RU2235850C1 - Hydromechanical packer - Google Patents

Abstract

FIELD: mining industry, particularly for closing axial channel of casing pipes under perforation space for isolation of bottom liquid against water.

SUBSTANCE: packer comprises shaft connected with pipe string through adapter. Arranged on adapter is case of hydraulic cylinder located from outside and forming annular chamber in which piston with releasing cone is installed. Case of hydraulic cylinder has metal sealing shell. Packer shaft comprises split collet with heads extending into metal sealing shell and surrounding releasing cone. Teeth of anchor member are disposed on outer side of split collet below metal sealing shell. Installed in axial channel is stepped spring-loaded bushing having seat and ball valve. Check valve is located in axial channel of stepped spring-loaded bushing. Radial orifices are formed in shaft body below seat. Stepped spring-loaded bushing is connected to shaft by means of thoriated shear member. Packer installation is carried out by placing ball valve on seat and applying overpressure to piston along with introducing releasing cone between split collet heads and deforming thereof and metal sealing shell up to contacting with casing pipe wall. Teeth of anchor means are depressed in pipe body, which results in packer fixing.

EFFECT: increased duration of well bore bridging, possibility of isolation mix feeding into under-packer area, blocking hydrodynamical communication with under-packer area after pressure relief.

3 dwg

Description

The invention relates to the mining industry and is intended to overlap the annular space of oil and gas wells during waterproofing of bottom water.

Known packing device (see and.with. No. 1118760, M. cl. E 21 In 33/12. Publ. 15.10.84. Bull. No. 38), consisting of a barrel on which a head is installed with a sealing element based on a support sleeve, a retainer and a retainer limiter, a special threaded sleeve of the casing string, the retainer being made in the form of a threaded nut spring-loaded relative to the support sleeve, connected to the barrel by a spline connection and having a thread on the outer surface for interacting with the coupling thread.

To overlap the annulus, the packer assembly is lowered into the well to the installation site of a special threaded sleeve and sits on the protrusion by the support sleeve. By right rotation of the pipe string, the threaded nut is engaged with the counter thread of the coupling. With the estimated axial force imparted to the sealing element, the latter loses its stability at the location of the internal groove and deforms in the radial direction with the formation of tight contact with the inner surface of the coupling.

Disadvantages. The device can only be used in a new well stock, when lowering the casing string, into which a special threaded sleeve is introduced.

The sealant is made of ductile metal capable of plastic deformation upon application of axial load.

In the old well stock, the device is not applicable, since it is not possible to equip the casing with a special threaded sleeve.

The device is intended for use mainly in steam injection wells, that is, under cyclic conditions of temperature and pressure. When the coolant is supplied to the well, the seal and a special threaded sleeve will be uneven in time, which can lead to an increase in the tightness of the connection at the initial moment and to a loss of tightness after heating of the special threaded sleeve and thermal change in size at the place of the sealing element.

In the case of mechanical particles on the seating surface of a special threaded sleeve, problems may arise associated with the loss of tightness of the packer.

Known heat-resistant packer (see and.with. No. 1548405, Mcl. 5 E 21 B 33/12, publ. 03.03.90. Bull. No. 9), containing a hollow barrel, the fixation unit of the packer, a saddle in the axial channel of the barrel equipped with a ball, a housing with a sealing element fixed to it, an expanding cone and spacer fixing elements - slips around the perimeter. The sealing element is made in the form of a cylindrical metal shell with an expansion unit in the form of balls interacting with the inner surface of the sealing element and the surface of the expanding cone.

The packer is planted by creating excess pressure under the expanding cone of the slips and transferring pressure to the cone of the expansion unit while rotating the string of pipes of the packer barrel and rolling the cylindrical metal shell with balls until it contacts the inner surface of the casing string. The slots of the anchor assembly also extend radially until the teeth penetrate the casing wall and fix the packer.

The axial channel of the packer barrel is freed from the saddle with the ball by exceeding the working fluid pressure in comparison with the landing pressure and dumping the saddle with the ball to the bottom. The packer is ready to go.

