RU2698348C1 - Packing unit of packer - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to sealing assembly of packer. Seal packer assembly includes collars made in the form of elastic elements separated by spacer rings, end calibration rings arranged on both sides of the collars, and a sleeve installed with possibility of axial movement and interaction with collars. Packer packer assembly also includes detachable mandrel with stepped outer surface installed relative to hollow packer housing with circular clearance for circulation. Sleeves are made of rubber with different Shore hardness. Calibration end rings are installed with the possibility of axial movement at the smaller stage of the mandrel, the end of which along the outer surface is threaded for connection to the hydraulic anchor. End of larger step of mandrel over outer surface is made with stepped end section, coupled with stepped end section, made on inner surface of sleeve, connected by threaded connection to end ring of calibration, installed on side of sleeve. Other calibrating end ring is threaded along the inner surface for connection to the hydraulic anchor.

EFFECT: technical result is increase in reliability.

1 cl, 4 dwg

Description

Packer Seal Assembly

The invention relates to the oil and gas industry, namely, to a packing device designed to isolate the space and isolate the layers during the construction, operation and repair of oil, gas and water wells.

When installing the packer at the wellhead by unloading the weight of the tubing string, controlling the readings on the column weight indicator provides the axial load that comes to compress the sealing elements (cuffs) in a strictly limited range, the values of which are indicated in the packer’s passport and operating manual . In case of exceeding the axial load, premature destruction of the packer sealing elements occurs, leading to the impossibility of its further operation.

Known sealing assembly of the packer, including elastic cuffs separated by spacer rings, and end rings (see the description of the utility model to the patent of the Russian Federation No. 108095 EV 33/12, publ. 09/10/2009).

All elements of the sealing unit with an inner diameter are mounted on the hollow barrel of the packer. The cuffs are in the form of a hollow cylinder and are made of an elastomer that swells when interacting, for example, with produced water. At both end sections of the sealing element, thrust rings are mounted rigidly fixed to the hollow barrel of the packer by any method known in the art, for example, locking screws.

The packer sealing assembly may be used (installed) only once in one location of the well.

Known sealing unit packer has the following disadvantages:

- installation of the sealing unit on a standard casing or tubing, having a variation in the outer diameter within the tolerance, directly at the drilling site is impossible or in some cases quite laborious, and does not provide sealing on the inner surface, since to ensure sealing of the sealing unit the inner surface requires its tight installation on the trunk (pipe nozzle), which must first be machined to a fixed diameter meter, which is possible only during assembly at the manufacturer;

- the possibility of self-sealing during descent into the well due to insufficient rigidity of the elastic elements;

- the design of the sealing assembly, which requires factory assembly on the packer barrel (pipe with sleeve), increases the rigidity of the liner from the casing that is lowered into the well, which complicates their passage in the curved and horizontal sections of the well, thereby limiting the scope of application of such a sealing assembly and the reliability of its descent into the well.

Known sealing assembly of the packer, including elastic cuffs and protective rings (see the description of the invention to the patent of the Russian Federation No. 2 0346 143 "Device for installing the shank of the casing string in the borehole", ЕВВ 33/14, publ. 02.10.2009).

In the known device, the sealing of the annular space is provided using a hydromechanical packer assembly.

The upper and lower elastic cuffs, including their end protection, are mounted on the shank. In addition, an annular saddle, a pusher with an end position retainer interacting with annular grooves made on the upper part of the shank is fixed with a pin on the shank. After the operation of anchoring produce rotation to the right of the transport column. In this case, the funnels, bushings, dowels in the longitudinal spline groove, pusher are moved down. As a result, the cuff is placed on the lateral surface of the annular saddle as a result of the "creep" of this cuff first on the conical and then on the cylindrical surface of the annular saddle.

The known sealing assembly cannot be used repeatedly, and it is installed only once at a specific location in the well. The sealing unit is intended only for use when installing the casing liner in the well for cementing the well. This sealing unit also cannot be used in packers with hydraulic anchors and a bypass valve, since it does not have a bypass channel, which limits its functionality.

In the known device there is no control on the application of axial load or speed. There is a danger that if the rotation of the transport column to the right is excessive (torsion), then the cuffs will shrink and collapse strongly, but if they are undercut, the well will not be compacted. In addition, a highly qualified worker is needed to calculate the axial loads that must be applied on the surface so that at the depth in the well the necessary force is applied to the sealing elements, which is a disadvantage of the known device.

Known sealing assembly of the packer, including annular elastic cuffs separated by spacer rings, end rings and a sleeve mounted with the possibility of axial movement and interaction with the cuffs (see the description of the utility model to the patent of the Russian Federation No. 173 491, ЕВВ 33/12, publ. 29.08 .2017).

All elements of the sealing assembly in terms of internal diameter are made with the possibility of their installation on a standard casing or tubing.

