Expansion type hydraulic grading hoop

Abstract

The invention discloses an expansion type hydraulic grading hoop. The technical problem that the sealing effect of circulation holes is poor is solved. The hydraulic grading hoop comprises a grading hoop body, an upper connector and a lower connector, a circulation hole is formed in the middle of the grading hoop body, an opening sleeve and a closing sleeve are arranged in the grading hoop body, the opening sleeve can close the circulation hole when located at the closing position, and the opening sleeve can open the circulation hole when moving downwards to the opening position under the action of external force; the closing sleeve is made of an expansion metal material, two groups of metal sealing rings are arranged on the closing sleeve, the hydraulic grading hoop further comprises a closing plug, and the closing plug is used for controlling the closing sleeve to move downwards to a closed position and then expand and deform, so that the two groups of metal sealing rings abut against the inner wall of the grading hoop body respectively. And the circulating hole is positioned between the two groups of metal sealing rings. The sealing effect of the circulation hole can be guaranteed, the risk of internal and external leakage of the hydraulic grading hoop is reduced, and therefore the use stability is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of oilfield cementing tools, and particularly relates to an expandable hydraulic stage collar. Background Art

[0002] A hydraulic stage collar is a tool used in oil and gas drilling operations, especially in the completion stage. The hydraulic stage collar is mainly used to control the fluid flow at different depth horizons in the oil well to achieve the purpose of layered production or injection. By using a hydraulic stage collar, operators can precisely control the opening and closing of each horizon, thereby optimizing production efficiency, preventing unnecessary cross-interference between horizons, and contributing to improving the final recovery rate.

[0003] After the stage collar in the related art is closed, the flow hole on the stage collar body is sealed by an O-ring on the closing sleeve. As time goes by, the rubber O-ring will gradually age and fail. At this time, if the cement sheath outside the wellbore casing is fractured due to geological reasons, cross-leakage will occur inside and outside the stage collar, resulting in an increase in maintenance costs, which needs to be improved. Summary of the Invention

[0004] To solve all or part of the above problems, the purpose of the present invention is to provide an expandable hydraulic stage collar, which can ensure the sealing effect of the flow hole, reduce the risk of cross-leakage inside and outside the hydraulic stage collar, and thus improve the use stability.

[0005] The present invention provides an expandable hydraulic stage collar, including:

[0006] A stage collar body, which is a vertically arranged cylindrical structure;

[0007] An upper joint, connected to the top of the stage collar body and used for connecting with external components;

[0008] A lower joint, connected to the bottom of the stage collar body and used for connecting with external components;

[0009] A flow hole, arranged at the middle position of the stage collar body;

[0010] An opening sleeve, which is a cylindrical structure and coaxially arranged inside the stage collar body. When the opening sleeve is in the closed position, it can close the flow hole, and when the opening sleeve moves downward to the open position under an external force, it can open the flow hole;

[0011] A closing sleeve, which is a cylindrical structure and coaxially arranged inside the stage collar body. The closing sleeve is located above the opening sleeve, and the closing sleeve is made of expandable metal material;

[0012] Metal sealing rings, two in number, and respectively fixedly sleeved on the closing sleeve;

[0013] A closing plug is used to control the closing sleeve to expand and deform after moving downward to a closed position, so that the two metal sealing rings are respectively pressed against the inner wall of the stage collar body, and the flow hole is located between the two metal sealing rings.

[0014] Optionally, the upper part of the closing sleeve is connected to the stage collar body by a first shear pin, and the closing sleeve can cut the first shear pin under the action of the closing plug.

[0015] Optionally, the inner diameter of the middle position of the stage collar body is larger than the inner diameter of its upper position, so that a first positioning step surface is formed at the upper position of the inner wall of the stage collar body, and the outer diameter of the upper position of the closing sleeve is larger than the outer diameters of its middle and lower positions, so that a second positioning step surface is formed at the upper position of the outer wall of the closing sleeve. When the closing sleeve moves downward to the closed position, the first positioning step surface and the second positioning step surface form an abutting limit.

[0016] Optionally, the outer diameters of the middle and lower positions of the closing sleeve are smaller than the inner diameter of the middle position of the stage collar body, and there is a gap between the outer wall of the metal sealing ring and the inner wall of the stage collar body, so that the closing sleeve can move downward smoothly.

[0017] Optionally, two mounting grooves are provided on the outer wall of the closing sleeve, and the two metal sealing rings are respectively fixedly embedded in the corresponding mounting grooves.

