RU2810117C1 - Device for cutting concave sections of wall in string casing - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: repair of crushed casing columns in order to restore their tightness. The device includes a milling mechanism to which a centering mechanism is coaxially and rigidly attached. During operation and transportation, the device is attached to the end of the drill string and placed inside the casing. The milling mechanism is a cylindrical body with a central axial channel, in which there is an internal annular protrusion. The side wall of the housing has through longitudinal windows in which cams with carbide cutting blades are installed. A rock cutting tool is rigidly attached to the lower end of the body. The main piston and the pusher are interconnected and placed in the central axial channel of the housing with the possibility of axial reciprocating movement. The pusher is made in the shape of a truncated cone, the larger of the bases of which faces the main piston. In the central axial channel of the pusher there is an internal annular protrusion, at the level of which radial channels are made in the pusher, hydraulically connected to its central axial channel. A return spring is installed in the central axial channels of the housing and the pusher, interacting with its ends with the end milling cutter and the pusher. An adjusting washer is located outside the return spring with the ability to interact with the smaller of the pusher bases. Outside the branch pipe, in the direction from the sub to the body, a hydraulic drive unit, a thrust bearing, at least two sliding sections and a thrust bearing are coaxially and sequentially placed, and a central axial channel is made in the bottom of the cup to accommodate the bushing. Sliding sections include reels, eyes, skis and rollers.

EFFECT: increasing reliability and efficiency of the device.

1 cl, 9 dwg

Description

The invention relates to the oil and gas industry, namely to the repair of crushed casing columns in order to restore their tightness.

In oil and gas wells, a fairly common type of casing failure is its collapse, sometimes accompanied by a through blow. The degree of casing collapse is assessed by the magnitude of the change in its internal bore diameter. If the length of the collapsed section does not exceed two outer diameters of the casing, as a result of which its internal bore diameter has decreased to 0.85 of the nominal value, then the collapse is classified as minor. If the length of the collapsed section of the casing string exceeds three outer diameters of the casing string and its internal bore diameter has decreased to 0.8 of the nominal value, then the collapse is considered significant.

Before repairing a collapsed casing, it is necessary to analyze the available information to determine the depth, size and nature of the violation. In practice, to obtain reliable information, various geophysical methods are widely used, as well as stamps, templates, etc. lowered into the wellbore.

In the event of a leak in the casing string, which may be accompanied by slight internal collapse of its wall, most often the internal surface of the casing string is milled and calibrated until an annular opening of the required diameter is obtained. Then, several internal annular grooves are milled in the upper and lower parts of the annular opening. After this, the defective section of the casing is covered with a metal patch, which is installed with a regulated interference (see, for example, SU 1616216, RU 2336408).

If the collapse cannot be corrected using mandrels and other special devices, then in many cases the defective section of the casing along with the cement stone is completely cut out using a sliding milling cutter, and then isolated by cementing under pressure and/or installing a metal patch (for example, a thin-walled sleeve , profile cover, etc.), tightly adjacent along the entire circumference to the inner surface of the casing. However, the specified overlap of the cut section of the casing is a technically complex and time-consuming technological process (see, for example, RU 2273718, RU 2347888).

Sometimes in a well being repaired, before milling a defective section of the casing with an internal narrowing, a cement bridge is installed. This technological technique reduces the likelihood of the milling tool jamming on a crumpled section of the casing and allows you to increase the speed of the operation (see, for example, RU 2386779).

In certain cases, in the collapse interval, it is advisable to remove only the concave sections of the casing wall. After this, if the nominal internal diameter of the casing string in the collapsed area is completely restored, the defective interval in it is isolated by installing a metal patch. In this case, the internal diameter of the casing string decreases slightly (see, for example, RU 2336408, RU 2438000, RU 2645060).

Removal of concave sections of the casing wall is carried out, as a rule, using milling cutters of various types, lowered into the well on a string of drilling or tubing pipes. But, since only concave sections of the crushed wall of the casing string are subject to milling, the outer diameter of the milling cutter is selected taking into account the possibility of its unhindered passage (i.e., with minimal allowable clearances) inside the casing string. As a result, it is the difference between the inner diameter of the casing and the outer diameter of the milling cutter that makes it difficult to reliably center the latter during operation and prevents the complete cutting of concave sections of the crumpled casing wall. For this reason, it is not possible to achieve complete restoration of the nominal internal diameter of the casing within the defective interval. Analysis of accumulated practical experience shows that the use of milling cutters is not only ineffective, but also often leads to rubbing of the casing wall and the unintentional formation of a through window in it.

