Pre-compressed time-delay expanding elastic centralizer

Abstract

This invention relates to a pre-compression delayed expansion elastic centralizer, comprising a retaining ring, an elastic centralizer, a support assembly, and a delayed buffer pressure locking assembly. The retaining ring and the support assembly are respectively sleeved at both ends inside the centralizer. The delayed buffer pressure locking assembly is disposed through the support assembly and detachably connected to the elastic centralizer. The cooperation between the delayed buffer pressure locking assembly and the support assembly is used to delay unlocking of the elastic centralizer. The elastic centralizer is used for centering and centralizing the casing. This device achieves centering and centralizing of the casing while reducing friction during the lowering of the elastic centralizer, thus improving cementing quality.

Description

Technical Field

[0001] This invention belongs to the technical field of oil and gas cementing tools, and in particular a pre-compression delayed expansion elastic centralizer. Background Technology

[0002] In daily work, when cementing enlarged wells, poor casing centering often leads to substandard cementing quality. Conventional rigid centralizers and elastic centralizers have limited outer diameters and cannot effectively improve casing centering in enlarged wells. Simply increasing the outer diameter of the centralizer will prevent the rigid centralizer from being lowered, and the elastic centralizer will have excessive friction when lowering, affecting the safety of casing installation. While differential pressure centralizers can solve the casing centering problem in enlarged wells, they cannot guarantee the integrity of the tubing string during operation, and damage to the sealing mechanism later will lead to the tubing string being scrapped. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and to propose a pre-compressed hydraulic delayed expansion elastic centralizer that improves the casing centering and cementing quality in enlarged wells, thus solving problems such as reducing friction during casing installation.

[0004] The technical problem solved by this invention is achieved through the following technical solution:

[0005] A pre-compression delayed expansion elastic centralizer includes a retaining ring, an elastic centralizer, a support assembly, and a delayed buffer pressure locking assembly. The retaining ring and the support assembly are respectively sleeved at both ends inside the centralizer. The delayed buffer pressure locking assembly passes through the support assembly and is detachably connected to the elastic centralizer. The cooperation between the delayed buffer pressure locking assembly and the support assembly is used for delayed unlocking of the elastic centralizer. The elastic centralizer is used for centering and centralizing the cannula.

[0006] The elastic centralizer includes a first centralizer end ring, a second centralizer end ring, and a centralizer spring plate. The first and second centralizer end rings are annular cylinders. The two ends of the centralizer spring plate are fixedly connected to one side of the first and second centralizer end rings, respectively. At least two centralizer spring plates are provided. A locking plate with a locking hole is provided on the inner side of the middle of each centralizer spring plate.

[0007] The support assembly includes support ribs and a collar. The support ribs are fixedly connected to both end faces of the collar. The support ribs on both sides of the collar form a set. There are at least two sets of support ribs that cooperate with the central spring plate. A support rib mounting hole is provided at the center of each support rib. Each set of support ribs communicates with the collar through the support rib mounting hole and corresponds to the locking hole.

[0008] The delayed buffer pressure locking assembly includes a shear head, a buffer piston, a hydraulic cylinder, a damper, and a sealing assembly. One end of the shear head engages with the locking plate through the locking hole, and the other end is detachably connected to the buffer piston. The other end of the buffer piston is fitted into one end of the hydraulic cylinder, the other end of the hydraulic cylinder is fitted into one end of the damper, and the other end of the damper is fitted into the sealing assembly.

[0009] The inner wall of the retaining ring is provided with a boss, and there are two or more bosses that cooperate with the centralizer spring plate. The outer diameter of the retaining ring and the collar is the same and smaller than the outer diameter of the first centralizer end ring and the second centralizer end ring.

[0010] Preferably, the buffer piston includes a piston rod and a spring. One end of the piston rod has an internal thread, and an elastic retaining ring is disposed near the internal thread. The piston rod is threadedly connected to the shear head via an external thread. The other end of the piston rod is sleeved to the hydraulic cylinder. The spring is sleeved between the piston rod and the hydraulic cylinder. The elastic retaining ring and the spring are used to limit the movement of the piston rod.

[0011] The sealing assembly includes a blocking tube and a plug. One end of the damper relative to the buffer piston is fitted inside the blocking tube, and the other end of the blocking tube is fitted with the plug. An expansion plug is provided at the fitting point between the damper and the blocking tube. The expansion plug has a hollow structure, and the plug is a sealing plug. The cooperation between the expansion plug and the plug is used to achieve expansion and fixation of the delayed buffer pressure locking assembly.

