RU2362003C2 - Procedure for removing pipes from well and facility for implementation of this procedure - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: group of inventions refers to drilling oil and gas wells, notably to procedures of removing column of frozen pipes from well. The procedure consists in lowering a facility into a well to operational depth on the right working pipes; the facility consists of a mechanism of fixation and of a mechanism of reverse, to the output shaft of which by means of a sub and a connecting pipe there is connected a fishing tool with a left thread; the facility is lowered till the fishing tool contacts a head of the frozen column; further the procedure consists in fixation of the facility by means of supply of flushing fluid into the mechanism of fixation and moving out spring-loaded anchors; in screwing the fishing tool to the left onto the head of the frozen column under influence of flow string right rotation converted with the reverse mechanism into left rotation of the fishing tool; in unscrewing the thread in the connection of flow string; in unfixturing the facility; and in removing part of pipes unscrewed from the frozen column out of the borehole of the well to surface. Upon determining the upper boundary of freeze-in and place of location of the mechanism of fixation (facility for unfixturing pipes -FUP) in the borehole and calculation of length of a connecting pipe, there is calculated M1 - maximum allowed torque for the structure of the free part of the frozen column; also weight P of the structure of the complex flow string is calculated; and maximum allowed stretching force for the structure of the complex flow string is calculated. Upon installation and screwing on the fishing tool on the head of the string and unfixturing FUP to the head of the working pipes there is applied maximum allowed for the structure of the complex flow string stretching strength at the well head; upon fixation of FUP in the well there is applied torque M1 to the flow string and there is performed smooth decreasing of stretching force to value P. If unscrewing of the flow string in the thread connection at the top of the frozen pipe does not commence, then there is performed successive stage reductions of stretching force by value corresponding to weight of the pipe in the free part of the frozen string starting from weight of the pipe screwed on to the frozen pipe. Upon each reduction of stretching force value beginning of unscrewing is controlled by readings of a sensor on the rotation drive.

EFFECT: increased reliability and efficiency of removing frozen pipes.

3 cl, 7 dwg

Description

The invention relates to the oil and gas industry, and in particular to methods for extracting pipes from the well and devices for unscrewing pipes (hereinafter URT) in the well.

The invention can be used in the elimination of accidents associated with sticking pipes during drilling, as well as in overhaul of wells.

There is a method of extracting not stuck part of a drill pipe string by unscrewing it in parts using a drill pipe with a left-hand thread (left drill pipe string) (see book: Kolomoets AV Prevention and elimination of sticking in exploration drilling. - M .: Nedra , 1985, p.90), which consists in the following:

- deliver the left drill string to the well and change the right (working) drill string to the left;

- on the left drill pipes, a left-handed fishing tool (left fishing tool) is lowered into the well and the columns of extracted pipes are installed on the head (upper end);

- rotate the drill string to the left together with the fishing tool and unscrew the part of the extracted pipes;

- raise the unscrewed part of the pipes to the surface and, if necessary, repeat the process of pipe extraction.

The disadvantages of this method:

- low reliability, since when unscrewing the pipes to be removed, it is necessary to apply a large torque to pull off (break) the threaded connection, which can lead under certain conditions, for example, a large length of the joined column, the presence of deformed or worn pipes in the column, to break the walls or threads of the pipes and thereby aggravate the emergency;

- low productivity associated with additional time costs for replacing the right drill pipe string with the left one, and vice versa;

- the need to have on the site a sufficient number of left pipes or to deliver them to the drilling site, which is associated with a large investment of time and money.

In production conditions, for several drilling rigs or for a batch, there is usually only one set of such a tool with left-hand thread. When accidents occur, it is transported from one drilling unit to another for tens, and sometimes hundreds of kilometers.

In addition, the presence on the rig of two columns (with right and left-hand threads), especially with a large depth of the well, increases the load on the rig and worsens working conditions.

There is also a method of extracting the unattached part of the pipe string (see book: Kolomoets AV Prevention and elimination of sticking in exploratory drilling. - M .: Nedra, 1985, p.200), which consists in sequentially unscrewing and removing drill pipes from the surface using URT, which is lowered into the well on working pipes with the right thread.

URT consists of a locking mechanism and a turning mechanism, to the output shaft of which a fishing tool with a left-hand thread is attached to the connecting pipe.

Before launching the URT, a profile or cavernometry of the well is carried out to determine the narrowing of the trunk closest to the upper end of the stuck drill pipes and the length of the connecting pipes between the output shaft of the URT and the fishing tool attached to it is determined so that when the fishing tool is placed on the head of the stuck pipe string, the fixing mechanism URT was in the narrowed part of the trunk.

The right-hand working tubes are lowered to the calculated depth in the URT well until the fishing tool contacts the head of the string of stuck pipes, then URT is fixed in the calculated position of the wellbore by increasing the pressure of the flushing fluid supplied through the working pipe string to the fixation mechanism, where it leads to expanding the injection hose to its contact (stop) with the walls of the well.

The fishing tool is screwed onto the head of the stuck pipe string under the action of the rotation of the right rotation of the working pipe string into the left rotation of the fishing tool.

Then, the thread is unscrewed in the pipe connection of the stuck string and the device is released by lowering the pressure of the flushing fluid, which leads to compression of the injection hose and termination of its contact with the walls of the well, i.e. return the locking mechanism to its original (transport) position.

Extraction is made from the well to the surface of the pipe unscrewed from the stuck column.

In the above method, there are a number of disadvantages.

The principle of discrete unscrewing of the predominantly upper pipe in the stuck-in column laid down in the method requires lowering and removing the URT as many times as there are pipes in the stuck-in column to the sticking point. Each hoisting operation is accompanied by large hydrodynamic pressure drops, collisions with the walls of the well, which, in turn, can cause such geological complications as impaired wellbore stability, collapse, talus and collapse of the well walls. These consequences can lead to a complication of the accident, which significantly reduces its reliability.

In addition, the low reliability of the method is also associated with the low reliability of the locking mechanism, in which an injection hose is used as a stop element, which can slip especially when exposed to large torques necessary to “break” the thread at the beginning of unscrewing.

A large number of tripping operations, unproductive single unscrewing by cyclic (discrete) rotation of the fishing tool and the same unproductive single process of pipe extraction from the well lead to a significant increase in the duration of extraction and liquidation of the accident.

In addition, threaded joints of unscrewed pipes, intensively loaded and partially deformed due to the weight of the combined pipe string and bending deformations created by the rotating string under the influence of the drive torque located on the surface of the borehole, to break and start guaranteed unscrewing require the application of such torque values moments that can lead to mechanical destruction of pipes. This leads, as practice shows, to unscrew, first of all, the most "weak" threaded connection, which is located much higher than the sticking point, which also reduces the effectiveness of the method.

