Variable-diameter centralizer and centralizing and cementing method
By designing a variable diameter stabilizer and utilizing the variable diameter function of the sleeve ring and the stabilizer unit, the problem of scraping of fixed diameter stabilizers in horizontal wells or large-angle inclined wells was solved, realizing the adaptability and stability of the stabilizer and improving cementing quality and core tube life.
Patent Information
- Application Number
- CN202410999759.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-24
- Publication Date
- 2026-01-27
AI Technical Summary
During the cementing process of horizontal wells or steeply inclined wells, fixed-diameter centralizers can easily scrape against well walls of different diameters, causing well wall chips or core tube wear, which affects the cementing quality.
A variable diameter centralizer is designed. Through a sleeve assembly and a variable diameter centralizer assembly, and by using two oppositely arranged sleeve rings and a centralizer unit, the opening or compression of the first and second centralizer bars can be achieved to adapt to different wellbore diameters and well wall conditions, avoid scraping, and keep the core tube centered.
It effectively avoids the centralizer scraping the well wall, reduces core tube wear, improves cementing quality and core tube service life, and ensures the stability and adaptability of the centralizer.
Smart Images
Figure CN121407856A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of cementing equipment technology, and in particular to a variable diameter centralizer and a centralizing cementing method. Background Technology
[0002] Cementing is an essential and indispensable part of the drilling and completion process, encompassing steps such as core casing installation, cementing, wellhead installation, and core casing pressure testing. Cementing technology is characterized by its systematic, one-off, and short-duration nature. The primary purpose of cementing is to protect and support the core casing within the oil and gas well to isolate oil, gas, and water formations. Among these components, the core casing centralizer is a key device for improving cementing quality after the core casing is run into the well. Its function is to suspend, support, straighten, and center the core casing within the annular space of the open hole wellbore, relying on cementing to isolate oil, gas, and water layers, thus making the core casing a channel for oil and gas to enter the well.
[0003] During cementing drilling in horizontal or steeply inclined wells, the core casing may adhere directly to the wellbore due to its own weight, affecting cement bonding and posing potential risks to subsequent operations. Therefore, rotating and moving the core casing up and down is typically necessary to improve cement displacement efficiency and thus cementing quality. While there are various types of centralizers available, conventional centralizers have a fixed diameter. If they move with the core casing, the centralizer bars can easily scrape against the wellbore, causing blockages and potentially wellbore collapse. Conversely, if the centralizer does not move with the core casing, sliding friction between them over time will cause wear and tear on the core casing, affecting its lifespan. Summary of the Invention
[0004] The purpose of this invention is to provide a variable diameter centralizer and a centralizing cementing method to solve the problem that in the drilling and cementing process of horizontal wells or inclined wells with large inclination angles, centralizers with fixed diameters are prone to scraping the well walls of different diameters.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] This invention discloses a variable diameter straightener, including a sleeve assembly and a variable diameter straightener assembly. The sleeve assembly includes two opposing sleeve rings. The variable diameter straightener assembly includes a plurality of straightener units distributed along the circumference of the sleeve rings. Each straightener unit includes a first straightener bar rotatably connected to one of the sleeve rings and a second straightener bar rotatably connected to the other sleeve ring. The first straightener bar and the second straightener bar are rotatably connected so that after the two sleeve rings move relative to each other, the first straightener bar and the second straightener bar open or compress to change their diameter.
[0007] Optionally, a first hinge is provided between the adjacent ends of the first straightening bar and the second straightening bar. The first hinge is connected to the inner side of the adjacent ends of the first straightening bar and the second straightening bar, and the included angle between the inner side of the first straightening bar and the second straightening bar can be opened or compressed within the range of 0°-180°.
[0008] Optionally, a second hinge is provided on the outer side of the first straightening strip and the corresponding sleeve ring adjacent ends. The first straightening strip is connected to the sleeve ring through the second hinge, and the included angle between the outer side of the first straightening strip and the corresponding sleeve ring is within the range of 90°-180°.
[0009] Optionally, a third hinge is provided on the outer side of the second straightening strip and the corresponding sleeve ring adjacent ends. The second straightening strip is connected to the sleeve ring through the third hinge, and the included angle between the outer side of the second straightening strip and the corresponding sleeve ring is within the range of 90°-180°.
[0010] Optionally, the sleeve ring is provided with a resistance ring body and a friction ring body, wherein the resistance ring body is a steel structure and the friction ring body is a silicone structure;
[0011] Both the first and second straightening strips have a number of silicone particles on their inner surfaces. The silicone particles have a resistance part and a friction part. The resistance part is a steel structure, and the friction part is a silicone structure.