[0018] Optionally, the lower position of the outer wall of the closing plug includes an expansion surface and a first sealing surface. The expansion surface is located above the first sealing surface, and the outer diameter of the expansion surface is larger than the outer diameter of the first sealing surface, so that a first driving step surface is formed between the expansion surface and the first sealing surface;

[0019] The inner wall of the closing sleeve includes a guiding surface, a second sealing surface and a stress surface which are arranged in sequence from top to bottom and have gradually decreasing inner diameters, so that a second driving step surface is formed between the guiding surface and the second sealing surface, a limiting step surface is formed between the second sealing surface and the stress surface, and the top of the guiding surface is flared;

[0020] The bottom of the closing plug can form an abutting limit with the limiting step surface, the first sealing surface can form an abutting seal with the second sealing surface, the first driving step surface can form an abutting limit with the second driving step surface, and the expansion force of the expansion surface can act on the stress surface, so that the closing sleeve expands and deforms.

[0021] Optionally, the closing sleeve includes a support column and a rubber sleeve vulcanized and fixed on the support column. The outer diameter of the rubber sleeve is larger than the outer diameter of the expansion surface, and the cross-section of the rubber sleeve is in a fishbone shape structure.

[0022] Optionally, the inner diameter of the middle position of the stage collar body is larger than the inner diameter of its lower position, so that an installation step surface is formed at the lower position of the inner wall of the stage collar body, and the lower joint is threadedly connected to the installation step surface. The lower part of the opening sleeve is connected to the lower joint by a second shear pin, and the opening sleeve can cut the second shear pin under an external force.

[0023] Optionally, the inner diameter of the lower joint is smaller than the inner diameter of the middle position of the stage collar body. The outer wall of the opening sleeve includes a first cylindrical surface and a second cylindrical surface. The first cylindrical surface is located above the second cylindrical surface, and the first cylindrical surface is used to close the flow hole;

[0024] The outer diameter of the first cylindrical surface is larger than the outer diameter of the second cylindrical surface. The first cylindrical surface is in close contact with the middle position of the inner wall of the stage collar body, and the second cylindrical surface is in close contact with the inner wall of the lower joint. A first limiting step surface is formed between the first cylindrical surface and the second cylindrical surface. When the opening sleeve moves downward to the opening position under an external force, the first limiting step surface forms an abutting limit with the upper end surface of the lower joint.

[0025] Optionally, a second limiting step surface is provided on the inner wall of the lower joint. When the opening sleeve moves downward to the opening position under an external force, the bottom of the opening sleeve can form an abutting limit with the second limiting step surface.

[0026] As can be seen from the above technical solutions, the expandable hydraulic stage collar provided by the present invention has the following advantages:

[0027] The hydraulic stage collar realizes metal sealing of the flow hole through the metal sealing ring and the stage collar body. Metal sealing will not age and fail over time. Therefore, the hydraulic stage collar can effectively improve the cementing quality, extend the service life of the casing and the cement sheath, and save the cementing cost and maintenance cost at the same time.

[0028] Other features and advantages of the present invention will be described in the following specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings are used to provide a further understanding of the technical solutions of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the technical solutions of the present invention, and do not constitute a limitation to the technical solutions of the present invention.

[0030] Figure 1 It is a schematic diagram of the overall structure of the expandable hydraulic stage collar in the embodiment of the present invention;

[0031] Figure 2 This is a cross-sectional view of an embodiment of the present invention, used to show the various components of the upper half of the stage collar body;

[0032] Figure 3 This is a cross-sectional view of the stage collar body in an embodiment of the present invention;

[0033] Figure 4 This is a cross-sectional view of the closing sleeve in an embodiment of the present invention;

[0034] Figure 5 This is a cross-sectional view of the closing plug in an embodiment of the present invention;

[0035] Figure 6 This is a cross-sectional view of an embodiment of the present invention, used to show the various components of the lower half of the stage collar body;

[0036] Figure 7 This is a cross-sectional view of the opening sleeve in an embodiment of the present invention.

[0037] Explanation of reference numerals:

[0038] 1. Stage collar body; 2. Upper joint; 3. Lower joint; 4. Flow hole; 5. Opening sleeve; 6. Closing sleeve; 7. Metal sealing ring; 8. Closing plug; 81. Support column; 82. Rubber sleeve; 9. First shear pin; 10. First positioning step surface; 11. Second positioning step surface; 12. Installation groove; 13. Expansion surface; 14. First sealing surface; 15. First driving step surface; 16. Guide surface; 17. Second sealing surface; 18. Force-bearing surface; 19. Second driving step surface; 20. Limiting step surface; 21. Installation step surface; 22. Second shear pin; 23. First cylindrical surface; 24. Second cylindrical surface; 25. First limiting step surface; 26. Second limiting step surface. Detailed implementation manner

[0039] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined arbitrarily with each other.