[0012] Preferably, the shear head includes a delay stop pin, a shear ring, and a threaded connector. The two ends of the shear ring are respectively fixedly connected to the delay stop pin and the threaded connector. The threaded connector is threadedly connected to the piston rod. The shear ring is a grooved annular structure.

[0013] Preferably, the damper is provided with a damper seal, and the damper is a hydraulic time-delay damper used to reduce the axial movement speed of the piston rod;

[0014] Preferably, a piston seal is provided on the piston rod near the elastic retaining ring;

[0015] Preferably, the connection between the retaining ring and the support assembly and the elastic centralizer is by bonding, welding or screw connection;

[0016] Preferably, the straightener spring sheet has an arc-shaped structure.

[0017] The advantages and positive effects of this invention are:

[0018] This invention relates to a pre-compression delayed expansion elastic centralizer, which, compared to the prior art, is equipped with a support assembly and a delayed buffer pressure locking assembly. After the elastic centralizer locks the casing with a hydraulic mechanism and lowers it into the enlarged well section, the annular groove of the shear head is delayed-cut by the cooperation of the support assembly and the delayed buffer pressure locking assembly, thereby unlocking the centralizer spring plate. The centralizer spring plate expands outward under the action of elastic force, realizing the centering and centralization of the casing, while reducing the friction of the elastic centralizer during lowering and improving the cementing quality. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0020] Figure 2 This is a schematic diagram of the structure of the elastic straightener of the present invention;

[0021] Figure 3 This is a schematic diagram of the structure of the support component of the present invention;

[0022] Figure 4 This is a schematic diagram of the installation structure of the support component and the delay buffer pressure locking component of the present invention;

[0023] Figure 5 This is a schematic diagram of the shear head structure of the present invention;

[0024] Figure 6 This is a schematic diagram of the installation structure of the retaining ring, elastic stabilizer and support assembly of the present invention;

[0025] Figure 7 This is a schematic diagram of the actual operation of the present invention and its installation with the sleeve.

[0026] The components are as follows: 1. Retaining ring; 2. Elastic centralizer; 3. Shear head; 4. Buffer piston; 5. Hydraulic cylinder; 6. Damper; 7. Expansion plug; 8. Plug; 9. Fixing ring; 2-1. Locking plate; 2-2. Locking hole; 2-3. First centralizer end ring; 2-4. Centralizer spring plate; 2-5. Second centralizer end ring; 3-1. Threaded joint; 3-2. Delay stop pin; 3-3. Shear ring; 4-1. Piston column; 4-2. Piston seal; 4-3. Spring; 4-4. Elastic retaining ring; 5-1. Support ridge; 5-2. Collar; 5-3. Support ridge mounting hole; 5-6. Plug tube. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings.

[0028] This invention proposes a pre-compression delayed expansion elastic centralizer, such as... Figure 1As shown, the device includes a retaining ring 1, an elastic centralizer 2, a support assembly, and a delayed buffer pressure locking assembly. The retaining ring 1 and the support assembly are respectively sleeved at both ends inside the centralizer 2. The delayed buffer pressure locking assembly is disposed through the support assembly and detachably connected to the elastic centralizer 2. The cooperation between the delayed buffer pressure locking assembly and the support assembly is used for delayed unlocking of the elastic centralizer 2. The elastic centralizer 2 is used for centering and straightening the sleeve.

[0029] like Figure 2 As shown, the elastic centralizer 2 includes a first centralizer end ring 2-3, a second centralizer end ring 2-5, and a centralizer spring plate 2-4. The first centralizer end ring 2-3 and the second centralizer end ring 2-5 are annular cylinders. The two ends of the centralizer spring plate 2-4 are fixedly connected to one side end face of the first centralizer end ring 2-3 and the second centralizer end ring 2-5, respectively. There are at least two centralizer spring plates 2-4. A locking plate 2-1 is provided on the inner side of the middle part of the centralizer spring plate 2-4, and a locking hole 2-2 is provided on the locking plate 2-1.

[0030] like Figure 3 As shown, the support assembly includes a support rib 5-1 and a collar 5-2. The two end faces of the collar 5-2 are respectively fixedly connected to the support rib 5-1. The support ribs 5-1 on both sides of the collar 5-2 form a group. There are at least two groups of support ribs 5-1, which cooperate with the centralizer spring plate 2-4. A support rib mounting hole 5-3 is provided at the center of each support rib 5-1. Each group of support ribs 5-1 communicates with the collar 5-2 through the support rib mounting hole 5-3 and corresponds to the locking hole 2-2.

