RU2645060C1 - Device for repair of casing and production strings with help of double cone-transformer - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: device comprises a plaster in the form of smooth metal branch pipe with elastic sealing rings on the outside, and an expanding mandrel, made in form of double cone-transformer and consisting of head and tail cones-transforms, each of them is formed by spring-loaded cone-shaped segments located in grooves of a conical part of body for longitudinal movement. At that, the vertex of each cone-transformer body is directed to the side opposite to the working stroke of the expanding mandrel, which provides the smoothest expansion of the plaster. The maximum diameter of the head cone-transformer is less than the maximum diameter of the tail cone, which creates the appearance of a non-contact band of deformation of the plaster and reduces the axial force. The device is provided with a counter-return device for preventing backward stroke. A block of power reinforced collars is used as a piston driving the cone-shaped sectors. To control the geometry of the double cone-transformer, a deblocking mechanism is provided, by means of which the double cone-transformer is returned to the original diametric dimensions.

EFFECT: by reducing the deformation force of the plaster, emergency situations are prevented in case of jamming of the expansion mandrel in course of repair of casing and production strings, reliability and efficiency of the device increase.

3 cl, 5 dwg

Description

FIELD OF TECHNOLOGY

The invention relates to the oil and gas industry, mainly to devices for sealing casing strings and shutting down formations.

BACKGROUND

A device for sealing a casing string, disclosed in the description of patent RU No. 2236550 C1, class. ЕВВ 29/10, publ. 09/20/2004.

The known device contains a patch in the form of a smooth cylindrical metal pipe, a hydraulic landing tool, which is a three-cylinder hydrostatic drive, and an expanding mandrel having the shape of a truncated cone; at the ends of the patch in the annular cylindrical grooves made in it, elastic seals are placed, and the hydraulic landing tool is equipped with a hydraulic anchor.

The disadvantages of this device include a large number of complex mating precision parts of hydraulic cylinders, leading to higher prices and lower reliability of the entire structure, as well as limited travel of the pistons of the hydraulic cylinders, which entails the inability to seal significant over the length of damage to the casing or several sections of leaks located on a significant distance from each other. In addition, the expansion of the repair patch from the initial diametric size to pressing it against the walls of the casing by pulling a conical mandrel in one step (in fact, cold deformation of the metal pipe billet) requires significant axial forces, which entails additional energy consumption during repair wells.

A device for repairing a casing string according to the copyright certificate SU 1659621 A1, IPC Е21В 29/10, publ. 06/30/1991, bull. Number 24. The device descends into the well on a geophysical cable and includes an electric motor with a gearbox, a plunger hydraulic pump, a system of control valves, a differential piston, and also an outgoing cone with spring-loaded floating dies and a rolling head kinematically connected to the motor shaft located in the casing. The differential piston moves the mandrel with spring-loaded floating dies inside the plaster, expanding it, and the rolling head with its rotation finally straightens and smoothes the plaster walls, pressing it to the production casing. Thus, the expansion of the patch occurs in two stages, which reduces the energy consumption for the metal deformation process.

The main disadvantage of the described device is the design complexity of the well module, in which an electro-hydromechanical drive system with many precision parts and components is mounted. In addition, the rolling method is applicable mainly for thin-walled longitudinally corrugated plasters, which limits the scope of the described device. And finally, the most important disadvantage of the known device is the restriction on the length of the patch arising from the design. The length of the patch is limited by the stroke of the piston and the length of the drive shaft of the rolling head. Thus, this device is not applicable for sealing extended defective sections of production casing.

The closest analogue of the claimed invention (prototype) is a three-stage cutting head disclosed in the description of patent RU 2154148 C2, class. ЕВВ 29/10, publ. 08/20/2000.

The device known from the closest analogue contains the main cone-punch, floating segments located on the self-sealing cuff, as well as spring-loaded conical dies installed between the cone-punch and floating segments with the possibility of longitudinal movement in the dovetail grooves made on the conical part of the main corps. In this case, the conical part of the body is directed upward, i.e. along the mandrel during the expansion of the patch. When the dorning head enters the patch, its preliminary expansion is carried out by the cone-punch, then the intermediate by conical dies due to their axial and peripheral displacement in the grooves, and the final one by floating segments under hydraulic pressure in the system.

