RU2453679C1 - Mechanical packer - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: mechanical packer contains shaft with shaped slot on external surface with short and long longitudinal sections, support which is rigidly attached to shaft, sealing element, cone and shell, which are located under it with possibility of axial movement relative to the shaft; in the shell there installed uniformly in its circumferential direction are toothed slips, ring installed in lower part of the shell with possibility of radial rotation relative to the shell, but which is rigidly attached to it in axial direction; at that, shell is fixed relative to the shaft in radial direction; springs of toothed slips are pressed to the shaft and located so that when they contact the cone, their inclined flat faces are parallel to inclined flat faces of the cone, and guide pin is arranged in shaped slot in which toothed slips, unlike the prototype, are arranged in the casing which is fixed on the shell which is provided in its middle part with slots in which there located are centralisers with springs, which are fixed in the shell with their upper and lower covers; at that, split ring on which the guide pin is installed is located under lower cover.

EFFECT: invention allows improving operating reliability and efficiency of packer during its installation, operation and removal in oil and gas wells.

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Description

The invention relates to the oil and gas industry and can be used in the development and operation of oil and gas wells.

Known packer, which contains a barrel with curly grooves on the outer surface, having longitudinal straight short and long sections. A support is rigidly connected to the barrel, under which a pressure sealing element and a cone are located. The cone is mounted with the possibility of axial movement relative to the barrel. On the barrel with the possibility of axial movement of the clip. Slips are evenly spaced on the cage along its circumference, which are pressed in the radial direction relative to the cage by a spring and in the middle part are held by a limiter. The lower part of the slips is made in the form of a guide cam. The ring is detachable and mounted in the lower part of the cage with the possibility of radial rotation relative to the latter, but rigidly connected with it in the axial direction. A groove of a rectangular profile is made on the inner surface of the ring, and on the outer surface of the cage in the form of separate sectors, flanges of a rectangular profile are made. The beads with a groove form a slip pair and additionally play the role of cleaning the groove from sludge. In the inner part of the ring along one axis, perpendicular to the axis of the packer, two diametrically opposite guide rails of the pin are rigidly installed along the interference fit. On the trunk inclined sections and straight sections are made. Each straight section goes counterclockwise into an inclined one, which, in turn, is adjacent to the next straight section at an acute angle. A recess is made at the end of the ring for fixing the input cam guides (RF patent No. 2209927, IPC ЕВВ 33/12, publ. 08/10/2003).

Closest to the proposed is a mechanical packer, consisting of a barrel with a curly groove on the outer surface with longitudinal short and long sections. A support is rigidly connected to the trunk. Under it there is a sealing element and a cone with inclined flat faces evenly spaced around its circumference. The cone is mounted with the possibility of axial movement relative to the barrel, fixed relative to the barrel in the radial direction by a key. Under the cone with the possibility of axial movement relative to the barrel, a cage is installed in which toothed slips are placed evenly around its circumference, pressed by springs to the barrel, the inner surfaces of which are made in the form of inclined flat faces. A guide pin is installed in the ferrule, located in the curly groove of the barrel. The inclined flat faces of the toothed slips are parallel to the inclined flat faces of the cone upon contact. A ring is installed at the bottom of the clip. It is made with the possibility of radial rotation relative to the cage, but is rigidly connected with the cage in the axial direction (RF patent No. 2232869, IPC ЕВВ 33/12, publ. July 20, 2004).

A disadvantage of the known devices is the low reliability due to the fact that the slips are not sufficiently protected from contact with the walls of the production casing of an inclined or horizontal well while the packer is moving along it, which leads to their premature wear, breakage of the springs pressing the centralizers, leads to insufficient contact of the centralizers with production casing, which can lead to the inability to install the packer, also two opposite guide pins can jam in the figured grooves, if they are inaccurate manufacture. In addition, the well-known designs of packers are technologically complex and laborious to manufacture.

The task to which the invention is directed is to increase the reliability and efficiency of the packer during its installation, operation and dismantling in oil and gas wells.

The positive effect of the use of the packer in wells is to reduce the number of accidents, increase its service life, increase the well overhaul period and, accordingly, increase fluid production.

