A double retainer packer

Abstract

The application relates to the technical field of oil and gas exploitation, and aims to provide a double-block-ring packer, which comprises a center pipe, a joint pipe sleeved outside the two ends of the center pipe, and a hydraulic cylinder sleeved outside the middle section of the center pipe; an O-ring assembly is arranged outside the center pipe between the two ends of the hydraulic cylinder and the end portions of the joint pipe; a sealing groove is arranged between the joint pipe and the section of the center pipe outside which the joint pipe is sleeved; and the double-block-ring sealing assembly comprises two block rings arranged in the sealing groove and a sealing ring clamped between the two block rings. The application can guarantee the stability of the radial deformation of the sealing ring, can avoid the sealing ring from entering the sealing gap under high pressure, can realize effective sealing of the sealing node, and has a longer service life.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas exploitation, and particularly relates to a double-check-ring packer. BACKGROUND

[0002] The compression packer is a core tool for sealing the annular space between the pipe string and the wellbore, which can realize annular sealing by compressing the rubber sleeve with axial force and making it expand radially to adhere to the inner wall of the wellbore, and can fix the position of the packer to prevent it from moving in the downhole operation. At present, some compression packers adopt hydraulic auxiliary setting type, which mainly includes a center pipe, upper and lower joints, a rubber sleeve assembly, a hydraulic cylinder and a locking assembly. The hydraulic cylinder drives the piston to move to assist or dominate the compression of the rubber sleeve, thereby solving the problem of insufficient mechanical setting force in large-diameter wellbores. The typical process is as follows: when the piston is locked by a pin during the downhole operation, the wellhead is pressurized to push the piston and shear the pin to extrude the rubber sleeve, and at the same time, the locking assembly is engaged to prevent rebounding. Some packers can be released by reverse pressurization or raising the pipe string. The packer has obvious advantages, such as controllable setting force, reduced pipe string load and adaptability to deviated wells / horizontal wells, and is mainly used in high-pressure oil and gas wells, deep wells / ultra-deep wells, and horizontal well staged fracturing and temporary sealing during well repair. The specific structure can refer to the applicant's published patent CN221053658U.

[0003] In order to ensure the stability of each component during work, a sealing ring needs to be arranged at the sealing node position between the hydraulic cylinder and the piston, between the joint and the center pipe, etc. for sealing. However, the existing hydraulic drive compression packer only seals the sealing node by a sealing ring, which is easy to enter the sealing gap under the high-temperature and high-pressure working environment, resulting in damage or sealing failure of the sealing ring. At the same time, since the sealing principle of the packer is to apply axial force to the rubber sleeve to make it extrude and expand to adhere to the inner wall of the casing or the open hole to form a seal, the expansion of the rubber sleeve is completely from the axial force, and lacks active extrusion in the radial direction, resulting in that the overall sealing effect needs to be improved. SUMMARY

[0004] The purpose of the present application is to provide a double-check-ring packer with stable sealing, reduced damage to the sealing ring and improved sealing life.

[0005] To achieve the above-mentioned purpose of the application, the technical scheme adopted by the present application is as follows: a double-check-ring packer, which comprises a center pipe, a joint pipe sleeved on one section of the outer part of the center pipe at both ends, and a hydraulic cylinder sleeved on the outer part of the middle section of the center pipe; a rubber sleeve assembly is arranged outside the center pipe between the two ends of the hydraulic cylinder and the end part of the joint pipe;

[0006] A sealing groove is arranged between the section of the joint pipe sleeved on the outer part of the center pipe and the center pipe, and a double-check-ring sealing assembly is arranged at the sealing groove; the double-check-ring sealing assembly comprises two check rings arranged in the sealing groove and a sealing ring clamped between the two check rings.

[0007] Preferably, the end face of the blocking ring towards the sealing ring is provided with an arc-shaped end groove, the cross section of the sealing ring is oval, and the long axis side of the oval is the same as the axial direction of the sealing ring, and the short axis side is the same as the radial direction of the sealing ring; the long axis side of the oval of the sealing ring is located in the end groove of the two blocking rings respectively.

[0008] Preferably, one side of the blocking ring is provided with a cutout, the cutouts on the two blocking rings located in the same sealing groove body are staggered by 180°, and the sealing ring is fluorine rubber with a hardness of 80±5 shore A.

[0009] Preferably, the cutout is an oblique cutout.