[0012] Optionally, the socket ring includes a first half-ring and a second half-ring disposed opposite to each other, and a fourth hinge is provided between the adjacent ends of the first half-ring and the second half-ring on one side of the socket ring. The fourth hinge is connected to the outer side surface of the adjacent ends of the first half-ring and the second half-ring so that the first half-ring and the second half-ring can be opened and closed by the fourth hinge.
[0013] A first locking component is provided between the adjacent ends of the first half-ring and the second half-ring on the other side of the sleeve ring, so that the first half-ring and the second half-ring can be closed and locked by the first locking component;
[0014] The first locking assembly includes a first latch connected to the first half-ring and a first padlock connected to the second half-ring. The first padlock includes a first lock body and a first locking ring disposed on the first lock body. The first padlock locks the first half-ring and the second half-ring by flipping the first locking ring onto the first latch.
[0015] Optionally, the variable diameter straightener further includes an axial positioning component, which includes a positioning ring and nylon connecting ropes. Several nylon connecting ropes are distributed along the circumference of the positioning ring, and the positioning ring is connected to one of the sleeve rings through several nylon connecting ropes, so that when the first straightener and the second straightener rotate to change diameter, the positioning ring axially positions the sleeve ring. A level is provided on the ring body of the positioning ring.
[0016] Optionally, the positioning ring includes a third half-ring and a fourth half-ring disposed opposite to each other, and a fifth hinge is provided between the adjacent ends of the third half-ring and the fourth half-ring on one side of the positioning ring. The fifth hinge is connected to the outer side surface of the adjacent ends of the third half-ring and the fourth half-ring so that the third half-ring and the fourth half-ring can be opened and closed by means of the fifth hinge.
[0017] A second locking component is provided between the adjacent ends of the third half ring and the fourth half ring on the other side of the positioning ring, so that the third half ring and the fourth half ring can be closed and locked by the second locking component;
[0018] The second locking assembly includes a second latch connected to the third half-ring and a second padlock connected to the fourth half-ring. The second padlock includes a second lock body and a second locking ring disposed on the second lock body. The second padlock is closed and locked to the third half-ring and the fourth half-ring by flipping and engaging the second locking ring with the second latch.
[0019] Optionally, an elastic element is connected between the two sleeve rings so that when the elastic element is in an undeformed state, the inner surfaces of the first straightening strip and the second straightening strip are set at an angle.
[0020] The present invention also provides a method for centralizing cementing, employing the aforementioned variable-diameter centralizer, the method comprising:
[0021] According to the preset core tube, match the appropriate size of the variable diameter stabilizer, put the two sleeve rings on the top and bottom of the core tube respectively, and flip the first stabilizer and the second stabilizer to the preset diameter state;
[0022] The core tube is lowered into a horizontal or inclined well. Depending on the wellbore diameter and well wall condition, the first and second centering bars adaptively flip to center the core tube.
[0023] Cement slurry is injected into the well, and the cement slurry in the well is displaced to the annular space outside the core tube by rotating and / or moving the core tube up and down until the cement slurry completely fills the annular space.
[0024] Stop injecting cement grout and keep the core tube rotating and moving up and down for a preset time until the cement is fully cured.
[0025] Compared with the prior art, the variable diameter centralizer and centralizing cementing method provided in this invention have the following advantages:
[0026] By setting up a socket assembly and a variable diameter centralizing assembly, the variable diameter centralizing assembly can be directly installed on the core tube using two opposing socket rings. Several centralizing units distributed along the circumference of the socket rings, through the opening or compression of the first and second centralizing bars under external force, can adjust the diameter of the entire variable diameter centralizer. Therefore, when installing the variable diameter centralizer and core tube, the first and second centralizing bars can be flipped to a preset diameter state, i.e., larger than the diameter of the socket ring. When the core tube with the variable diameter centralizer is lowered into a horizontal or inclined well, the first and second centralizing bars can adaptively flip according to the wellbore diameter and wellwall conditions to avoid the fixed-diameter centralizer scraping against different wellbore diameters and wellwalls, and to ensure that the core tube remains centered and centrally centered within the wellbore. Attached Figure Description
[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. In the accompanying drawings:
[0028] Figure 1 This is a schematic diagram of the overall structure of the variable diameter centralizer provided in an embodiment of the present invention;
[0029] Figure 2 This is a schematic diagram of the unfolded structure of the variable diameter centralizer provided in an embodiment of the present invention;
[0030] Figure 3 This is a schematic diagram of the structure of the straightening unit provided in an embodiment of the present invention;
[0031] Figure 4 This is a schematic diagram of the assembly structure of the axial positioning component provided in an embodiment of the present invention;
[0032] Figure 5 This is a schematic diagram of the positioning ring provided in an embodiment of the present invention.