The technical result is achieved by eliminating the contacts of the slips with the wall of the production casing, eliminating emergency situations due to breakage of the centralizer springs and jamming of the clamps, as well as reducing the complexity of manufacturing the packer and, accordingly, its price while maintaining high performance and reliability.

The problem is solved by a mechanical packer containing a barrel with a figured groove on the outer surface with longitudinal short and long sections, a support rigidly connected to the barrel, a sealing element located under it with the possibility of axial movement relative to the barrel, a cone and a holder, in which they are mounted uniformly around its circumference toothed slips, a ring mounted in the lower part of the cage with the possibility of radial rotation relative to the cage, but rigidly connected with it in the axial direction, ixed relative to the barrel in the radial direction, the toothed slips are spring-loaded to the barrel and arranged so that upon contact with the cone their inclined flat faces are parallel to the inclined flat faces of the cone, and the guide pin is placed in a figured groove in which, in contrast to the prototype, the toothed slips are placed in the casing, which is fixed on a cage, having in its middle part grooves in which centralizers with springs are located, fixed in a cage of upper and lower covers, and under the lower cover there is a carved ring on which the guide pin is mounted.

According to the invention, the barrel of the mechanical packer can be made of two parts - the upper and lower, connected by a threaded connection, the lower barrel being larger in diameter than the upper one and forming a shoulder at the connection point, restricting the cone from moving down the barrel.

According to the invention, each packer centralizer may comprise three springs.

According to the invention, the support can be formed by a coupling attached to the upper part of the barrel and a nut connected to it by a threaded connection.

According to the invention, the packer sealing element may be formed by three sealing cuffs.

According to the invention, the packer ring may have an annular outer groove in its lower part so as to interact with the annular inner shoulder of the split ring.

The purpose of the invention is achieved due to the following.

The slips are placed in a casing, which excludes the contact of the slips with the walls of the production string when the packer moves along the well.

Each centralizer has three springs, the stiffness of each of which is lower than the stiffness of the springs of the prototypes. This allows you to expand the range of use of the packer in production casing with different wall thickness, reducing the likelihood of spring breakage and providing the necessary force to press the centralizers to the production casing.

The bottom cover restricting the radial movement of the centralizers is made separately from the split ring. This design allows you to prevent jamming, which excludes the rotation of the split ring with a retainer relative to the centralizers when falling into the gap between the centralizers and the split ring of sludge.

The figured groove on the surface of the lower barrel has the minimum area necessary to ensure reliable operation of the packer. The trunk section allows you to withstand increased loads in case of complications with a packer breakdown. The groove is located on the trunk with a uniform arrangement of two long (working) vertical sections and two short (transport) vertical sections, which are interconnected by two inclined sections located at an acute angle to the vertical, and very short vertical (transitional) sections.

To further strengthen the lower trunk, a closed figured groove is used, which consists of a long vertical section (working position) and a short vertical section (transport position). In the lower part, the vertical sections are connected by a selection having a triangular shape. The top of the triangular selection is located on a short vertical section, and the side adjacent to the top is located vertically, being a continuation of the outer contour of the short vertical section. The side adjacent to the apex of the triangular selection on the other hand forms an acute angle with a short vertical section, and a blunt one with a long section. The base of the triangular selection forms an acute angle with a long vertical section, and a dull angle with a short one. The upper part of the short vertical section is completed by an inclined section located at an acute angle to the short vertical section. The upper part of the inclined section is located between the short and long vertical sections and is made in the form of a triangular ledge, one side of which is located vertically, and the second forms an acute angle with the long vertical section. Between the long and short vertical sections is a protrusion made in the form of a parallelogram. The outer vertical sides of the protrusion are the inner vertical sides of the short and long vertical sections. The upper side of the protrusion is adjacent to a short vertical section, forming an acute angle inside the parallelogram. The lower side of the protrusion is the base of the triangular selection and forms with a short vertical section an obtuse angle inside the parallelogram.

The invention and the achievement of the technical result are illustrated by drawings, where in Fig.1 shows a mechanical packer assembly; figure 2 - scan circular curly groove; figure 3 - scan closed groove.