Disadvantages of the packer design:

- the need for thorough preparation of the surface of the casing string at the site of the packer;

- the need to transfer torque to the packer barrel during landing - deformation of the seal;

- the presence of a small contact spot with the casing in height in the presence of sufficient rigidity of the sealant and the existence of various defects on the wall of the casing pipe does not allow reliable isolation of the under-packer zone from the over-packer;

- if it is necessary to drill the packer, it becomes necessary to exclude the rotation of its trunk, which is not provided by the design and can significantly increase the drilling time.

The presence of slips with teeth embedded in the casing wall located around the perimeter helps to keep the packer in place when axial loads are perceived. However, removing the packer from the installation site is also difficult due to the lack of a mechanism for returning the expanding cones of the seal and the armature to its original position.

Known heat-resistant packer (see and.with. No. 1361303, Mcl. 4 E 21 B 33/12, publ. 12/23/87. Bull. No. 47), consisting of a hollow body, on which the lower end of the sealing element is fixed - a thin-walled cylindrical shell forming an annular cavity filled with a filler - rubber. The housing is equipped with a pressure element in the form of an annular piston. The device is equipped with a slip anchor.

The packer is planted by transmitting the axial load from the weight of the pipes to the pressure element, by creating compressive stresses in the rubber, which are transmitted to the thin-walled metal shell with its plastic deformation in the radial direction until tight contact with the casing wall is formed. The packer is fixed in this position due to the withdrawal of the anchor slips in the radial direction by the expanding cone until it contacts the casing wall.

Disadvantages. Since the deformation of a thin-walled metal shell occurs due to the creation of pressure in a closed volume and the transfer of radial pressure to the shell with a gap between the shell and the annular piston, over time, after the rubber has lost its elastic properties, a gap is formed through which the sub-packer cavity communicates with the over-packer, which undesirable.

It is unclear how it is possible to radially move the anchor slips to fix the packer inside the casing, since there is no mechanism for transferring the load to the anchor slips.

Known heat-resistant packer (see and.with. No. 1731937, M. Cl. 5 E 21 B 33/12, publ. 07.05.92. Bull. No. 17), taken by the authors as a prototype.

The packer contains a hollow barrel on which a cylinder with a thin-walled metal shell is mounted. An expanding cone is installed in the cylinder to form a gap between it and the metal shell, in which there is a split collet in the form of wedge-shaped cams with a figured annular groove in which a figured ring extending beyond the metal shell is installed. In the axial bore of the barrel, a saddle is installed under the ball valve, and at its lower end there is a protrusion for interaction with the cone.

On the tubing string, the packer is lowered into the well to a predetermined depth, the axial bore of the barrel is closed with a ball and the pressure of the working fluid is increased, which is communicated to the expanding cone. In this case, the latter moves axially downward with conversion to the radial movement of the wedge-shaped cams of the split collet, which is transmitted to the metal shell with a wave-like curved ring. The outer diameter of the metal shell increases with exceeding the yield strength of the shell material. The wave-like curved ring also increases its diametrical size and is brought into contact with the casing wall with penetration into the surface layer. The pressure in the tubing is raised from the nominal one, with the further introduction of the sharp outer edge of the wave-like ring into the casing, which serves as an anchor. At the same time, the saddle with the ball is removed from the axial bore of the barrel and dumped to the bottom.

The pressure is released and the packer barrel is loaded by the weight of the tubing string, which is communicated to the expanding cone, which provides continuous compression of the metal shell and the wave-like ring to the casing wall.

Design flaws. When transmitting radial deformation to the sealant, the latter changes (increases) its diameter to the diameter of the casing with obtaining contact stresses between them sufficient, in the authors' opinion, to seal the under-packer cavity from the over-packer. However, it is known that the casing has an ellipsoidal shape of the axial channel, from which it follows that along the perimeter of the interaction of the metal shell with the inner surface of the casing, contact stresses along the smaller axis of the ellipse will be acceptable for the further operation of the packer, and along the larger axis of the ellipse there is a possibility of maintaining a gap, which makes it difficult to achieve sealing of the under-packer zone from the over-packer. The installation on the outside of the sealant of the anchor, made in the form of a wave-like curved ring, also introduces uncertainty in the determination and creation of the necessary landing forces, in addition, the presence of a wave-like ring on the outside of the seal negatively affects its sealing ability, that is, to bring the seal to contact with the casing wall, it is necessary to ensure the introduction of the ring, which is problematic because it is necessary to develop a sufficiently high force, and when changing the diameter of the sealant is a change in pitch bends undulating rings and, respectively, the wave height, which is practically impossible to carry out in the presence of the contact rings with a casing wall.

