A piston mounting structure, packer and mounting tool

Abstract

A piston mounting structure, packer and mounting tool belong to the field of packer structure, the piston mounting structure is used for limiting the axial position of the piston on the central pipe, the outer part of the central pipe is also provided with an outer annular groove, the piston is coaxially sleeved on the outer part of the central pipe, the inner wall of the piston is provided with an inner annular groove, the side wall of the piston is provided with a insertion hole in communication with the inner annular groove, the axis of the insertion hole is spaced apart from the axis of the piston; a steel bar is inserted into the inner annular groove and the outer annular groove through the insertion hole, a part of the cross section of the steel bar is embedded in the inner annular groove, and the other part is embedded in the outer annular groove. The mounting tool comprises a guide pipe and a push rod, the front end of the guide pipe is connected with the threaded hole through a threaded structure, the inner diameter of the guide pipe is larger than the outer diameter of the steel bar, and the push rod is detachably arranged at the end of the guide pipe. The scheme can effectively ensure the stability of the piston installation, prevent it from falling off, and the mounting structure is simple and easy to realize.

Description

Technical Field

[0001] This invention belongs to the field of packer structures, and particularly relates to a piston mounting structure, a packer, and a mounting tool. Background Technology

[0002] Hydraulic packers typically have two piston mounting structures: one mounted at the end of the central tube, and the other sleeved on the outside of the central tube, requiring only axial positioning of the piston after installation. The sleeved-on method primarily uses locating pins for fixation. During assembly, the locating pin passes through the sidewall of the piston's non-sealing surface and its tip is inserted into the outer wall of the central tube. Because the piston needs to withstand significant pressure during pressurized setting, occasional momentary hydraulic shocks can cause the locating pin to break, leading to setting failure. Furthermore, although locating pins are usually installed using an interference fit, the packer is constantly subjected to impacts from both above and below during downhole operation and setting. Frequent impacts can easily cause the locating pin to loosen or even fall off, affecting the packer's normal operation.

[0003] Existing technologies also employ open snap rings for axial positioning of parts. However, such snap rings are only suitable for use at the ends of rods or pipes to block parts mounted on them and prevent them from falling off. Multi-stage hydraulic packers require multiple pistons in the middle section of the central tube. If snap rings are used to limit the pistons, snap rings need to be placed at both ends of the pistons, resulting in numerous annular grooves on the outside of the central tube for installing the snap rings. This has a certain impact on the structural strength of the central tube. Moreover, during installation, the snap rings need to be opened and moved from the end of the central tube to the middle, resulting in a long installation stroke and impacting installation efficiency. On the other hand, since the snap rings are installed on the end face of the pistons, there is usually no limiting structure on the outside of the snap rings. When the snap rings are subjected to high pressure, their locking points are prone to opening, causing the snap rings to fall off. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a piston mounting structure, packer, and mounting tool, which can effectively ensure the stability of piston mounting, prevent it from falling off, and has a simple and easy-to-implement mounting structure.

[0005] In order to achieve the objective of this invention, the following solution is proposed:

[0006] The piston mounting structure is used to limit the axial position of the piston on the central tube. The outer annular groove is also provided on the outside of the central tube. The piston is coaxially sleeved on the outside of the central tube. An inner annular groove is provided on the inner wall of the piston. An insertion hole communicating with the inner annular groove is provided on the side wall of the piston. The axis of the insertion hole is spaced apart from the axis of the piston.

[0007] A steel bar is inserted through a hole between the inner and outer annular grooves. A portion of the steel bar's cross-section is embedded in the inner annular groove, and the other portion is embedded in the outer annular groove.

[0008] The installation tool includes a conduit and a push rod. The front end of the conduit is connected to a threaded hole via a threaded structure. The inner diameter of the conduit is larger than the outer diameter of the steel bar. The push rod is detachably inserted into the end of the conduit.

[0009] The beneficial effects of this invention are: this solution provides a higher connection strength between the piston and the central tube, effectively preventing the piston from falling off, and the overall structure is simple and easy to install. Attached Figure Description

[0010] The accompanying drawings described herein are merely illustrative of selected embodiments, not all possible implementations, and are not intended to limit the scope of the invention.

[0011] Figure 1 A cross-sectional view of one embodiment of the piston and central tube of this application is shown.

[0012] Figure 2 A cross-sectional view of a preferred embodiment of the piston of this application is shown.