In addition to these milling machines, devices designed to clean the inner surface of the casing can also be used to mill the concave wall of the casing. An indispensable condition is the ability of the cutting elements of the mentioned devices to ensure the completion of the task. However, the efficiency and reliability of devices for cleaning the inner surface of the casing is quite low, since their main purpose is to remove asphaltene-paraffin and salt deposits, cement crust, rust, burrs and other minor mechanical damage to the casing wall. In most cases, the cutting elements of these devices turn out to be unsuitable for milling concave sections of the wall of a crushed casing in order to completely restore its nominal internal diameter (see, for example, SU 715773, RU 2317402, RU 2424421).

A downhole milling cutter is known [1], which includes a cylindrical body, at the upper end of which there is a thread for attaching a drill string, and the lower end is reinforced with rows of carbide cutters. In the lower part of the body there are blades on which carbide cutters are soldered in the form of step-type plates. There are flushing channels at the lower end of the body and between the blades. On the side surface of the body between the blades there is a composite carbide material made of calibrated tungsten carbide chips combined with solder. In the middle part of the body, stabilizers with a wear-resistant coating are located evenly around the circumference.

The main disadvantage of the known downhole milling machine is that, due to its design features and insufficient degree of centering inside the crushed casing, it is not able to provide the ability to restore the nominal internal diameter of the latter.

A device is known for cleaning the inner surface of a casing [2], containing a housing with a central axial channel and transverse grooves. In the latter, pistons with two cutting elements are installed with the possibility of radial movement. Each piston is equipped with a holder with a ski attached to it, while the cutting elements have an arcuate shape and are placed in the holder. The specified device is attached to the lower end of the tubing string and moves with it in the axial direction without rotation inside the casing.

However, due to its design features, the known device is not capable of effectively milling concave sections of the wall of a crumpled casing.

A device for cleaning the inner surface of a casing pipe is known [3], which can be offered as a prototype. The device is part of the drill string and is placed between the downhole motor and the rock cutting tool. The device has a cylindrical body with a central axial channel and through longitudinal windows in the side wall. A sub is attached to the upper end of the housing, through which a rigid connection is provided with the downhole motor shaft, and a rock-cutting tool in the form of a chisel is attached to the lower end. The design of the bit is not disclosed in the source of information, however, it should be noted that all types of rock cutting tools used in the rotational method of drilling wells have a body (hereinafter referred to as the body) with external weapons, as well as with connecting threads. The body of the rock-cutting tool must include an axial channel with an internal annular bore and flushing channels that are hydraulically interconnected.

In the longitudinal windows of the housing, with the possibility of radial movement, retractable flat cutting elements are placed. In the central axial channel of the housing, a piston with a central axial channel, a cylindrical compression spring, a wedge, removable and limiting bushings are coaxially installed. The wedge has a central axial channel in which an internal annular protrusion is made. The piston is spring-loaded relative to the body and is rigidly connected to the wedge. The piston and wedge are capable of reciprocating axial movement relative to the housing. The amount of axial movement of the piston relative to the body is adjusted using removable and limiting bushings. Sealing of the piston in the central axial channel of the housing is ensured by sealing rings installed on it. The spring is located outside the wedge and has the ability to interact with the piston and removable sleeve. On the outer side surface of the wedge there are splined grooves in the shape of a “dovetail” for placing cutting elements in them. The latter are made with projections corresponding to splined grooves on the wedge. The working edges of the cutting elements are reinforced with carbide inserts.

To ensure the possibility of axial reverse of the wedge, the angle at its apex exceeds the angle of friction between the materials of the working surfaces of the wedge and the cutting elements. When the device rotates, the cutting elements clean the inner surface of the casing from cement cake and other deposits. Misalignment between the rock-cutting tool and the device, which is typical for threaded connections, helps to increase the cleaning effect.

The main disadvantages of the known device when used for milling concave sections of the wall of a crumpled casing are low reliability and operational efficiency, which are caused by the design features of the device and the insufficient degree of its centering inside the casing.

The objective of the present invention is to increase the reliability and efficiency of the device when cutting out concave sections of the wall inside a crushed casing.

