Pre-compression hydraulic starting elastic centralizer

Abstract

The pre-compression hydraulic starting elastic centralizer comprises an elastic centralizer body and a hydraulic locking mechanism, the hydraulic locking mechanism is sleeved with the elastic centralizer body, and a lock hook connected with the hydraulic locking mechanism in a hanging mode is arranged in an inner cavity of the elastic centralizer body; according to the invention, the lowering friction resistance of the centralizer can be reduced, meanwhile, the centering degree of a reaming well casing is improved, and the well cementation quality is improved.

Description

Technical Field

[0001] The present invention belongs to the field of drilling, and particularly relates to a pre-compressed hydraulic start elastic centralizer. Background Art

[0002] During cementing of reamed wells, the cementing quality is often unqualified due to poor centrality of the casing. Therefore, a centralizer is used to assist the casing to improve the centrality of the casing.

[0003] Centralizers include rigid centralizers, elastic centralizers, and in-tube differential pressure centralizers. Conventional rigid centralizers and elastic centralizers have limited outer diameters and cannot effectively improve the centrality of the casing in reamed wells. If the outer diameter of the centralizer is simply increased, it will cause the rigid centralizer to be unable to be lowered, and the running friction of the elastic centralizer will be too large, affecting the safety of casing running. The in-tube differential pressure centralizer can solve the problem of casing centrality in reamed wells, but the integrity of the pipe string is poor, and the damage of the later sealing mechanism will lead to the scrapping of the pipe string. Therefore, a special centralizer suitable for reamed wells needs to be designed. Summary of the Invention

[0004] The purpose of the present invention is to provide a pre-compressed hydraulic start elastic centralizer, which solves the defect of poor effect existing in the existing centralizer when correcting the centrality of the casing.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A pre-compressed hydraulic start elastic centralizer provided by the present invention includes an elastic centralizer body and a hydraulic locking mechanism. Among them, the elastic centralizer body is sleeved on the hydraulic locking mechanism, and a locking hook connected to the hydraulic locking mechanism is arranged in the inner cavity of the elastic centralizer body.

[0007] Preferably, the elastic centralizer body is an integral structure, including an upper end ring, a lower end ring, spring pieces, and locking hooks. Among them, the upper end ring and the lower end ring are arranged in parallel, and the two are connected by a plurality of spring pieces arranged therebetween;

[0008] The plurality of spring pieces are evenly distributed in the circumferential direction and are arranged coaxially with the upper end ring and the lower end ring;

[0009] A locking hook connected to the hydraulic locking mechanism is arranged on the inner side wall of each spring piece.

[0010] Preferably, the hydraulic locking mechanism includes a piston, a shear pin, and a hydraulic cylinder. Among them, the piston is sleeved at one end of the hydraulic cylinder and is connected to the hydraulic cylinder by a shear pin; the piston is connected to the locking hook in a hanging manner; the free end of the hydraulic cylinder is connected to the inner wall of the elastic centralizer body.

[0011] Preferably, the piston comprises a ring body, and a groove is provided on the inner wall of the other end of the ring body, and the groove serves as a locking ring, and the locking ring is hooked and connected with the locking hook;

[0012] A plurality of shear pin threaded holes are evenly distributed along the circumferential direction on the side wall of the other end of the annular body.

[0013] Preferably, a sealing groove is provided on the inner wall of the annular body on one side close to the locking hook, and a first sealing member is installed in the sealing groove.

[0014] Preferably, the hydraulic cylinder includes a circular ring structure body, one end of which is provided with a support claw, and the support claw is connected to the elastic stabilizer body; a side wall of the circular ring structure body is provided with a plurality of shear pin holes evenly distributed along the circumferential direction close to the support claw, and the shear pin holes and the shear pin threaded holes are connected by shear pins.

[0015] Preferably, the supporting claw comprises a plurality of circumferentially arranged columns, and a boss is provided on the outer wall of the free end of the column.

[0016] Preferably, a sealing ring groove is provided on the outer wall of the annular structure body, and a second sealing member is installed in the sealing ring groove.