[0031] like Figure 4 As shown, the delayed buffer pressure locking assembly includes a shear head 3, a buffer piston 4, a liquid cylinder 5, a damper 6, and a sealing assembly. One end of the shear head 3 engages with the locking plate 2-1 through the locking hole 2-2, and the other end is detachably connected to the buffer piston 4. The other end of the buffer piston 4 is fitted to one end of the liquid cylinder 5, the other end of the liquid cylinder 5 is fitted to one end of the damper 6, and the other end of the damper 6 is fitted to the sealing assembly.

[0032] The inner wall of the retaining ring 1 is provided with a boss (not labeled in the figure). There are two or more bosses that cooperate with the centralizer spring plate 2-4. The outer diameter of the retaining ring 1 and the collar 5-2 are the same and smaller than the outer diameter of the first centralizer end ring 2-3 and the second centralizer end ring 2-5.

[0033] In this embodiment, the buffer piston 4 includes a piston rod 4-1 and a spring 4-3. One end of the piston rod 4-1 is provided with an internal thread, and an elastic retaining ring 4-4 ​​is provided near the internal thread. The piston rod 4-1 is threadedly connected to the shear head 3 through the external thread. The other end of the piston rod 4-1 is fitted to the hydraulic cylinder 5. The spring 4-3 is sleeved between the piston rod 4-1 and the hydraulic cylinder 5. The elastic retaining ring 4-4 ​​and the spring 4-3 are used to limit the movement of the piston rod 4-1.

[0034] The sealing assembly includes a blocking tube 5-6 and a blocker 8. One end of the damper 6 relative to the buffer piston 4 is fitted inside the blocking tube 5-6, and the other end of the blocking tube 5-6 is fitted with the blocker 8. An expansion plug 7 is provided at the fitting point between the damper 6 and the blocking tube 5-6. The expansion plug 7 has a hollow structure. The blocker 8 is a sealing blocker. The cooperation between the expansion plug 7 and the blocker 8 is used to achieve expansion and fixation of the delayed buffer pressure locking assembly.

[0035] In this embodiment, as Figure 5 As shown, the shear head 3 includes a delay stop pin 3-2, a shear ring 3-3, and a threaded connector 3-1. The two ends of the shear ring 3-3 are fixedly connected to the delay stop pin 3-2 and the threaded connector 3-1, respectively. The threaded connector 3-1 is threadedly connected to the piston column 4-1. The shear ring 3-3 is a grooved annular structure.

[0036] In this embodiment, the damper 6 is provided with a damper seal 6-1. The damper 6 is a hydraulic time-delay damper used to slow down the axial movement speed of the piston rod 4-1.

[0037] In this embodiment, a piston seal 4-2 is provided on the piston rod 4-1 near the elastic retaining ring 4-4.

[0038] In this embodiment, the connection between the retaining ring 1 and the support assembly and the elastic straightener 2 is by bonding, welding or screw connection.

[0039] In this embodiment, the straightener spring plate 2-4 has an arc-shaped structure.

[0040] Working principle:

[0041] First, the retaining ring 1 and the support assembly are respectively installed at both ends of the elastic centralizer 2, ensuring that the boss and the support ridge correspond to the centralizer spring plate 2-4. Then, the centralizer spring plate 2-4 is radially compressed to a certain position using special equipment. After the buffer piston 4, the hydraulic cylinder 5, and the damper 6 are respectively fitted and connected, they are connected through the support ridge mounting hole 5-3 to the support assembly and the locking hole 2-2. At the same time, the shear head 3 is threadedly connected to the buffer piston 4 to achieve radial fixation of the elastic centralizer 2. After the above installation work is completed, the sealing assembly is used to seal the delayed buffer pressure locking assembly.

[0042] Then, the assembled centralizer is installed on the sleeve, and the upper and lower ends are fixed by the fixing rings 9. When the centralizer is lowered to a certain depth with the sleeve, under the action of the hydrostatic column pressure, it pushes the piston column 4-1 to move axially. Under the buffering action of the spring 4-3 and the damper 6, the annular groove of the shear ring 3-3 is sheared after a delay. At this time, the delay stop pin 3-2 passes through the locking hole 2-2 after a delay, the centralizer spring plate 2-4 is unlocked, and the centralizer spring plate 2-4 expands outward under the action of elasticity to achieve the centering and centralization of the sleeve.