[0040] As Figures 1 - 7 shown in the embodiment of the present invention, an expandable hydraulic stage collar is disclosed, including a vertically arranged stage collar body 1. The top of the stage collar body 1 is threadedly connected with an upper joint 2, and the bottom is threadedly connected with a lower joint 3. The upper joint 2 and the lower joint 3 are respectively used to connect with external components. The stage collar body 1, the upper joint 2, and the lower joint 3 are respectively in a cylindrical structure and are interconnected. At the same time, a flow hole 4 is penetrated through the middle position of the stage collar body 1.

[0041] In one embodiment, as Figure 1 shown, an opening sleeve 5 is coaxially arranged inside the stage collar body 1. When the opening sleeve 5 is in the closed position, the opening sleeve 5 can seal the flow hole 4. When the opening sleeve 5 moves downward to the open position under an external force, the opening sleeve 5 moves to the lower side of the flow hole 4 to open the flow hole 4.

[0042] In one embodiment, as Figure 1 shown, a closing sleeve 6 is coaxially arranged inside the stage collar body 1. The closing sleeve 6 is located above the opening sleeve 5. The closing sleeve 6 is made of an expandable metal material so that the closing sleeve 6 can undergo an expansion deformation. Two groups of metal sealing rings 7 are fixedly sleeved on the closing sleeve 6. After the closing sleeve 6 undergoes an expansion deformation, the metal sealing rings 7 can be in close contact with the inner wall of the stage collar body 1.

[0043] In one embodiment, as Figure 1 shown, the hydraulic stage collar further includes a closing plug 8. The closing plug 8 can enter the closing sleeve 6 from the upper sub 2, and the closing plug 8 is used to control the closing sleeve 6 to move downward to the closed position and then undergo an expansion deformation, so that the two groups of metal sealing rings 7 are respectively pressed against the inner wall of the stage collar body 1, and the flow hole 4 is located between the two groups of metal sealing rings 7. At the same time, after the closing sleeve 6 completes the expansion deformation, the closing plug 8 can enter the lower sub 3 from the closing sleeve 6 and be discharged from the bottom of the lower sub 3.

[0044] This hydraulic stage collar realizes metal sealing of the flow hole 4 through the metal sealing ring 7 and the stage collar body 1. Metal sealing will not age and fail over time. Therefore, the hydraulic stage collar can effectively improve the cementing quality, extend the service life of the casing and the cement sheath, and save the cementing cost and maintenance cost at the same time.

[0045] In this embodiment, the closing sleeve 6 is made of an expandable metal material such as copper alloy steel, that is, the closing sleeve 6 can undergo a plastic expansion deformation. The metal sealing ring 7 is preferably made of copper material so that the metal sealing ring 7 can also undergo a plastic deformation, and copper has a certain softness to ensure the contact effect between the metal sealing ring 7 and the stage collar body 1, thereby ensuring the sealing stability.

[0046] In one embodiment, as Figure 2 、 Figure 3 、 Figure 4 shown, the upper part of the closing sleeve 6 is connected to the stage collar body 1 through a first shear pin 9. The closing sleeve 6 can cut the first shear pin 9 under the action of the closing plug 8. This design can realize the fixation of the initial position of the closing sleeve 6 and avoid risks such as displacement of the closing sleeve 6 during the transportation or use of the hydraulic stage collar.

[0047] In one embodiment, as Figure 2 、 Figure 3As shown, the inner diameter of the middle position of the grading collar body 1 is larger than that of the upper position, so that a first positioning step surface 10 is formed at the upper position of the inner wall of the grading collar body 1, and the upper joint 2 is threadedly connected to the first positioning step surface 10.

[0048] In one embodiment, as Figure 2 , Figure 4 shown, the outer diameter of the upper position of the closing sleeve 6 is larger than the outer diameters of its middle and lower positions, that is, the outer diameter of the upper position of the closing sleeve 6 is larger, so that a second positioning step surface 11 is formed at the upper position of the outer wall of the closing sleeve 6. When the closing sleeve 6 moves downward to the closed position, the first positioning step surface 10 can form abutting and limiting with the second positioning step surface 11 to limit the maximum sliding stroke of the closing sleeve 6.