[0033] The labels for the attached figures are as follows:
[0034] 1. Connecting ring; 11. First half ring; 12. Second half ring; 2. Straightening unit; 21. First straightening bar; 22. Second straightening bar; 23. Silicone granules; 3. First hinge; 4. Second hinge; 5. Third hinge; 6. Fourth hinge; 7. First locking assembly; 71. First latch; 72. First lock body; 73. First locking ring; 8. Axial positioning assembly; 81. Positioning ring; 811. Third half ring; 812. Fourth half ring; 813. Fifth hinge; 82. Nylon connecting rope; 83. Level; 9. Second locking assembly. Detailed Implementation
[0035] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[0036] This invention discloses a variable diameter centralizer, such as... Figure 1 and Figure 2 As shown, the assembly includes a connecting assembly and a reducing and straightening assembly. The connecting assembly includes two opposing connecting rings 1. The reducing and straightening assembly includes a plurality of straightening units 2 distributed along the circumference of the connecting rings 1. Each straightening unit 2 includes a first straightening bar 21 rotatably connected to one of the connecting rings 1 and a second straightening bar 22 rotatably connected to the other connecting ring 1. The first straightening bar 21 and the second straightening bar 22 are rotatably connected so that after the two connecting rings 1 move relative to each other, the first straightening bar 21 and the second straightening bar 22 open or compress to change the diameter.
[0037] Through the above-described implementation of the variable diameter straightener, the variable diameter straightener assembly can be directly installed on the core tube using two opposing connecting rings 1. By controlling the relative movement of the two connecting rings 1, the first straightener 21 and the second straightener 22 can be opened or compressed to change the diameter of the variable diameter straightener assembly formed by the several straightener units 2 distributed along the circumference of the connecting rings 1. Therefore, when installing the variable diameter stabilizer and core tube, the first stabilizer bar 21 and the second stabilizer bar 22 are first compressed to a preset diameter. When the core tube with the variable diameter stabilizer of this embodiment is lowered into a horizontal well or a steeply inclined well, and the core tube is rotated and moved up and down, the rotating connection of the first stabilizer bar 21 and the second stabilizer bar 22 can be subjected to pressure from the cement slurry around the wellbore to adaptively rotate, depending on the wellbore diameter and well wall condition. By opening or compressing the first stabilizer bar 21 and the second stabilizer bar 22, the distance between the two sets of connecting rings 1 can be increased or decreased, so that the stabilizer unit 2 can still be supported in the wellbore while changing diameter, and the core tube can be kept centered. Thus, the variable diameter stabilizer of this embodiment can adaptively adjust to the wellbore diameter to avoid scraping the well wall of different wellbore diameters when rotating and moving the core tube up and down. The variable diameter stabilizer of this invention can be applied to drilling and cementing of horizontal wells, steeply inclined wells, or conventional wells.
[0038] Preferably, one of the connecting rings 1 is located at the top of the first straightening bar 21 and the other connecting ring 1 is located at the bottom of the second straightening bar 22, so that when the variable diameter straightener of the present invention is installed, the first straightening bar 21 and the second straightening bar 22 are fixed at the top and bottom of the variable diameter straightener respectively to ensure the stability of the structure.
[0039] Furthermore, a first hinge 3 is provided between the adjacent ends of the first straightening bar 21 and the second straightening bar 22. The first hinge 3 is connected to the inner side of the adjacent ends of the first straightening bar 21 and the second straightening bar 22, and the included angle between the inner side of the first straightening bar 21 and the second straightening bar 22 can be opened or compressed within the angle range of 0°-180°.