The above analysis shows that the disadvantages of this prototype method are low reliability and low productivity.

The above method is implemented using the well-known URT for unscrewing the unattached part of the pipe string (see the same book: Kolomoets AV, Prevention and elimination of sticking in exploratory drilling. - M .: Nedra, 1985, p.200).

URT consists of a locking mechanism and a rotation mechanism, made in the form of a hydraulic drive piston engine of differential action and a rotary assembly, to which the fishing tool is connected to the spindle.

The URT fixation mechanism includes a housing, oil seals through which a drill pipe with a pressure reducing valve passes, an injection hose laid in turns on the housing, a spring suspension and a spline connection.

A hydraulic piston engine consists of a discharge chamber, a cylinder with covers, a piston connected to the upper and lower rods, valves sitting on a common thrust and protected by cups from flushing fluid pressure, two springs and two piston stroke limiters.

The rotary assembly of the URT consists of a housing with a spline coupling, a limiter and a heel having angular contact bearings and ratchet cams, a spline rod and a helical rod connected to the lower stem of a hydraulic motor, a helicoidal ratchet coupling having cam engagement with a spindle, an adapter for attaching with a tap or bell, a ratchet control clutch having a slotted connection to the spindle and resting on a spring.

The connections of the engine parts and the rotary unit, as well as the fishing tool with the spindle, are left-handed. Working (drill) pipes above the locking mechanism have a right-hand thread.

The hose of the locking mechanism communicates with the drill pipes, therefore, when flushing fluid is supplied, it inflates, abuts against the walls of the well and keeps the housing from rotation and simultaneously holds the drill pipes through the spline connection during operation.

The hydraulic piston engine operates when flushing fluid is supplied to the discharge chamber and provides reciprocating movement with the spline and helicoidal rods of the rotary assembly associated with it. When the helicoidal rod moves upward, the helicoidal ratchet clutch rotates clockwise, while due to the oblique teeth it disengages from the spindle. The latter engages with the base plate through the control ratchet clutch and this ensures that the fishing tool is kept from turning clockwise due to the elasticity of the drill string and emergency drill pipes. When the helicoidal rod moves downward, the helicoidal ratchet clutch will engage with the spindle and rotate it together with the fishing tool to the left by a certain angle.

Thus, a cyclic (discrete) rotation of the fishing tool to the left is carried out, which ensures the winding of a bell or tap, as well as the unscrewing of the threads of the extracted pipes. In this case, the necessary movement of the URT up or down when screwing the fishing tool or unscrewing evacuated pipes is provided by a spring suspension in the upper part of the locking mechanism. When the process of unscrewing the next pipe is completed, the locking mechanism is brought into an inoperative state and the unscrewed pipe is raised to the surface.

The disadvantage of this device is its low reliability due to the great complexity of the design, as well as the presence in its operation of shock loads that adversely affect the condition of the walls of the well, which can lead even after removing the first pipe to block the well and increase the emergency situation.

Low reliability is also a consequence of the low reliability of the locking mechanism, in which an injection hose is used as a stop element, which can slip especially when exposed to large torques necessary to “break” the thread at the beginning of the unscrewing process.

In addition, piecewise unscrewing and removing pipes determine the low productivity of the process.

The closest in technical essence to the proposed URT is “Device for unscrewing pipes in a well” (patent of the Republic of Belarus No. 4314 according to Cl. ЕВВ 23/00, Е21В 23/04, publ. March 30, 2002), which is based on a sinus ball gearbox. URT consists of a sinus ball reducer case, in which external sleeves are located on the key, a thrust sleeve is screwed on top of it, and a thread is made for securing the fishing tool from below. An input hollow shaft is installed inside the housing, on which internal sleeves are located on the key; a threaded sleeve is movably mounted on the top of the hollow shaft for connecting the working string pipes. A carrier is located between the inner and outer bushings, along the slots of which, like the closed sinusoidal grooves of the inner and outer bushings, the rolling bodies — balls — move. In the upper part of the carrier on the axes are three anchors, spring-loaded with leaf springs. In the selected kinematic diagram of the sinus ball reducer, the input shaft with the internal bushings is the driving link of the gearbox, the external bushes with the housing and fishing tool are the driven link, and the carrier with the anchors is the inhibited link of the gearbox.

The disadvantage of this device is the low reliability of fixing the URT in the well, especially manifested in the unsatisfactory condition of the walls of the well (the presence of local physical and mechanical heterogeneity in the rock structure, outfalls, voids, etc.). In such conditions, due to the possible lack of emphasis, for example, due to the partial movement of one of the anchors into the wall of the well when it is destroyed or collapsed, the location of the fishing tool relative to the axis of the well may be skewed, making it difficult to start the process of screwing the fishing tool onto the head of the stuck string, which reduces its reliability.

In addition, the locking mechanism is activated when the tap reaches the head of the stuck column by forcing the axial movement of this device downward using a drilling rig system. Only in this case, the carrier of the sinus ball reducer moves downward relative to the body, as a result of which the spring-loaded anchors move along the protrusion of the sleeve and, opening, stop the URT inside the well. This leads to significant loads on the connecting threads of the pipes in the stuck string. The loaded and clamped state of the threaded connection of the unscrewed pipes in the stuck string due to the weight of the working string of pipes with URT and reinforced by the vertical load from the rig system (for fixing the URT in the well), as well as a significant distance from the point of application of torque to the unscrewing point, lead to bending deformations of the combined column of working and emergency pipes. This does not allow due to the possibility of destruction of the pipes to apply a torque of such a magnitude that guarantees a "breakdown" of the thread and the beginning of its unscrewing, which also reduces reliability.

The disadvantage of this device is also low productivity, due to the need to implement the process of sequential turning and extraction from the well through one pipe starting from the top, because it is on its threaded connection that the smallest vertical load will be affected in comparison with the pipes located below.

The realized principle of discrete unscrewing of the thread of the upper pipe in the stuck string requires so many times to lower and remove the URT, how many pipes were in the stuck string to the sticking point. Each hoisting operation is accompanied by large hydrodynamic pressure drops, collisions with the walls of the well, which, in turn, can cause such geological complications as impaired wellbore stability, collapse, talus and collapse of the well walls. These consequences can lead to a complication of the accident, which also significantly reduces reliability.

Described in the aforementioned book A. Kolomoyets a method for extracting an unattached part of a pipe string and “Device for unscrewing pipes in a well” (patent of the Republic of Belarus No. 4314 according to Cl. Е21В 23/00, Е21В 23/04, publ. March 30, 2002) are the closest to the proposed technical solution.

Thus, the disadvantages of the known method and device for its implementation are low reliability and low productivity.

The technical problem solved by the invention is to increase the reliability and productivity of extracting from the well string of stuck pipes.