The problem is solved and the technical result is achieved by the fact that the device for cutting concave sections of the wall inside the crushed casing is equipped with sliding sections with reels, earrings, skis and rollers, a pipe, thrust bearings and a hydraulic drive unit with an additional piston, a pressure spring, a cup with a bottom and a sleeve with a collar, wherein the collar is made at the end of the bushing, and an end mill is used as a rock-cutting tool, and the pipe is coaxially attached to the sub and to the body, and outside the pipe, in the direction from the sub to the body, a hydraulic drive unit and a thrust bearing are coaxially and sequentially placed , at least two sliding sections and a thrust bearing, and in the bottom of the cup there is a central axial channel for placing a bushing in it, and the internal annular protrusion in the central axial channel of the pusher is made on the side facing the main piston, while in the central axial channels of the housing and pusher, as well as in the inner annular bore of the axial channel in the face milling machine there is a return spring, the ends of which interact with the inner surface of the end milling machine and with the inner annular protrusion of the pusher, and the adjusting washer is installed outside the return spring in the inner annular bore of the axial channel in the end milling machine with the possibility interaction with the smaller of the bases of the pusher, moreover, the pusher has radial channels evenly spaced around the circumference and hydraulically connecting the central axial channels of the body and the pusher, while the radial channels are located at the level of the inner annular protrusion in the central axial channel of the pusher, and the axis of each radial channel is located in the plane of axial symmetry of the corresponding splined groove in the pusher, and an additional piston is coaxially installed at the end of the sleeve opposite to the location of the collar, while the cup is attached to the sub, and in the annular space between the cup and the sleeve there is an additional piston and a pressure spring, the ends of which interact with the bottom of the glass and with an additional piston, wherein the sleeve with a collar and the additional piston are installed outside the nozzle with the possibility of axial reciprocating movement relative to it, and the sliding sections are capable of axial reciprocating movement and rotation relative to it, while radial holes are made in the nozzle , hydraulically connecting its internal cavity with the supra-piston cavity formed by the inner side surface of the cup, the outer side surface of the nozzle, as well as the end surfaces of the sub and the additional piston, each sliding section consisting of two coils, between which skis are placed evenly around the circumference, while on On one flange of the coil there are external eyes for hinged connection of the earrings, and on the other flange there are axial holes evenly spaced around the circumference for installing fastening elements in them, and the opposite ends of each ski are hingedly connected by means of earrings to the corresponding external eyes on the flanges of the coils, while the coils are adjacent sliding sections are connected to each other using fasteners, which are placed in the axial holes in the flanges of the coils, and the sliding sections are installed outside the pipe with uniform axial rotation relative to each other, and the ski has a rectangular cross section, and on both sides of the ski, symmetrically and evenly along its length, rollers mounted on axes with the possibility of rotation are placed, the lateral outer surface of which has the shape of a spherical layer, while in the operating position of the device the rollers are able to interact with the inner surface of the casing wall.

The design of the proposed device for cutting out concave sections of the wall inside a crushed casing is illustrated by drawings, where: Fig. 1 shows a general view of the assembled device; figure 2 is a general view of the device in the transport position; Fig. 3 is a general view of the device transferred from the transport position to the working position; Fig.4 is a general view of the device when cutting out concave sections of the wall in a crumpled casing; Figure 5 is a cross section A-A in Figure 2; Fig.6 - cross section BB in Fig.2; Fig.7 - cross section B-B in Fig.3; Fig.8 - cross section GG in Fig.3; Fig.9 - cross section D-D in Fig.4.

The proposed device for cutting concave sections of the wall inside a crushed casing consists of a milling and centering mechanism, coaxially and rigidly connected to each other. The centering mechanism includes a hydraulic drive unit. The device, during its operation and transportation (i.e., when performing tripping operations in the well), is attached to the end of the drill string 1 and placed inside the casing string 2.

The milling mechanism includes a cylindrical body 3 with a central axial channel 4, made with an internal annular protrusion 5.

In the side wall of the housing 3 there are through longitudinal windows 6, evenly spaced around the circumference, in which cams 7 are installed with the possibility of radial movement, having, for example, the shape of a tetrahedral plate of rectangular cross-section. Each cam 7 is equipped with a carbide cutting blade 8.

Attached to the lower end of the body 3 is a rock-cutting tool - a face milling cutter 9 (for example, a downhole face milling cutter of type F32 or F3S2, serially produced by NLP Burintech), in the body of which there is an axial channel with an annular internal boring 10 and flushing channels 11, hydraulically connected between yourself. The end and lower part of the outer side surface of the end mill 9 is reinforced with carbide inserts 12 (or carbide chips).

