A self-sealing expandable isolation packer

Abstract

The present invention discloses a self-sealing expandable isolation packer, wherein the self-sealing expandable isolation packer includes a central tube, the upper end of the central tube is threadedly connected to an upper joint, the lower end of the central tube is threadedly connected to a lower joint, the outer sleeve of the central tube is provided with a locking head, the locking head is located on the lower side of the upper joint, the outer wall of the locking head is provided with a groove, and the inner side surface of the groove of the locking head is fixedly connected to a tension adjustment ring at the edge. Through the above structure, the expansion rubber cylinder fits the casing with sufficient thickness and elasticity, has stronger adaptability to the roughness of the inner wall of the casing, and has a longer validity period. During the sealing process, the sealing performance of the packer and the casing can be automatically verified, so that it can be determined whether the sealing position is correct. It also has the function of repeated sealing and unsealing. Once the sealing fails, the position can be changed and the sealing can be re-set, avoiding the trouble of re-drilling on site.

Description

Technical Field

[0001] The present invention relates to the technical field of packers, in particular to a self-testing expandable isolation packer. Background Art

[0002] With the advancement of oil well exploitation, casing corrosion and scaling, water production or flooding in oil layers are becoming increasingly serious, the wellbore working conditions are deteriorating, and the workload of water control and oil production is gradually increasing. At present, the commonly used isolation schemes in oil fields are mostly to first run leak detection and water detection pipe strings to squeeze the casing to detect leaks and water, determine the casing damage and leakage points or water-producing layer sections, and then run compression isolation packers to isolate and produce oil.

[0003] This conventional solution has the following drawbacks:

[0004] 1. Before isolation mining, leak detection and water detection tests are required, which takes a long time and the test results are greatly affected by on-site conditions.

[0005] 2. Conventional compression packers have poor adaptability to harsh well conditions such as corrosion and scaling, and their effective period is short.

[0006] 3. The commonly used hydraulically set Y341 compression packer has no good verification method once it is incorrectly sealed or poorly set, and it cannot be re-set. After the setting fails, the string must be removed and the isolation string must be re-inserted. Summary of the Invention

[0007] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a self-sealing expandable isolation packer.

[0008] To achieve the above object, the present invention adopts the following technical solution: a self-sealing expandable isolation packer, comprising: a central tube, an upper joint being threadedly connected to the upper end of the central tube, and a lower joint being threadedly connected to the lower end of the central tube;

[0009] The outer sleeve of the center tube is provided with a locking head, the locking head is located at the lower side of the upper joint, the outer side wall of the locking head is provided with a groove, the inner side surface of the groove of the locking head and the edge of the locking head are fixedly connected to a tension adjustment ring, the groove of the locking head and the side facing the center tube are provided with a sealing groove, a positioning steel ball is provided inside the sealing groove, and a tension spring is provided between the positioning steel ball and the tension adjustment ring;

[0010] The outer wall of the central tube is provided with an unsealing groove for accommodating a positioning steel ball, the unsealing groove is located in the inner cavity of the locking head, and the outer wall of the central tube is provided with a pressure relief groove, the pressure relief groove is located at the sheath connected to the locking head;

[0011] A bridge joint is provided on the lower side of the locking head, and a spring seat is threadedly connected to the lower end of the bridge joint. A seal verification sleeve and a seal verification spring are provided between the spring seat and the outer recessed portion of the bridge joint. The seal verification sleeve is slidably connected to the bridge joint and the spring seat. One end of the seal verification spring is fixedly connected to the spring seat, and the other end of the seal verification spring is fixedly connected to the seal verification sleeve. A reset piston is provided on the lower side of the spring seat.

[0012] An expansion rubber cylinder is provided between the locking head and the bridging head, the spring seat and the reset piston, and both ends of the expansion rubber cylinder are respectively inserted into the corresponding inner cavity;

[0013] Gaps are provided between the center tube and the expansion rubber cylinder, the bridge joint, and the spring seat. A through hole is provided on the bridge joint, which is interconnected with the gap on the outside of the center tube. The through hole of the bridge joint is connected to the left side of the sealing sleeve. Two liquid inlet holes are provided on the side wall of the center tube. The upper liquid inlet hole is interconnected with the gap on the outside of the center tube and is fixedly connected with a single flow ring. The lower liquid inlet hole is connected to the chamber formed between the reset piston and the lower joint.

[0014] Preferably, the lower end of the locking head, the upper end of the bridging head, the lower end of the spring seat and the upper end of the reset piston are all threadedly connected with a sleeve, and the sleeve is close to the outer side surface of the corresponding expansion rubber cylinder.

