Impact-resistant elastic centralizer

Abstract

The utility model belongs to the field of petroleum, natural gas well completion cementing equipment, specifically relates to an anti -impact elastic centralizer, aims at solving the problem of the structure of rigid assembly and rigid connecting point in related art can not effectively disperse and absorb dynamic impact load, leads to stress concentration in connecting point, and further causes structural fatigue failure even in the problem of disintegration. The anti -impact elastic centralizer adopts articulated unit and links multiple centralizing units into a collapsible annular structure. Any single point impact load can be dispersed to adjacent centralizing units through the chain transmission capacity of articulated unit, avoiding the local stress concentration phenomenon of rigid connecting point, thereby improving the structural integrity and reliability of the centralizer in complex well conditions, overcoming the problem that the existing casing centralizer cannot effectively disperse and absorb dynamic impact load due to the structure of rigid assembly and rigid connecting point, leading to stress concentration in connecting point, and further causing structural fatigue failure even in the problem of disintegration.

Description

Technical Field

[0001] This utility model belongs to the field of well completion and cementing equipment for oil and gas wells, and specifically relates to an impact-resistant elastic centralizer. Background Technology

[0002] In casing operations at oil and gas wells, centralizers are crucial tools for ensuring casing centering and guaranteeing cementing quality. For ease of on-site installation, existing casing centralizers typically employ a split structure consisting of two rigid semi-rings connected by bolts or other fasteners. However, in deep or complex well environments, the centralizer, along with the tubing string, is subjected to severe dynamic impacts and vibrations. Because the semi-ring components of the centralizer are rigid, they lack the elastic buffering capacity to absorb and dissipate impact energy, making them ineffective in handling dynamic impact loads under complex conditions. All impact loads are directly and concentratedly transferred to a limited number of bolted connection points. These connection points, as stress concentration areas and weakest points in the structure, are highly susceptible to failure due to fatigue, shearing, or vibration loosening, leading to structural disintegration of the centralizer downhole, loss of its centralizing function, and operational risks.

[0003] Existing sleeve centralizers suffer from the problem that their rigid components and rigid connection points cannot effectively disperse and absorb dynamic impact loads, leading to stress concentration at the connection points, which in turn causes structural fatigue failure or even disintegration. Utility Model Content

[0004] To address the aforementioned problems in the prior art, namely the inability of existing casing centralizers to effectively disperse and absorb dynamic impact loads due to the rigidity of their components and connection points, leading to stress concentration at the connection points and consequently structural fatigue failure or even disintegration, this invention provides an impact-resistant elastic centralizer, comprising:

[0005] At least three straightening units and the same number of hinge units are provided. Each straightening unit includes a single hoop and a bow plate. Each end of the bow plate is fixedly connected to a single hoop, and the single hoop is arc-shaped. The single hoops are connected end to end in sequence through the hinge units so that the straightening units together form a retractable annular structure that surrounds the sleeve.

[0006] Specifically, the single hoop ring is provided with a first through groove and a second through groove at intervals. The ends of the bow pieces pass through the first through groove and the second through groove in sequence, and are stamped and shaped so that the connecting section formed on the outside of the single hoop ring and the fixed end formed on the inside of the single hoop ring are tightly fitted with the single hoop ring.

[0007] Specifically, the straightening unit also includes rivets. Both the bow plate and the single hoop ring are provided with through holes, and the rivets pass through the through holes to rivet the bow plate and the single hoop ring together.

[0008] Specifically, the through hole is formed within the clamping interface between the bow piece and the single hoop ring.

[0009] Specifically, the hinge unit includes a bolt and a nut. The single hoop is configured as a spring steel plate with hinge hole structures on both sides that are parallel to the sleeve axis. The bolt passes through the hinge hole structures (101) of two adjacent single hoops simultaneously and achieves a locking connection through cooperation with the nut.

[0010] Specifically, the hinge unit further includes a wear-resistant hinge sleeve. The wear-resistant hinge sleeve is fixedly connected to the inner wall of the hinge hole structure and sleeved on the bolt to enhance the wear resistance and impact resistance of the hinge hole structure.

[0011] Specifically, the wear-resistant hinge sleeve is fused to the single hoop ring by laser deep penetration welding.

[0012] Specifically, the bow segment includes a convex portion and concave portions interspersed with the convex portion. The convex portion protrudes radially outward along the single hoop ring, providing a force to center the casing by abutting against the well wall. The inner surface of the concave portion conforms to the outer wall of the casing to provide support for the convex portion.

[0013] Specifically, multiple convex portions are spaced apart along the axial direction of the sleeve to form a multi-point support structure.