[0010] Preferably, the hydraulic cylinder comprises a cylinder body, a cylinder sleeve arranged at one end of the cylinder body, and an upper piston and a lower piston arranged in the cylinder body, and a pressurized cavity for the pressurized liquid is formed between the upper piston and the lower piston.

[0011] Preferably, a dog mechanism for forming a packer and a casing is arranged in the cylinder body corresponding to the position of the upper piston and the steel sleeve.

[0012] Preferably, a sealing groove is arranged between the outer side wall of the upper piston and the inner side wall of the cylinder body, between the inner side wall of the upper piston and the central pipe, between the outer side wall of the lower piston and the inner side wall of the cylinder body, and between the inner side wall of the upper piston and the central pipe, and a double-blocking-ring sealing assembly is arranged in the sealing groove.

[0013] Preferably, each of the sealing grooves is composed of two groove bodies, and a group of double-blocking-ring sealing assemblies is arranged in each groove body.

[0014] Preferably, the rubber cylinder assembly comprises two tapered expansion rubber cylinders arranged outside the central pipe and bowl-shaped cylinder seats arranged at the two ends of the expansion rubber cylinders, and the cylinder seats are matched with the two ends of the expansion rubber cylinders.

[0015] Preferably, a ring-shaped extrusion platform is arranged on the outer side wall of the central pipe corresponding to the middle part of the expansion rubber cylinder, and an extrusion inclined surface is arranged at the two ends of the extrusion platform.

[0016] Preferably, the cross section of the extrusion platform is isosceles trapezoidal, and a ring groove extending along the axial direction of the extrusion platform is arranged on the top surface of the isosceles trapezoidal extrusion platform; a plurality of radial holes extending along the radial direction of the extrusion platform are arranged in the interior of the extrusion platform, a top pin is arranged in the radial hole, the inner end of the top pin is conical, and an axial hole extending along the axial direction of the extrusion platform and penetrating through the two end surfaces of the extrusion platform is further arranged at the inner end of the radial hole.

[0017] The center pipe outside both ends of the extrusion platform is sleeved with an extrusion disc capable of sliding along the center pipe in the axial direction, a push pin is arranged on the extrusion disc at a position opposite to the axial hole, the inner end of the push pin is also conical and matched with the inner end of the ejector pin.

[0018] Preferably, an elastic expansion ring is arranged in the annular groove, the elastic expansion ring is wavy, and the inner concave part of the wavy elastic expansion ring is opposite to the outer end of the ejector pin; the outer end of the ejector pin is provided with a concave arc-shaped pin head.

[0019] The beneficial effects of the present application are mainly reflected in the following aspects: the stability of the radial deformation of the sealing ring can be ensured, the sealing ring can be prevented from entering the sealing gap under high pressure, effective sealing of the sealing node can be realized, and the service life is longer. Specifically, in the use process, two check rings are used in the sealing groove to axially constrain the sealing ring in two directions, when the sealing ring is deformed under pressure, the stability of the position of the sealing ring can be effectively ensured, and the sealing ring is prevented from being excessively deformed under pressure; the sealing effect is ensured, the pressure resistance of the sealing ring is improved, so that the packer can maintain high sealing for a long time, and the service life under high sealing is improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a structural schematic view of the present application;

[0021] Figure 2 It is Figure 1 an enlarged view of A part in the middle;

[0022] Figure 3 It is a structural schematic view of the cutout on the two check rings in the sealing groove;

[0023] Figure 4 It is Figure 3 a top view of the check ring on the left side in the middle;

[0024] Figure 5 It is a structural schematic view of the rubber tube assembly;

[0025] Figure 6 It is Figure 5 an enlarged view of B part in the middle;

[0026] Figure 7 It is a structural schematic view of the elastic expansion ring;

[0027] Figure 8 It is a structural schematic view of the ejector pin;

[0028] Reference numerals: 0. Expansion sleeve; 1. Central tube; 2. Connector tube; 3. Hydraulic cylinder; 4. Sleeve assembly; 5. Sealing groove; 6. Retaining ring; 7. Sealing ring; 8. End groove; 9. Cutout; 10. Cylinder body; 11. Cylinder liner; 12. Upper piston; 13. Lower piston; 14. Pressurization chamber; 15. Sleeve seat; 16. Extrusion platform; 17. Annular groove; 18. Radial hole; 19. Top pin; 20. Axial hole; 21. Extrusion plate; 22. Push pin; 23. Elastic expansion ring; 24. Pin head. Detailed Implementation