[0040] Through the above-described implementation of the variable diameter straightener, the relative rotation between the first straightener 21 and the second straightener 22 can be achieved using the first hinge 3. By connecting the first hinge 3 to the inner surfaces of the adjacent ends of the first straightening bar 21 and the second straightening bar 22, a rotation limit is formed between the adjacent ends of the first straightening bar 21 and the second straightening bar 22. That is, when the first straightening bar 21 and the second straightening bar 22 are opened to be collinear, the adjacent ends of the first straightening bar 21 and the second straightening bar 22 are pressed together. Thus, under the synergistic effect of the first hinge 3, the first straightening bar 21 and the second straightening bar 22 are restricted from continuing to rotate. When the first straightening bar 21 and the second straightening bar 22 are in a compressed state of relative rotation, the first straightening bar 21 and the second straightening bar 22 can only flip inward based on the transition point where the first hinge 3 is located. That is, they can only open or compress by changing the angle between the inner surfaces of the first straightening bar 21 and the inner surfaces of the second straightening bar 22 within the angle range of 0°-180°. This ensures that the first straightening bar 21 and the second straightening bar 22 always maintain better contact with the wellbore wall when changing diameter, improves the straightening effect, and reduces core tube deviation and wear. When the first straightening bar 21 and the second straightening bar 22 are opened to be collinear, the diameter formed by the plurality of straightening units 2 is the same as the diameter of the sleeve ring 1, which is the minimum diameter formed by the plurality of straightening units 2. When the two sleeve rings 1 move relative to each other and come into contact, the first straightening bar 21 and the second straightening bar 22 are compressed to the minimum included angle, which is the maximum diameter formed by the plurality of straightening units 2. Thus, by changing the diameter through the opening or compression between the first straightening bar 21 and the second straightening bar 22, the variable diameter straightener of the present invention can better adapt to well walls or pipes of different diameters, providing a tighter fit and support, and improving the straightening effect.
[0041] Furthermore, a second hinge 4 is provided on the outer side of the adjacent ends of the first straightening strip 21 and the corresponding sleeve ring 1. The first straightening strip 21 is connected to the sleeve ring 1 through the second hinge 4, and the included angle between the outer sides of the first straightening strip 21 and the corresponding sleeve ring 1 is within the range of 90°-180°.
[0042] Through the above-described implementation of the variable diameter straightener, when the first straightener 21 and the second straightener 22 rotate relative to each other, the second hinge 4 enables the relative rotation of the top end of the first straightener 21 and the corresponding sleeve ring 1, thereby facilitating the normal flipping of the first straightener 21. By connecting the second hinge 4 to the outer surface of the top end of the first straightener 21, a rotation limit is formed between the top end of the first straightener 21 and the bottom of the corresponding sleeve ring 1. That is, when the first straightener 21 and the second straightener 22 are opened to be collinear, the top end of the first straightener 21 and the bottom of the corresponding sleeve ring 1 come into contact and press together. Thus, under the synergistic effect of the second hinge 4, the top end of the first straightener 21 is restricted from continuing to rotate, so that when the first straightener 21 and the second straightener 22 rotate relative to each other in a compressed state, the first straightener 21 can only flip outward based on the transition point where the second hinge 4 is located. That is, it can only rotate by changing the angle between the outer side of the first straightening bar 21 and the outer wall of the corresponding sleeve ring 1 within the range of 90°-180°, so as to ensure that the straightening unit 2 will not be smaller than the diameter of the sleeve ring 1 when changing diameter, so that the first straightening bar 21 and the second straightening bar 22 always maintain better contact with the well wall when changing diameter, improve the straightening effect, and reduce the wear of the core tube by the first straightening bar 21.
[0043] Furthermore, a third hinge 5 is provided on the outer side of the adjacent ends of the second straightening strip 22 and the corresponding sleeve ring 1. The second straightening strip 22 is connected to the sleeve ring 1 through the third hinge 5, and the included angle between the outer sides of the second straightening strip 22 and the corresponding sleeve ring 1 is within the range of 90°-180°.
[0044] Through the above-described implementation of the variable diameter straightener, when the first straightener 21 and the second straightener 22 rotate relative to each other, the third hinge 5 enables the relative rotation of the bottom end of the second straightener 22 and the corresponding sleeve ring 1, thereby facilitating the normal flipping of the second straightener 22. By connecting the third hinge 5 to the outer surface of the bottom end of the second straightener 22, a rotation limit is formed between the bottom end of the second straightener 22 and the top of the corresponding sleeve ring 1. That is, when the first straightener 21 and the second straightener 22 are opened to be collinear, the bottom end of the second straightener 22 and the top of the corresponding sleeve ring 1 come into contact and press together. Thus, under the synergistic effect of the third hinge 5, the bottom end of the second straightener 22 is restricted from continuing to rotate, so that when the first straightener 21 and the second straightener 22 rotate relative to each other in a compressed state, the second straightener 22 can only flip outward based on the transition point where the third hinge 5 is located. That is, it can only rotate by changing the angle between the outer side of the second straightening bar 22 and the outer wall of the corresponding sleeve ring 1 within the range of 90°-180°, so as to ensure that the straightening unit 2 will not be smaller than the diameter of the sleeve ring 1 when changing diameter, so that the first straightening bar 21 and the second straightening bar 22 always maintain better contact with the well wall when changing diameter, improve the straightening effect, and reduce the wear of the core tube by the second straightening bar 22.
