RU2815799C1 - Packer cup collar and method of its manufacturing - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: invention is designed for oil production from wells, and can be used as sealing elements for packers designed for hermetically sealing well casing intervals during various technological operations at the well. A cup collar of a packer and methods for its manufacturing are claimed. The cup collar of the packer is made in form of an expanding sleeve with a through stepped hole. The bushing is made of material having a Shore hardness of A 90±5, tensile strength not less than 5 MPa, elongation at break not less than 30% and compressive modulus of elasticity not less than 150 MPa. A thin-walled metal sleeve is installed on the side of the narrow end, the outer surface of which seamlessly transitions into the outer surface of the expanding sleeve. The collar material contains the following components, mixed in the following proportions in mass fractions: shungite powder with particle size 1…20 mcm – from 90 to 110; binding elastomer of the “БКНС” brand from nitrile butadiene rubber - from 25 to 35; crosslinking agent in form of organic peroxide – from 1 to 2; mineral fibres - from 1 to 30.

EFFECT: increase in the reliability of operation and service life of the packer, as well as an increase in manufacturability and a reduction in the labour intensity of manufacturing the packer collar due to the use of a material with certain properties and design.

8 cl, 5 dwg

Description

The invention relates to the oil industry, in particular to oil production from wells, and can be used as sealing elements for packers designed for hermetically sealing well casing intervals during various technological operations at the well.

The cuffs of the packer for patents RU 81249 (MPC E21V 33/12, publ. 10.03.09) and RU195714 (MPC E21V 33/12, publ. 04.02.20), US 20030098153 are known ), having a fundamentally similar design, containing an elastic element made in the form of a trapezoidal ring with a longitudinal axial section, reinforced with metal elements with a sleeve.

The disadvantage of these solutions is the relatively high labor intensity of the cuff production, associated with the need to manufacture reinforcing elements and their positioning in the mold before vulcanization of the rubber mixture; the use of reinforcing elements leads to uncontrolled radial deformation of the supporting part of the cuff and its wear, exposing the reinforcement, which in this case may break off. The most important problem in using fittings is that after the first actuation, the fittings do not allow the collar to return to its original state, thereby maintaining the interaction between the collar and the casing. Further movement of the cuff along the column promotes abrasive wear of the thin layer of rubber on the surface of the reinforcement, which most likely leads to the destruction of the inner rubber layer of the cuff and, as a result, the latter’s leakage. To solve this problem, to protect the inner rubber surface of the cuff, it is necessary to use fittings with two rows of petals, which impairs the manufacturability of such cuffs. The cuff injury is shown in Fig. 1.

A packer collar is also known, which is made in the form of a sleeve having an intermediate part and two end parts. The intermediate part is made of elastic material with a strength of 15÷40 MPa and a hardness of 60÷80 Shore units. The end parts are made of elastic material and reinforced with a metal element made of turns of steel wire with a bulk density of 70÷90%, which allows for a hardness of 90÷100 Shore units. Steel wire has a tensile strength of 290÷350 N/mm, and a relative elongation of 5÷12%. The longitudinal axial section of each end part has the shape of a truncated rectangular trapezoid, inside of which there are coils of steel wire with a bulk density of 70÷90% (according to patent RU 164011, IPC E21B 33/12, publ. 08.20.16).

The disadvantage of this solution is the relatively high labor intensity of the cuff production, associated with the need to manufacture reinforcing elements and their positioning in the mold before vulcanization of the rubber mixture.

A cup seal packer is known for sealing the inside of a pipe under pressure. The cuff is made in the shape of a bell. The wide end has a lip made of a softer material, which is an integral part of the cuff body, which is a harder material (according to US patent 7261153B2, IPC E21B 33/12, publ. 08/28/07).

A cup seal packer is known for sealing the interior of a pipe under pressure, which includes a first portion of relatively soft material and a second portion of relatively hard material. A portion of the relatively softer material begins at the edge of the cuff and extends from the outside one-third of the way to the entire length of the cuff. The cuff may additionally contain a sleeve or retainer fixed in solid material for fastening to the packer (according to US patent 7959155B2, IPC E21B 33/126, publ. 06.14.11).

The disadvantage of these cuffs is that the hard material provides rigidity to the cuff, but limits its opening under pressure and pressing against the walls of the casing, and the sealing of the cuff is ensured by elastic compression of the soft material. As a result, the tightness of the collar may not be sufficient, especially if there are defects on the inner wall of the casing.