To solve this technical problem in the proposed method, as well as in the known,

- conduct profile- or cavernometry of the well, determine the upper boundary of the sticking point and the closest place in the well (undeveloped, with stable and strong walls) to the URT;

- calculate the length of the connecting pipe and install it with the fishing tool on the URT based on the requirement that when setting the fishing tool on the head of the tacked column, the URT fixation mechanism is in a certain (previous action) location that provides reliable fixation in the well;

- carry out the descent on the right working pipes to the calculated depth in the URT well until the contact of the fishing tool with the head of the stuck pipe string;

- perform fixation of URT in the calculated location of the well by increasing the pressure of the flushing fluid supplied through the column of working pipes into the mechanism for fixing and extending the spring-loaded anchors to the stop with the walls of the well;

- make screwing (to the left) of the fishing tool on the head of the stuck pipe string (under the action of the reverse rotation of the right rotation of the working pipe string into the left rotation of the fishing tool);

- perform unscrewing (to the left) of the thread in the pipe joint of the stuck column;

- URT is unlocked in the well (by lowering the pressure of the flushing fluid in the fixation mechanism and returning the spring-loaded anchors to their original (transport) position);

- removed from the well to the surface on the working pipes: URT with a connecting pipe, a fishing tool and a pipe unscrewed from the stuck column.

In contrast to the prototype in the proposed method, after conducting a profile or cavernometry of the well, determining the upper sticking edge and location of the URT fixation mechanism in the barrel, calculating the length and installation of the connecting pipe with the fishing tool on the URT:

- calculate L1 - the length of the free part of the stuck column from the sticking point to the reversal mechanism of the URT;

- calculate L2 - the length of the composite string from the sticking point to the drive rotation of the string on the surface of the wellhead;

- calculate M1 - the maximum allowable torque for the construction of the free part of the stuck column length L1;

- calculate P is the weight of the structure of the composite columns of length L2, taking into account the weight of the URT;

- calculate F is the maximum allowable tensile force for the construction of a composite column of length L2, taking into account the design of the URT,

and after installing and screwing the fishing tool onto the head of the string of stuck pipes and unlocking the URT in the well by lowering the pressure of the flushing fluid to the head of the working pipes at the wellhead, the tensile force F, which is most acceptable for the construction of the composite string, is applied and, after the URT is fixed in the well, the rotational drive applies torque M _cr to the column of working pipes of a value of not more than M1 and produce a smooth decrease in tensile force F to a value of P; if the unscrewing of the column in the threaded connection on top of the stuck pipe does not begin, sequential stepwise decreases in tensile force F <P are made by the value corresponding to the weight of the pipe in the free part of the stuck pipe, starting from the weight of the pipe screwed to the stuck pipe and after each drop the magnitude of the tensile force controls the beginning of the unscrewing of the threaded connection according to the testimony of the corresponding sensor on the rotation drive of the working pipe string on the well surface.

After loosening and lifting to the surface of a part of the stuck column, all operations are repeated until the pipes are completely removed or until a decision is made to stop the liquidation of the accident.

Salient features of the claimed method in comparison with the prototype are the following.

1. After conducting a profile - or cavernometry of the well and determining the upper boundary of the sticking and location of the fixing mechanism of the URT, calculating the length and installation of the connecting pipe, the necessary for the method are calculated:

L1 is the length of the free part of the stuck column from the sticking point to the reversal mechanism of the URT.

L2 is the length of the composite column from the sticking point to the rotation of the column on the surface of the wellhead;

M1 is the maximum allowable torque for the construction of the free part of the stuck column length L1;

P is the weight of the construction of the composite columns of length L2, taking into account the weight of the URT;

F is the maximum allowable tensile force for the construction of a composite column of length L2, taking into account the design of the URT.

The practice of eliminating accidents associated with sticking and removing pipes of a stuck column by unscrewing testifies to the low efficiency of the known method, which is determined, on the one hand, by the low productivity of unscrewing and curing single pipes from the column, and, on the other hand, by a high probability of mechanical failure of pipes or threads. This is a consequence of the application of not calculated values of mechanical forces to the combined design of the working and stuck pipe columns. In the first case, the loads were small compared to those required for sufficient efficiency, and in the second case they exceeded the tensile strength of the structural elements of the combined pipe string.

The proposed calculations allow us to determine and use the maximum allowable loads on structural elements to increase the efficiency of unscrewing.

2. After screwing the fishing tool onto the head of the stuck pipe string, the URT is released and the tensile force F. is applied to the head of the working pipes at the wellhead, which is the maximum allowable for the construction of the composite string, taking into account the URT.

After screwing the fishing tool onto the head of the stuck pipe string, a composite string is formed, which includes a sticked pipe string and a working pipe string with an attached URT with a connecting pipe and a fishing tool. The threaded pipe connections in the columns will be loaded with the weight of a certain part of the combined column and the load in each particular connection will be the greater, the more pipes will be located above this threaded connection. In addition, the effect of torque from the rotation drive of the working pipe string on the surface of the well will lead to spiral deformation of the combined string, which, especially with its long length, will lead to distortions of the threaded pipe joints, which will significantly increase the amount of torque required for " disruption of the thread and the beginning of unscrewing. At the same time, such deforming and weight loads on the threaded joint can lead to destruction of the pipe in the threaded joint when a corresponding torque value is applied. The application of the maximum allowable tensile force F, exceeding the weight load P of the composite pipe string, will guarantee the creation of tensile forces in the threaded joints of the pipe string that exceed the compressive forces from the weight of the column. This is necessary in order to have guaranteed "zeroing" of the load in the threaded connection of the string of stuck pipes as close as possible to the place of sticking, which will create conditions for the extraction of stuck columns in one operation. This will ensure maximum reliability and productivity of extraction of string of stuck pipes from the well.

3. The URT is fixed by increasing the pressure of the flushing fluid and the rotation drive at the wellhead applies torsion moment M _cr to the working pipe string, which corresponds to the value of M1 calculated by the maximum value M1 that is maximum allowed for the construction of the free part of the stuck string from the sticking point to the reverse mechanism.

The design of a composite column when exposed to its own weight and torque is in a complex force loading and has its structurally weak points and elements. In this regard, the maximum allowable torque value, determined from the condition of ensuring the mechanical strength of the combined columns, cannot be exceeded in order to avoid complications of the accident.

Given that if M _cr less than M1 i × q times,

where i is the gear ratio of the sinus ball reducer,

q is the efficiency (hereinafter referred to as efficiency) of a sinus ball transfer, then the magnitude of the torque M _cr , providing the most effective process for unscrewing, is determined from the expression

0.9M1 / i × q≤M _cr ≤0.95M1 / i × q,

where M1 is the maximum allowable torque for the construction of the free part of the stuck column of length L1 from the point of sticking to the reversal mechanism of the URT,

i is the gear ratio of the sinus ball reducer,

q is the efficiency of the sinus ball transfer.