[0015] Preferably, the cross section of the expansion rubber cylinder is convex-shaped.

[0016] Preferably, the bridge joint, the spring seat and the reset piston are all sleeved on the outside of the central tube.

[0017] Preferably, sealing rings are provided at the junctions of the expansion rubber cylinder and the center tube, the bridge joint, and the spring seat, and sealing rings are provided between the upper joint and the center tube, the bridge joint and the sealing sleeve, the sealing sleeve and the spring seat, the reset piston and the lower joint, and the reset piston and the center tube.

[0018] Preferably, the expansion rubber cylinder is made of rubber material.

[0019] Beneficial effects:

[0020] 1. The expansion rubber tube of this tool fits the casing with sufficient thickness and elasticity, has stronger adaptability to the roughness of the casing inner wall and longer validity period.

[0021] 2. This tool has a self-sealing function, which can automatically verify the sealing between the packer and the casing during the setting process, so as to determine whether the sealing position is correct.

[0022] 3. This tool has the function of repeated setting and unsetting. Once the setting fails, the position can be changed and the setting can be repeated, avoiding the trouble of re-tripping the drill on site.

[0023] 4. The tool's repeated sealing and unsealing function can realize integrated water detection and blocking operations, that is, after completing leak detection and water detection tests using the water detection string, it can directly switch to isolated production, simplifying the measures work. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a diagram of the internal structure of a self-sealing expandable isolation packer of the present invention.

[0025] Legend:

[0026] 1. Upper joint; 2. Tension adjustment ring; 3. Tension spring; 4. Locking head; 5. Sheath; 6. Expansion rubber cylinder; 7. Sealing inspection sleeve; 8. Bridge joint; 9. Sealing inspection spring; 10. Spring seat; 11. Single flow ring; 12. Center tube; 13. Reset piston; 14. Lower joint; 15. Positioning steel ball; 16. Setting groove; 17. Unsealing groove; 18. Pressure relief groove; 19. Liquid inlet hole. DETAILED DESCRIPTION

[0027] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it should not be understood as a limitation on the scope of protection of the present invention.

[0028] Reference Figure 1 The embodiment of the present invention provides a self-sealing expandable isolation packer, which includes: a central tube 12, an upper joint 1 being threadedly connected to the upper end of the central tube 12, and a lower joint 14 being threadedly connected to the lower end of the central tube 12;

[0029] The outer sleeve of the center tube 12 is provided with a locking head 4, which is located on the lower side of the upper joint 1. A groove is provided on the outer wall of the locking head 4. A tension adjustment ring 2 is fixedly connected to the inner side of the groove of the locking head 4 and located at the edge. A sealing groove 16 is provided on the side of the groove of the locking head 4 facing the center tube 12. A positioning steel ball 15 is provided inside the sealing groove 16. A tension spring 3 is provided between the positioning steel ball 15 and the tension adjustment ring 2.

[0030] The outer wall of the central tube 12 is provided with an unsealing groove 17 for accommodating the positioning steel ball 15. The unsealing groove 17 is located in the inner cavity of the locking head 4. The outer wall of the central tube 12 is provided with a pressure relief groove 18. The pressure relief groove 18 is located at the sheath 5 connected to the locking head 4.

[0031] A bridging joint 8 is provided on the lower side of the locking head 4. A spring seat 10 is threadedly connected to the lower end of the bridging joint 8. A seal verification sleeve 7 and a seal verification spring 9 are provided between the spring seat 10 and the outer recessed portion of the bridging joint 8. The seal verification sleeve 7 is slidably connected to the bridging joint 8 and the spring seat 10. One end of the seal verification spring 9 is fixedly connected to the spring seat 10, and the other end of the seal verification spring 9 is fixedly connected to the seal verification sleeve 7. A reset piston 13 is provided on the lower side of the spring seat 10.

[0032] An expansion rubber cylinder 6 is provided between the locking head 4 and the bridging head 8, the spring seat 10 and the reset piston 13, and both ends of the expansion rubber cylinder 6 are respectively inserted into the corresponding inner cavity. The cross section of the expansion rubber cylinder 6 is convex;

[0033] The bridging joint 8, the spring seat 10 and the reset piston 13 are all sleeved on the outside of the central tube 12. The lower end of the locking head 4, the upper end of the bridging joint 8, the lower end of the spring seat 10 and the upper end of the reset piston 13 are all threadedly connected with a sleeve 5. The sleeve 5 is close to the outer side surface of the corresponding expansion rubber cylinder 6. The expansion rubber cylinder 6 is made of rubber material. The expansion rubber cylinder 6 is made of a steel pipe and rubber integrally vulcanized. There is a liquid inlet hole 19 on the steel pipe for internal and external communication. The rubber has sufficient thickness to meet the expansion sealing sleeve and fill the annular gap between the packer and the casing for a certain distance, and the packer rubber cylinder can adapt to the roughness and undulations of the inner wall of the casing.