[0017] Preferably, a retaining ring is further provided in the inner cavity of the elastic centralizer body.

[0018] Preferably, the pre-compression hydraulically activated elastic centralizer is sleeved on the casing when in use, and a fixing ring is provided at each of its two ends.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention provides a pre-compression hydraulically activated elastic centralizer, which compresses the outer diameter of the elastic centralizer body to be smaller than the inner diameter of the upper casing and locks it through a hydraulic mechanism. After the centralizer is lowered to the reaming well section, the shear pin of the hydraulic mechanism is sheared off by the static liquid column pressure difference, and the elastic centralizer body is unlocked and opened under the action of elastic force to realize the centering of the casing. This structure can reduce the friction resistance of the centralizer when it is lowered, and at the same time, improve the centering degree of the reaming well casing and improve the cementing quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the installation effect of the pre-compression hydraulic start elastic centralizer;

[0022] Figure 2 It is a schematic diagram of the structure of a pre-compression hydraulically activated elastic centralizer;

[0023] Figure 3 This is a schematic diagram of the appearance of a pre-compressed hydraulically activated elastic centralizer;

[0024] Figure 4 is a schematic diagram of the structure of an elastic centralizer;

[0025] Figure 5 It is a schematic diagram of the hydraulic cylinder structure;

[0026] Figure 6 It is a schematic diagram of the piston structure;

[0027] Among them, 1 is a retaining ring, 2 is an elastic stabilizer, 3 is a piston, 4 is a first seal, 5 is a first seal, 6 is a shear pin, 7 is a hydraulic cylinder, 8 is a fixing ring, 2-2 is an upper end ring, 2-4 is a lower end ring, 2-3 is a spring sheet, 2-1 is a locking hook, 3-1 is a shear pin threaded hole, 3-2 is a sealing groove, 3-3 is a locking ring, 7-1 is a supporting claw, 7-2 is a shear pin hole, 7-3 is a sealing ring groove, and 7-4 is a sealing surface. DETAILED DESCRIPTION

[0028] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0029] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0030] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0031] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0032] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0033] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0034] Example 1

[0035] The present embodiment provides a pre-compression hydraulically activated elastic centralizer, comprising a retaining ring 1, an elastic centralizer body 2, a hydraulic locking mechanism and a fixing ring 8, wherein:

[0036] One end of the elastic centralizer body 2 is sleeved on the retaining ring 1, and the other end of the elastic centralizer body 2 is sleeved on the hydraulic locking mechanism, and the hydraulic locking mechanism is connected with the elastic centralizer body 2.

[0037] When in use, the elastic centralizer body 2 is sleeved on the casing, and a fixing ring 8 is arranged at both ends of the elastic centralizer body 2 but not evenly.

[0038] The workflow of this embodiment is as follows:

[0039] When in use, the elastic centralizer body 2 is hooked and connected to the hydraulic locking mechanism, and then the elastic centralizer is sleeved on the casing, and a fixing ring 8 is fixed to both ends of the elastic centralizer.

[0040] Under the pressure of the hydrostatic column, the hydraulic locking mechanism and the elastic centralizer body 2 are decoupled, and the elastic centralizer body 2 expands outward to realize the centralization of the sleeve, thereby solving the problem that the existing centralizer cannot improve the centering degree of the casing due to the limited outer diameter.

[0041] Example 2

[0042] The present embodiment provides a pre-compression hydraulically activated elastic centralizer, comprising a retaining ring 1, an elastic centralizer body 2, a piston 3, a first seal 4, a second seal 5, a shear pin 6, a cylinder 7 and a fixing ring 8, wherein:

[0043] The retaining ring 1 is installed in the inner cavity at one end of the elastic centralizer body 2.

[0044] The piston 3 and the cylinder 7 are installed in the inner cavity of the other end of the elastic centralizer body 2 in sequence from the inside to the outside.

[0045] At the same time, the piston 3 is sleeved on one end of the cylinder 7 .