The magnitude of the torque from the expression M _cr ≥0.9 M1 / i × q determines such a magnitude of the torque that will have an effective force effect on the threaded joint of the pipes in the process of untwisting the pipe threads, less than which, with a possible “sticking” or misalignment of the threads, the start of unscrewing and its completion are problematic. At M _cr ≤0.95 M1 / i × q, the torque value is limited to a value that is sufficiently close to the maximum, exceeding which may destroy the pipe material by thread or in another locally stressed or worn place.

When the above conditions for determining M _cr are satisfied, both maximum reliability and maximum efficiency are provided, since For unscrewing, the maximum allowable torque is applied from the strength point of view, which is also the most effective.

4. When applied to the maximum possible torque M _kr for the construction of the composite column, the tensile force F is smoothly reduced to a value of P, which compensates at the threaded joint of the stuck pipe and the pipe connected to it from above, compressing the load from the weight of the composite column. This is necessary in order to guarantee that the threaded connection is unloaded from the weight of the composite column in the immediate vicinity of the sticking point and there is no possibility of premature unwinding at a level of screw joints higher from the sticking point.

This provides a more productive and reliable extraction of pipes from the well.

5. If the unscrewing of the column does not begin in this case, in the immediate vicinity of the sticking point, successive stepwise reductions of the tensile force F are made by the value corresponding to the weight of the pipe in the free part of the stuck pipe, starting from the weight of the pipe screwed to the stuck pipe.

If after the application of the maximum permissible torque there was no “breakdown” of the thread and its unscrewing did not begin, then they proceed to unscrew the threaded joint next up the unscrewed threaded connection in the string of stuck pipes. For this threaded connection, another value of the compensating force will be optimal, which must be switched in stages, i.e. as quickly as possible, which will allow you to dynamically change (decrease) the amount of compensating effort and will contribute to the "breakdown" of the thread and the successful start of unscrewing.

If the thread does not unscrew when switching to a new value of the compensating force to unscrew the new threaded connection, then the next stepwise decrease in the compensating force is performed, and so on, they continue until the unscrewing of one of the threaded joints in the string of stuck pipes begins.

6. Reducing the compensating force by an amount corresponding to the weight of the pipe in the string of stuck pipes.

The decrease in the compensating force by an amount corresponding to the weight of the pipe in the stuck string is determined by the fact that the compensating force will be applied in the place of the stuck string spaced apart from the original in the upper direction by the length of the drill pipe. Therefore, the force should be reduced by the value of the weight of the drill pipe.

7. After each decrease in the magnitude of the tensile force, the beginning of the unscrewing of the threaded joint is controlled according to the readings of the sensor on the rotation drive of the working pipe string on the well surface.

A string of stuck pipes is subject to various factors determined by the well (geological composition of rocks, texture and fractional composition of rocks, formation pressure, location geometry, etc.), which affect the indicators of difficulty of sticking (accident): local sticking or extended, the intensity and amount of sticking force, etc. This, in turn, affects the possibility of unscrewing threaded pipe joints in a stuck string. Therefore, a sequential stepwise transition to a new threaded connection with a new reduced compensating force leads to the finding of such a threaded connection where the pipes of the stuck column are unscrewed. Such an important moment of the end of one technological operation and the transition to another - extraction from the well disconnected from the stuck pipe string is determined by the readings of the sensor on the rotation drive of the working pipe string (for example, by the pressure drop in the discharge line of the pump unit or by reducing the power consumption of the drive motor the rotation mechanism of the working column).

The above significant distinguishing features were not known to us from the patent and scientific and technical information and meet the criterion of "novelty", i.e. salient hallmarks are new.

Given that the above significant distinguishing features are not obvious to the average person skilled in the art, we believe that the invention meets the criterion of "inventive step". The invention meets the criterion of "industrial applicability", because its implementation does not present technical difficulties and can be carried out using existing drilling equipment and partial use of fishing equipment used to eliminate accidents.

It should be noted that according to the proposed method, after extracting part of the stuck column to the remaining part, it will be possible to apply M _cr larger than with the previous unscrewing, since the remaining part of the stuck column will have a shorter length and due to this will have greater mechanical strength, and the value of the calculated M1 will be greater. This will increase the reliability of unscrewing the most stressed threaded joints in the immediate vicinity of the sticking point. It will also allow maximizing the productivity of pipe extraction, which will be carried out practically from one or two lowerings of the URT into the well, and will ensure not only the extraction of pipes of the stuck string to the sticking point, but also contribute to the elimination of sticking. For this, the URT must be docked (screwed) with the stuck pipe and cyclically applied to it with the maximum torque developed by the drive rotation of the working pipe string, which will be increased by the reverse mechanism - a sinus-ball reducer. Calculations and practical tests show that the efforts arising from this in some cases can not only eliminate the cause of sticking (for example, collapse, etc.) by means of mechanical action from the stuck pipe on the wall of the well, but also mechanically destroy the stuck pipe itself. At the same time, the integrity and operability of the URT design, working pipes, connecting pipe and fishing tool are maintained.

The described method can be carried out, in particular, using the proposed device for unscrewing pipes, which, like the known prototype device, contains a housing, a reverse mechanism in the form of a sinus ball reducer, the input shaft of which is rigidly connected to the adapter, and the carrier is mounted movably relative to the housing , and the locking mechanism in the form of a pusher with a number of spring-loaded anchors movably mounted at a distance from each other around the perimeter of the carrier.

The proposed device differs from the prototype in that the locking mechanism contains at least two rows of spring-loaded anchors with pushers, and the second and each subsequent row of spring-loaded anchors are installed from the previous row at a distance of at least two diameters of the well.

The proposed device is characterized in that it further comprises a locking mechanism consisting of a housing in which a rigid gear coupling and a concentric hollow shaft with holes are mounted, on which a pusher with a spring and a pressure gear coupling are movably mounted on the splines, the housing and the hollow shaft with one the sides are rigidly connected to the hollow shaft and the housing of the locking mechanism, and on the other hand, to the adapter, the hollow shaft is rigidly and the housing is movable.

The device is characterized in that each pusher with a number of spring-loaded anchors is mounted on a separate hollow shaft inside a separate housing, while the anchors are located under the windows made in the housings, individual hollow shafts are connected to each other and to the input shaft of the reverse mechanism by internal bushings, and the housings are connected between themselves and the carrier of the reverse mechanism by external couplings.

Salient features of the claimed device are as follows.