In the central axial channel 4, with the possibility of axial reciprocating movement relative to the body 3, a rigidly interconnected main piston 13 and a pusher 14, made in the shape of a truncated cone, the larger of the bases of which faces the main piston 13, are coaxially placed.

The main piston 13, which has a cylindrical shape, is made with a central axial channel. The flow area of the central axial channel in the main piston 13 is chosen to be smaller than the flow area of the drill string 1 in order to create the required pressure drop across the main piston 13 during the circulation of the flushing fluid. On the outer side surface of the main piston 13 there are sealing collars.

The pusher 14 also has a central axial channel 15 with an internal annular protrusion 16 located on the side facing the main piston 13. In the pusher 14, at the level of the inner annular protrusion 16, radial channels 17 are made, evenly spaced around the circumference and hydraulically connected to the central axial channel 15.

In the central axial channels 4 and 15, as well as in the internal annular bore 10 of the axial channel of the end mill 9, a cylindrical return spring 18 is installed, the ends of which interact with the inner surface of the end mill 9 and with the annular internal projection 16. Outside the return spring 18, in the inner annular bore 10, an adjusting washer 19 is placed. It has the ability to interact with the smaller of the bases of the pusher 14, which limits the amount of axial movement of the latter, and, consequently, the amount of radial extension of the cams 7 from the longitudinal windows 6.

In the pusher 14, to accommodate the cams 7, splined grooves 20 are made in the shape of a “dovetail”, evenly placed on its outer conical surface, and on the cams 7 there are protrusions corresponding to the specified splined grooves 20. In this case, the axis of each radial channel 17 is located in the plane of axial symmetry of the corresponding spline groove 20 in the pusher 14.

The cams 7 placed in the splined grooves 20, during the axial movement of the pusher 14, have the ability to overlap the radial channels 17. When the latter are blocked on the riser, an increase in wellhead pressure is noted, which is a signal about the radial extension of the cams 7 from the longitudinal windows 6 by the calculated value.

The angle of inclination of the surface of the spline grooves 20 in the pusher 14, in order to eliminate the possibility of self-jamming of the cams 7, is chosen equal to or less than the sliding friction angle (depending, in turn, on the coefficient of sliding friction between the materials from which the cams 7 and the pusher 14 are made).

The centering mechanism includes a pipe 21, made with radial holes 22. One end of the pipe 21 is rigidly connected to the body 3, and the other to the sub 23, which, in turn, is connected to the lower end of the drill string 1. Radial holes 22 are located at the end of the pipe 21, facing the sub 23.

Outside the pipe 21, in the direction from the sub 23 to the housing 3, a hydraulic drive unit, a thrust bearing 24, at least two sliding sections and a thrust bearing 24 are placed sequentially and coaxially.

The hydraulic drive unit includes a cup 25 with a bottom 26, a sleeve 27 with a collar 28 at one end, an additional piston 29 and a cylindrical pressure spring 30. The cup 25 is coaxially attached to the sub 23, and in its bottom 26 there is an axial channel for placing the sleeve 27.

An additional piston 29, a pressure spring 30 and a sleeve 27 are coaxially placed inside the cup 25. A pressure spring 30 is installed in the annular space between the cup 25 and the sleeve 27, and the ends of the pressure spring 30 interact with the annular piston 29 and the bottom 26.

At the end of the sleeve 27, opposite to the location of the collar 28, an additional piston 29 is fixed, which, together with the sleeve 27, is capable of axial reciprocating movement relative to the cup 25. Sealing collars are installed on the outer side surface of the additional piston 29. The sleeve 27 and the additional piston 29 are placed outside the pipe 21 with the possibility of axial reciprocating movement relative to it.

The above-piston cavity of the hydraulic drive unit, formed by the inner side surface of the cup 25, the outer side surface of the nozzle 21, as well as the end surfaces of the sub 23 and the additional piston 29, is hydraulically connected through radial holes 22 to the internal cavity of the nozzle 21 and, accordingly, to the internal cavity of the drill string 1 .

The sliding sections are installed outside the pipe 21 with the possibility of axial reciprocating movement and axial rotation (which is ensured by the placement of thrust bearings 24) relative to it.

Each sliding section includes two coils 31, each of which is hingedly connected by means of earrings 32 with three skis 33, evenly placed around the circumference outside the pipe 21.

On one flange of the coil 31 there are external eyes for hinged connection of the earrings 32, and on the other flange there are axial holes evenly spaced around the circumference for installing fasteners (bolts or studs) into them. Each earring 32 is connected by means of hinges, respectively, to the end of the ski 33 and to the outer eye on the reel 31. In cross section, the skis 33 have a rectangular shape.