The disadvantages of the known closest analogue of the device include its initial focus on working with longitudinally corrugated plasters, which sharply limits the scope of its application. Thin-walled corrugated patches can provide sealing of defective sections of the production string only at low reservoir pressure of the fluid in the well. To repair wells with large reservoir pressures, sometimes reaching 100 or more atmospheres, it is necessary to press a metal patch to the column wall using elastic o-rings, which are installed (for example, can be vulcanized) on the outer surface of smooth cylindrical plasters. Only in this case, a guaranteed cut-off of the defective section of the production casing is achieved. In addition, the design of the mandrel head implies its entry into the patch from the end, and then the beginning of expansion, i.e. the patch should be anchored. Thus, the set of equipment should additionally include a patch anchoring system, which complicates and increases the cost of repair of the production casing. And finally, the most significant drawback of the proposed design is that the main expansion of the patch is made by the cone-punch almost immediately to the required radial size, and further effects on the walls of the patch are aimed only at squeezing and smoothing out the irregularities remaining after straightening the longitudinal corrugations. As a result, the axial pulling force of the mandrel head along the expandable patch is not reduced.

SUMMARY OF THE INVENTION

The task of the invention is to develop a device for repair of casing and production strings using a double transformer-cone, as well as improving the reliability and expanding the scope of applicability of the device as a whole.

The technical result of the invention is to increase the reliability and efficiency of the device due to the use of an expanding mandrel in the form of a double transformer cone, which provides a reduction in force for the distribution of the patch and, in addition, equipped with a release mechanism, which allows in case of emergency to remove the device from the patch by reducing its diametric dimension. The specified technical result is achieved due to the fact that in the inventive device, in order to reduce the axial force necessary for the deformation of the patch, the expanding mandrel is equipped with an additional transformer cone with the formation of a double transformer cone consisting of head and tail transformer cones kinematically connected to each other another with the help of pushers, and the angle at the apex of the conical body of the head transformer cone is less than the same angle of the transformer tail cone. In addition, the device is equipped with a release mechanism for the return of the expanding mandrel to the original diametric dimension. At the same time, the transformer head and tail cones are mounted on a tubular rod with angular displacement relative to each other so that the middle of each cone-shaped segment of any of the transformer cones is located opposite the gap between the segments of the second transformer cone.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more clear from the description, which is not restrictive and given with reference to the accompanying drawings, which depict:

FIG. 1 is a longitudinal section of a device for repairing casing and production strings using a double transformer cone at the beginning of the expansion process of the patch:

1 - production casing; 2 - patch; 3 - elastic sealing ring; 4 - expanding mandrel (dual cone-transformer); 5 - spacer of the head cone-transformer; 6 - spacer of the tail cone-transformer; 7 - block power reinforced cuffs; 8 - anti-return mechanism; 9 - spring; 10 - restrictive sleeve; 11 - landing unit; 12 - drilled shoe with check valve; 13 - resettable plug; 14 - release mechanism for the return of the expanding mandrel to the original diametric dimension; 15 - tubular traction (mandrel); 16 - threaded sub.

FIG. 2 is a view A in FIG. 1 on a magnification scale (production casing (1) and patch (2) are conventionally not shown):

17 - head cone-transformer; 18 - tail cone-transformer.

FIG. 3 is a view B in FIG. 1 to scale:

19 - conical body of the head cone-transformer; 20 - segment of the head cone-transformer; 21 - a pusher; 22 - conical body of the tail cone-transformer; 23 - segment of the tail cone-transformer.

FIG. 4 - projection views, including isometry of the head cone-transformer in magnification.

FIG. 5 - the same tail cone-transformer.