1. The locking mechanism contains at least two rows of spring-loaded anchors with pushers. This is necessary for reliable fixation and compensation of spiral deformation in the joint column, which arises from the effect of the maximum allowable (calculated for a given length of the stuck column) torque M _{cr max} and which leads to distortions of the pipe threaded joints and, accordingly, additional efforts to unscrew such deformed threads. In addition, the unscrewing of such highly loaded deformed threads leads to intensive wear, which reduces reliability and service life. To reduce the distortions of the threaded connections, it is necessary to reduce the spiral deformation of the joint pipe string. For this, the spring-loaded anchors center the parts of the pipe string relative to the walls of the well, and if one row of anchors is used, the effect will be practically not observed, because one row of anchors provides centering in only one local place, which can only change the configuration of the bending deformations of the joint column. When two or more rows of anchors are used for centering, then the directional orientation of the deformed part of the combined column and URT relative to the axis of the borehole occurs. The conditions for this orientation are mainly the efforts developed by the spring-loaded anchors, the value of which should be sufficient to overcome the force of bending deformations of the pipe string. Elimination of bending deformations in the part of the combined column located directly in front of the sticking point, which is ensured by the presence of at least two rows of anchors located at a certain distance from each other, ensures the centering of the parts of the combined column above and below the URT for a certain distance, which depends on the strain value, which , in turn, depends on the length of the combined string, its rigidity, the diameter of the well, the magnitude of the torque applied to the string. Elimination of bending deformations of the joint string at the sticking point, significantly improving the alignment of the joint string and eliminating the distortions of the threaded pipe joints, significantly reduces the force required to “break” the thread and unscrew the threaded joint without destructive wear.

This significantly increases the reliability of unscrewing the threaded joints of the stuck column exactly in the place close to the grab, which will allow to unscrew and remove at the same time the largest part of the stuck column in length. This improves productivity and the associated reliability of the entire pipe extraction process.

To ensure reliable operation of the reverse mechanism, reliable fixation of its carrier is necessary, therefore two or more rows of spring-loaded anchors with pushers provide more reliable fixation of the housing of the locking mechanism, which is rigidly connected to the carrier of the reverse mechanism and thereby increases the reliability of the URT and the method.

2. The arrangement of the rows of spring-loaded anchors so that the second and each subsequent row is installed from a previous row at a distance of at least two diameters of the well, provides orientation (direction) of the application of force from the rows of spring-loaded anchors to the spiral-shaped design of the joint pipe string, leading to liquidation or significant reduction of deformation and reorientation of the deformed part of the pipe string near the sticking point.

For borehole diameters less than 100 mm, the rigidity of the combined pipe string, especially when its length is large, is objectively significantly less than for large diameters, and its effect on deformations in threaded joints is quite strong. Therefore, the most characteristic is the determination of the minimum distance between the rows of spring-loaded anchors for the joined pipe columns with such small diameters.

Two limiting cases can be considered.

The first, when the URT falls directly onto the head of the pipe of the stuck column located near the sticking point. In this case, the distance between the rows of spring-loaded anchors does not have much significance and influence, since the free part of the stuck string (up to the sticking point) can be considered as a rod with a clamped end, when exposed to the bare clamped end (contact of the rows of spring-loaded anchors with the walls of the well), deformation and axisymmetric orientation of the longitudinal axis of the stuck string relative to the longitudinal axis of the well will occur. This will lead to a significant reduction in bending deformation in threaded joints. In this case, the distance between the rows of spring-loaded anchors will be determined only by the requirements of structural design: the dimensions of the spring-loaded anchors and associated structural elements (springs, pushers, etc.), the dimensions of the hydraulic cavity, determined on the basis of the strength calculation, the difference in diameter of the housing of the locking mechanism and hollow shaft.

Based on the above structural justifications, the minimum distance between the rows of spring-loaded anchors is within two well diameters.

On the other hand, if you make this distance (between the rows of spring-loaded anchors) smaller, then there is a greater likelihood that the efforts from the spring-loaded anchors on the wall of the well can lead to destruction of the material of the wall of the well, its possible chipping or chipping, which will significantly complicate or even make impossible to fix spring-loaded anchors on the wall of the well. This will significantly reduce the reliability of fixing URT, and hence the reliability of its work.

The second limiting case - the head of the stuck column is at a considerable distance from the place of sticking. In this case, it is necessary to increase the distance between the rows of spring-loaded anchors, while again only structural limitations are imposed, associated with the dimensions of the structure, the convenience of its transportation, operation and maintenance.

3. Implementation in the URT of a locking mechanism consisting of a housing in which a rigidly gear coupling and a concentric hollow shaft with holes are installed, on which a pusher with a spring and a pressure gear coupling are movably mounted on the splines, the housing and the hollow shaft, on the one hand, rigidly connected to the hollow shaft and the housing of the locking mechanism, and on the other hand, to the adapter, and the hollow shaft is rigid, and the housing is movable, increases the safety of URT from possible side and vertical impacts when moving in the well, and therefore increases its performance and reliability in general. In addition, in the locked (transport) position, the locking mechanism makes it impossible to rotate the hollow shaft relative to the housing of the locking mechanism, which improves the reliability of the URT when applying vertical tensile loads. This also ensures the impossibility of arbitrary rotation of the driven shaft with possible hooks in the well during lifts, which also increases reliability and extends the technological capabilities during operation of the URT.

The proposed method and device for its implementation are disclosed in more detail by the following examples, which, however, do not exhaust all possible implementation options.

The invention is illustrated by drawings, where figure 1 shows a diagram of the implementation of the method; figure 2 schematically shows the URT; figure 3 shows part of the design of the locking mechanism of the URT; figure 4 shows the transport position of the spring-loaded anchors of the fixing mechanism of the URT; figure 5 shows the working position of the spring-loaded anchors of the fixing mechanism of the URT; figure 6 shows the reverse mechanism of URT.

The proposed method of extracting pipes from the well is as follows:

- conduct a profile - or cavernometry of the well 1 and determine the upper boundary of the sticking 2 and closest to the head of the stuck column 3 place in the trunk (undeveloped, with stable and strong walls) for reliable fixation URT 4;

- calculate the length of the connecting pipe 5 and install it between the output shaft 6 of the reversal mechanism 7 of the URT 4 and the fishing tool 8 attached to it based on the requirement that when the fishing tool 8 is placed on the head of the stuck column 3, the fixing mechanism 9 of the URT 4 is in a certain previous action the place providing its reliable fixation in the well 1;

- calculate L1 - the length of the free part of the stuck column 3 from the sticking point 2 to the reverse mechanism of the URT;

- calculate L2 - the length of the composite column from the sticking point 2 to the drive rotation of the column on the surface of the wellhead;

- calculate M1 - the maximum allowable torque for the construction of the free part of the stuck column 3 of length L1;

- calculate P - the weight of the structure of the composite columns L2, taking into account the weight of URT 4;

- calculate F - the maximum allowable tensile force for the construction of a composite column of length L2, taking into account the design of URT 4;

