A casing protector for well repair

Abstract

The utility model relates to a casing protector for workover, and relates to the technical field of oilfield downhole tools, and the structure comprises a central cylinder, an upper joint, a lower joint and a ball, the outer side of the middle part of the central cylinder is provided with a ball mounting plate in the circumferential direction, a spring A is arranged between the ball mounting plate and the central cylinder, the two ends of the central cylinder are respectively sleeved with a limiting sleeve, the two ends of the ball mounting plate are respectively located on the inner side of the limiting sleeve, the ball mounting plate comprises an inner plate and an outer plate, the ball is limitedly mounted between the inner plate and the outer plate, the ball rotates freely relative to the ball mounting plate, and the inner plate is fixedly connected with the outer plate. In the application, the ball can not only bear the axial sliding of the workover string relative to the casing, but also bear the circumferential rotation of the workover string relative to the casing, so that the abrasion of the workover string on the casing is reduced to the maximum extent. In addition, the application relieves the vibration impact under the action of the spring A, has the effect of protecting the casing, and avoids the vibration damage of the casing.

Description

Technical Field

[0001] This utility model belongs to the field of oilfield downhole tool technology, and in particular relates to a casing protection device for well workover. Background Technology

[0002] Oil well casing is a steel pipe used to support the wellbore of oil and gas wells to ensure the drilling process and the normal operation of the entire well after completion.

[0003] Well workover operations are comprehensive technical measures to maintain the normal production of oil wells during the oil extraction process. They fall under the category of oil well maintenance and upkeep measures and mainly ensure the normal production of oil and water wells by repairing downhole faults and restoring production capacity.

[0004] During downhole operations, the workover string rubs against the casing, especially in deviated and horizontal wells where wear is particularly severe. This wear consists of two parts: axial wear from the lifting and lowering of the workover string relative to the casing, and circumferential wear from the rotation of the workover string relative to the casing. Both parts of wear cause significant damage to the casing. Furthermore, when the rotational speed of the workover string relative to the casing is high, it also generates significant vibration and impact on the casing string. Utility Model Content

[0005] To address the problems in the background art, this utility model provides a casing protection device for well workover. The application of this utility model can reduce friction and wear in two ways: firstly, by reducing friction and wear caused by axial sliding between the workover string and the casing; and secondly, by reducing friction and wear caused by circumferential rotation between the workover string and the casing. Simultaneously, this application can also reduce the vibration impact on the casing caused by the rotation of the workover string.

[0006] The technical solution provided by this utility model is: a casing protection device for well workover, which structurally includes a central cylinder, an upper connector, a lower connector, and ball bearings. The two ends of the central cylinder are threadedly connected to the upper connector and the lower connector, respectively. A ball bearing mounting plate is circumferentially arranged on the outer side of the middle part of the central cylinder. A spring A is arranged between the ball bearing mounting plate and the central cylinder. Under the action of the spring force, the ball bearing mounting plate has a tendency to move away from the central cylinder. Limiting sleeves are respectively fitted on both ends of the central cylinder. The two ends of the ball bearing mounting plate are respectively located inside the limiting sleeves. The ball bearing mounting plate includes an inner plate and an outer plate. The inner plate and the outer plate are respectively equipped with ball seats. The ball bearings are limited and installed between the inner plate and the outer plate and are located in the ball seats. The ball bearings can rotate freely in the ball seats. The inner plate and the outer plate are fixedly connected.

[0007] In the above-mentioned technical solution, the balls can rotate freely relative to the ball bearing mounting plate. When the outer side of the balls rubs against the casing, sliding friction is converted into rolling friction, significantly reducing wear on the casing. The balls can withstand both axial sliding of the workover string relative to the casing and circumferential rotation of the workover string relative to the casing, minimizing wear on the casing. Furthermore, when the workover string rotates rapidly relative to the casing, it generates strong radial vibrations in the casing. The above solution, with the action of spring A, mitigates these vibrations, protecting the casing and preventing vibration damage.

[0008] A further technical solution is that a guide pin is provided between the ball bearing mounting plate and each limiting sleeve.

[0009] A further technical solution is that a sliding bearing is provided between the ball bearing mounting plate and the guide pin.

[0010] A further technical solution is as follows: a flushing channel is provided between the inner plate and the outer plate, the flushing channel is connected to the ball seat, a piston cylinder is provided on the inner side of the inner plate, the inner cavity of the piston cylinder is connected to the flushing channel, a piston is inserted in the piston cylinder, one end of the piston abuts against the central cylinder, and a spring B is provided between the other end of the piston and the outer plate. The outer plate corresponding to the piston cylinder has a liquid inlet hole, and a one-way valve A is provided at the liquid inlet hole. One-way valve A allows liquid to enter the liquid inlet hole from the outside and prevents liquid in the piston cylinder from flowing out of the liquid inlet hole. A one-way valve B is provided on the flushing channel at the end of the inner plate. One-way valve B allows liquid in the flushing channel to flow out from the end of the inner plate and prevents liquid from entering the flushing channel from the end of the inner plate. A filter plate is installed on the outer plate outside the liquid inlet hole.