[0045] Furthermore, combined Figure 3 As shown, the sleeve ring 1 is provided with a resistance ring body and a friction ring body. The resistance ring body is a steel structure and the friction ring body is a silicone structure.
[0046] Several silicone particles 23 are provided on the inner surfaces of the first straightening bar 21 and the second straightening bar 22. The silicone particles 23 are provided with a resistance part and a friction part. The resistance part is a steel structure and the friction part is a silicone structure.
[0047] In the above-described implementation of the variable diameter stabilizer, the sleeve ring 1 is half steel and the other half silicone. When the sleeve ring 1 is fitted onto the core tube, on the one hand, the resistance ring of the steel structure generates resistance through contact with the core tube, thus hindering the downward trend of the core tube and preventing it from falling out or slipping out of the sleeve ring 1. This makes the process of lowering the core tube with the variable diameter stabilizer of this embodiment into a horizontal or inclined well more stable. On the other hand, the friction ring of the silicone structure generates friction through contact with the core tube, increasing the friction between the sleeve ring 1 and the core tube. This prevents relative displacement or rotation between the core tube and the sleeve ring 1 when the core tube rotates or moves up and down, thereby improving the centering effect and stability of the variable diameter stabilizer of this embodiment. At the same time, the friction ring, based on the softness of silicone, can play a certain buffering role when the core tube rotates or moves up and down, reducing direct impact and wear between the sleeve ring 1 and the core tube, thus improving the service life of the core tube.
[0048] In addition, through the silicone particles 23 on the inner surfaces of the first straightening strip 21 and the second straightening strip 22, when the first straightening strip 21 and the second straightening strip 22 are opened to be collinear, the silicone particles 23 prevent the inner surfaces of the first straightening strip 21 and the second straightening strip 22 from directly contacting the tube wall of the core tube, thereby avoiding wear on the core tube when the straightening unit 2 changes diameter. Meanwhile, by utilizing the fact that half of the silicone particles 23 are steel and the other half are silicone, when the silicone particles 23 come into contact with the outer wall of the core tube, on the one hand, the resistance generated by the contact between the steel structure and the core tube further hinders the downward trend of the core tube, thereby preventing the core tube from falling out or slipping out of the variable diameter stabilizer. This makes the process of lowering the core tube with the variable diameter stabilizer of this embodiment into a horizontal or inclined well more stable. On the other hand, the friction generated by the contact between the silicone structure and the core tube increases the friction between the first and second stabilizer bars 21 and the core tube, preventing relative displacement or rotation between the core tube and the variable diameter stabilizer, thereby improving the stabilization effect and stability of the variable diameter stabilizer of this embodiment on the core tube. At the same time, the friction part, based on the softness of silicone, can play a certain buffering role, reducing the wear of the first and second stabilizer bars 21 and 22 on the core tube, and improving the service life of the core tube.
[0049] Furthermore, looking back Figure 1 and Figure 2 The socket ring 1 includes a first half-ring 11 and a second half-ring 12 disposed opposite to each other. A fourth hinge 6 is disposed between adjacent ends of the first half-ring 11 and the second half-ring 12 on one side of the socket ring 1. The fourth hinge 6 is connected to the outer surfaces of adjacent ends of the first half-ring 11 and the second half-ring 12 so that the first half-ring 11 and the second half-ring 12 can be opened and closed by means of the fourth hinge 6.
[0050] A first locking component 7 is provided between the adjacent ends of the first half-ring 11 and the second half-ring 12 on the other side of the sleeve ring 1, so that the first half-ring 11 and the second half-ring 12 can be closed and locked by the first locking component 7.
[0051] The first locking assembly 7 includes a first latch 71 connected to the first half-ring 11 and a first padlock connected to the second half-ring 12. The first padlock includes a first lock body 72 and a first locking ring 73 disposed on the first lock body 72. The first padlock locks the first half-ring 11 and the second half-ring 12 by flipping and engaging the first locking ring 73 with the first locking ring 73.