- carry out the descent on the right working pipes 10 to the calculated depth in the well 1 of URT 4 until the contact of the fishing tool 8 with the head of the stuck pipe string 3;

- perform fixing URT 4 in the calculated location of the well 1 by increasing the pressure of the flushing fluid supplied through the column of working pipes 10 to the locking mechanism 9 and the extension of the spring-loaded anchors 11 to contact (stop) with the walls of the well 1;

- make screwing of the fishing tool 8 to the left of the stuck pipe string 3 to the left under the action of the right rotation of the working pipe string 10 rotated by the reverse mechanism 7 into the left rotation of the fishing tool 8;

- release URT 4 by lowering the pressure of the flushing fluid and returning the spring-loaded anchors 11 of the fixing mechanism 9 to its original (transport) position;

- the estimated tensile force F is applied to the head of the working pipes 10 with a drive (not shown) at the wellhead 1;

- perform fixing URT 4 in the well 1 by increasing the pressure of the flushing fluid through the column of working pipes 10 into the mechanism of fixation 9 and the extension of the spring-loaded anchors 11 to contact (stop) with the walls of the well 1;

- apply a rotation drive (not shown) with a torque M _cr to the column of working pipes 10, the value of which corresponds to the calculated value M1 and is within

0.9 M1 / i × q≤M _cr ≤0.95 M1 / i × q,

where M1 is the maximum allowable torque for the construction of the free part of the stuck column of length L1 from the point of sticking to the reverse mechanism of the URT,

i is the gear ratio of the sinus ball reducer,

q is the efficiency of the sinus ball transfer.

- produce a smooth decrease in the tensile force F to a value of P, if this does not begin to unscrew the column in the threaded connection on top of the stuck pipe, produce sequential stepwise decrease in the value of the tensile force F = P by the value corresponding to the weight of the pipe in the free part of the stuck column 3, starting from the value of the weight of the pipe screwed to the stuck pipe, and after each decrease in the value of the tensile force, the start of unscrewing the threaded joint according to the sensor on a rotation drive (not shown) of the string of working pipes 10 on the surface of the well;

- after unscrewing the threaded connection, the unscrewed part of the stuck pipe string 3 is removed from the well 1 to the surface.

After loosening and lifting to the surface of the free part of the stuck column 3 of length L1, decisions are made to stop the liquidation of the accident, and if only part of the stuck column 3 is removed, then all operations are repeated.

Thus, the invention (method) provides an increase in the reliability and productivity of extraction from the well of a string of stuck pipes.

In the best way, the method is implemented by the proposed URT for extracting from the well of a string of stuck pipes.

URT 4 consists (figure 2) of the locking mechanism 12, the locking mechanism 9 and the reverse mechanism 7 with the transition mechanism 13.

The locking mechanism 12 and the locking mechanism 9 are located on the hollow composite shaft 14 in the composite housing 15. Parts of the hollow composite shaft 14 of the locking mechanism 12 and the locking mechanism 9 are connected by internal threaded sleeves 16, and parts of the composite housing 15 are connected by external threaded nipples 17. The hollow composite shaft 14 in the upper part is rigidly connected to the adapter 18, intended for connection with a column of working 10 pipes. The hollow composite shaft 14 in the lower part is connected by a coupling 19 to the hollow input shaft 20 of the reverse mechanism 7.

The reverse mechanism 7 is made in the form of a sinus ball reducer, the output shaft 6 of which is connected at the bottom with the housing 21 of the transition mechanism 13, in which a valve 23 with an adapter 24 is installed on the spline connection 22 for connecting the fishing tool 8. If necessary, increase the distance between the URT 4 and fishing tool 8 on the adapter 24 is installed connecting pipe 5.

The locking mechanism 12 consists (Fig. 3) of a pressure sleeve 25 with teeth 26 mounted on the slots 27 on a hollow composite shaft 14 with holes 28, sleeve 29 with teeth 30, rigidly fixed in the composite housing 15 with pins 31, pusher 32 and return spring 33.

The locking mechanism 12 provides, with increasing pressure of the flushing fluid to a predetermined (defined) value, compression of the return spring 33, movement of the pusher 32 and disengagement of the teeth 26 and 30 of the respective couplings 25 and 29, which leads to the separation of the kinematic connection between the hollow composite shaft 14 and the composite housing 15 In this case, the right rotation of the working string 10 of the pipes is transmitted through the hollow composite shaft 14 to the input shaft 20 of the reverse mechanism 7, in which it changes to the left rotation of the output shaft 6 and, accordingly, the fishing tool Rumenta 8.

When the pressure of the washing fluid decreases below a predetermined value, the locking mechanism 12 establishes a mechanical (kinematic) connection between the hollow composite shaft 14 and the composite housing 15, as a result of the movement of the pusher 32 under the action of the spring 33 and the entry of the teeth 26 of the coupling 25, rigidly connected to the hollow composite shaft 14 through a spline connection 27, in engagement with the teeth 30 of the coupling 29, rigidly fixed in the composite housing 15 with pins 31.

The locking mechanism 9 consists (Figs. 4, 5) of two rows of spring-loaded anchors 11 located at the same distance from each other around the circumference in the windows 34 of the composite housing 15 and resting on the conical part of the pushers 35. The pushers 35 are mounted with the possibility of longitudinal movement on the floor composite shaft 14 with holes 28.

In each spring-loaded anchor 11 of each row, a flat spring 36 is movably mounted in a profiled groove (dovetail type — not shown), one end of which is located in a clutch 37 mounted on a hollow composite shaft 14. The flat springs 36 of each rows of anchors 11 are worn a round spring 38 fixed at one end near the sleeve 37.

The distance between the rows of anchors 11 is not less than two diameters of the well 1.

The locking mechanism 9 is designed to fix from the movements of the composite body 15 in the well 1 and ensure the operation of the reverse mechanism 7.

The reverse mechanism 7 consists (Fig. 6) of a hollow shaft 20 with grooves 39, an intermediate shaft - a carrier 40 with grooves 41, covering bushings 42 with sinusoidal treadmills 43, rigidly fixed inside the hollow output shaft by 6 pins 44, ball bearings 45, a bearing 46, lower 47 and upper 48 seals. The carrier 40 is rigidly connected to the composite housing 15 of the locking mechanism 9 and forms a stepped sleeve with it.

The reverse mechanism 7 is designed to change the right rotation of the working string 10 of pipes to the left rotation of the output shaft 6 with a gear ratio i.

The transition mechanism 13 consists of a housing 21 with a throttle washer 49, in which a valve 23 with a cone 51, a channel system 52 and an adapter 24 for connecting directly or through a connecting pipe 5 to a fishing tool 8 is mounted on the spline connection 22 with a spring 50. The housing 21 is rigidly connected to the output shaft 6 of the reverse mechanism 7.

