RU2639006C1 - Device for restoration of defective sections of production strings of oil and gas wells with controlled cone-transformer - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: device comprises a plaster in the form of a smooth metal branch pipe with elastic sealing rings outside, and an expanding mandrel made in the form of cone-transformer formed by cone-shaped sectors located in the grooves of the body conical part configured for longitudinal movement. The vertex of the 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 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 geometry of the cone-transformer, the latter is equipped with a deblocking mechanism.

EFFECT: emergency situations are prevented when eliminating a leakage from production strings in case of expanding mandrel jamming, reliability and efficiency of device operation is increased.

3 cl, 10 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 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 control valve system, a differential piston, as well as an external cone with spring-loaded floating dies and a rolling head kinematically connected to the motor shaft. 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.

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 only 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 sectors located on the self-sealing cuff, as well as spring-loaded conical dies installed between the cone-punch and floating sectors 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 a punch-cone, then the intermediate one is made by cone dies due to their axial and peripheral displacement in the grooves, and the final one by floating sectors 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.

SUMMARY OF THE INVENTION

The task of the invention is to develop a device for repairing defective sections of production casing of oil and gas wells with a controlled 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 through the use of a controlled transformer cone, in which the main body is fixed on a tubular rod (mandrel) and is equipped with a release mechanism that allows in case of emergency to remove the device from the patch by reducing the dimensions of the transformer cone used as a dispensing mandrel. The specified technical result is achieved due to the fact that in the claimed device the unlocking mechanism is made in the form of a cross, in the eyes of which spring-loaded dogs are mounted that can swing on the axes, abutting the ends of their nose parts against the walls of the transverse recesses, alternating with the longitudinal recesses on the outer cylindrical surface of the tubular traction (mandrels). However, the transverse profile of the bottom of each of the transverse and longitudinal recesses on the surface of the specified traction has a curved concave shape. In addition, each of the dogs of the release mechanism has a convex sole, the curvature of which in cross section is similar to the curvature of the concavity of the bottom of the recesses on the outer surface of the tubular rod.

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 through a device for repairing defective sections of oil and gas production casing strings with a controlled transformer cone before the patch expansion process begins:

1 - production casing; 2 - patch; 3 - elastic sealing ring; 4 - expanding mandrel (cone-transformer); 5 - block power reinforced cuffs; 6 - a spacer; 7 - anti-return mechanism; 8 - spring; 9 - restrictive sleeve; 10 - tubular traction (mandrel); 11 - drilled shoe with check valve; 12 - release mechanism.

FIG. 2 - the same, at the time the patch began to expand:

13 - hydraulic landing unit.

FIG. 3 - the same, in the process of further expansion of the patch.

FIG. 4 is a view A in FIG. 1 to scale:

16 - a cross; 17 - dog anti-return mechanism; 18 - pressure housing; 19 - axis.

FIG. 5 is a view G in FIG. 4 to scale.

FIG. 6 is a view B in FIG. 1 to scale:

14 - transformer cone body; 15 - cone-shaped segment; 20 - resettable plug; 21 - dog unlocking mechanism; 23 - sub.

FIG. 7 is a view B in FIG. 4 to scale:

22 - torsion spring.

FIG. 8 is a view D in FIG. 6 to scale.

FIG. 9 is a section DD in FIG. 8.

FIG. 10 is a section EE in FIG. 6 to scale.

DETAILED DESCRIPTION OF THE INVENTION

A device for repairing defective sections of oil and gas well production cores with a controlled 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 transformer cone inside the patch ( 2) and worn on tubular traction (mandrel) (10). On the one hand, the expanding mandrel (4) is in contact with the release mechanism (12), and on the other hand, with the spacer (6), which in turn is supported by a block of power reinforced cuffs (5). The expanding mandrel (4) is a transformer cone including a housing (14), in the conical part of which longitudinal dovetail grooves are arranged with cone-shaped segments (15) longitudinally movable (FIG. 6, FIG. 8, FIG. . 10). The anti-return mechanism (7) serves to prevent unwanted axial rearward movement of the expansion mandrel (4) after starting the expansion process of the patch (2) (Fig. 2, Fig. 4) and includes a cross (16), in the eyes of which with the help of the axes (19) the dogs (17) are installed, and the pressure housing (18), the rectangular slots of which are designed for the unhindered swing of the dogs (17) (Fig. 7). The latter with the help of torsion springs (22) are constantly pressed against the outer surface of the tubular rod (mandrel) (10), on which annular notches are made in the longitudinal section in the area of possible movement of the spider (16) of the anti-return mechanism (7) (Fig. . 5). In fact, the anti-return mechanism (7) is a ratchet mechanism in which the ratchet wheel degenerated into a rail. The spring (8) serves to force-close the device parts located between the shoulder of the tubular rod (mandrel) (10) and the release mechanism (12). The latter is designed to provide axial movement of the housing (14) of the transformer cone in an emergency, freeing it from a fixed position, which allows the expanding mandrel (4) to return to its original dimensions. The restriction sleeve (9) prevents springing and breaking of the spring (8) when lifting the tubular rod (mandrel) (10), which is connected by an adapter (23) to the rig rig (not shown) via rods (not shown), for example, in the form of a column tubing (tubing). The lower end of the patch (2) is hermetically sealed with a drilled shoe (11) with a check valve (not shown). A drillable shoe (11) with a non-return valve together with a seat (not shown) for the discharge plug (20) forms a hydraulic landing unit (13), which serves to redirect the pumped working fluid and create pressure that initiates the movement of the reinforced cuff block (5) and expanding mandrel (4).