[0049] In one embodiment, as Figure 2 , Figure 4 shown, two sets of installation grooves 12 are provided on the outer wall of the closing sleeve 6, and two sets of metal sealing rings 7 are respectively fixedly embedded in the corresponding installation grooves 12. The outer diameters of the middle and lower positions of the closing sleeve 6 are smaller than the inner diameter of the middle position of the grading collar body 1, and there is a gap between the outer wall of the metal sealing ring 7 and the inner wall of the grading collar body 1, so that the closing sleeve 6 can move downward smoothly and avoid problems such as jamming of the closing sleeve 6.

[0050] In one embodiment, as Figure 4 , Figure 5 shown, the lower position of the outer wall of the closing plug 8 includes an expansion surface 13 and a first sealing surface 14, the expansion surface 13 is located above the first sealing surface 14, and the outer diameter of the expansion surface 13 is larger than the outer diameter of the first sealing surface 14, so that a first driving step surface 15 is formed between the expansion surface 13 and the first sealing surface 14.

[0051] In one embodiment, as Figure 2 , Figure 4 shown, the inner wall of the closing sleeve 6 includes a guiding surface 16, a second sealing surface 17 and a stress surface 18 which are arranged in sequence from top to bottom and have gradually decreasing inner diameters, so that a second driving step surface 19 is formed between the guiding surface 16 and the second sealing surface 17, a limiting step surface 20 is formed between the second sealing surface 17 and the stress surface 18, and the top of the guiding surface 16 is flared to improve the guiding effect.

[0052] In one embodiment, as Figure 4 , Figure 5 shown, the bottom of the closing plug 8 can form abutting and limiting with the limiting step surface 20, the first sealing surface 14 can form abutting and sealing with the second sealing surface 17, the first driving step surface 15 can form abutting and limiting with the second driving step surface 19, and the expansion force of the expansion surface 13 can act on the stress surface 18 to cause the closing sleeve 6 to undergo expansion deformation.

[0053] In one embodiment, as Figure 4 , Figure 5 shown, the closing sleeve 6 includes a support column 81 and a rubber sleeve 82 vulcanized and fixed on the support column 81. The outer diameter of the rubber sleeve 82 is larger than the outer diameter of the expansion surface 13, and the cross-section of the rubber sleeve 82 is in a fishbone-shaped structure. Specifically, the rubber sleeve 82 has a plurality of annular barbed sealing structures, which can isolate the fluids above and below the rubber plug, prevent the mixing of the fluids above and below, can also scrape the cement residues on the casing wall, and can also center the rubber plug.

[0054] In this embodiment, the support column 81 is made of high-strength alloy structural steel and heat-treated to a relatively high hardness so that the closing sleeve 6 can stably undergo expansion deformation, thereby ensuring the smooth sealing of the flow hole 4.

[0055] In one embodiment, as Figure 3 , Figure 6 , Figure 7 shown, the inner diameter of the middle position of the stage collar body 1 is larger than the inner diameter of its lower position, so that an installation step surface 21 is formed at the lower position of the inner wall of the stage collar body 1, and the lower joint 3 is threadedly connected to the installation step surface 21. At the same time, the lower part of the opening sleeve 5 is connected to the lower joint 3 by a second shear pin 22, and the opening sleeve 5 can cut the second shear pin 22 under an external force, so that the opening sleeve 5 can be stably held in the closed position during the transportation of the hydraulic stage collar, etc.

[0056] In one embodiment, as Figure 6 , Figure 7 shown, the inner diameter of the lower joint 3 is smaller than the inner diameter of the middle position of the stage collar body 1. The outer wall of the opening sleeve 5 includes a first cylindrical surface 23 and a second cylindrical surface 24. The first cylindrical surface 23 is located above the second cylindrical surface 24, and the first cylindrical surface 23 is used to close the flow hole 4.

[0057] In one embodiment, as Figure 6 , Figure 7 shown, the outer diameter of the first cylindrical surface 23 is larger than the outer diameter of the second cylindrical surface 24. The first cylindrical surface 23 is in close contact with the middle position of the inner wall of the stage collar body 1, and the second cylindrical surface 24 is in close contact with the inner wall of the lower joint 3. A first limiting step surface 25 is formed between the first cylindrical surface 23 and the second cylindrical surface 24, and when the opening sleeve 5 moves downward to the open position under an external force, the first limiting step surface 25 forms an abutting limit with the upper end surface of the lower joint 3.