[0046] The elastic centralizer body 2 and the other end of the hydraulic cylinder 7 are fixedly connected.

[0047] A fixing ring 8 is mounted on the outer walls of both ends of the elastic centralizer body 2 .

[0048] Example 3

[0049] The present embodiment provides a pre-compression hydraulically activated elastic centralizer, comprising a retaining ring 1, an elastic centralizer body 2, a piston 3, a first seal 4, a second seal 5, a shear pin 6, a cylinder 7 and a fixing ring 8, wherein:

[0050] The inner wall of the retaining ring 1 is evenly distributed with key grooves in the circumferential direction, the number of which is the same as that of the spring sheets 2-3. A boss is formed between two adjacent key grooves. The width of the boss is consistent with and aligned with the width of the spring sheets 2-3. The retaining ring 1 and the upper end ring 2-2 can be fixed by bonding, welding or screws.

[0051] The function of the retaining ring 1 is to support the centralizer, and at the same time, the keyway structure is used to reduce the overall weight of the tool and increase the circulation channel area.

[0052] The elastic centralizer body 2 is an integral elastic centralizer, which is integrally stamped and mainly comprises an upper ring 2-2, a lower ring 2-4, a spring sheet 2-3 and a lock hook 2-1, wherein the upper ring 2-2 and the lower ring 2-4 are arranged in parallel and are connected by a plurality of spring sheets 2-3.

[0053] A plurality of spring sheets 2 - 3 are evenly distributed along the circumferential direction and are arranged coaxially with the upper end ring and the lower end ring.

[0054] A locking hook 2-1 is arranged on the inner wall of each of the spring sheets 2-3.

[0055] The locking hook 2 - 1 is an L-shaped plate structure.

[0056] The hydraulic locking mechanism comprises a piston 3, a first seal 4, a second seal 5, a shear pin 6 and a cylinder 7, wherein the piston 3 is sleeved on one end of the cylinder 7 and the two are connected via the shear pin 6.

[0057] A first sealing member 4 and a second sealing member 5 are further provided between the piston 3 and the cylinder 7 .

[0058] The piston 3 comprises a circular ring body, and a plurality of shear pin threaded holes 3-1 are evenly distributed along the circumference of the side wall of one end of the circular ring body; a locking ring 3-3 is arranged on the inner wall of the other end of the circular ring body.

[0059] On the inner wall of the toroid near one side of the locking ring 3-3, a sealing groove 3-2 is provided.

[0060] A first seal 4 is fitted and installed in the sealing groove 3-2.

[0061] The hydraulic cylinder 7 includes the toroidal structure body, and one end of the toroidal structure body is provided with a support claw 7-1.

[0062] On the side wall of the toroidal structure body near the support claw 7-1, a plurality of shear pin holes 7-2 are evenly distributed along its circumference, and the shear pin holes 7-2 and the shear pin threaded holes 3-1 are connected by shear pins 6.

[0063] On the outer wall of the toroidal structure body, a sealing ring groove 7-3 is provided, and a second seal 5 is fitted and installed in the sealing ring groove 7-3.

[0064] The support claw 7-1 includes a plurality of columns arranged circumferentially, and a boss is provided on the outer wall of the free end of the column.

[0065] The length of the support claw 7-1 is 2-3 times the length of the lower end ring.

[0066] The boss on the support claw 7-1 and the lower end ring 2-4 are fixed by bonding, welding or screws.

[0067] The specific implementation method is as follows:

[0068] After the spring piece 2-3 is radially compressed to a certain position by special equipment, the centralizer locking hook 2-1 cooperates with the locking ring 3-3 to realize the radial fixation of the centralizer body 2. The initial position of the piston is fixed by the shear pin 6 to realize the axial fixation of the piston 3.

[0069] Then, the support claw 7-1 and the retaining ring 1 are respectively fixed to the lower end ring 2-4 and the upper end ring 2-2 by bonding, welding or screws.