A device for recovering defective sections of production casing oil and gas wells with a transformer cone operates as follows.

The device is lowered into the well with 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, a plug (20) is dropped from above, which sits in the saddle of the hydraulic landing unit (13), and pumping of the working fluid begins. The latter penetrates into the cavity between the outer surface of the wall of the tubular rod (mandrel) (10) and the inner surface of the wall of the patch (2) (Fig. 2), causing axial movement of the block of power reinforced cuffs (5), which acts as a piston. At the same time, through the spacer (6), the cuff block (5) presses on the cone-shaped segments (15), which move along the dovetail grooves (Fig. 2, Fig. 3, Fig. 10) of the case (14) of the transformer cone, simultaneously making a movement to the periphery and acting on the walls of the patch (2), thereby smoothly making its preliminary distribution (Fig. 2). The beginning of the process of distribution of the patch (2) simultaneously produces its anchoring in the production string (1) due to the deformation of the nearest elastic sealing rings (3) (Fig. 2). The block of power reinforced cuffs (5), 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 (7) under the influence of the spring (8) moves after the block of cuffs (5) until the dogs (17) mounted on the axles (19) and pressed by torsion springs (22) to the outer surface of the tubular rod (mandrel) (10) and sliding along it, will not fall into one of the annular grooves, which have a rectangular triangle in longitudinal section, making reverse movement of the moving parts impossible (Fig. 4, Fig. 5). At the same time, the spacer (6), having passed the working stroke distance under the influence of the power cuff block (5), abuts its end against the end face of the body (14) of the transformer cone fixed on the tubular rod (mandrel) (10) by the dogs (21) of the unlocking mechanism (12), which nose pieces abut against the walls of the transverse recesses made on the cylindrical outer surface of the tubular rod (mandrel) (10) (Fig. 2, Fig. 3, Fig. 8). Thus, further movement in the grooves of the cone-shaped segments (15) becomes impossible, which determines the desired diameter of the patch (2) after expansion (Fig. 2). This moment is determined by the pressure jump of the injected working fluid. Then, with the help of a lift (not shown) and pressure of the working fluid, the tubular rod (mandrel) (10) begins to move upward (Fig. 3), producing the main process of expanding the patch (2) or its sectional assembly, which lasts until the mandrel (transformer cone) (4) will not pass its entire length. The restriction sleeve (9) abuts against the pressure housing (18) of the anti-return device (7), unloading the spring (8) and protecting it from gouging and breakage (Fig. 3). In an emergency, for example, when the expanding mandrel is jammed (4), the tubular rod (mandrel) (10) with the help of the tubing string is rotated by a certain angle, for example, by 30 degrees, in any direction, while the dogs (21) of the release mechanism ( 12) rise, overcoming the resistance of torsion springs (22), and jump from transverse recesses to longitudinal, releasing the transformer cone body (14) for axial movement along the tubular rod (mandrel) (10) (Fig. 6, Fig. 8, Fig . 9). The device is lifted upward, due to the friction forces against the walls of the patch (2) in the place of the narrowing formed, the cone-shaped segments (15) are extruded to the top of the body (14) of the transformer cone, i.e. from the periphery to the center, while the latter moves along the tubular traction (mandrel) (10). As a result, the expanding mandrel (4) in the form of a cone-transformer returns to its original dimensions, which allows you to remove the device in case of an emergency.

Thus, the present invention allows to obtain a device for the repair of defective sections of production casing of oil and gas wells with a controlled 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. A device for repairing defective sections of oil and gas well production cores with a controlled transformer cone, consisting of a smooth-walled metal tubular patch with sealing elastic rings located on the outer surface, a hydraulic landing unit and an expanding mandrel in the form of a transformer cone, including a housing fixed on a tubular rod , on the conical surface of which are made longitudinal dovetail grooves with conical segments, with the possibility of longitudinal movement, characterized in that in order to return the transformer cone to its original dimensions in an emergency, it is equipped with a release mechanism in the form of a cross, in the eyes of which spring-loaded dogs are mounted that can swing on the axes, abutting the ends of their nose parts in walls of transverse recesses alternating with longitudinal recesses on the outer cylindrical surface of the tubular rod. 2. A device for repairing defective sections of oil and gas well production cores with a controlled transformer cone according to claim 1, characterized in that the transverse bottom profile of each of the transverse and longitudinal recesses on the surface of the tubular rod has a curved concave shape. 3. A device for recovering defective sections of oil and gas well production cores with a controlled transformer cone according to claim 1, characterized in that each of the dogs of the release mechanism has a convex plantar part, the curvature of which in cross section is similar to the curvature of the bottom concavity on the surface of the tubular rod.

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