The mechanical packer consists of the lower 1 and upper 2 trunks connected by means of a threaded connection, the lower 1 trunk in outer diameter is larger than the upper 2 and forms a collar at the junction. A coupling 3 is attached to the upper barrel 2 by means of a threaded connection from above. A nut 4 is connected by means of a threaded connection. Together with the coupling 3, they form a support for the sealing cuffs 5, which are located on the upper barrel below the nut 4. A cone 6 is located below the sealing cuffs 5. The movement of the cone along the upper trunk is limited downward by the collar of the lower trunk, upward by sealing cuffs 5. An anchor unit is put on the lower barrel 1, the base of which is a holder 7. From above, the holder 7 is threaded of the compound is attached a casing 8. The casing slips 9 are arranged uniformly pressed against the lower trunk of the springs 10, in such a situation is excluded the possibility of contact with the walls 9 slips production string at any of its location. In the middle part of the casing 7, longitudinal grooves are uniformly made, in which centralizers 11 are located, which are pressed by springs 12 against the walls of the production casing. The centralizers 11 are held in the housing by covers: upper 13 and lower 14. A split ring 15 is installed in the lower part of the housing, which interacts with the annular outer groove of the housing by an annular inner shoulder. Such a connection allows the split ring 15 to rotate relative to the holder 7, having the possibility of longitudinal movement only together with it. A guide pin 16 is mounted on the split ring 15 by means of a threaded connection, the inner end of which is constantly in the figured groove, thus forming the command unit of the anchor assembly. This design allows through axial movements of the trunks 1 and 2 to provide the anchor node transport or working position.

When using a closed figured groove (Fig. 3), the packer differs from that described by the configuration of the figured groove.

Mechanical packer works as follows.

1. The use of a circular shaped groove (figure 2).

Before the descent into the well, the packer is in a vertical position (Fig. 1), the guide pin 16 in the figured groove must be installed at point A. This position of the latch in the figured groove is due to the weight of the parts of the anchor assembly and the need to ensure the transport position of the anchor assembly when lowering the packer. The descent of the packer into the well is carried out using tubing (tubing). When the packer enters the wellhead, the centralizers 11 interact with the walls of the production casing and do not allow the anchor assembly to move down until the combined force of the springs 12 is overcome by the weight of the casing. Thus, the anchor unit will stop at the entrance to the production casing of the well, and the barrel 1 will continue to move down. The guide pin 16 will move along a very short vertical section I (Fig. 2), then along an inclined section II and a short vertical section III until it reaches point B. At this point, the movement of the barrel 1 relative to the anchor node will stop, and they begin to move down together. At the same time, the springs 12 are compressed, providing constant contact of the centralizers 11 with the walls of the production casing of the well. This position of the packer parts will be maintained until the descent tubing is installed on the wedge suspension of the wellhead. After installing the next descent tubing to the previous one, the tubing string should be raised to remove from the wedge suspension. When lifting the tubing string, the following occurs: the anchor unit held on the walls of the production string by the centralizers 11 pressed to it will remain in place. The barrel 1 will begin to move upward relative to the anchor unit standing in place. At the same time, the guide pin 16 will move down a short vertical section III. To ensure the transport position of the anchor assembly, such movement can only be continued to point B, at which achievement the descent of the tubing string should begin. Moving the tubing string upwards when removing it from the wedge suspension is 100-200 mm. The descent will lead to a downward movement of the barrel 1 relative to the anchor node. This movement will continue until the guide pin 16 reaches point B. After that, the barrel 1 and the anchor unit will begin to move down together until the next lower tubing is mounted on the wedge suspension. Thus, when the packer moves down, the guide pin 16 will move in a short vertical section III from point B to point C, providing the transport position of the anchor assembly. After the packer reaches the planned installation interval, the anchor assembly should be moved from the transport position to the working position by the following manipulations: raise the tubing string to a height equal to or slightly higher than Hm (Fig. 2). At the same time, the guide pin 16 will move along the short vertical section III, the inclined section IV until the point G is reached. After that, the tubing string should be lowered until the packer is installed (planted). At the same time, the guide pin 16 will move from point G along a very short vertical section V, along the inclined section VI and along the long vertical section VII, trying to reach point D. The packer parts will change their position as follows: trunks 1 and 2 will move downward relative to the standing in place of the anchor node. Slips 9, moving along the cone 6, will diverge radially and, compressing the springs 10, will approach the wall of the production casing of the well before cutting into it. At the same time, the anchor device and cone 6 will stop and be fixed on the wall of the production casing of the well. Clutch 3, nut 4, barrel 2 will continue to move downward relative to the stopped cone and anchor assembly, compressing the sealing cuffs 5 until they come into contact with the wall of the production casing of the well. This movement will continue until the weight of the tubing string is equal to the total reactive forces of the friction forces in all joints and the elastic forces of the sealing collars 5. After compression of the sealing collars, the inner space of the production casing of the well will be hermetically divided into sub-packer and over-packer ones.