[0014] Specifically, a wear-resistant reinforcing layer is provided on the outer peripheral surface of the convex portion to increase the wear resistance of the bow plate.

[0015] Combining the above solutions, the beneficial effects that this utility model can achieve are as follows:

[0016] This utility model provides an impact-resistant elastic centralizer, comprising:

[0017] At least three straightening units and the same number of hinge units are provided. Each straightening unit includes a single hoop and a bow plate. Each end of the bow plate is fixedly connected to a single hoop, and the single hoop is arc-shaped. The single hoops are connected end to end in sequence through the hinge units so that the straightening units together form a retractable annular structure that surrounds the sleeve.

[0018] In practical applications, multiple straightening units are sequentially rotatably connected and linked end-to-end via the hinged units, forming a retractable annular structure that encircles the sleeve. Unlike traditional rigid connection methods, when the impact-resistant elastic straightener is subjected to external impact, the load is no longer concentrated on a few fixed weak points. Instead, through the minute rotation of each hinged unit, the load is rapidly dispersed and transferred to all the straightening units on the entire annular structure. This achieves effective stress dissipation and distributed energy absorption, fundamentally eliminating the risk of connection point failure due to stress concentration.

[0019] As can be seen, compared with the existing technology, this impact-resistant elastic centralizer uses the hinge unit to connect multiple centralizing units in series into a retractable ring structure. Any single-point impact load can be distributed to the adjacent centralizing units through the chain transmission capability of the hinge unit, avoiding local stress concentration at rigid connection points. This improves the structural integrity and reliability of the impact-resistant elastic centralizer under complex well conditions, and overcomes the problem of existing casing centralizers where the rigid components and rigid connection points cannot effectively disperse and absorb dynamic impact loads, leading to stress concentration at the connection points, which in turn causes structural fatigue failure or even disintegration. Attached Figure Description

[0020] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0021] Figure 1 This is a schematic diagram of the combined structure of the impact-resistant elastic straightener provided in this embodiment of the present invention when it uses a single convex bow plate;

[0022] Figure 2 This is a schematic diagram of the combined structure of the impact-resistant elastic centralizer when a double-convex bow plate is used;

[0023] Figure 3 This is a schematic diagram of the flattened structure of the impact-resistant elastic centralizer when it uses a double-convex bow plate.

[0024] Figure 4 A schematic diagram of the structure when a single convex bow plate is used for the straightening unit;

[0025] Figure 5 This is a schematic diagram of a single hoop ring structure;

[0026] Figure 6 This is a schematic diagram of the structure of a single convex bow plate;

[0027] Figure 7 This is a schematic diagram of the structure of the double-convex bow plate.

[0028] icon:

[0029] 100. Straightening unit; 110. Single hoop ring; 101. Hinge hole structure; 102. First through slot; 103. Second through slot; 120. Bow plate; 104. Convex part; 105. Concave part; 130. Rivet;

[0030] 200, Hinged unit; 210, Bolt; 220, Nut; 230, Wear-resistant hinge sleeve. Detailed Implementation

[0031] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] This utility model provides an impact-resistant elastic centralizer, comprising:

[0034] At least three straightening units 100 and the same number of hinge units 200 are provided. Each straightening unit 100 includes a single hoop 110 and a bow plate 120. Each end of the bow plate 120 is fixedly connected to a single hoop 110, and the single hoop 110 is arc-shaped. The single hoop 110s are connected end to end in sequence through the hinge units 200 so that the straightening units 100 together form a retractable annular structure that surrounds the sleeve.

[0035] In summary, the impact-resistant elastic centralizer provided by this utility model can achieve the following technical effects:

[0036] This impact-resistant elastic centralizer uses a hinged unit 200 to connect multiple centralizing units 100 in series into a retractable ring structure. Any single-point impact load can be distributed to adjacent centralizing units 100 through the chain-like transmission capability of the hinged unit 200, avoiding local stress concentration at rigid connection points. This improves the structural integrity and reliability of the impact-resistant elastic centralizer under complex well conditions, overcoming the problem of existing casing centralizers where the rigid components and rigid connection points cannot effectively disperse and absorb dynamic impact loads, leading to stress concentration at the connection points and thus causing structural fatigue failure or even disintegration.

[0037] The following combination Figures 1 to 5 The structure and shape of the impact-resistant elastic centralizer provided in this embodiment are described in detail below:

[0038] Regarding how the single hoop ring 110 achieves a fixed connection with the bow plate 120, specifically:

[0039] The single hoop ring 110 is provided with a first through groove 102 and a second through groove 103 spaced apart. The ends of the bow pieces 120 pass through the first through groove 102 and the second through groove 103 in sequence, and are stamped and shaped to eliminate gaps in the tight fit, so that the connecting section formed by the bow pieces 120 on the outside of the single hoop ring 110 and the fixed end formed on the inside of the single hoop ring 110 are both tightly fitted with the single hoop ring 110.

