was wrong. Now the presence of a seismic transition is explained by a change in the properties of the rock 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 this, it was believed that as the depth and pressure increase, they, on the contrary, should become more and more dense. Miniature cracks were filled with an aqueous solution, whose origin remained absolutely 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 out” from the surrounding rock under the influence of colossal pressures.
Another surprise: life on planet Earth arose, 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 types of fossilized microorganisms were found. They were found in highly uncharacteristic carbon-nitrogen deposits (instead of the usual limestone or silica) that are over 2.8 billion years old. At even greater depths, where there are no longer sedimentary rocks, methane appeared in huge concentrations. This completely and utterly destroyed the theory of the biological origin of hydrocarbons such as oil and gas.
Scientists were also extremely surprised by the speed with which the temperature increased as the well deepened. At a mark of 7 km 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 had a negative effect on the work of the bit, so the drilling fluid was cooled before being pumped into the well. This measure turned out to be quite effective, however, after passing the mark of 12 km, 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 swim during the next extraction of the drill string. Further progress turned out to be impossible without new technological solutions and significant financial costs, so in 1994 drilling was suspended. By that time, the well had deepened to 12,262 m.