A packer collar is known, made in the form of a rubber bushing with a hole and additionally containing a protective conical cup made of nylon or a metal tip (according to patent US 2852323, IPC F16J 15/3204, publ. 02/13/56).

The disadvantage of this solution is the insufficient protection of the rubber bushing by the nylon cup and the insufficient strength of fixing the metal tip on the rubber bushing.

The closest technical solution is a cup seal packer, which according to its design consists of a body with a longitudinal hole. The outer part of the housing and the opening expand in the longitudinal direction from one end to the other. The body is made of an elastomer selected from the group of butadiene-nitrile and hydrogenated butadiene-nitrile rubbers with a surface hardness pop Shore A from 80 to 90 (according to patent US 6668938 B2, IPC E21B 33/128, publ. 12/30/03).

In this solution, only the material and its hardness are indicated, while other properties of the material used are also important for effective operation, for example, strength and tensile strength, elastic modulus. Various materials can be used to provide these properties.

The technical result achieved by using the present invention is to increase the reliability and service life of the packer, as well as to increase manufacturability and reduce the labor intensity of manufacturing the packer collar due to the use of a material with certain properties and design.

The technical result is achieved in that the cup collar of the packer is made in the form of an expanding sleeve with a through stepped hole and is characterized in that the sleeve is made of a material having a Shore A hardness of 90±5, a tensile strength of at least 5 MPa, and an elongation at break of at least 30 % and a modulus of elasticity in compression of at least 150 MPa, while a thin-walled metal sleeve is installed on the side of the narrow end, the outer surface of which continuously transitions into the outer surface of the expanding sleeve.

In addition, the cuff material may contain the following components, mixed in the following proportions in mass fractions:

- shungite powder with a particle size of 1...20 microns - from 90 to 110;

- binding elastomer of the BKNS brand from nitrile butadiene rubber - from 25 to 35;

- crosslinking agent in the form of organic peroxide - from 1 to 2;

- mineral fibers - from 1 to 30.

In addition, a thin-walled bushing can consist of three parts: an end part, made perpendicular to the axis of the cuff with a hole equal to the diameter of the hole of the expanding bushing; conical and cylindrical, repeating the contour of the expanding sleeve.

The cup collar of the packer is manufactured by a method that consists in molding a workpiece from a mixture mass in the molding cavity of a mold and is characterized in that the mixture mass for the workpiece is mixed on laboratory rollers until a homogeneous mass is obtained from the following components, mixed in the following proportions in mass fractions:

- shungite powder with a particle size of 1...20 microns - from 90 to 110;

- binding elastomer of the BKNS brand from nitrile butadiene rubber - from 25 to 35;

- crosslinking agent in the form of organic peroxide - from 1 to 2;

- mineral fibers - from 1 to 30

then a blank is made from the mixture mass, the volume of which corresponds to the volume of the mold cavity of the mold minus the volume of the thin-walled sleeve, the blank together with the thin-walled sleeve is placed in the mold and vulcanized, after vulcanization the resulting sleeve is kept in a free state for at least 4 hours.

Also, the cup collar of the packer is manufactured by a method that consists in molding a workpiece from a mixture mass in the mold cavity of the mold and is characterized in that the mixture mass for the workpiece is mixed on laboratory rollers until a homogeneous mass is obtained from the following components, mixed in the following proportions in mass fractions:

- shungite powder with a particle size of 1...20 microns - from 90 to 110;

- binding elastomer of the BKNS brand from nitrile butadiene rubber - from 25 to 35;

- crosslinking agent in the form of organic peroxide - from 1 to 2;

- mineral fibers - from 1 to 30

then a workpiece is made from the mixture mass, the volume of which corresponds to the volume of the forming cavity of the mold, the workpiece is placed in the mold and vulcanized, after vulcanization, the resulting expanding sleeve with a place for installing a thin-walled sleeve is kept in a free state for at least 4 hours, after which it is glued to a thin-walled bushing for an expanding bushing.

The preferred time for mixing the mixture mass is 30±5 minutes with a friction of 1:1.25.

Vulcanization is preferably carried out at a temperature of 160 to 180°C for 10 to 40 minutes.