It is not possible to attach a mechanical or hydraulic packer anchor to a known sealing assembly to ensure retention of the packer or sealing assembly when pressure occurs in the well during operation, as a result of which it is not possible to use this sealing assembly during technological operations, the implementation of which requires creating excess pressure above or below the packer , which is its disadvantage.

It is also impossible to use this sealing unit in packers with a controlled valve (bypass) for circulating fluid through a packer installed in the column for any technological operations.

Seals are worn directly on tubing pipes (tubing), the outer surface of which is not prepared for high-quality sealing by cuffs, that is, the outer surface of the pipe has a rough, uneven surface, which leads to incomplete fit of the cuff during sealing.

The elastic elements separated by a spacer ring have the shape of a hollow cylinder and are made of an elastomer swelling in wellbore fluids, which does not exclude the elastomer swelling when the device is installed. The sleeve is made in the form of a cage with stepped end sections. The non-adjacent end sections of the elastic elements have anti-extrusion protections containing a stop ring fixed on the pipe with a stepped end section, an annular ring with stepped end sections and a cup-shaped cuff made of non-swelling rubber. Under the action of the pressure drop that is created during the period of operation of the well from the side of the isolated interval, the elastic elements transfer the axial load to the cuff and the cage and shift them towards the thrust ring, restricting the movement of the cage relative to the original installation site. When moving the cage compresses the sealing ring until it contacts the outer surface of the pipe, thereby providing sealing on the inner surface of the sealing assembly in the presence of an allowable radial clearance S between the casing and the anti-extrusion protection elements of the elastic elements. Under the action of axial force from the side of the elastic element, the conical end section of the cuff and the end section of the cage are deformed in the radial direction until they come into contact with the open borehole.

The known sealing unit does not have a circulation channel between the mandrel, on which the cuffs are worn, and the packer body, which narrows the scope of its application. This sealing assembly cannot be used in packers having a bypass circulation channel.

The packer sealing assembly can only be installed once in one place in the well, which is its drawback.

The closest in technical essence to the proposed technical solution is the packer sealing assembly, including elastic ring cuffs with end protection, a spacer ring placed between the cuffs, a push rod installed on the housing with the possibility of axial movement and interaction with the cuffs (see the description of the utility model to the patent of the Russian Federation No. 96 164, ЕВВ 33/12, publ. 20.07.2010).

All elements of the sealing unit in internal diameter are mounted on a hollow body. In the known sealing unit, as in the proposed device, the seal is installed by axial compression.

When creating an axial load hydraulically or mechanically on the pusher sleeve, the latter, moving in the axial direction, deforms the upper and lower elastic cuffs. Due to the annular protrusions located in the annular bores of the spacer ring, the upper and lower cuffs are loop-shaped to deform in the annular gap between the outer surface of the spacer ring and, for example, the wall of the open borehole. Such deformation of the cuffs ensures that the doubled cuff thickness is installed in the overlapped annular gap of the borehole and significantly increases the risk of the cuff not being returned to its original state due to the complex geometry of the cuff body after installation, which complicates further extraction of the packer with this sealing unit.

The known sealing assembly cannot be used in packers with a controlled valve (bypass) for circulating fluid through a packer installed in the column, which narrows the scope of its application.

In the known device there is no mechanical limiter on axial loads, and as a result, when the axial compressive loads on the cuffs are exceeded, they are destroyed, which leads to accidents and is its disadvantage.

The technical task and the result of the present invention is the creation of a reusable packer sealing assembly that ensures reliable operation in a wide range of loads aimed at axial compression of the packer sealing elements when installed in the production casing of the well, expanding the functionality of the packer and increasing its working life.

The technical result is achieved in that the packer sealing assembly includes cuffs made in the form of elastic elements separated by spacer rings, gauge end rings placed on both sides of the cuffs, a sleeve installed with the possibility of axial movement and interaction with the cuffs, while it differs in which additionally contains a removable mandrel with a stepped outer surface mounted relative to the hollow packer body with an annular clearance for circulation, while the cuff made of rubber with different Shore hardness, as well as gauge end rings, are mounted with the possibility of axial movement at a lower step of the mandrel, the end of which on the outer surface is made with a thread for connection with a hydraulic armature, and the end of the larger step of the mandrel on the outer surface is made with a step end a section mating with a stepped end section made on the inner surface of the sleeve connected by a threaded connection to the end ring calibration, installed on the side bushings, while the other end ring calibration is made with a thread on the inner surface for connection with a hydraulic armature. Cuffs can be made of rubber compounds based on nitrile butadiene rubber (NBR) with a shore hardness of 70-90 units.

The proposed packer sealing assembly is removable and can be reused. After removing the load, the sealing elements return to their original (initial) state, and the packer can be installed in another place in the well without removing it to the surface.