[0052] In the above-described implementation of the variable diameter centralizer, since the sleeve ring 1 is composed of two independent semi-rings, the first semi-ring 11 and the second semi-ring 12, the adjacent ends of the first semi-ring 11 and the second semi-ring 12 on one side are connected by the fourth hinge 6, and the first locking component 7 locks and unlocks the adjacent ends of the first semi-ring 11 and the second semi-ring 12 on the other side. When disassembling the sleeve ring 1, it is only necessary to unscrew the first locking ring 73 from the first locking buckle 71 to unlock the first semi-ring 11 and the second semi-ring 12, and allow the first semi-ring 11 and the second semi-ring 12 to be unfolded based on the transition point where the fourth hinge 6 is located. The maximum unfolding angle is preferably 180°, so that the unfolded sleeve ring 1 has a large space for movement, thereby facilitating the disassembly of the variable diameter centralizer of the present invention from the core tube and facilitating the subsequent cleaning of the variable diameter centralizer. Similarly, simply close the first half-ring 11 and the second half-ring 12 along the core tube, and then fasten the first locking ring 73 onto the first locking buckle 71, thereby locking the sleeve ring 1 onto the core tube to facilitate the installation of the variable diameter centralizer in this embodiment of the invention. Preferably, an elastic element for the first locking ring 73 to rotate is provided between the first locking body 72 and the first locking ring 73.
[0053] Furthermore, combined Figure 4 and Figure 5 As shown, the variable diameter straightener also includes an axial positioning component 8. The axial positioning component 8 includes a positioning ring 81 and nylon connecting ropes 82. Several nylon connecting ropes 82 are distributed along the circumference of the positioning ring 81, and the positioning ring 81 is connected to one of the sleeve rings 1 via several nylon connecting ropes 82, so that when the first straightening bar 21 and the second straightening bar 22 rotate to change diameter, the positioning ring 81 axially positions the sleeve ring 1. A level 83 is also provided on the ring body of the positioning ring 81.
[0054] In the above-described implementation of the variable diameter centralizer, when the sleeve assembly is installed on the core tube, the positioning ring 81 is also installed on the core tube. Since the centralizing unit 2 causes relative movement between the two sleeve rings 1 during the diameter change process, this can lead to a significant axial displacement of the entire variable diameter centralizer during the diameter change. Therefore, by sleeved a positioning ring 81 on the core tube, the positioning ring 81 is not affected by the opening and compression of the centralizing unit 2; that is, the positioning ring 81 and the core tube are fixed together. This provides axial limitation for the entire variable diameter centralizer when the centralizing unit 2 opens and compresses, ensuring that the variable diameter centralizer does not experience large-scale axial displacement. This ensures the reliability of the variable diameter centralizer's installation position and improves the centralizing effect and stability of the variable diameter centralizer on the core tube. Furthermore, the positioning ring 81 is connected to one of the sleeve rings 1 via several nylon connecting ropes 82. The material properties of the nylon connecting ropes 82 ensure the robustness and reliability of the connection structure between the positioning ring 81 and the sleeve ring 1. Additionally, the nylon connecting ropes 82 can connect with the outer wall of the core tube.
[0055] The contact generates friction to increase the friction between the positioning ring 81 and the corresponding sleeve ring 1 on the core tube, thereby preventing relative displacement or rotation between the core tube and the positioning ring 81, thus improving the reliability of the positioning ring 81 fixation, as well as the straightening effect and stability of the variable diameter centralizer on the core tube.
[0056] Furthermore, by using the level 83, the horizontal position of the variable diameter centralizer in this embodiment of the invention can be directly observed, thereby ensuring the centralization and alignment of the core tube. Preferably, one half of the positioning ring 81 is made of steel, and the other half is made of silicone, achieving the same effect as the sleeve ring 1.
[0057] Furthermore, the positioning ring 81 includes a third half-ring 811 and a fourth half-ring 812 disposed opposite to each other, and a fifth hinge 813 is provided between adjacent ends of the third half-ring 811 and the fourth half-ring 812 on one side of the positioning ring 81. The fifth hinge 813 is connected to the outer surface of the adjacent ends of the third half-ring 811 and the fourth half-ring 812, so that the third half-ring 811 and the fourth half-ring 812 can be opened and closed by the fifth hinge 813;
[0058] A second locking component 9 is provided between the adjacent ends of the third half ring 811 and the fourth half ring 812 on the other side of the positioning ring 81, so that the third half ring 811 and the fourth half ring 812 can be closed and locked by the second locking component 9.
[0059] The second locking assembly 9 includes a second latch connected to the third half-ring 811 and a second padlock connected to the fourth half-ring 812. The second padlock includes a second lock body and a second locking ring disposed on the second lock body. The second padlock is closed and locked by flipping the second locking ring onto the second latch, thereby closing and locking the third half-ring 811 and the fourth half-ring 812.