[0034] Sealing rings are provided at the junction of the expansion rubber cylinder 6 and the center tube 12, the bridge joint 8, and the spring seat 10. Sealing rings are also provided between the upper joint 1 and the center tube 12, the bridge joint 8 and the sealing sleeve 7, the sealing sleeve 7 and the spring seat 10, the reset piston 13 and the lower joint 14, and the reset piston 13 and the center tube 12.

[0035] There are gaps between the center tube 12 and the expansion rubber cylinder 6, the bridge joint 8, and the spring seat 10. The bridge joint 8 is provided with a through hole that is interconnected with the gap on the outside of the center tube 12. The through hole of the bridge joint 8 is connected to the left side of the sealing sleeve 7. The side wall of the center tube 12 is provided with two liquid inlet holes 19. The upper liquid inlet hole 19 is interconnected with the gap on the outside of the center tube 12 and is fixedly connected to a single flow ring 11. The lower liquid inlet hole 19 is connected to the chamber formed between the reset piston 13 and the lower joint 14.

[0036] Working principle:

[0037] Structure: The upper joint 1, the center tube 12, and the lower joint 14 are rigidly connected by threads; the remaining parts are rigidly connected to the outside of the center tube 12 by threads, and their axial relative position with the center tube 12 is limited by the positioning steel ball 15.

[0038] Setting seal: When lowering into the well, the positioning steel ball 15 is located in the setting seal groove 16, and the outer rigid connection components (all accessories except the upper joint 1, the central pipe 12, and the lower joint 14) are in the setting seal standby state; after the tool is lowered to the designed position, the oil pipe (central pipe 12) is pressurized, and the high pressure of the central pipe 12 enters the outside of the central pipe 12 through the single flow ring 11, and further enters the inner cavity of the two-stage expandable rubber cylinder, driving the expansion rubber cylinder 6 to fit the casing to form a seal.

[0039] Self-sealing: When the sealing pressure in the inner cavity of the center tube 12 and the expansion rubber cylinder 6 further increases and reaches the opening pressure of the sealing sleeve 7, the sealing sleeve 7 slides downward and opens under the action of the internal pressure to overcome the elastic force of the sealing spring 9, and the sealing pressure in the inner cavity of the center tube 12 and the expansion rubber cylinder 6 leaks out of the tool through the single flow ring 11 and the sealing sleeve 7 in turn; if the two-stage expansion rubber cylinder 6 is well sealed (the packer is well sealed), the instantaneous pressure inside and outside the sealing sleeve 7 is balanced and stable, and the center tube 12 can stabilize the pressure; if the sealing of any one-stage expansion rubber cylinder 6 is poor (the packer is not well sealed or the sealing position is wrong), the high pressure in the sealing sleeve 7 will continue to leak out, and the center tube 12 will not be able to stabilize the pressure, then it can be determined that the packer is poorly sealed or the sealing position is wrong.

[0040] Unsealing: Lifting the tubing string drives the upper joint 1, the central tube 12 and the lower joint 14 upward to overcome the locking force of the positioning steel ball 15, and all the rigid connectors in the outer layer (expansion rubber tube 6, sheath 5, locking head 4, bridge joint 8, sealing sleeve 7, spring seat 10, sealing spring 9 and reset piston 13) move downward relatively until the positioning steel ball 15 slides into the unsealing groove 17 outside the central tube 12, and the packer is in the unsealing state; the single flow ring 11 is squeezed by the inner wall of the spring seat 10 to block the liquid inlet 19 of the central tube 12, and at the same time, the upper and lower sealing rings of the expansion rubber tube 6 slide to the pressure relief groove 18 on the central tube 12, and the high pressure in the inner cavity of the expansion rubber tube 6 is discharged to the casing through the pressure relief groove 18, the internal and external pressures of the expansion rubber tube 6 are balanced and recovered, and the packer is unsealed.

[0041] Reset: After the tubing string is lifted and lowered to replace the new setting position, the center tube 12 is pressurized. Since the liquid inlet hole 19 of the center tube 12 is squeezed and closed by the single flow ring 11, the high pressure of the center tube 12 enters the lower end face of the reset piston 13 through the bottom liquid inlet hole 19, pushing the reset piston 13 and all outer accessories rigidly connected to it to slide upward until the positioning steel ball 15 slides into the setting groove 16 outside the center tube 12. The packer is in the state of switching to the setting standby state and continues to increase the pressure. The setting process is exactly the same as the above-mentioned setting process.