[0070] During use, the centralizer is installed on the casing, and both ends are fixed by the upper and lower fixing rings 8. The upper and lower fixing rings 8 are conventional centralizer locking rings.

[0071] When the centralizer descends with the casing to a certain depth, under the action of the static liquid column pressure, the piston 3 is pushed to move axially, the shear pin 6 is cut off, the locking ring 3-3 is separated from the locking hook 2-1, the centralizer body is unlocked, and the spring piece 2-3 expands outwards under the action of the elastic force to realize the centralization of the casing.

[0072] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A pre-compression hydraulically activated elastic centralizer, It is characterized in that It comprises an elastic centralizer body (2) and a hydraulic locking mechanism, wherein the elastic centralizer body (2) is sleeved on the hydraulic locking mechanism, and a locking hook (2-1) connected to the hydraulic locking mechanism is arranged in the inner cavity of the elastic centralizer body (2).

2. A pre-compression hydraulically activated elastic centralizer according to claim 1, It is characterized in that The elastic centralizer body (2) is an integrated structure, comprising an upper end ring (2-2), a lower end ring (2-4), a spring sheet (2-3) and a locking hook (2-1), wherein the upper end ring (2-2) and the lower end ring (2-4) are arranged in parallel and are connected by a plurality of spring sheets (2-3); A plurality of spring sheets (2-3) are evenly distributed along the circumferential direction and are arranged coaxially with the upper end ring and the lower end ring; The inner side wall of each spring sheet (2-3) is provided with a lock hook (2-1) which is hooked with a hydraulic locking mechanism.

3. A pre-compression hydraulically activated elastic centralizer according to claim 1, It is characterized in that The hydraulic locking mechanism comprises a piston (3), a shear pin (6) and a hydraulic cylinder (7), wherein the piston (3) is sleeved on one end of the hydraulic cylinder (7), and the two are connected via the shear pin (6); the piston (3) is hooked and connected to a locking hook (2-1); and the free end of the hydraulic cylinder (7) is connected to the inner wall of the elastic centralizer body (2).

4. A pre-compression hydraulically activated elastic centralizer according to claim 3, It is characterized in that The piston (3) comprises a circular ring body, and a groove is provided on the inner wall of the other end of the circular ring body, the groove serves as a locking ring (3-3), and the locking ring (3-3) is hooked and connected to the locking hook (2-1); A plurality of shear pin threaded holes (3-1) are evenly distributed along the circumferential direction on the side wall of the other end of the annular body.

5. A pre-compression hydraulically activated elastic centralizer according to claim 4, It is characterized in that A sealing groove (3-2) is provided on the inner wall of the annular body on one side close to the locking hook, and a first sealing member (4) is installed in the sealing groove (3-2).

6. A pre-compression hydraulically activated elastic centralizer according to claim 4, It is characterized in that The hydraulic cylinder (7) comprises a circular ring structure body, one end of which is provided with a support claw (7-1), and the support claw is connected to the elastic centralizer body; a side wall of the circular ring structure body close to the support claw is evenly distributed along the circumferential direction with a plurality of shear pin holes (7-2), and the shear pin holes (7-2) and the shear pin threaded holes (3-1) are connected via shear pins (6).

7. A pre-compression hydraulically activated elastic centralizer according to claim 6, It is characterized in that The supporting claw (7-1) comprises a plurality of columns arranged in a circumferential direction, and a boss is provided on the outer wall of the free end of the column.

8. A pre-compression hydraulically activated elastic centralizer according to claim 6, It is characterized in that A sealing ring groove (7-3) is provided on the outer wall of the annular structure body, and a second sealing component (5) is installed in cooperation with the sealing ring groove (7-3).

9. A pre-compression hydraulically activated elastic centralizer according to claim 1, It is characterized in that A retaining ring (1) is also provided in the inner cavity of the elastic centralizer body (2).

10. A pre-compression hydraulically activated elastic centralizer according to claim 1, It is characterized in that When in use, the pre-compression hydraulically activated elastic centralizer is sleeved on a casing, and a fixing ring (8) is provided at each of its two ends.

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