[0058] In one embodiment, as Figure 6 , Figure 7 shown, a second limiting step surface 26 is provided on the inner wall of the lower joint 3, and when the opening sleeve 5 moves downward to the open position under an external force, the bottom of the opening sleeve 5 can form an abutting limit with the second limiting step surface 26 to realize the limit of the maximum sliding stroke of the opening sleeve 5.

[0059] The expandable hydraulic stage collar in this embodiment is used as follows:

[0060] (1) Control the opening of the flow hole 4

[0061] At the wellhead, a plug is used to build up pressure (that is, after the primary plug passes through the stage collar and reaches the lower casing float collar for a pressure build-up). Since the cross-sectional areas of the upper and lower parts of the opening sleeve 5 are different, the opening sleeve 5 can cut the second shear pin 22 under the pressure difference between its upper and lower parts. Subsequently, the opening sleeve 5 moves downward to the closed position, that is, the first limiting step surface 25 abuts against the upper end surface of the lower joint 3, and the bottom of the opening sleeve 5 abuts against the second limiting step surface 26. At this time, the opening sleeve 5 is located below the flow hole 4 to open the flow hole 4, and the staff can carry out the cementing operation.

[0062] (2) Control the opening of the flow hole 4

[0063] After the cementing is completed, a closing plug 8 is dropped into the wellhead and pressured at the wellhead to push the closing plug 8 downward until the closing plug 8 enters the closing sleeve 6. At this time, the first sealing surface 14 closely abuts against the second sealing surface 17, the first driving step surface 15 abuts against the second driving step surface 19, and the bottom of the closing plug 8 abuts against the limiting step surface 20 for limiting.

[0064] As the wellhead continues to be pressured, the closing sleeve 6 cuts the first shear pin 9, and then the closing plug 8 drives the closing sleeve 6 downward until the first positioning step surface 10 abuts against the second positioning step surface 11 for limiting. At this time, one set of metal sealing rings 7 is located above the flow hole 4, and the other set of metal sealing rings 7 is located below the flow hole 4.

[0065] As the wellhead continues to be pressured, the closing plug 8 continues to move downward. At this time, the expansion surface 13 abuts against the stress surface 18, and the closing sleeve 6 undergoes radial expansion deformation under the extrusion of the expansion surface 13, and the two sets of metal sealing rings 7 respectively closely abut against the inner wall of the stage collar body 1 to close the flow hole 4. Subsequently, the wellhead continues to be pressured, and the closing plug 8 continues to move downward until it reaches the artificial bottom hole.

[0066] As can be seen from the above, using this hydraulic stage collar can ensure the sealing effect of the flow hole 4, thereby improving the use stability of the hydraulic stage collar. At the same time, it can effectively improve the cementing quality, extend the service life of the casing and the cement sheath, and also save the cementing cost and maintenance cost.

[0067] It should be noted that unless otherwise specified, the technical terms or scientific terms used in this invention should have the ordinary meanings understood by those skilled in the field to which this invention belongs.

[0068] Furthermore, terms such as "first", "second", etc. are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. In the description of the present invention, "a plurality of" means more than two unless otherwise specifically defined.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An expandable hydraulic stage collar, characterized in that Comprising: A staging collar body (1), which is in a vertically arranged cylindrical structure; An upper joint (2), connected to the top of the staging collar body (1) and used for connecting with an external component; A lower joint (3), connected to the bottom of the staging collar body (1) and used for connecting with an external component; A flow-through hole (4), arranged at the middle position of the staging collar body (1); An opening sleeve (5), which is in a cylindrical structure and coaxially arranged inside the staging collar body (1). When the opening sleeve (5) is in the closed position, it can seal the flow-through hole (4), and when the opening sleeve (5) moves downward to the open position under an external force, it can open the flow-through hole (4); A closing sleeve (6), which is in a cylindrical structure and coaxially arranged inside the staging collar body (1). The closing sleeve (6) is located above the opening sleeve (5), and the closing sleeve (6) is made of an expandable metal material; Metal sealing rings (7), two in number and respectively fixedly sleeved on the closing sleeve (6); A closing plug (8), used to control the closing sleeve (6) to expand and deform after moving downward to the closed position, so that the two metal sealing rings (7) respectively abut against the inner wall of the staging collar body (1), and the flow-through hole (4) is located between the two metal sealing rings (7).

2. The expandable hydraulic stage collar according to claim 1, wherein, The upper part of the closing sleeve (6) is connected to the staging collar body (1) through a first shear pin (9), and the closing sleeve (6) can cut the first shear pin (9) under the action of the closing plug (8).