[0029] like Figure 1 As shown, the present invention is a double-ring packer, which is a compression packer that uses hydraulic setting to form a seal. It is similar to existing hydraulic compression packers in that it also includes a central tube 1, a connector tube 2 sleeved around both ends of the central tube 1, and a hydraulic cylinder 3 sleeved around the middle section of the central tube 1. The connector tube 2 includes two tubes, an upper connector tube and a lower connector tube, with one end of each connector tube sleeved around the central tube 1. A rubber sleeve assembly 4 is provided outside the central tube 1 between the two ends of the hydraulic cylinder 3 and the ends of the connector tubes 2.

[0030] The hydraulic cylinder 3 typically includes a cylinder body 10, a cylinder sleeve 11 disposed at one end of the cylinder body 10, and an upper piston 12 and a lower piston 13 disposed within the cylinder body 10. The upper piston 12 and the lower piston 13 form a pressurizing chamber 14 for injecting pressurizing fluid. Pressurizing fluid can be injected into the pressurizing chamber 14 through a side hole on the central tube 1. The main function of the hydraulic cylinder 3 is to apply axial force to the rubber sleeve assembly 4, thereby pushing the rubber sleeve assembly 4 to expand and achieve sealing. To prevent piston retraction, a toothed mechanism for forming a settling seal between the packer and the sleeve is generally provided in the cylinder body 10 at the position corresponding to the upper piston 12 and the steel sleeve. The design of the toothed mechanism is prior art, and it can also be designed with reference to the slips in prior art, which will not be described in detail in this invention.

[0031] As a crucial sealing element of this invention, a sealing groove 5 is provided between the section of the connector pipe 2 sleeved outside the central pipe 1 and the central pipe 1. The sealing groove 5 typically employs a double-groove design, comprising two adjacent grooves. A unique feature of this invention compared to traditional packers is the inclusion of a double-retaining ring sealing assembly at the sealing groove 5. In this double-groove design, each groove contains a set of double-retaining ring sealing assemblies. The double-retaining ring sealing assembly includes two retaining rings 6 disposed within the sealing groove 5, and a sealing ring 7 sandwiched between the two retaining rings 6. The sealing ring 7 is made of fluororubber with a hardness of 80±5 Shore A, capable of undergoing 15-20% radial deformation under pressure, exhibiting high stability and good corrosion resistance.

[0032] On the basis of the foregoing double-piston design, a sealing groove 5 is arranged between the outer side wall of the upper piston 12 and the inner side wall of the cylinder body 10, between the inner side wall of the upper piston 12 and the center tube 1, between the outer side wall of the lower piston 13 and the inner side wall of the cylinder body 10, and between the inner side wall of the upper piston 12 and the center tube 1 as a sealing node, and a double-retainer sealing assembly is arranged in the sealing groove 5.

[0033] In use, the two retainers in the sealing groove 5 axially constrain the sealing ring in two directions, and when the sealing ring is deformed under pressure, the position of the sealing ring can be effectively stabilized, and the sealing ring can be prevented from being excessively deformed under pressure, thereby ensuring the sealing effect, improving the pressure resistance of the sealing ring, and enabling the packer to maintain high sealing for a long time and improve the service life thereof in a high sealing state.

[0034] The retainers 6 can be two flat rings, or as shown in Figure 2 , the end faces of the retainers 6 towards the sealing ring 7 are provided with arc-shaped end grooves 8, the cross section of the sealing ring 7 is oval, and the long axis side of the oval is the same as the axial direction of the sealing ring 7, and the short axis side is the same as the radial direction of the sealing ring 7. The long axis side of the oval of the sealing ring 7 is located in the end groove 8 of each retainer 6. This structure can strengthen the constraint on the sealing ring 7, further reduce the risk of extrusion of the sealing ring 7, and also provide sufficient space for the deformation of the sealing ring 7, thereby preventing the sealing ring 7 from being excessively extruded while ensuring sealing.