Interacting coils 31 belonging to adjacent sliding sections are connected to each other using fasteners. The number of axial holes made in the coils 31 should provide the possibility of mutual axial rotation of adjacent sliding sections during installation of the device. The preferred option is to make twelve axial holes in each of the coils 31, which makes it possible to connect two or more sliding sections in series with uniform angular rotation (a multiple of 30°).

On both sides of the ski 33 there are rollers 34, which are mounted on axles 35 with the possibility of rotation. The rollers 34 are installed along the length of the ski 33 evenly and symmetrically. In the operating position of the device, the rollers 34 are able to interact with the inner surface of the wall of the casing 2.

The lateral outer surface of the roller 34 has the shape of a spherical layer. Installation of rollers 34 on skis 33, during the process of axial movement of the latter along the wall of the casing 2, can significantly reduce the amount of friction, since in this case sliding friction is replaced by rolling friction.

In practical conditions, the required number of sliding sections that must be placed on the nozzle 21 is determined mainly depending on the degree and nature of the collapse of the wall of the casing string 2, the length of the defective section, the value of the zenith angle of the wellbore in the interval of the defective section, etc. For this reason, it is recommended to place at least two sliding sections in the device, which will significantly reduce the likelihood of skis 33 falling inside the windows formed when cutting out concave sections of the wall of the crushed casing column 2.

The operation of the device for cutting out concave sections of the wall inside a crumpled casing is carried out as follows.

After completing a set of measures to clarify the depth and nature of the collapse of the casing 2, the device is assembled on the surface. The required thickness of the adjusting washer 19 is selected depending on the nominal value of the internal bore diameter of the casing 2 in the defective interval.

In the transport position of the device, the spring-loaded main piston 13 interacts with the internal annular protrusion 5 in the central axial channel 4, while the cams 7 do not protrude outward from the longitudinal windows 6.

The device, connected to the lower end of the drill string 1 by means of a sub 23, is lowered into the well. The flushing fluid located in the well fills the device and enters the drill string 1, as well as through the radial holes 22 into the above-piston cavity of the hydraulic drive unit.

After placing the device over the crumpled section of the casing 2, direct circulation of the flushing fluid is organized, while fixing the value of the wellhead pressure on the riser.

Under the pressure of the flushing liquid, the main piston 13 together with the pusher 14 moves in the axial direction relative to the housing 3. With the axial movement of the main piston 13 and the pusher 14, the return spring 18 is gradually compressed, and the cams 7, which interact with the splined grooves 20 of the pusher 14, are forced outward of longitudinal windows 6 in building 3.

The amount of axial movement of the main piston 13 with the pusher 14 is limited when the lower end of the pusher 14 rests on the adjusting washer 19. The cams 7, during their radial movement in the direction of the wall of the casing 2, overlap the radial channels 17 in the pusher 14, which is noted on the surface as they increase wellhead pressure on the riser.

When organizing the circulation of the flushing liquid, excess pressure is transmitted to the above-piston cavity of the hydraulic drive unit and acts on the additional piston 29, causing it to move in the axial direction relative to the pipe 21. Together with the additional piston 29, overcoming the force of the pressure spring 30, the sleeve 27 also moves.

The axial movement of the sleeve 27 through the collar 28 is transmitted to the sliding sections, which begin to compress in the axial direction. As a result of the axial compression of the sliding sections, the skis 33 move in the radial direction, while the rollers 34 are pressed against the wall of the casing 2, thereby achieving reliable centering of the device inside the casing 2.

Next, using a rotor, they organize the rotation of the drill string 1, after which they slowly and smoothly begin to lower the device, controlling the weight of the drill string 1 according to the readings of the hydraulic weight indicator (HWI).

The contact of the end milling machine 9 with the concave section of the wall of the casing string 2 is determined on the surface according to the readings of the GIV, which records the decrease in the mass of the drill string 1. During the operation of the device, the calculated value of the axial load on the end milling machine 9 is created by partially unloading the drill string 1.

In the process of further axial movement of the end milling cutter 9, cutting blades 8 mounted on cams 7 come into contact with the concave sections of the wall of the casing string 2. They cut off the concave sections of the wall of the casing string 2, thereby ensuring the restoration of its nominal internal diameter.