The working (drill) pipes and the locking mechanism have a right-hand thread, and the connections of the URT parts and the fishing tool have a left-hand thread.

The transition mechanism 13 is designed to shut off the flow of flushing fluid passing through the hollow composite shaft 14 in the locking mechanisms 12 and fixing 9, the input shaft 20 of the reverse mechanism 7, the throttle washer 49 and the channel system 52 of the valve 23, at the time of setting the working string 10 pipes on the head stuck column 3, as well as to transmit rotation from the working string 10 of pipes to fishing tool 8 and to compensate for the axial movement of the string of stuck pipes 3 when it is unscrewed.

Removing pipes from the well by the method using URT is as follows.

According to geophysical studies in well 1 or from existing core material, a stable undisturbed section in well 1 is located that is closest to the “head” of the stuck pipe string 3, in which URT 4 can be firmly fixed. Then, the length of the connecting pipe 5, which is one end attached to the adapter 24 of the valve 23, and the other end is connected to the fishing tool 8. The connecting pipe 5 should be of such a length that when fixing URT 4 in the well section 1 fishing tool 8 is distributed Color was placed a stuck pipe string 3.

If the well section 1 provides reliable fixation of URT 4 at its location when installing the fishing tool 8 on the “head” of the stuck pipe string 3, then there is no need to install the connecting pipe 5 and the fishing tool 8 is installed directly on the adapter 24.

Curb URT 4 on the working column 10 pipes are installed on the head of the stuck column 3 pipes. When this is compressed, the spring 50 of the transition mechanism 13 and the valve 23, moving, blocks the cone 51 of the hole of the throttle washer 49, which leads to an increase in the pressure of the flushing fluid in the URT 4. Under pressure, the flushing fluid through the hollow composite shaft 14 and the holes 28 enters the locking mechanisms 12 and fixation 9.

Flushing fluid is supplied (injected) through the working string 10 of the pipes, which through the openings 28 in the hollow composite shaft 14 enters the internal cavities of the locking mechanism 9 and exerts pressure on the pushers 35, which, while moving, push the spring-loaded anchors 11 into the windows 34 to the stop with the walls wells 1 and thereby fix the composite housing 15. At the same time, the flushing fluid enters the internal cavity of the locking mechanism 12 and puts pressure on the pusher 32, which, moving, moves the pressure sleeve 25, removing its teeth 26 from tsepleniya with 30 teeth clutch 29.

Then, the working string 10 of pipes at the wellhead 1 is given the right rotation, which is transmitted through the hollow shaft 14 to the reverse mechanism 7, in which the carrier 40, rigidly connected to the composite body 15 fixed in the borehole 1, is also fixed from possible movements. In the URT, the ball satellites 45 are driven, which, rolling along the grooves 39 on the input shaft 20, interacting with the grooves 41 of the carrier 40 and the sinusoidal treadmills 43 of the covering bushings 42, cause the hollow output shaft 6 to be rigidly connected with the pins 44 to rotate in left side. Bearing 46 accepts axial loads, and the lower 47 and upper 48 seals protect the reverse mechanism 7 from the influence of the external environment. The reverse mechanism 7 changes the right rotation of the working string 10 of pipes to the left rotation of the fishing tool 8, which is screwed onto the “head” of the stuck pipe string 3. In this case, the axial movement of the adapter 24 is provided by the valve 23.

Stop the rotation of the working string 10 pipes and relieve the pressure of the flushing fluid. When the pressure of the flushing fluid in the locking mechanism 9 decreases, the flat spring 36 returns the pusher 35 to its original position, and the spring-loaded anchors 11 move inside the composite housing 15. At the same time, in the locking mechanism 12, the return spring 33 returns the pressure sleeve 25 to its place, engaging the teeth 26 and 30. The composite body 15 is fixed relative to the wellbore 1.

Produce the necessary to implement the method of calculating the lengths, weight and load parameters of the combined columns and its parts:

L1 is the length of the free part of the stuck column from the sticking point to the reversal mechanism of URT;

L2 is the length of the composite column from the sticking point to the rotation of the column on the surface of the wellhead;

M1 is the maximum allowable torque for the construction of the free part of the stuck column length L1;

P is the weight of the construction of a composite column of length L2, taking into account the weight of URT 4;

F is the maximum allowable tensile force for the construction of a composite column of length L2, taking into account the design of URT 4.

To the head of the working string 10 of pipes at the wellhead 1, an upward maximum permissible tensile force F is applied, exceeding the compressive axial load from the weight P of the composite string of working pipes 10 in the place of the threaded joint closest to the stick 2.

Flushing fluid is supplied (injected) through the working string 10 of the pipes, which through the openings 28 in the hollow composite shaft 14 enters the internal cavities of the locking mechanism 9 and exerts pressure on the pushers 35, which, while moving, push the spring-loaded anchors 11 into the windows 34 to the stop with the walls wells 1. URT is fixed 4. At the same time, the flushing fluid enters the internal cavity of the locking mechanism 12 and puts pressure on the pusher 32, which, moving, moves the pressure sleeve 25, disengaging its teeth 26 from the mesh 30 clutch teeth 29. Unlocking occurs composite hollow shaft 14, i.e., there is a separation of the kinematic connection with the composite housing 15.

Then, the working string 10 of pipes at the wellhead 1 is given the right rotation, which is transmitted through the hollow shaft 14 to the reverse mechanism 7, in which the carrier 40, rigidly connected to the composite body 15 fixed in the borehole 1, is also fixed from possible movements. In the reverse mechanism 7, the ball satellites 45 are driven, which, rolling along the grooves 39 on the input shaft 20, interacting with the grooves 41 of the carrier 40 and the sinusoidal racetracks 43 of the covering bushings 42, force the latter and the hollow output shaft 6 rigidly connected by pins 44 rotate to the left. The reverse mechanism 7 changes the right rotation of the working string 10 pipes to the left rotation of the stuck column 3 pipes.

It is controlled that the magnitude of the applied torque M _cr to the column of working pipes 10 corresponds to the calculated value M1 and determined from the inequality

0.9 M1 / i × q≤M _cr ≤0.95 M1 / i × q,

where M1 is the maximum allowable torque for the construction of the free part of the stuck column of length L1 from the point of sticking to the reverse mechanism of the URT,

i is the gear ratio of the sinus ball reducer,

q is the efficiency of the sinus ball transfer,

and at the wellhead 1, a tensile force F is gradually reduced to a value of R. The reactive moment from the rotation of the output shaft 6 of the reverse mechanism 7 is perceived by the anchors 11 in the windows 34 of the locking mechanism 9. Since the upward force F compensates the compressive axial load from the threaded joint from weight P of the composite column L2, then in this threaded connection occurs the so-called “zeroing” of the weight. Under the influence of the torque transmitted by the working string of pipes 10 and increased by the reverse mechanism 7 by the gear ratio of the sinus ball transfer to the maximum possible value M _cr for the particular design of the composite column L2, a “breakdown” and loosening of the threaded joint occurs.