The present invention is illustrated by the following drawings:

Fig. 2 - packer collar, axonometry;

Fig. 3 - packer collar, longitudinal section;

Fig. 4 - thin-walled bushing, axonometry;

Fig. 5 - packer.

The cup collar of the packer 1 (Fig. 2, 3) according to the first embodiment of the invention is made in the form of an expanding sleeve 2 with a through stepped hole 3.

The cup collar of the packer 1 (Fig. 2, 3) is made in the form of an expanding sleeve 2 with a through stepped hole 3. A thin-walled sleeve 5 is installed on the side of the narrow end 4, the outer surface 6 of which seamlessly transitions into the outer surface 7 of the expanding sleeve 2.

Thin-walled bushing 8 (Fig. 4) consists of three parts: end 8, conical 9 and cylindrical 10. The end surface 8 is made perpendicular to the axis of the cuff with a hole 11 equal to the diameter of the stepped hole 3 on the side of end 4, on which the thin-walled bushing 5 is installed. Conical and the cylindrical surface follows the contour of the expanding sleeve 2.

The cup collar of the packer according to the first embodiment of the invention is manufactured in the following way. To create a carbon-carbon matrix (CC), the following components are used:

- shungite powder with a particle size of 1...20 microns - from 90 to 110;

- binding elastomer of the BKNS brand from nitrile butadiene rubber - from 25 to 35;

- crosslinking agent in the form of organic peroxide - from 1 to 2;

- mineral fibers - from 1 to 30.

Mixing of these components is carried out on laboratory rollers PD 320 160/160 with a friction of 1:1.25, for 30±5 minutes until a homogeneous mixture mass is obtained. A blank corresponding to the volume of the forming cavity of the mold is made from the mixture mass.

The workpiece is vulcanized in the mold cavity using mold technology for the production of an elastomeric product at a temperature of 160 to 180°C and a process duration of 10 to 40 minutes. The vulcanized blank from the prepared elastomeric mixture has an elongation at break of 50-140% and a strength of at least 5 MPa. After vulcanization, the workpiece is kept in a free state for 4 hours to relieve stress.

The cup cuff manufactured according to the described method has the following characteristics: hardness Shore A 90±5, tensile strength of at least 5 MPa, elongation at break of at least 30% and compressive modulus of elasticity of at least 150 MPa.

The thin-walled bushing can be installed at the pressing stage or by gluing after vulcanization and curing. In the first case, a thin-walled sleeve is installed in the mold along with the workpiece before vulcanization. In this case, it is possible to use a mold that is used to manufacture a one-piece cuff. In the second case, it is necessary to use a special mold, which creates an expanding sleeve with space for installing a thin-walled sleeve.

Application.

The cup collar is used as part of a packer, which is mounted on the production string. For example, as part of a cup packer used in hydraulic fracturing (hydraulic fracturing). The packer (Fig. 5) consists of a body 12 with an upper coupling 13 and a lower coupling 14 screwed onto it. Cup collars 1 are installed between couplings 13 and 14. A protective sleeve 15 is installed on each collar 1 on the narrow side. Cuffs 1 are tightened by adjusting sleeves 16 and clamping ring 17.

After installing the packer on the string, it is lowered into the well. During the lowering process, the cup collars are pressed against the packer body and do not interfere with movement during the lowering process.

After installing the packer in a given interval, its use for its intended purpose begins. The separation of the well zones is carried out by opening the cup cuffs under pressure in such a way as to ensure a tight fit of the cuff edges to the walls of the well.

If it is necessary to change the packer placement interval by raising or lowering, the cup cuffs, after removing the pressure, are pressed against the packer body, and the placement is changed, after which at a given point the cuffs are opened again, ensuring separation of the well zones in accordance with the functional purpose.

Manufacturing a cuff from a material having the characteristics according to the proposed invention makes it possible to increase operational reliability and service life due to:

- increased wear resistance of the cuff during hoisting and hoisting operations (hardness Shore A 90±5);

- ability to withstand high pressure up to 70 MPa (tensile strength of at least 5 MPa)

- the necessary elasticity to ensure the opening of the cuff during packer operation (tension at rupture of at least 30%, modulus of elasticity in compression of at least 150 MPa).

The specified properties can be obtained in the material composition and manufacturing method, which is described in the proposed invention.