After the device has completely passed the defective section of the casing string 2, the rotation of the drill string 1 and then the circulation of the flushing fluid are sequentially stopped. In this case, the main piston 13 with the pusher 14, under the influence of the compressed return spring 18, moves to its original transport position. When the pusher 14 moves axially, the cams 7 are forced into the longitudinal windows 6 in the housing 3.

The additional piston 29 and bushing 27, under the influence of the compressed pressure spring 30, also return to their original position, as a result of which the sliding sections move from the working position to the transport position.

After the final transition of the device from the working position to the transport position, they begin to lift the drill string 1 to the surface.

Information sources:

1. RF Patent No. 111882 U1, E21B 29/00, publ. 12/27/2011.

2. RF Patent No. 2042792 C1, E21B 37/02, publ. 08/27/1995.

3. RF Patent No. 2099507 C1, E21B 37/02, publ. 12/20/1997.

Claims (1)

A device for cutting concave sections of the wall inside a crushed casing, including a cylindrical body with a central axial channel and with through longitudinal windows evenly spaced around the circumference of its side wall, coaxially placed in the central axial channel of the body with the possibility of reciprocating axial movement and rigidly connected between consists of a main piston with a central axial channel and a pusher in the shape of a truncated cone, facing with its large base towards the main piston with a central axial channel in which an internal annular protrusion is made, and with splined grooves evenly placed on its outer side surface, cams with cutting blades installed in the longitudinal windows of the housing with the possibility of radial movement and interaction with the slotted grooves of the pusher, an adjusting washer, a return spring, a sub for connecting to the drill string, as well as a rock-cutting tool connected to the lower end of the housing, in the body of which there are hydraulically interconnected axial a channel with an internal annular bore and through flushing channels, characterized in that it is equipped with sliding sections with coils, earrings, skis and rollers, a pipe, thrust bearings and a hydraulic drive unit with an additional piston, a pressure spring, a cup with a bottom and a sleeve with a collar, with In this case, the collar is made at the end of the bushing, and an end mill is used as a rock-cutting tool, and the pipe is coaxially attached to the sub and to the body, and outside the pipe in the direction from the sub to the body, a hydraulic drive unit, a thrust bearing, and at least two sliding sections are coaxially and sequentially placed and a thrust bearing, and in the bottom of the cup there is a central axial channel for placing a bushing in it, and the internal annular protrusion in the central axial channel of the pusher is made on the side facing the main piston, while in the central axial channels of the housing and the pusher, as well as in the inner In the annular bore of the axial channel in the end mill there is a return spring, the ends of which interact with the inner surface of the end mill and with the inner annular protrusion of the pusher, and the adjusting washer is installed outside the return spring in the inner annular bore of the axial channel in the end mill with the possibility of interaction with the smaller of the bases of the pusher , wherein the pusher has radial channels evenly spaced around the circumference and hydraulically connecting the central axial channels of the housing and the pusher, while the radial channels are located at the level of the internal annular protrusion in the central axial channel of the pusher, and the axis of each radial channel is located in the plane of axial symmetry of the corresponding spline groove in the pusher, and an additional piston is coaxially installed at the end of the sleeve opposite to the location of the collar, while the cup is attached to the sub, and in the annular space between the cup and the sleeve there is an additional piston and a pressure spring, the ends of which interact with the bottom of the cup and with the additional piston , wherein a sleeve with a collar and an additional piston are installed outside the nozzle with the possibility of axial reciprocating movement relative to it, and the sliding sections are installed with the possibility of axial reciprocating movement and rotation relative to it, while radial holes are made in the nozzle that hydraulically connect its internal cavity with an above-piston cavity formed by the inner side surface of the cup, the outer side surface of the nozzle, as well as the end surfaces of the sub and an additional piston, each sliding section consists of two coils, between which skis are placed evenly around the circumference, with external eyes made on one flange of the coil for hinged connection of earrings, and on the other flange there are axial holes evenly spaced around the circumference for installing fasteners in them, and the opposite ends of each ski by means of earrings are hingedly connected to the corresponding outer eyes on the flanges of the coils, while the coils of adjacent sliding sections are connected to each other at with the help of fastening elements, which are placed in the axial holes in the flanges of the coils, and the sliding sections are installed outside the pipe with a uniform axial rotation relative to each other, and the ski has a rectangular cross-section, and on both sides of the ski, installed symmetrically and evenly along its length on axes with the possibility of rotation there are rollers, the lateral outer surface of which has the shape of a spherical layer, while in the operating position of the device the rollers are able to interact with the inner surface of the casing wall.

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