[0042] Related terms:

[0043] 1. Setting: The process of transitioning a packer tool from a standby state to a sealed state (which can be driven by hydraulic, mechanical, or other means)

[0044] 2. Unsealing: The process of releasing the sealing anchor state of the packer tool so that it can be raised and lowered freely.

[0045] 3. Pipe string: An oilfield term that generally refers to the pipes lowered into the wellbore and the tools and accessories connected to them.

[0046] 4. Rigid connection: A connection method in which the parts connected by threads or other means do not experience axial or radial relative movement. For example, multiple parts connected by axial threads cannot experience axial relative displacement. These threaded parts are rigidly connected and can be considered as a single unit.

[0047] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the scope of the present invention.

Claims

1. A self-sealing expandable isolation packer, characterized in that: include: A central tube (12), wherein the upper end of the central tube (12) is threadedly connected to an upper joint (1), and the lower end of the central tube (12) is threadedly connected to a lower joint (14); The center tube (12) is provided with a locking head (4) on the outside, the locking head (4) is located at the lower side of the upper joint (1), the outer wall of the locking head (4) is provided with a groove, the inner side surface of the groove of the locking head (4) is fixedly connected to the edge thereof with a tension adjustment ring (2), the groove of the locking head (4) is provided with a sealing groove (16) on the side facing the center tube (12), a positioning steel ball (15) is provided inside the sealing groove (16), and a tension spring (3) is provided between the positioning steel ball (15) and the tension adjustment ring (2); The outer wall of the central tube (12) is provided with an unsealing groove (17) for accommodating a positioning steel ball (15), and the unsealing groove (17) is located in the inner cavity of the locking head (4). The outer wall of the central tube (12) is provided with a pressure relief groove (18), and the pressure relief groove (18) is located at the sheath (5) connected to the locking head (4); A bridge joint (8) is provided on the lower side of the locking head (4), and a spring seat (10) is threadedly connected to the lower end of the bridge joint (8), and a sealing inspection sleeve (7) and a sealing inspection spring (9) are provided between the spring seat (10) and the outer recessed portion of the bridge joint (8). The sealing inspection sleeve (7) is slidably connected to the bridge joint (8) and the spring seat (10), one end of the sealing inspection spring (9) is fixedly connected to the spring seat (10), and the other end of the sealing inspection spring (9) is fixedly connected to the sealing inspection sleeve (7), and a reset piston (13) is provided on the lower side of the spring seat (10); An expansion rubber cylinder (6) is provided between the locking head (4) and the bridging head (8), the spring seat (10) and the reset piston (13), and both ends of the expansion rubber cylinder (6) are respectively inserted into corresponding inner cavities; Gaps are provided between the central tube (12) and the expansion rubber cylinder (6), the bridge joint (8), and the spring seat (10); a through opening is provided on the bridge joint (8) and is communicated with the gap on the outside of the central tube (12); the through opening of the bridge joint (8) is communicated with the left side of the sealing sleeve (7); two liquid inlet holes (19) are provided on the side wall of the central tube (12); the upper liquid inlet hole (19) is communicated with the gap on the outside of the central tube (12) and is fixedly connected with a single flow ring (11); the lower liquid inlet hole (19) is communicated with a chamber formed between the reset piston (13) and the lower joint (14); the lower end of the locking head (4), the upper end of the bridge joint (8), the lower end of the spring seat (10), and the upper end of the reset piston (13) are all threadedly connected with a sleeve (5), and the sleeve (5) is close to the outer side of the corresponding expansion rubber cylinder (6); the cross section of the expansion rubber cylinder (6) is convex.

2. The self-sealing expandable isolation packer according to claim 1, characterized in that: The bridge joint (8), spring seat (10) and reset piston (13) are all sleeved on the outside of the central tube (12).

3. The self-sealing expandable isolation packer according to claim 1, characterized in that: Sealing rings are provided at the junctions of the expansion rubber cylinder (6) and the central tube (12), the bridge joint (8), and the spring seat (10); sealing rings are provided between the upper joint (1) and the central tube (12), the bridge joint (8) and the seal-checking sleeve (7), the seal-checking sleeve (7) and the spring seat (10), the reset piston (13) and the lower joint (14), and the reset piston (13) and the central tube (12).

4. The self-sealing expandable isolation packer according to claim 1, characterized in that: The expansion rubber cylinder (6) is made of rubber material.

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