In addition, depending on the wall thickness of the casing string, it is necessary to adjust the outer diameter of the sealant and the wave-like ring, which requires reliable information on the casing string of each particular well.

The technical result that can be obtained by implementing the invention is reduced to the following:

- the possibility of hydraulic landing of the packer with reliable overlapping of the annular space with a combined sealant with the simultaneous fixation of the packer in the casing;

- the combination of the anchor assembly with a collet for simultaneous fit-fixation of the packer and deformation of the seal in the radial direction simplifies the design;

- the possibility of forming a hydraulic connection between the axial channel of the packer barrel and the sub-packer region, for example, in the case of supplying an insulating composition to the sub-packer region and the termination of this connection after depressurization in the axial channel of the pipe lift string.

An analysis of the inventive step showed the following:

the known design of the packing device (see AS No. 1153040, Mcl E 21 V 33/12, publ. 04/30/85, Bull. No. 16), where the sealing element is made integral with the cylinder and is a thin-walled metal shell equipped with a cylindrical girdle playing the role of a locking element when landing the packer in a special landing sleeve.

Known heat-resistant packer (see and.with. No. 1252477, M.cl. E 21 V 33/12, publ. 08/23/86. Bull. No. 31), where the sealing element is combined with a steel shell having ring protrusions on which has a shell made of low-melting metal, which, when the packer is planted, melts due to the temperature obtained by setting the thermite charge on fire.

When conducting patent research on scientific and technical literature, we did not find a description of the design of mechanical packers, in which a drive aimed at deformation-fitting of the seal and subsequent fixation of the anchor of the packer inside the casing, creating tight contact with the casing by transmitting tensile stresses is combined in one node from the side of a thin-walled metal shell to an elastic sealant when it is radially moved to the casing wall.

Also not found is the implementation of the sealing element in the form of a thin-walled metal shell having a conical shape, on the outside of which an elastic sealing element is installed.

Also, the combination of anchor elements with a split collet, which is part of the simultaneous interaction with the expanding cone and the thin-walled metal shell of the sealant, was not found.

Thus, the achieved technical result is due to the unknown properties of the parts of the device in question and the relationships between them.

The invention does not explicitly follow from the prior art, that is, it meets the criterion of inventive step.

The technical result is achieved in that in a hydromechanical packer including a barrel connected through an adapter with an elevator column, a hydraulic cylinder with a expanding cone and a metal sealing shell, an anchor, a split collet, according to the invention, the metal sealing shell is made conical and provided with a sealing ring on the outside, the barrel equipped with a stepped spring-loaded sleeve in the axial channel with a seat under the ball valve in the upper part and a check valve mounted axially move and form a hydraulic connection between the axial bore of the barrel and the under-packer cavity in the lowermost position and connected with the barrel by a calibrated shear element, the split collet is rigidly connected to the barrel, the anchor is made in the form of an annular protrusion with teeth along the perimeter and installed below the location of the metal sealing shell .

The design of the packer is illustrated by the following drawings, where

figure 1 shows the design of the packer in the context, in the initial position;

figure 2 - the relative position of the parts of the packer when it is planted;

figure 3 - the relative position of the parts of the packer in the position of supply of insulating material into the under-packer cavity;

The hydromechanical packer consists of a barrel 1, rigidly connected with its upper end to a sub 2, on the outside of which a hydraulic cylinder housing 3 is installed, with the formation of an annular chamber 4 between them, in which a piston 5 with an expanding cone 6 is placed. The hydraulic cylinder housing 3 is rigidly connected to a metal sealing casing 7. At the lower end of the barrel 1, a split collet 8 is installed, entering its upper end into the metal sealing shell 7 and covering the expanding cone 6. The cutting collet 8 below the location of m the metallic sealing membrane 7 is provided with an annular projection 9 on which are fixed on the perimeter of the anchor barbs 10, and rigidly connected to the lower end of the barrel 1. On the outer side of the metal seal casing 7 an O-ring 11 held by the threaded nut 12.