[0060] In the above-described implementation of the variable diameter centralizer, the positioning ring 81 is composed of two independent semi-rings, a third semi-ring 811 and a fourth semi-ring 812. The third semi-ring 811 and the fourth semi-ring 812 are connected by a fifth hinge 813 on one side of adjacent ends. The second locking component 9 locks and unlocks the other side of adjacent ends of the third semi-ring 811 and the fourth semi-ring 812. When disassembling the positioning ring 81, it is only necessary to unscrew the second locking ring from the second locking buckle to unlock the third semi-ring 811 and the fourth semi-ring 812, allowing the third semi-ring 811 and the fourth semi-ring 812 to unfold based on the transition point where the fifth hinge 813 is located. The maximum unfolding angle is preferably 180°, so that the unfolded positioning ring 81 has a large space for movement, which facilitates the disassembly of the positioning ring 81 from the core tube and facilitates the subsequent cleaning of the variable diameter centralizer. Similarly, simply close the third half-ring 811 and the fourth half-ring 812 along the core tube, and then fasten the second locking ring onto the second locking buckle to lock the positioning ring 81 onto the core tube, so as to facilitate the installation of the positioning ring 81.
[0061] Furthermore, an elastic element is connected between the two connecting rings 1 so that when the elastic element is in an undeformed state, the inner surfaces of the first straightening strip 21 and the second straightening strip 22 are set at an angle.
[0062] In the above-described implementation of the variable diameter centralizer, the elastic element is preferably a spring, with both ends of the spring connected to two connecting rings 1 respectively. Furthermore, based on the clear and complete structure of the variable diameter centralizer in this embodiment, the specific arrangement of the spring is a conventional technique used by those skilled in the art. The elastic element ensures that several centralizing units 2 are initially in a compressed state. When the core tube equipped with the variable diameter stabilizer of this embodiment is lowered into a horizontal or inclined well, when the wellbore diameter decreases, the rotating connection of the first stabilizer 21 and the second stabilizer 22 is subjected to pressure from the cement slurry around the wellbore to adaptively rotate. By opening the first stabilizer 21 and the second stabilizer 22, the stabilizer unit 2 adaptively changes its diameter and remains centered on the core tube, at which time the spring is stretched. When the wellbore diameter increases, the first stabilizer 21 and the second stabilizer 22 rotate under the action of the spring restoring its deformation. By compressing the first stabilizer 21 and the second stabilizer 22, the stabilizer unit 2 adaptively changes its diameter and can still be supported in the wellbore to remain centered on the core tube. Thus, the variable diameter stabilizer of this embodiment can better adapt to well walls or pipes of different diameters, providing a tighter fit and support to improve the stabilizer effect.
[0063] The present invention also provides a method for centralizing cementing, which employs the aforementioned variable-diameter centralizer. The method for centralizing cementing includes:
[0064] According to the preset core tube, match the appropriate size of the variable diameter stabilizer, put the two connecting rings 1 on the top and bottom of the core tube respectively, and flip the first stabilizer 21 and the second stabilizer 22 to the preset diameter state.
[0065] The core tube is lowered into a horizontal or inclined well. Depending on the wellbore diameter and well wall condition, the first and second stabilizer bars 21 and 22 adaptively flip to stabilize the centered core tube.
[0066] Cement slurry is injected into the well, and the cement slurry in the well is displaced to the annular space outside the core tube by rotating and / or moving the core tube up and down until the cement slurry completely fills the annular space.
[0067] Stop injecting cement grout and keep the core tube rotating and moving up and down for a preset time until the cement is fully cured.
[0068] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and all such modifications and substitutions should fall within the protection scope of the appended claims of the present invention.
Claims
1. A variable diameter centralizer, characterized in that: The variable diameter straightener includes a sleeve assembly and a variable diameter straightening assembly. The sleeve assembly includes two opposing sleeve rings. The variable diameter straightening assembly includes a plurality of straightening units distributed along the circumference of the sleeve rings. Each straightening unit includes a first straightening bar rotatably connected to one of the sleeve rings and a second straightening bar rotatably connected to the other sleeve ring. The first straightening bar and the second straightening bar are rotatably connected so that after the two sleeve rings move relative to each other, the first straightening bar and the second straightening bar open or compress to change their diameter.