These properties make it possible to avoid the use of metal reinforcement in the cuff design located in the body of the cuff, which leads to damage to the polymer material of the cuff during repeated use, and also significantly increase manufacturability and reduce the labor intensity of manufacturing, since complex positioning of metal reinforcement in the mold is not required . When attaching a thin-walled bushing during the pressing stage, the bushing is simply inserted into the mold, no additional complex positioning is required. When attaching a thin-walled bushing by gluing, the bushing is installed in a place specially made for it on the cuff after its manufacture, which also does not require positioning.

The thin-walled bushing further increases the reliability and service life of the packer, since the bushing protects the collar during running and lifting operations of the packer. The stepless transition of the bushing into the surface of the expanding bushing of the cuff, as well as the construction of the bushing in three parts - end, conical and cylindrical, reliably protect the cuff from damage during operation.

Thus, the solutions used in the invention make it possible to increase the reliability of operation and service life of the packer, as well as improve manufacturability and reduce the labor intensity of manufacturing the cuff, and thereby contribute to the achievement of a technical result.

Claims (23)

1. Cup seal of a packer, made in the form of an expanding sleeve with a through stepped hole, characterized in that the sleeve is made of a material having a Shore A hardness of 90±5, tensile strength of at least 5 MPa, elongation at break of at least 30% and modulus compressive elasticity of at least 150 MPa, and the cuff material contains the following components mixed in the following proportions in mass fractions: - shungite powder with a particle size of 1...20 microns - from 90 to 110; - binding elastomer of the BKNS brand from nitrile butadiene rubber - from 25 to 35; - crosslinking agent in the form of organic peroxide – from 1 to 2; - mineral fibers – from 1 to 30, in this case, a thin-walled metal sleeve is installed on the side of the narrow end, the outer surface of which seamlessly transitions into the outer surface of the expanding sleeve. 2. The cuff according to claim 1, characterized in that the thin-walled sleeve consists of an end part made perpendicular to the axis of the cuff with a hole equal to the diameter of the hole of the expanding sleeve, conical and cylindrical parts that follow the contour of the expanding sleeve. 3. A method for manufacturing a cup collar of a packer, which consists in molding a workpiece from a mixture mass in the molding cavity of a mold, characterized in that the mixture mass for the workpiece is mixed on laboratory rollers until a homogeneous mass is obtained from the following components, mixed in the following proportions in mass fractions: - shungite powder with a particle size of 1...20 microns - from 90 to 110; - binding elastomer of the BKNS brand from nitrile butadiene rubber - from 25 to 35; - crosslinking agent in the form of organic peroxide – from 1 to 2; - mineral fibers – from 1 to 30, then a blank is made from the mixture mass, the volume of which corresponds to the volume of the mold cavity of the mold minus the volume of the thin-walled sleeve, the blank together with the thin-walled sleeve is placed in the mold and vulcanized, after vulcanization the resulting sleeve is kept in a free state for at least 4 hours. 4. The method according to claim 3, characterized in that the mixing time of the mixture mass is 30±5 minutes with a friction of 1:1.25. 5. Method according to claim 3 or 4, characterized in that vulcanization is carried out at a temperature from 160 to 180°C for 10 to 40 minutes. 6. A method for manufacturing a cup collar of a packer, which consists in molding a workpiece from a mixture mass in a mold cavity of a mold, characterized in that the mixture mass for the workpiece is mixed on laboratory rollers until a homogeneous mass is obtained from the following components, mixed in the following proportions in mass fractions: - shungite powder with a particle size of 1...20 microns - from 90 to 110; - binding elastomer of the BKNS brand from nitrile butadiene rubber - from 25 to 35; - crosslinking agent in the form of organic peroxide – from 1 to 2; - mineral fibers – from 1 to 30, then a workpiece is made from the mixture mass, the volume of which corresponds to the volume of the forming cavity of the mold, the workpiece is placed in the mold and vulcanized, after vulcanization, the resulting expanding sleeve with a place for installing a thin-walled sleeve is kept in a free state for at least 4 hours, after which it is glued to a thin-walled bushing for an expanding bushing. 7. The method according to claim 6, characterized in that the mixing time of the mixture mass is 30±5 minutes with a friction of 1:1.25. 8. Method according to claim 6 or 7, characterized in that vulcanization is carried out at a temperature of 160 to 180°C for 10 to 40 minutes.