To dismantle the packer, it is necessary to lift the tubing string. In this case, the following movements of the packer parts will occur: trunks 1 and 2, clutch 3, nut 4 will move upward, sealing cuffs 5 will return to their original position. This movement will occur until the cone contacts the collar of the lower barrel 1. After this, under the action of the springs 10, the slips will come out of contact with the wall of the production casing of the well and press against the lower barrel 1. At the same time, the guide pin 16 will move along the long vertical section of the figured groove VII, inclined section VIII to point A '. After that, the movement of the trunks 1 and 2 relative to the anchor node will stop and their joint movement up will begin until the tubing string is mounted on the wedge suspension, which is accompanied by the tubing string moving down. At the same time, the anchor assembly is fixed on the production casing using centralizers 11, and the trunks 1 and 2 are moved down. At the same time, the guide pin 16 from point A 'along a very short vertical section I', inclined section II 'goes into a short vertical section III' and with further lifting of the tubing string moves from point A 'to point B' in it, ensuring the transport position of the anchor unit when moving the packer from the well.

2. The use of a closed curly groove (figure 3).

Before the descent into the well, the packer is in a vertical position (figure 1), the guide pin 16 in the figured groove (figure 3) is installed at point A. This position of the guide pin in the figured groove is due to the weight of the parts of the anchor assembly. The descent of the packer into the well is carried out using tubing (tubing). When the packer enters the wellhead, the centralizers 11 interact with the walls of the production casing and do not allow the anchor assembly to move down until the combined force of the springs 12 is overcome by the weight of the casing. Thus, the anchor unit will stop at the entrance to the production casing of the well, and the barrel 1 will continue to move down. At the same time, the guide pin 16 will move along the short vertical section I, then along the inclined section II until it reaches point B. At this point, the movement of the barrel 1 relative to the anchor assembly will stop and they will begin to move down together. In this case, the springs 12 are compressed, providing constant contact of the centralizers 11 with the walls of the production casing of the well. This position of the packer parts will be maintained until the descent tubing is installed on the wedge suspension. After installing the next descent tubing to the previous column, the tubing should be raised to remove from the wedge suspension to a height equal to or slightly higher than Hm (Fig. 3), which will ensure the transport position of the anchor assembly. When lifting the tubing string, the following occurs: the anchor unit held on the walls of the production string by the centralizers 11 pressed to it will remain in place. The barrel 1 will begin to move upward relative to the anchor unit standing in place. At the same time, the guide pin 16 will move downward relative to the barrel 1 until it contacts the protrusion III at point B, after which the guide pin 16 will move obliquely along the upper side of the protrusion III, along the long vertical section IV, the side of the lower selection, forming an obtuse angle with a long groove to point A. During the subsequent descent of the tubing string, the barrel 1 will move downward relative to the anchor node. This movement will continue until the guide pin 16 reaches point B. After that, the barrel 1 and the anchor unit will begin to move down together until the next lower tubing is mounted on the wedge suspension. Thus, when the packer moves downward, the guide pin 16 will move in a closed circuit from point B along the upper side of the protrusion, the long vertical section to point A, then along the short vertical and inclined sections to point B, ensuring the transport position of the anchor assembly. After the packer reaches the planned installation interval, the lower anchor assembly should be transferred from the transport position to the working one by the following manipulations: raise the tubing string to a height not exceeding Нр (Fig. 3). At the same time, the guide pin 16 will move from point B down to contact with the protrusion III, on the right side of the protrusion III to a long vertical section, along a long vertical section not lower than point G. Switching from the transport position to the working one can be made from point E to point G. When the guide pin is located between points E and G, the tubing string should be lowered before the packer is installed (planted). At the same time, the guide pin 16 will move upward along the long vertical section IV, trying to reach point D. The packer parts will change their position as follows: trunks 1 and 2 will move downward relative to the anchor unit in place. Slips 9, moving along the cone 6, will diverge radially and, compressing the springs 10, will approach the wall of the production casing of the well before cutting into it. At the same time, the anchor device and cone 6 will stop and be fixed on the wall of the production casing of the well. The coupling 3, the nut 4, the barrel 2, the cuffs will continue to move downward relative to the stopped cone and the anchor assembly, compressing the sealing cuffs 5 until they come into contact with the wall of the production casing of the well. This movement will continue until the weight of the tubing string being lowered is equal to the total reactive forces of the friction forces in all the mates and the elastic forces of the sealing cuffs 5. After compression of the sealing cuffs 5, the inner space of the production casing of the well will be hermetically divided into sub-packer and over-packer ones.