[0035] Since the retainer 6 is a non-elastic part, a cutout 9 is arranged on one side of the retainer 6 to cut off the retainer 6 and facilitate the installation of the retainer 6 into the sealing groove 5. In this double-retainer 6 structure, the cutouts 9 on the two retainers 6 in the same sealing groove 5 are staggered by 180°, as shown in Figure 3 , that is, the cutouts on the two retainers 6 are opposite, one is on the top, and the other needs to be on the bottom. Meanwhile, as shown in Figure 4 , the cutout 9 is arranged as an oblique cutout. In this structure, the retainer 6 forms a relatively continuous whole while ensuring convenient installation, thereby preventing stress concentration caused by overlapping or too close distance of the cutouts 9.

[0036] The rubber sleeve assembly 4 is used to expand and deform under the action of the hydraulic cylinder 3 to achieve sealing of the casing or open hole. The specific structure is various, but the most common one is a double-seat extrusion structure, as shown in Figure 5As shown in the background, the rubber sleeve assembly 4 of the present application comprises a tapered expansion rubber sleeve 0 sleeved on the outer side wall of the central pipe 1 and bowl-shaped sleeve seats 15 arranged at the two ends of the expansion rubber sleeve 0, which are matched with the two ends of the expansion rubber sleeve 0. The conical structure of the two ends of the expansion rubber sleeve 0 and the matched bowl-shaped sleeve seats 15 can further disperse the extrusion stress and avoid local stress concentration, so that the uniformity of extrusion is better.

[0037] As mentioned in the background, the lack of radial thrust when the expansion rubber sleeve 0 is deformed, the outer side wall of the central pipe 1 corresponding to the middle part of the expansion rubber sleeve 0 is provided with a ring-shaped extrusion platform 16, and the two ends of the extrusion platform 16 are provided with extrusion inclined surfaces. In this way, the middle section of the expansion rubber sleeve 0 is extruded and guided by the extrusion inclined surfaces, which can effectively improve the stability of the radial expansion.

[0038] On this basis, it is better to further ensure the stability of the expansion by applying active radial thrust. Figure 6 As shown in the background, the cross section of the extrusion platform 16 is isosceles trapezoidal, and the top surface of the isosceles trapezoidal is provided with a ring groove 17 extending along the axial direction of the extrusion platform 16. The inside of the extrusion platform 16 is provided with a plurality of radial holes 18 extending along the radial direction of the extrusion platform 16, and the inside of the radial hole 18 is provided with a top pin 19, and the inner end of the top pin 19 is conical. The inner end of the radial hole 18 is also provided with an axial hole 20 extending along the axial direction of the extrusion platform 16 and penetrating to the two end surfaces of the extrusion platform 16.

[0039] The outer side wall of the central pipe 1 at the two ends of the extrusion platform 16 is sleeved with an extrusion disc 21 which can slide along the axial direction of the central pipe 1, and the position opposite to the axial hole 20 on the extrusion disc 21 is provided with a push pin 22, and the inner end of the push pin 22 is also conical and matched with the inner end of the top pin 19.

[0040] When the two ends of the expansion rubber sleeve 0 are extruded by the sleeve seat 15, on the one hand, the inclined surfaces on both sides of the extrusion platform 16 can guide, and on the other hand, the expansion rubber sleeve 0 drives the extrusion disc 21 to move after being pressed, and the top pin 19 is driven by the push pin 22, so that the outer end of the top pin 19 extrudes the expansion rubber sleeve 0, and a certain radial thrust is applied to the expansion rubber sleeve 0, so as to improve the hole sealing effect.

[0041] However, since the top pin 19 is a plurality of independent non-continuous structures, there is still a problem of uneven distribution of extrusion force in the process of pushing the expansion rubber sleeve 0 radially; therefore, the better way of the present application is also to combine Figure 6 and 7 As shown in the background, the ring groove 17 is provided with an elastic expansion ring 23, the elastic expansion ring 23 is wave-shaped, and the concave part of the wave-shaped elastic expansion ring 23 is opposite to the outer end of the top pin 19.

[0042] The inner recess of the elastic expansion ring 23 is pushed by the ejector pin 19, so that the elastic expansion ring 23 is deformed and expanded, and is opened, the overall outer diameter is expanded, and the continuous and uniform extrusion force of the expansion rubber cylinder 0 is ensured, so that the balance of the extrusion force in the circumferential direction is ensured. In order to ensure the contact of the ejector pin 19 and the elastic expansion ring 23, as shown in Figure 8 The outer end of the ejector pin 19 is provided with a concave arc-shaped pin head 24.