[0043] Unless otherwise specifically stated, the relative steps, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0044] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the system and apparatus described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0045] In summary, the content of this invention is not limited to the above-described embodiments. Those skilled in the art can propose other embodiments within the technical guiding principles of this invention, but these embodiments are all included within the scope of this invention.

[0046] It should be emphasized that the embodiments described in this invention are illustrative rather than limiting. Therefore, this invention includes, but is not limited to, the embodiments described in the specific implementation. Any other implementations derived by those skilled in the art based on the technical solutions of this invention are also within the scope of protection of this invention.

Claims

1. A pre-compression delayed expansion elastic centralizer, characterized in that: The device includes a retaining ring, an elastic centralizer, a support assembly, and a delayed buffer pressure locking assembly. The retaining ring and the support assembly are respectively sleeved at both ends inside the centralizer. The delayed buffer pressure locking assembly passes through the support assembly and is detachably connected to the elastic centralizer. The cooperation between the delayed buffer pressure locking assembly and the support assembly is used to unlock the elastic centralizer after a delay. The elastic centralizer is used for centering and straightening the cannula. The elastic centralizer includes a first centralizer end ring, a second centralizer end ring, and a centralizer spring plate. The first and second centralizer end rings are annular cylinders. The two ends of the centralizer spring plate are fixedly connected to one side of the first and second centralizer end rings, respectively. At least two centralizer spring plates are provided. A locking plate with a locking hole is provided on the inner side of the middle of each centralizer spring plate. The support assembly includes support ribs and a collar. The support ribs are fixedly connected to both end faces of the collar. The support ribs on both sides of the collar form a set. There are at least two sets of support ribs that cooperate with the central spring plate. A support rib mounting hole is provided at the center of each support rib. Each set of support ribs communicates with the collar through the support rib mounting hole and corresponds to the locking hole. The delayed buffer pressure locking assembly includes a shear head, a buffer piston, a hydraulic cylinder, a damper, and a sealing assembly. One end of the shear head engages with the locking plate through the locking hole, and the other end is detachably connected to the buffer piston. The other end of the buffer piston is fitted into one end of the hydraulic cylinder, the other end of the hydraulic cylinder is fitted into one end of the damper, and the other end of the damper is fitted into the sealing assembly. The inner wall of the retaining ring is provided with a boss, and there are two or more bosses that cooperate with the centralizer spring plate. The outer diameter of the retaining ring and the collar is the same and smaller than the outer diameter of the first centralizer end ring and the second centralizer end ring.

2. The pre-compression delayed expansion elastic centralizer according to claim 1, characterized in that: The buffer piston includes a piston rod and a spring. One end of the piston rod has an internal thread, and an elastic retaining ring is disposed near the internal thread. The piston rod is threadedly connected to the shear head via the internal thread. The other end of the piston rod is sleeved to the hydraulic cylinder. The spring is sleeved between the piston rod and the hydraulic cylinder. The elastic retaining ring and the spring are used to limit the movement of the piston rod. The sealing assembly includes a blocking tube and a plug. One end of the damper relative to the buffer piston is fitted inside the blocking tube, and the other end of the blocking tube is fitted with the plug. An expansion plug is provided at the fitting point between the damper and the blocking tube. The expansion plug has a hollow structure, and the plug is a sealing plug. The cooperation between the expansion plug and the plug is used to achieve expansion and fixation of the time-delay buffer pressure locking assembly.

3. The pre-compression delayed expansion elastic centralizer according to claim 2, characterized in that: The shear head includes a delay stop pin, a shear ring, and a threaded connector. The two ends of the shear ring are fixedly connected to the delay stop pin and the threaded connector, respectively. The threaded connector is threadedly connected to the piston rod. The shear ring is a grooved annular structure.

4. The pre-compression delayed expansion elastic centralizer according to claim 2, characterized in that: The damper is equipped with a damper seal, and the damper is a hydraulic time-delay damper used to reduce the axial movement speed of the piston rod.

5. The pre-compression delayed expansion elastic centralizer according to claim 2, characterized in that: A piston seal is provided on the piston rod near the elastic retaining ring.

6. The pre-compression delayed expansion elastic centralizer according to claim 1, characterized in that: The connection between the retaining ring and the support assembly and the elastic centralizer is by bonding, welding or screw connection.

7. The pre-compression delayed expansion elastic centralizer according to claim 1, characterized in that: The centralizer spring sheet has an arc-shaped structure.

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