To dismantle the packer, it is necessary to lift the tubing string. At the same time, the following movements of the packer parts will occur: trunks 1 and 2, clutch 3, nut 4 will move up, sealing cuffs 5 will come to their original position. This movement will occur until the cone contacts the collar of the lower barrel 1. After this, under the action of the springs 10, the slips 9 released by the cone 6 come out of contact with the wall of the production casing of the well and press against the lower barrel 1. At the same time, the guide pin 16 will move along the long vertical section IV the inclined part of the lower sample to point A. After this, the movement of trunks 1 and 2 relative to the anchor node will stop and their joint movement will begin upward until the tubing string is installed on the wedge suspension, which is accompanied by the movement of the tubing string down. At the same time, the anchor assembly is fixed on the production casing using centralizers 11, and the trunks 1 and 2 are moved down. At the same time, the guide pin 16 will move from point A along a short vertical section I, inclined section II to point B, providing the transport position of the anchor unit when moving the packer from the well.

The proposed design of the packer eliminates the contact of the slips with the wall of the production casing, eliminates emergency situations due to breakage of the centralizer springs and jamming of the guide pins.

Thus, the invention improves the reliability and efficiency of the packer during its installation, operation and dismantling in oil and gas wells.

Claims (6)

1. A mechanical packer comprising a barrel with a figured groove on the outer surface with longitudinal short and long sections, a support rigidly connected to the barrel, a sealing element located under it with the possibility of axial movement relative to the barrel, a cone and a holder in which gears are evenly arranged around its circumference slips, a ring mounted in the lower part of the cage and with the possibility of radial rotation relative to the cage, but rigidly connected with it in the axial direction, and the cage is fixed relative to the ol is in the radial direction, the toothed slips are spring-loaded to the barrel and arranged so that upon contact with the cone their inclined flat faces are parallel to the inclined flat faces of the cone, and the guide pin is placed in a figured groove, characterized in that the gear slips are placed in a casing, which fixed on a clip having in its middle part grooves in which centralizers with springs are located, fixed in a clip by upper and lower covers, and under the lower cover there is a split ring on which guide pin. 2. The mechanical packer according to claim 1, characterized in that the barrel is made of two parts - the upper and lower, connected by a threaded connection, the lower barrel being larger in diameter than the upper one and forming a shoulder at the connection point, restricting the cone from moving down the barrel. 3. The mechanical packer according to claim 1, characterized in that each centralizer contains three springs. 4. The mechanical packer according to claim 1, characterized in that the support is formed by a coupling attached to the upper part of the barrel and a nut connected to it by a threaded connection. 5. The mechanical packer according to claim 1, characterized in that the sealing element is formed by three sealing cuffs. 6. The mechanical packer according to claim 1, characterized in that the cage has in its lower part an annular outer groove with the possibility of interaction with the annular inner shoulder of the split ring.

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