Claims

1. A double-block packer, comprising a central pipe (1), a joint pipe (2) sleeved on the outer part of both ends of the central pipe (1), and a hydraulic cylinder (3) sleeved on the middle part of the central pipe (1); a rubber sleeve assembly (4) is arranged on the outer part of the central pipe (1) between the two ends of the hydraulic cylinder (3) and the end part of the joint pipe (2); a sealing groove (5) is arranged between the part of the joint pipe (2) sleeved on the outer part of the central pipe (1) and the central pipe (1); a double-block sealing assembly is arranged at the sealing groove (5); the double-block sealing assembly comprises two blocks (6) arranged in the sealing groove (5) and a sealing ring (7) clamped between the two blocks (6); the rubber sleeve assembly (4) comprises an inflatable rubber sleeve (0); a ring-shaped extrusion platform (16) is arranged on the outer sidewall of the central pipe (1) corresponding to the middle part of the inflatable rubber sleeve (0); the two ends of the extrusion platform (16) are provided with extrusion inclined surfaces; the cross section of the extrusion platform (16) is isosceles trapezoidal, and the top surface of the isosceles trapezoid is provided with a ring groove (17) extending along the axial direction of the extrusion platform (16); a plurality of radial holes (18) extending along the radial direction of the extrusion platform (16) are arranged in the inside of the extrusion platform (16); a top pin (19) is arranged in the radial hole (18); the inner end of the top pin (19) is conical; an axial hole (20) extending along the axial direction of the extrusion platform (16) and penetrating through the two end surfaces of the extrusion platform (16) is further arranged at the inner end of the radial hole (18); the outer part of the extrusion platform (16) is sleeved with an extrusion disc (21) capable of sliding along the axial direction of the central pipe (1); a push pin (22) is arranged on the extrusion disc (21) at a position opposite to the axial hole (20); the inner end of the push pin (22) is also conical and matched with the inner end of the top pin (19); an elastic expansion ring (23) is arranged in the ring groove (17); the elastic expansion ring (23) is wavy, and the inner concave part of the elastic expansion ring (23) is opposite to the outer end of the top pin (19); the outer end of the top pin (19) is provided with an inner concave arc-shaped pin head (24); the end surface of the block (6) facing the sealing ring (7) is provided with an arc-shaped end groove (8); the cross section of the sealing ring (7) is elliptical, and the long axis side of the elliptical shape is the same as the axial direction of the sealing ring (7), and the short axis side is the same as the radial direction of the sealing ring (7); the long axis side of the elliptical shape of the sealing ring (7) is located in the end groove (8) of the two blocks (6) respectively; a cutout (9) is arranged on one side of the block (6); the cutouts (9) on the two blocks (6) located in the same sealing groove (5) are distributed in 180° staggered manner; the sealing ring (7) is fluorine rubber with a hardness of 80±5 shore A; the hydraulic cylinder (3) comprises a cylinder body (10), a cylinder sleeve (11) arranged at one end of the cylinder body (10), and an upper piston (12) and a lower piston (13) arranged in the cylinder body (10); the upper piston (12) and the lower piston (13) form a pressurizing cavity (14) for the pressurized liquid. characterized in that ​ ​ ​ ​ ​ ​ 2. The dual retainer packer of claim 1, wherein: ​ 3. The dual retainer packer of claim 2, wherein: ​ 4. The dual retainer packer of claim 3, wherein: ​ 5. The dual retainer packer of claim 4, wherein: The outer side wall of the upper piston (12) and the inner side wall of the cylinder (10), the inner side wall of the upper piston (12) and the center tube (1), the outer side wall of the lower piston (13) and the inner side wall of the cylinder (10), and the inner side wall of the upper piston (12) and the center tube (1) are provided with sealing grooves (5), and the sealing grooves (5) are provided with double-retainer-ring sealing assemblies.

6. The dual retainer packer of claim 5, wherein: Each of the sealing grooves (5) is composed of two groove bodies, and each groove body is provided with a set of double-retainer-ring sealing assemblies.

7. The dual retainer packer of claim 6, wherein: The rubber tube assembly (4) comprises two tapered expansion rubber tubes (0) sleeved outside the center tube (1) and bowl-shaped tube seats (15) arranged at the two ends of the expansion rubber tubes (0), and the tube seats (15) are matched with the two ends of the expansion rubber tubes (0).

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