[0040] Specifically, the end of the bow piece 120 first passes through the first through groove 102 from the inside of the single hoop ring 110 to the outside of the single hoop ring 110, and then passes through the second through groove 103 back to the inside of the single hoop ring 110. The overlapping area of ​​the bow piece 120 and the single hoop ring 110 is pressed and fixed together by stamping, eliminating loose gaps. Simultaneously, the inner wall of the single hoop ring 110 is stamped to a curvature that matches the outer wall of the casing, so that when the retractable annular structure is wrapped around the casing, it can fit closely to the casing, and the closed inner diameter of the annular structure is consistent with the outer diameter of the casing.

[0041] To further enhance the connection strength between the single hoop ring 110 and the bow plate 120, in this embodiment, the straightening unit 100 also includes a rivet 130. Both the bow plate 120 and the single hoop ring 110 are provided with through holes, and the rivet 130 passes through these through holes to rivet the bow plate 120 and the single hoop ring 110 together. The rivet 130 provides auxiliary anchoring for the pressed structure, offering double protection for the connection between the single hoop ring 110 and the bow plate 120, thus achieving a fail-safe design.

[0042] In this embodiment, the through hole is opened within the clamping interface between the bow plate 120 and the single hoop ring 110, thereby optimizing mechanical efficiency and protecting the overall strength of the component.

[0043] Specifically, regarding the composition of the hinge unit 200:

[0044] The hinge unit 200 includes a bolt 210 and a nut 220. The single hoop 110 is constructed of spring steel plate with hinge hole structures 101, parallel to the sleeve axis, wound around both sides. The bolt 210 passes through the hinge hole structures 101 of two adjacent single hoops 110 and is locked in place by cooperating with the nut 220. The two adjacent hinged single hoops 110 can transmit force through relative rotation, thus dispersing the impact load.

[0045] To enhance the wear resistance of the hinge hole structure 101 and maintain hinge accuracy, and to prevent the loosening of the annular structure due to dimensional changes caused by wear accumulation, the hinge unit 200 in this embodiment further includes a wear-resistant hinge sleeve 230. The wear-resistant hinge sleeve 230 is fixedly connected to the inner wall of the hinge hole structure 101 and sleeved on the bolt 210 to enhance the wear resistance and impact resistance of the hinge hole structure 101.

[0046] To ensure the bonding strength between the wear-resistant hinge sleeve 230 and the hinge hole structure 101, in this embodiment, the wear-resistant hinge sleeve 230 is fused to the single hoop ring 110 by laser deep penetration welding. Specifically, the weld penetration depth is ≥2mm, and the weld tensile strength is ≥90% of the base material.

[0047] Regarding the structure of the bow plate 120, specifically:

[0048] The bow segment 120 includes a convex portion 104 and concave portions 105 interposed with the convex portion 104. The convex portion 104 protrudes radially outward along the single hoop 110 to provide a force for centering the casing by abutting against the well wall. The inner surface of the concave portion 105 conforms to the outer wall of the casing to provide support for the convex portion 104. The bow segment 120 may be made of spring steel plate. The central region of the convex portion 104 may be widened to enhance wear resistance.

[0049] To enhance the straightening performance of the bow section 120, in this embodiment, multiple convex portions 104 are spaced apart along the axial direction of the casing to form a multi-point support structure. By distributing the contact load to multiple contact points, the load pressure at each contact point is reduced. At the same time, the axially dispersed support layout enhances the straightening stability of the casing and the ability to pass through complex wellbores.

[0050] To enhance the wear resistance of the bow plate 120 and thus extend its service life, in this embodiment, a wear-resistant reinforcing layer is provided on the outer peripheral surface of the convex portion 104 to increase the wear resistance of the bow plate 120 and reduce the downward friction. Specifically, the wear-resistant reinforcing layer can be a locally sprayed tungsten carbide powder coating.

[0051] In summary, the specific working process of the impact-resistant elastic centralizer provided in this embodiment is as follows:

[0052] Taking a single straightening unit 100 occupying a 60-degree central angle as an example, with a total of six straightening units 100 forming a complete ring structure.

[0053] The six straightening units 100 are arranged in a row and bolts 210 are passed through the wear-resistant hinge sleeves 230 on the adjacent single hoop rings 110 and screwed in nuts 220 to secure them, forming an open chain structure.