3. The expandable hydraulic stage collar according to claim 1, wherein The inner diameter of the middle position of the staging collar body (1) is larger than the inner diameter of its upper position, so that a first positioning step surface (10) is formed at the upper position of the inner wall of the staging collar body (1). The outer diameter of the upper position of the closing sleeve (6) is larger than the outer diameters of its middle and lower positions, so that a second positioning step surface (11) is formed at the upper position of the outer wall of the closing sleeve (6). When the closing sleeve (6) moves downward to the closed position, the first positioning step surface (10) and the second positioning step surface (11) form an abutting limit.

4. The expandable hydraulic stage collar according to claim 1, wherein The outer diameters of the middle and lower positions of the closing sleeve (6) are smaller than the inner diameter of the middle position of the staging collar body (1), and there is a gap between the outer wall of the metal sealing ring (7) and the inner wall of the staging collar body (1), so that the closing sleeve (6) can move downward smoothly.

5. The expandable hydraulic stage collar according to claim 4, wherein, Two mounting grooves (12) are arranged on the outer wall of the closing sleeve (6), and the two metal sealing rings (7) are respectively fixedly embedded in the corresponding mounting grooves (12).

6. The expandable hydraulic stage collar according to claim 1, wherein The lower position of the outer wall of the closing plug (8) includes an expansion surface (13) and a first sealing surface (14). The expansion surface (13) is located above the first sealing surface (14), and the outer diameter of the expansion surface (13) is larger than the outer diameter of the first sealing surface (14), so that a first driving step surface (15) is formed between the expansion surface (13) and the first sealing surface (14); The inner wall of the closing sleeve (6) includes a guiding surface (16), a second sealing surface (17), and a stress-bearing surface (18) which are arranged in sequence from top to bottom and have gradually decreasing inner diameters, so as to form a second driving step surface (19) between the guiding surface (16) and the second sealing surface (17), and a limiting step surface (20) between the second sealing surface (17) and the stress-bearing surface (18), and the top of the guiding surface (16) is flared; The bottom of the closing plug (8) can form abutting and limiting with the limiting step surface (20), the first sealing surface (14) can form abutting and sealing with the second sealing surface (17), the first driving step surface (15) can form abutting and limiting with the second driving step surface (19), and the expansion force of the expansion surface (13) can act on the stress-bearing surface (18) to cause the closing sleeve (6) to undergo expansion deformation.

7. The expandable hydraulic stage collar according to claim 6, wherein, The closing sleeve (6) includes a support column (81) and a rubber sleeve (82) vulcanized and fixed on the support column (81), the outer diameter of the rubber sleeve (82) is larger than the outer diameter of the expansion surface (13), and the cross-section of the rubber sleeve (82) is in a fishbone-shaped structure.

8. The expandable hydraulic stage collar according to claim 1, characterized in that, The inner diameter of the middle position of the stage collar body (1) is larger than the inner diameter of its lower position, so as to form a mounting step surface (21) at the lower position of the inner wall of the stage collar body (1), and the lower sub (3) is threadedly connected to the mounting step surface (21), the lower part of the opening sleeve (5) is connected to the lower sub (3) by a second shear pin (22), and the opening sleeve (5) can cut off the second shear pin (22) under an external force.

9. The expandable hydraulic stage collar according to claim 1, wherein, The inner diameter of the lower sub (3) is smaller than the inner diameter of the middle position of the stage collar body (1), the outer wall of the opening sleeve (5) includes a first cylindrical surface (23) and a second cylindrical surface (24), the first cylindrical surface (23) is located above the second cylindrical surface (24), and the first cylindrical surface (23) is used to close the flow hole (4); The outer diameter of the first cylindrical surface (23) is larger than the outer diameter of the second cylindrical surface (24), the first cylindrical surface (23) is in close contact with the middle position of the inner wall of the stage collar body (1), the second cylindrical surface (24) is in close contact with the inner wall of the lower sub (3), a first limiting step surface (25) is formed between the first cylindrical surface (23) and the second cylindrical surface (24), and when the opening sleeve (5) moves downward to the opening position under an external force, the first limiting step surface (25) forms abutting and limiting with the upper end surface of the lower sub (3).

10. The expandable hydraulic stage collar according to claim 9, wherein, The inner wall of the lower sub (3) is provided with a second limiting step surface (26), and when the opening sleeve (5) moves downward to the opening position under an external force, the bottom of the opening sleeve (5) can form abutting and limiting with the second limiting step surface (26).

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