[0011] When the ball bearing mounting plate rebounds towards the center cylinder under the pressure of the sleeve, the piston is forced into the piston cylinder, squeezing the liquid remaining in the piston cylinder into the flushing channel. Since the flushing channel is connected to the ball bearing seat, it flushes out the impurities retained in the ball bearing seat, thereby preventing the ball bearing from getting stuck after the impurities enter the ball bearing seat.

[0012] A further technical solution is that the piston cylinder is located in the middle of the inner plate, and the piston cylinder is connected to the flushing channels on both sides.

[0013] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0014] 1. In existing sleeve protection devices, the balls roll relative to both the central cylinder and the sleeve, with opposite forces acting on them. Therefore, the balls sometimes do not rotate (when they do not rotate, sliding friction is not converted into rolling friction). Although existing technologies incorporate balls, they do not completely convert sliding friction into rolling friction. However, the balls in this application only roll relative to the sleeve and do not contact the central cylinder; therefore, this application can completely convert sliding friction into rolling friction.

[0015] 2. This application can withstand both the axial sliding of the workover string relative to the casing and the circumferential rotation of the workover string relative to the casing, thereby minimizing the wear of the workover string on the casing.

[0016] 3. The ball bearing mounting plate of this application can bounce relative to the central cylinder. Therefore, when the workover string rotates at high speed relative to the casing and generates strong vibration, the spring A can alleviate the vibration impact and protect the casing from damage caused by vibration impact.

[0017] 4. The balls in this application will not get stuck in the ball seat. Because the ball seat is connected to the flushing channel, when the ball mounting plate is squeezed by the sleeve, the liquid in the piston cylinder flows through the flushing channel. Each time the liquid flows through the flushing channel, it flushes out the impurities retained in the ball seat, thereby ensuring smooth ball rolling. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of Embodiment 1.

[0019] Figure 2 This is a schematic diagram of the structure of Embodiment 2.

[0020] Figure 3 yes Figure 2 A magnified view of a section at point I.

[0021] In the diagram: 1. Lower connector; 2. Limiting sleeve; 3. Guide pin; 4. Sliding bearing; 5. Ball bearing; 6. Outer plate; 7. Inner plate; 8. Spring A; 9. Center cylinder; 10. Upper connector; 11. Flushing channel; 12. One-way valve B; 13. Liquid inlet; 14. One-way valve A; 15. Spring B; 16. Piston cylinder; 17. Piston; 18. Filter plate. Detailed Implementation

[0022] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0023] Example 1, as shown in the appendix Figure 1 As shown, this embodiment includes a central cylinder 9, an upper connector 10, a lower connector 1, and ball bearings 5. The two ends of the central cylinder 9 are threadedly connected to the upper connector 10 and the lower connector 1, respectively. The upper connector 10 and the lower connector 1 are threadedly connected to the workover string, thus connecting this embodiment to the workover string. Multiple ball bearing mounting plates are circumferentially arranged on the outer side of the central cylinder 9, with no fewer than three plates. The ball bearing mounting plates are independent of each other. A spring A8 is installed between each ball bearing mounting plate and the central cylinder 9. Under the elastic force of the spring A8, the ball bearing mounting plate tends to move away from the central cylinder 9. Limiting sleeves 2 are fitted onto both ends of the central cylinder 9. The two ends of the ball bearing mounting plates are located inside the limiting sleeves 2, which restrict the maximum displacement of the ball bearing mounting plates away from the central cylinder 9. The ball bearing mounting plate includes an inner plate 7 and an outer plate 6. The inner plate 7 and the outer plate 6 are each equipped with a ball seat. The ball bearing 5 is limited and installed between the inner plate 7 and the outer plate 6 and is located inside the ball seat. The ball bearing 5 can rotate freely inside the ball seat. The inner plate 7 and the outer plate 6 are fixedly connected.

[0024] In this embodiment, the ball bearing 5 can rotate freely relative to the ball bearing mounting plate. When the outer side of the ball bearing 5 rubs against the casing, the sliding friction is converted into rolling friction, significantly reducing wear on the casing. The ball bearing 5 can withstand both the axial sliding of the workover string relative to the casing and the circumferential rotation of the workover string relative to the casing, minimizing wear on the casing from the workover string. In addition, when the workover string rotates rapidly relative to the casing, it will generate strong radial vibration of the casing. In this embodiment, the vibration impact is mitigated by the spring A8, which protects the casing and prevents the ball bearing 5 from strongly vibrating and impacting the casing, thus avoiding vibration damage to the casing.

[0025] A guide pin 3 is provided between the ball bearing mounting plate and each limiting sleeve 2, and the guide pin 3 plays the role of sliding guide for the ball bearing mounting plate.

[0026] A sliding bearing 4 is provided between the ball bearing mounting plate and the guide pin 3, which improves the smoothness of sliding between the ball bearing mounting plate and the guide pin 3.