DETAILED DESCRIPTION OF THE INVENTION

A device for repairing casing and production strings using a double transformer cone contains a patch (2) in the form of a thin-walled smooth pipe with external elastic sealing rings (3) at the ends and an expanding mandrel (4) in the form of a double transformer cone inside the patch ( 2) and worn on tubular traction (mandrel) (15). On the one hand, the expanding mandrel (4) is in contact with the release mechanism (14), and on the other hand, through the spacer (6) of the tail transformer cone (18) it is supported by a block of power reinforced cuffs (7). The expanding mandrel (4) is a double transformer cone (Fig. 2), consisting of a head (17) and a tail (18) transformer cones, each of which has a conical body (19) and (22) in which for example, parallel to forming a cone, dovetail grooves with cone-shaped segments (20) and (23) placed in them with the possibility of longitudinal movement (Fig. 3, Fig. 4, Fig. 5), the angle at the top of the conical body ( 19) the head cone-transformer (17) is less than the same angle of the body (22) of the tail cone-transf omerra (18). In the conical housing (22) of the tail cone-transformer (18), additional through dovetail grooves are made parallel to the cone axis to accommodate pushers (21) that serve to transmit movement from the tail cone-transformer segments (23) (18) to the segments (20) transformer head cone (17). The anti-return mechanism (8) serves to prevent unwanted axial rearward movement of the expanding mandrel (4) after starting the expansion process of the patch (2) (Fig. 1) and is essentially a ratchet mechanism in which the ratchet wheel degenerates into a rail (in this case, in a series of grooves (notches) on the outer cylindrical surface of the tubular rod (mandrel) (15)). The spring (9) serves to force-close all parts of the device located between the shoulder of the tubular rod (mandrel) (15) and the release mechanism for returning the expanding mandrel to the initial diametric dimension (14) (hereinafter referred to as the "release mechanism"). The latter is designed to ensure unimpeded axial upward movement of the conical bodies (19) and (22) of both transformer cones in an emergency, freeing them from a fixed position, which allows both transformer cones (17) and (18) to return to their original diametric dimensions. The head (17) and tail (18) transformer cones are located on a tubular rod (mandrel) (15) with an angular displacement relative to each other so that the middle of each cone-shaped segment (20) or (23) of any of the transformer cones is opposite the gap between the segments of the second cone-transformer (Fig. 2). In the general case, the optimum angular displacement described above is 180 ° / n, where n is the number of segments. The maximum diametrical dimension d _max of the transformer head cone (17) and the maximum diametrical dimension D _{max of} the transformer tail cone (18) are limited by the longitudinal section geometry of the spacers (5) and (6), which abut against the ends of the respective housings (19) and (22) ) and do not allow segments (20) and (23) to be moved when reaching maximum sizes (Fig. 2). Moreover, d _max <D _max . The restriction sleeve (10) prevents springing and breaking of the spring (9) when lifting the mandrel (15), which is connected using a sub (16) to the rig rig (not shown in the figures) by means of rods, for example, in the form of a tubing string (Tubing). The lower end of the patch (2) is hermetically sealed with a drilled shoe (12) with a check valve (not shown in the figures). A landing device (11) with a seat (not shown) for a resettable plug (13) is mounted in the shoe (12) (Fig. 1).

A device for repair of casing and production strings using a double transformer cone operates as follows.