Control the start of unscrewing the threaded connection according to the sensor on the rotation drive (not shown) of the working pipe string 10 on the surface of the well 1. When unscrewing the pipes, the axial movement of the stuck pipe string 3 through the adapter 24 is provided (compensated) by the valve 23.

After unscrewing the threaded connection, the rotation of the working string 10 of the pipes is stopped and the pressure of the washing liquid is relieved. When the pressure of the washing fluid in the locking mechanism 12 decreases, the return spring 33 returns the pressure sleeve 25 into place, engaging the teeth 26 and 30. This creates a rigid kinematic connection and the composite body 15 is fixed relative to the hollow composite shaft 14. In the locking mechanism 9, a flat spring 36 returns the pusher 35 to its original position, and the anchors 11 are moved inside the composite housing 15. URT 4 is unblocked in the well 1 and the unscrewed h is extracted to the surface on the working pipes 10 STI column 3 stuck pipe.

If not all the free part of the stuck column 3 is removed, then all operations are repeated, and a new location of fixation of the URT is determined and the parameters L1, L2, F, P, M _cr and M1 are again calculated.

If, with a smooth decrease in the tensile force F to a value of P, the sticking of the stuck pipe string 3 does not start in the threaded connection on the top of the stuck pipe, which is determined by the sensor on the rotation drive (not shown) of the string of working 10 pipes on the surface of the well 1, a stepwise (sharp ) a decrease in tensile force F = P by an amount corresponding to the weight of the pipe in the free part of the stuck column 3, starting from the pipe screwed to the stuck pipe. In this case, the “zero” section, i.e. the place where the weight of the composite pipe string and the tensile force F (directed to the surface) are equal in magnitude and directed in different directions, moves to the upper threaded joint of the pipe screwed to the stuck pipe. The start of unscrewing the threaded connection is monitored according to the readings of the sensor on the rotation drive (not shown) of the working pipe string 10 on the well surface and the unscrewed part of the stuck pipe string 3 is extracted to the surface of the working pipe 10.

If the unscrewing does not occur, then again the tensile force F is reduced stepwise by the amount corresponding to the weight of the next upward pipe in the free part of the stuck column 3 and the start of unscrewing the threaded joint is controlled.

The claimed technical solution is original, does not follow obviously from the existing level of technology and meets the requirements of "inventive step".

Thus, the claimed technical solution fully fulfills the task of increasing productivity and reliability of extracting from the well string of stuck pipes using a string of working pipes with a right-hand thread with an attached URT with a connecting pipe and fishing tool.

The claimed technical solution is currently not known in the Russian Federation and abroad and meets the requirements of the criterion of "novelty."

The technical solution can be implemented industrially in mass production using well-known technical means, technologies and materials and meets the requirements of the criterion of "industrial applicability".

The present invention meets the "industrial applicability", because the principle of operation of the device has been tested in a production environment with a positive result, there are acts of industrial and industrial testing of a prototype of URT.

The present invention can be used in the elimination of accidents associated with sticking pipes during drilling, as well as in overhaul of wells.

Claims (3)

1. A method of extracting pipes from a well, including the descent on the right working pipes to the calculated depth into the well of a device consisting of a locking mechanism and a reverse mechanism, to the output shaft of which a fishing tool with a left thread is connected through an adapter and a connecting pipe until the fishing tool contacts head of the stuck pipe string, fixing the device in the calculated location of the wellbore by supplying flushing fluid through the working pipe string to the mechanism for fixing and extending the spring-loaded anchors to stop with the borehole, screwing the fishing tool to the left of the stuck pipe string under the action of the reverse rotation of the right rotation of the working pipe string into the left rotation of the fishing tool, unscrewing the thread in the pipe connection of the stuck string, unlocking the device as a result of pressure relief of the flushing fluid and the return of spring-loaded anchors the mechanism of fixation in the initial position, the extraction from the wellbore to the surface unscrewed from the stuck string hour and pipes, characterized in that, after determining the upper limit of sticking and fixing mechanism URT location in the barrel and calculating the length of the connection pipe
calculate L1 - the length of the free part of the stuck column from the sticking point to the reversal mechanism of the URT;
calculate L2 - the length of the composite string from the sticking point to the drive rotation of the column on the surface of the wellhead;
calculate M1 - the maximum allowable torque for the construction of the free part of the stuck column length L1;
calculate P is the weight of the structure of the composite columns of length L2, taking into account the weight of the URT;
calculate F is the maximum allowable tensile force for the construction of a composite column of length L2, taking into account the design of the URT,
and after installing and screwing the fishing tool onto the head of the string of stuck pipes and unlocking the URT in the well by lowering the pressure of the flushing fluid to the head of the working pipes at the well head, the tensile force F, which is most acceptable for the construction of the composite string, is applied and, after the URT is fixed in the well by a rotation drive, apply torque M _cr to the column of working pipes of size Ml and produce a smooth decrease in tensile force F to a value of P, if this does not begin to unscrew the column in the threaded connection at the top of the stuck pipe, successive stepwise reductions of the tensile force F = P are made by an amount corresponding to the weight of the pipe in the free part of the stuck pipe, starting from the weight of the pipe screwed to the stuck pipe, and after each decrease in the tensile force, the start of unscrewing of the threaded connection is controlled according to the testimony of the corresponding sensor on the drive rotation of the column of working pipes on the surface of the well. 2. A device for unscrewing pipes, comprising a housing, a reverse mechanism in the form of a sinus ball reducer, the input shaft of which is connected through an adapter to the column of working pipes, and the carrier is mounted movably relative to the housing, and a locking mechanism in the form of a pusher with a number of spring-loaded anchors that are installed at a distance from each other along the perimeter of the carrier with the ability to move in a radial direction relative to the longitudinal axis of the carrier, characterized in that it is equipped with a locking mechanism consisting of a hollow shaft holes, on which the pusher with spring and splines are movably mounted, a clutch engaged with a clutch fixedly mounted in the housing, the hollow shaft and the housing being connected in the upper part to the adapter and in the lower part to the hollow shaft and the fixing mechanism housing, and the fixing mechanism contains at least two rows of spring-loaded anchors, the second and each subsequent row of spring-loaded anchors installed at a distance of at least two diameters of the well from the previous row. 3. The device according to claim 2, characterized in that each pusher with a number of spring-loaded anchors is mounted on a separate hollow shaft inside a separate case, while the spring-loaded anchors are located under the windows made in the cases, individual hollow shafts are connected to each other and to the input shaft the reverse mechanism by internal bushings, and the cases are interconnected and the carrier of the reverse mechanism by external couplings.

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