The presence of mating stepped end sections restricting the movement of the mandrel relative to the landing sleeve during their interaction, eliminates the destruction of the cuffs when the axial load increases during their compression, which reduces the risk of failure in the operation of the sealing assembly and increases its service life.

The packer sealing assembly is illustrated by drawings, where: in FIG. 1 shows a longitudinal section (without axial load); in FIG. 2 - remote element A from FIG. one; in FIG. 3 - longitudinal section (under axial load); in FIG. 4 - remote element B from FIG. 3.

The packer sealing assembly has a removable mandrel 1 mounted relative to the hollow packer body 2 with a gap to form an annular channel for fluid circulation.

Mandrel 1 is made with a stepped outer surface, at the lower stage of which cuffs 3 and 4 are installed. Cuffs 3 and 4 are made of rubber compounds based on nitrile butadiene rubbers (NBR) of different hardness. Cuffs 3 have a shore hardness of 90 units, and cuffs 4 have a shore hardness of 70 units. Cuffs 3 with greater hardness are the first to perceive the axial load and thereby additionally protect the middle cuff 4 of lesser hardness from a sharp jump in axial force. In case of damage to the outer cuffs 3, the middle cuff 4 remains intact, which extends the life of the device.

Between the cuffs 3 and 4, spacer rings 5 are located. The cuffs 3 and 4 and the spacer rings 5 are mounted with the possibility of axial movement along the mandrel 1. The spacer rings 5 prevent leakage and layering of the cuffs upon compression. On both sides of the cuffs 3 on the mandrel 1 there are protective rings 6 and 7, made of a L-shaped section with thread on the inner surface on a horizontally placed element. Protective gauge rings 6 and 7 are also designed to determine the size of cuffs used relative to the size of the well.

The calibration ring 6 is connected by a threaded connection 8 to the landing sleeve 9 mounted on the hollow body 2 with a gap. The calibration ring 6 and the landing sleeve 9 can freely move along the mandrel 1 to interact with the cuffs 3 and 4. The threaded connection 10 of the calibration ring 7 is designed to connect to the external thread of the hydraulic packer armature or another packer assembly located above the sealing assembly (hydraulic packer armature not shown in the drawing).

The mandrel 1 on the outer surface of the larger stage has a stepped end section 11, mating with a stepped end section 12, made on the inner surface of the sleeve 9 of the landing. The other end of the mandrel 1 is made with a thread 13 for connection with the internal thread of the hydraulic anchor of the packer or other packer assembly located above the sealing assembly. The stepped end sections 11 and 12, when coupled, limit the movement of the mandrel 1 relative to the sleeve 9 of the landing.

The size (length) of the stepped end sections 11 and 12 should be sufficient to ensure compression of the cuffs until the annular space of the casing 14 is completely sealed and equal to 85% of the cuff width on average.

The magnitude (length) of the stepped end sections 11 and 12 in the absence of axial load is sufficient for the cuffs to expand to the initial (transport) state, in which the outer diameter of the cuffs is less than or equal to the outer diameter of the calibration rings, and the packer can be moved to another section casing pipe 14.

The sealing unit packer operates as follows.

Under the action of the axial load created by the weight of the tubing string 9, the landing sleeve 9 axially moves relative to the mandrel 1 and compresses the cuffs 3 and 4 of the packer. Cuffs 3 and 4 are compressed, the outer surface is pressed against the casing of the pipe 14 of the well and hermetically cut off the upper part from the bottom.

The stepped end section 12 of the sleeve 9 moves along the stepped end section 11 of the mandrel 1 until it stops against the end. When pairing the stepped end sections 11 and 12, the movement of the mandrel 1 relative to the sleeve 9 of the landing stops, thereby the compression force ceases to flow on the cuffs 3 and 4, which allows them to be destroyed under possible axial overloads.

Claims (2)

1. The sealing assembly of the packer, including cuffs made in the form of elastic elements separated by spacer rings, gauge end rings placed on both sides of the cuffs, and a sleeve mounted for axial movement and interaction with the cuffs, characterized in that it further comprises a removable a mandrel with a stepped outer surface mounted relative to the hollow packer body with an annular clearance for circulation, while cuffs made of rubber with different Shore hardness, and gauge end rings are also installed with the possibility of axial movement at a lower mandrel stage, the end of which on the outer surface is threaded for connection with a hydraulic armature, and the end of the greater mandrel stage on the outer surface is made with a stepped end section, mating with a stepped end section made on the inner surface of the sleeve connected by a threaded connection to the end ring calibration, installed on the side of the sleeve, while the other end ring potassium Brow is made with a thread on the inner surface for connection with a hydraulic anchor. 2. The packer sealing assembly according to claim 1, characterized in that the cuffs are made of rubber compounds based on butadiene-nitrile rubbers (NBR) with a Shore hardness of 70-90 units.

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