2. The variable diameter centralizer according to claim 1, characterized in that: A first hinge is provided between the adjacent ends of the first straightening bar and the second straightening bar. The first hinge is connected to the inner side of the adjacent ends of the first straightening bar and the second straightening bar, and the included angle between the inner side of the first straightening bar and the second straightening bar can be opened or compressed within the range of 0°-180°.
3. The variable diameter centralizer according to claim 1, characterized in that: A second hinge is provided on the outer side of the first straightening strip and the corresponding sleeve ring adjacent to each other. The first straightening strip is connected to the sleeve ring through the second hinge, and the included angle between the outer side of the first straightening strip and the corresponding sleeve ring is within the range of 90°-180°.
4. The variable diameter centralizer according to claim 1, characterized in that: A third hinge is provided on the outer side of the second straightening strip and the corresponding sleeve ring adjacent to each other. The second straightening strip is connected to the sleeve ring through the third hinge, and the included angle between the outer side of the second straightening strip and the corresponding sleeve ring is within the range of 90°-180°.
5. The variable diameter centralizer according to any one of claims 1, characterized in that: The sleeve ring is provided with a resistance ring body and a friction ring body. The resistance ring body is a steel structure, and the friction ring body is a silicone structure. Both the first and second straightening strips have a number of silicone particles on their inner surfaces. The silicone particles have a resistance part and a friction part. The resistance part is a steel structure, and the friction part is a silicone structure.
6. The variable diameter centralizer according to any one of claims 1-5, characterized in that: The socket ring includes a first half-ring and a second half-ring disposed opposite to each other. A fourth hinge is provided between the adjacent ends of the first half-ring and the second half-ring on one side of the socket ring. The fourth hinge is connected to the outer side of the adjacent ends of the first half-ring and the second half-ring so that the first half-ring and the second half-ring can be opened and closed by the fourth hinge. A first locking component is provided between the adjacent ends of the first half-ring and the second half-ring on the other side of the sleeve ring, so that the first half-ring and the second half-ring can be closed and locked by the first locking component; The first locking assembly includes a first latch connected to the first half-ring and a first padlock connected to the second half-ring. The first padlock includes a first lock body and a first locking ring disposed on the first lock body. The first padlock locks the first half-ring and the second half-ring by flipping the first locking ring onto the first latch.
7. The variable diameter centralizer according to claim 1, characterized in that: The variable diameter straightener also includes an axial positioning component, which includes a positioning ring and nylon connecting ropes. Several nylon connecting ropes are distributed along the circumference of the positioning ring, and the positioning ring is connected to one of the sleeve rings through several nylon connecting ropes, so that when the first straightener and the second straightener rotate to change diameter, the positioning ring axially positions the sleeve ring. A level is provided on the ring body of the positioning ring.
8. The variable diameter centralizer according to claim 7, characterized in that: The positioning ring includes a third half-ring and a fourth half-ring arranged opposite to each other. A fifth hinge is provided between the adjacent ends of the third half-ring and the fourth half-ring on one side of the positioning ring. The fifth hinge is connected to the outer side of the adjacent ends of the third half-ring and the fourth half-ring so that the third half-ring and the fourth half-ring can be opened and closed by the fifth hinge. A second locking component is provided between the adjacent ends of the third half ring and the fourth half ring on the other side of the positioning ring, so that the third half ring and the fourth half ring can be closed and locked by the second locking component; The second locking assembly includes a second latch connected to the third half-ring and a second padlock connected to the fourth half-ring. The second padlock includes a second lock body and a second locking ring disposed on the second lock body. The second padlock is closed and locked to the third half-ring and the fourth half-ring by flipping and engaging the second locking ring with the second latch.
9. The variable diameter centralizer according to claim 1, characterized in that: An elastic element is connected between the two sleeve rings so that when the elastic element is in an undeformed state, the inner surfaces of the first straightening strip and the second straightening strip are set at an angle.
10. A method for centralizing cementing, employing a variable-diameter centralizer as described in any one of claims 1-9, characterized in that, The method for corrective cementing includes: According to the preset core tube, match the appropriate size of the variable diameter stabilizer, put the two sleeve rings on the top and bottom of the core tube respectively, and flip the first stabilizer and the second stabilizer to the preset diameter state; The core tube is lowered into a horizontal or inclined well. Depending on the wellbore diameter and well wall condition, the first and second centering bars adaptively flip to center the core tube. Cement slurry is injected into the well, and the cement slurry in the well is displaced to the annular space outside the core tube by rotating and / or moving the core tube up and down until the cement slurry completely fills the annular space. Stop injecting cement grout and keep the core tube rotating and moving up and down for a preset time until the cement is fully cured.