The device is lowered into the well by traction, for example, on the tubing string, until the defective section of the production string (1) is in the interval between the elastic sealing rings (3) of the patch (2). Moreover, the latter, depending on the nature and location of defects in the production string (1), can be extended by composing from separate sections, for example, using low-profile threaded connections. Then, the plug (13) is dumped from above (Fig. 1), which sits in the saddle of the landing device (11), and pumping of the working fluid begins. The latter penetrates into the cavity between the walls of the tubular rod (mandrel) (15) and the patch (2), causing axial movement of the block of power reinforced cuffs (7), which acts as a piston. Through the spacer (6) of the tail cone-transformer (18), the cuff block (7) presses on the cone-shaped segments (23) of the latter, which move along the dovetail grooves (Fig. 1, Fig. 3) of the conical body (22), simultaneously making a movement to the periphery and acting on the walls of the patch (2), thereby smoothly distributing it (Fig. 2). At the same time, segments (23) of the tail transformer cone (18) through the pushers (21) drive the segments (20) of the head transformer cone (17), which also, sliding in their grooves, increase the diametrical dimension of the latter and create their own patch expansion zone (2). Since the angle at the apex of the conical body (19) of the transformer head cone (17) is smaller than the same angle at the transformer tail cone (18), and the dovetail grooves in the conical bodies (19) and (22) of both transformer cones made parallel to the generatrix, the angle of inclination of each groove of the head transformer cone (17) in the longitudinal plane is also smaller than that of the tail transformer cone (18). It follows that with the same axial movement of all moving structural members, the diametric dimension d _max of the transformer head cone (17) will be smaller than the similar size D _{max of} the transformer tail cone (18) (Fig. 2). Thus, two zones of cold deformation of a smooth-walled pipe arise, formed by two conical mandrels. In this case, there is a significant (up to 2 times!) Decrease in the axial force of distribution of the patch. Reducing the pulling force of the expanding mandrel is based on the effect of combining non-contact deformation zones during cold expansion of pipes. This effect consists in the fact that during cold deformation of a pipe by a punch in the form of a series of truncated cones, the axial pulling force of the punch decreases by 1.5 ... 2 times in comparison with the expansion of a pipe by one cone to the same size, ceteris paribus due to the formation of a free deformation wave between adjacent cones (AM Rosenberg, OA Rosenberg "The mechanics of plastic deformation in cutting and deformation pulling processes" - Kiev: Naukova Dumka, 1990, pp. 154-155; pp. 158-159). The beginning of the process of distribution of the patch (2) simultaneously produces its anchoring in the production casing (1) due to deformation of the nearest elastic sealing rings (3) (Fig. 1). If a patch (2) is used without a section previously expanded from the lower end, the power reinforced cuff block (7), straightening in the expanded part of the patch (2), maintains contact with its walls and continues to play the role of a piston. The anti-return mechanism (8) under the influence of the spring (9) moves after the block of cuffs (7), making it impossible to return the moving parts (Fig. 1). At the same time, the spacer (6) of the tail transformer cone (18), having passed the working stroke distance under the influence of the power cuff block (7), rests its end against the end face of the stationary body (22) of the same transformer cone. Thus, further movement of the cone-shaped segments (23) in the dovetail grooves becomes impossible, which determines the desired diameter of the tail cone-transformer (18) (Fig. 1, Fig. 3). The same thing happens with the transformer head cone (17). This moment is determined by the pressure jump of the injected fluid. Then, with the help of a hoist (not shown), the tubular rod (mandrel) (15) starts to move upward, performing the main process of expanding the patch (2) or its sectional assembly, which lasts until the expanding mandrel (double cone-transformer) (4 ) will not pass its entire length. In this case, in case of failure of the anti-return mechanism (8), the restrictive sleeve (10) becomes disputed between the shoulder of the mandrel (15) and the anti-return mechanism (8), unloading the spring (9) and protecting it from bending and breaking. In the process of expanding the patch (2), the release mechanism (14) serves as a lock for the housings (19) and (22) of both transformer cones and is not involved in the process of expanding the patch (2). In an emergency, for example, when the expanding mandrel is jammed (4), the fluid pressure is released, leaving an interference fit on the tubing string, then the threaded sub (16) using the tubing string is rotated several turns, for example, counterclockwise, since the expanding mandrel (4) is jammed, the conical bodies (19) and (22) of both transformer cones and the mandrel (15) connected to it by splines are also jammed. As a result, the end face of the sub (16) moves axially (up) to a distance sufficient to release the z-shaped legs (Fig. 1), which in turn release the conical bodies (19) and (22) of the transformer cones for axial movement along the mandrel (15). Further, the device is lifted upward, while due to the friction forces on the walls of the patch (2) in the place of the narrowing formed, the cone-shaped segments (20) and (23) are extruded to the tops of the conical bodies (19) and (22) of both transformer cones, i.e. . from the periphery to the center, while the latter move upward along the mandrel (15). As a result, the expanding mandrel (4) in the form of a double transformer cone returns to the initial diametric dimensions, which allows you to remove the device in case of an emergency. The block of power cuffs (7) due to elasticity narrows and does not prevent the device from being removed from the unexpanded part of the patch.

Thus, the present invention allows to obtain a device for the repair of casing and production strings using a double transformer cone, which increases the reliability and efficiency. The device has a fairly simple design, and the technology of working with it is easily feasible.

The invention has been disclosed above with reference to a specific embodiment. Other specialists may be obvious to other embodiments of the invention, without changing its essence, as it is disclosed in the present description. Accordingly, the invention should be considered limited in scope only by the following claims.

Claims (3)

1. Device for repairing casing and production strings using a double transformer cone, consisting of a smooth-walled metal tubular patch with sealing elastic rings located on the outer surface, a seat assembly, a tubular rod connected by a threaded sub with a lift, and an expanding mandrel in the form a cone-transformer, including a conical body fixed on a tubular rod, on the surface of which longitudinal dovetail grooves are made with a ra placed in them by cone-shaped segments with the possibility of longitudinal movement, characterized in that in order to reduce the axial force required to deform the patch, the expanding mandrel is equipped with an additional transformer cone with the formation of a double transformer cone, consisting of head and tail transformer cones, kinematically connected to each other by means of pushers, and the angle at the apex of the conical body of the transformer head cone is less than the same angle of the tail mustache-transformer. 2. A device for repairing casing and production strings using a double transformer-cone according to claim 1, characterized in that the latter is equipped with a release mechanism for returning the expanding mandrel to the initial diametric dimension. 3. A device for repairing casing and production strings using a double transformer cone according to claim 1, characterized in that the head and tail transformer cones are mounted on a tubular rod with angular displacement relative to each other so that the middle of each cone-shaped segment of any transformer cones is located opposite the gap between the segments of the second transformer cone.

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