[0027] Example 2: As shown in the attached document Figure 2 , 3As shown, in this embodiment, based on the first embodiment, a flushing channel 11 is provided between the inner plate 7 and the outer plate 6. The flushing channel 11 is connected to the ball seat, and the liquid flowing through the flushing channel 11 will flush the ball seat. A piston cylinder 16 is provided on the inner side of the inner plate 7. The inner cavity of the piston cylinder 16 is connected to the flushing channel 11. A piston 17 is inserted into the piston cylinder 16. One end of the piston 17 abuts against the central cylinder 9. A spring B15 is provided between the other end of the piston 17 and the outer plate 6. Under the action of the spring B15, the piston tends to move away from the outer plate 6. The outer plate 6 corresponding to the piston cylinder 16 has a liquid inlet hole 13. A one-way valve A14 is provided at the liquid inlet hole 13. The one-way valve A14 allows liquid to enter the liquid inlet hole 13 from the outside and prevents liquid in the piston cylinder 16 from flowing out of the liquid inlet hole 13. A one-way valve B12 is provided on the flushing channel 11 at the end of the inner plate 7. The one-way valve B12 allows liquid in the flushing channel 11 to flow out from the end of the inner plate 7 and prevents liquid from entering the flushing channel 11 from the end of the inner plate 7. A filter plate 18 is installed on the outer plate 6 outside the liquid inlet hole 13.

[0028] When a ball bearing mounting plate is squeezed by the sleeve and moves towards the central cylinder 9, the piston 17 is forced into the piston cylinder 16, squeezing the liquid remaining in the piston cylinder 16 into the flushing channel 11. Since the flushing channel 11 is connected to the ball seat of the ball 5, it flushes out impurities retained in the ball seat, thereby preventing impurities from entering the ball seat and causing the ball 5 to get stuck in the ball seat. Therefore, in this embodiment, the ball 5 does not get stuck during use (once the ball 5 gets stuck, the rolling friction between the ball 5 and the sleeve will be converted into sliding friction, and the damage of sliding friction to the sleeve is much greater than that of rolling friction), and the rolling friction between the ball 5 and the sleeve remains relatively stable.

[0029] The piston cylinder 16 is located in the middle of the inner plate 7. The piston cylinder 16 is connected to the flushing channels 11 on both sides. The movement of the piston 17 enables both flushing channels 11 to achieve flushing.

Claims

1. A casing protection device for well workover, characterized in that: The device includes a central cylinder (9), an upper connector (10), a lower connector (1), and a ball bearing (5). The two ends of the central cylinder (9) are threadedly connected to the upper connector (10) and the lower connector (1), respectively. A ball bearing mounting plate is provided circumferentially on the outer side of the middle part of the central cylinder (9). The number of ball bearing mounting plates is not less than three. A spring A (8) is provided between the ball bearing mounting plate and the central cylinder (9). Under the elastic force of the spring A (8), the ball bearing mounting plate has a tendency to move away from the central cylinder (9). The two ends of the central cylinder (9) are respectively fitted with limit sleeves (2). The two ends of the ball bearing mounting plate are respectively located inside the limit sleeves (2). The ball bearing mounting plate includes an inner plate (7) and an outer plate (6). The inner plate (7) and the outer plate (6) are respectively equipped with ball seats. The ball bearing (5) is limited and installed between the inner plate (7) and the outer plate (6) and is located in the ball seat. The ball bearing (5) can rotate freely in the ball seat. The inner plate (7) and the outer plate (6) are fixedly connected.

2. The casing protection device for well workover as described in claim 1, characterized in that: A guide pin (3) is provided between the ball bearing mounting plate and each limiting sleeve.

3. A casing protection device for well workover as described in claim 2, characterized in that: A sliding bearing (4) is provided between the ball bearing mounting plate and the guide pin (3).

4. The casing protection device for well workover as described in claim 1, characterized in that: A flushing channel (11) is provided between the inner plate (7) and the outer plate (6), and the flushing channel (11) is connected to the ball seat. A piston cylinder (16) is provided on the inner side of the inner plate (7), and the inner cavity of the piston cylinder (16) is connected to the flushing channel (11). A piston (17) is inserted into the piston cylinder (16), one end of the piston (17) abuts against the central cylinder (9), and a spring B (15) is provided between the other end of the piston (17) and the outer plate (6). The outer plate (6) corresponding to the piston cylinder (16) has a liquid inlet hole (13) for liquid inlet. A one-way valve A (14) is installed at the hole (13). The one-way valve A (14) allows liquid to enter the inlet hole (13) from the outside and prevents liquid in the piston cylinder (16) from flowing out of the inlet hole (13). A one-way valve B (12) is installed on the flushing channel (11) at the end of the inner plate (7). The one-way valve B (12) allows liquid in the flushing channel (11) to flow out from the end of the inner plate (7) and prevents liquid from entering the flushing channel (11) from the end of the inner plate (7). A filter plate (18) is installed on the outer plate (6) outside the inlet hole (13).

5. A casing protection device for well workover as described in claim 4, characterized in that: The piston cylinder (16) is located in the middle of the inner plate (7), and the piston cylinder (16) is connected to the flushing channels (11) on both sides respectively.

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