[0054] The chain structure can be unfolded or folded according to the shape of the storage space to reduce space occupation and facilitate storage and carrying.

[0055] When a centralizer needs to be installed during on-site construction, the open chain structure is wrapped around the coupling of the sleeve, with the convex part 104 of the bow plate 120 protruding radially outward. At the joint of the first and last ends of the chain structure, bolts 210 are inserted into the wear-resistant hinge sleeve 230 and screwed in nuts 220 for tightening, forming a complete ring structure.

[0056] After installation, the casing string is lowered into the well, and the impact-resistant elastic centralizer is lowered into the wellbore along with the casing. The bow plate 120 provides the centralizing force of the casing through the abutment reaction force of the convex part 104 against the well wall.

[0057] When encountering irregular wellbore or reduced diameter, the bow plate 120 can temporarily shrink in size through radial elastic deformation to pass smoothly. After passing, it recovers with its high elastic restoring force, maintaining a good straightening effect on the casing, which can effectively improve displacement efficiency and cementing quality.

[0058] The terms “first”, “second”, etc., are used to distinguish similar objects, not to describe or indicate a specific order or sequence.

[0059] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent in such process, method, article, or apparatus / device.

[0060] The technical solution of this utility model has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the protection scope of this utility model is obviously not limited to these specific embodiments. Without departing from the principle of this utility model, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of this utility model.

Claims

1. An impact-resistant elastic centralizer, characterized in that, include: At least three straightening units (100) and the same number of hinge units (200), wherein the straightening unit (100) includes a single hoop (110) and a bow plate (120), wherein a single hoop (110) is fixedly connected to each end of the bow plate (120), and the single hoop (110) is arc-shaped; Each of the single hoop rings (110) is connected end to end in sequence through the hinge unit (200) so that the straightening unit (100) together form a retractable ring structure that surrounds the sleeve.

2. The impact-resistant elastic centralizer according to claim 1, characterized in that: The single hoop ring (110) is provided with a first through groove (102) and a second through groove (103) spaced apart; The ends of the bow pieces (120) pass through the first through groove (102) and the second through groove (103) in sequence, and are stamped and shaped so that the connecting section formed by the bow pieces (120) on the outside of the single hoop ring (110) and the fixed end formed on the inside of the single hoop ring (110) are both tightly fitted with the single hoop ring (110).

3. The impact-resistant elastic centralizer according to claim 2, characterized in that: The straightening unit (100) also includes rivets (130). Both the bow piece (120) and the single hoop ring (110) are provided with through holes, and the rivet (130) passes through the through holes to rivet the bow piece (120) and the single hoop ring (110) together.

4. The impact-resistant elastic centralizer according to claim 3, characterized in that: The through hole is formed within the clamping interface between the bow piece (120) and the single hoop ring (110).

5. The impact-resistant elastic centralizer according to claim 1, characterized in that: The hinge unit (200) includes a bolt (210) and a nut (220); The single hoop ring (110) is set as a spring steel plate, with hinge hole structures (101) on both sides that are parallel to the sleeve axis. The bolt (210) is simultaneously inserted into the hinge hole structure (101) of the two adjacent single hoop rings (110) and is locked in place by cooperating with the nut (220).

6. The impact-resistant elastic centralizer according to claim 5, characterized in that: The hinge unit (200) also includes a wear-resistant hinge sleeve (230). The inner wall of the hinge hole structure (101) is fixedly connected to a wear-resistant hinge sleeve (230). The wear-resistant hinge sleeve (230) is fixedly connected to the inner wall of the hinge hole structure (101) and sleeved on the bolt (210) to enhance the wear resistance and impact resistance of the hinge hole structure (101).

7. The impact-resistant elastic centralizer according to claim 6, characterized in that: The wear-resistant hinge sleeve (230) is fused to the single hoop ring (110) by laser deep penetration welding.

8. The impact-resistant elastic centralizer according to claim 1, characterized in that: The bow plate (120) includes a convex portion (104) and a concave portion (105) that is alternately arranged with the convex portion (104). The convex portion (104) protrudes radially outward along the single hoop ring (110) to provide a force for centering the casing by abutting against the well wall; The inner surface of the concave portion (105) is attached to the outer wall of the sleeve to provide support for the convex portion (104).

9. The impact-resistant elastic centralizer according to claim 8, characterized in that: Multiple convex portions (104) are spaced apart along the axial direction of the sleeve to form a multi-point support structure.

10. The impact-resistant elastic centralizer according to claim 8, characterized in that: A wear-resistant reinforcing layer is provided on the outer peripheral surface of the convex part (104) to increase the wear resistance of the bow piece (120).

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