In the axial channel 13 of the barrel 1, there is installed a spring-loaded step sleeve 14 with a seat 15 and a ball valve 16. A check valve 18 is installed in the axial channel 17 of the spring-loaded step sleeve 14. 20 from its axial channel 13. The stepped spring-loaded sleeve 14 is connected with the barrel 1, a calibrated shear element 21. The annular chamber 4 above the piston 5 is constantly hydraulically connected with the axial channel 13 of the barrel 1 radial channels 22.

The operation of the device.

The device through a bayonet lock is attached to the lower end of the tubing string and lowered into the well to a predetermined depth. The ball valve 16 is not mounted on the seat 15 and the axial channel 13 of the barrel 1 freely communicates with the axial channel 17 of the stepped spring sleeve 14.

In this position, the wellbore is flushed by supplying the working fluid to the tubing string. The working fluid is fed into the axial channel 13 of the barrel 1 of the device, squeezes the check valve 18 and returns to the surface along the annular gap between the device and the casing wall.

A ball valve 16 is dropped into the axial channel of the pipe tubing string with its seating on the seat 15 (see Fig. 1). Thereby, the hydraulic connection between the cavity of the tubing string and the under-packer cavity of the well is closed. Excess pressure is created in the pipe tubing string, which is fed through the radial channels 22 to the annular chamber 4 of the hydraulic cylinder body 3 and acts on the piston 5 with the expanding cone 6. The expanding cone 6 moves relative to the barrel 1 and the hydraulic cylinder body 3 and is inserted inside the split collet 8, which moves apart in the radial direction to ensure radial deformation of the metal sealing shell 7 with the sealing ring 11 until it contacts the inner surface of the casing. With the further movement of the piston 5 downward, the sealing ring 11 is compressed and the teeth of the anchor 10 enter into interaction with the casing wall (see Fig. 2). Thereby, the annular gap is closed between the elevator and casing string of the pipes and the device is fixed.

An insulating composition is fed into the axial channel of the pipe tubing string and the pressure is increased above the packer landing pressure, which is communicated to the cross-sectional area of the stepped spring-loaded sleeve 14. When the calculated force is applied, the calibrated shear element 21 is cut by moving the stepped spring-loaded sleeve 14 down below the radial holes 19 of the barrel 1, which opens a hydraulic connection between the axial channel 13 of the barrel 1 with a sub-packer cavity (see figure 3). The estimated volume of the insulating composition is pressed into the sub-packer zone by a squeeze plug, dumped from above into the pipe lift string. The fluid that plugs the well is displaced into the surrounding rocks with replacement for an insulating composition. The cork plug reaches the stop ring and the process is stopped. The check valve 18 closes with excess pressure in the under-packer cavity, the spring-loaded stepwise spring sleeve 14 returns to its original position with the help of a compressed spring, and the hydraulic connection between the under-packer cavity and the cavity of the pipe tubing is terminated. Disconnect the pipe tubing from the packer and lift it to the surface. The device in this position remains in the well. If necessary, return to the underlying horizon, which was blocked by an insulating composition, the device can be drilled, because it is made of easily destroyed materials.

Claims (1)

Hydro-mechanical packer, including a barrel connected through an adapter with an elevator column, a hydraulic cylinder with a expanding cone and a metal sealing shell, an anchor, a split collet, characterized in that the metal sealing shell is conical and provided with a sealing ring on the outside, the barrel is equipped with a spring-loaded stepwise spring sleeve in axial channel with a seat under the ball valve in the upper part and a check valve installed with the possibility of axial movement and the formation of hydraulic ligature of the axial channel of the barrel with the under-packer cavity in the lowest position and connected with the barrel by a calibrated shear element, the split collet is rigidly connected to the barrel, the anchor is made in the form of an annular protrusion with teeth along the perimeter and installed below the location of the metal sealing shell.

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