[0013] Figure 3 A cross-sectional view of the piston mounting structure of this application with steel bars inserted is shown.

[0014] Figure 4 A cross-sectional view of a preferred embodiment of the piston mounting structure of this application is shown.

[0015] Figure 5 A cross-sectional view of another preferred embodiment of the piston mounting structure of this application is shown.

[0016] Figure 6 A schematic diagram showing the state when the installation tool of this application is in use is shown.

[0017] Figure 7 A cross-sectional view of the mounting tool and piston mounting structure of this application is shown.

[0018] Figure 8 A cross-sectional view of a packer using the piston mounting structure of this application is shown.

[0019] The markings in the diagram are: 1-piston, 11-inner annular groove, 12-insertion hole, 13-anti-reverse groove, 14-threaded hole, 15-step groove, 16-observation hole, 2-center tube, 21-outer annular groove, 3-steel bar, 31-screw section, 4-threaded plug, 5-guide tube, 6-push rod. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the implementation methods of the present invention will be described in detail below with reference to the accompanying drawings. However, the embodiments described in this invention are only some embodiments of the present invention, and not all embodiments.

[0021] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0022] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, and are only for the convenience of describing the invention and simplifying the description. The terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. The terms "parallel," "vertical," etc., do not mean that the components are required to be absolutely parallel or perpendicular, but can be slightly tilted.

[0023] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection, an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] Example 1

[0025] like Figures 1 to 4 As shown, a piston mounting structure is used to define the axial position of piston 1 on central tube 2. An outer annular groove 21 is also provided on the outside of central tube 2. Piston 1 is coaxially sleeved on the outside of central tube 2. An inner annular groove 11 is provided on the inner wall of piston 1. As a further preferred embodiment, the annular center points of both outer annular groove 21 and inner annular groove 11 coincide with the axis of central tube 2.

[0026] Specifically, such as Figure 1 As shown, the side wall of the piston 1 has an insertion hole 12 that communicates with the inner annular groove 11, and the axis of the insertion hole 12 is spaced apart from the axis of the piston 1.

[0027] Specifically, such as Figure 3 , Figure 4As shown, a steel bar 3 is inserted through the insertion hole 12 between the inner annular groove 11 and the outer annular groove 21. A portion of the cross-section of the steel bar 3 is embedded in the inner annular groove 11, and the other portion is embedded in the outer annular groove 21. In this way, the steel bar 3 can be used to limit the position of the piston 1 in the axial direction of the central tube 2, and simultaneously satisfy the limiting function in two directions along the axis.

[0028] The above structure only requires an outer annular groove 21 to be opened on the central tube 2, which, together with the inner annular groove 11 and the steel strip 3, can achieve positioning of the piston 1 axis in two directions, reducing the impact on the strength of the central tube 2. The steel strip 3 is stuck between the inner annular groove 11 and the outer annular groove 21. Compared with the positioning pin fixing method, it can effectively prevent falling off. Moreover, the entire steel strip bears the pressure transmitted by the piston 1, and the shear strength is higher. Compared with the positioning pin, it can effectively avoid the failure of the limiting position. On the other hand, the steel strip 3 is confined within the inner annular groove 11 and the outer annular groove 21, which can prevent it from unfolding outward from the opening and falling off. In the specific scheme, the cross-section of the steel strip 3 is circular, so as to facilitate the acquisition of materials and facilitate its smooth insertion between the inner annular groove 11 and the outer annular groove 21.

[0029] Preferred, such as Figures 1 to 3 As shown, the insertion hole 12 is tangent to the inner annular groove 11, so as to facilitate the insertion of the steel strip 3 between the inner annular groove 11 and the outer annular groove 21.

[0030] Preferably, the inner annular groove 11 and the outer annular groove 21 both have semi-circular cross-sections and the same cross-sectional radius, and the inner annular groove 11 and the outer annular groove 21 have the same annular radius.

[0031] Preferred, such as Figures 2 to 4 As shown, the side wall of the inner annular groove 11 is provided with a retaining groove 13 at the junction with the insertion hole 12. After the steel bar 3 is inserted into the inner annular groove 11, its end is located in the retaining groove 13. Since the steel bar 3 is made of metal, it must have elasticity. When it is inserted between the inner annular groove 11 and the outer annular groove 21, it is forced to bend into the piston 1 due to the restriction of the inner annular groove 11 and the outer annular groove 21. After assembly, its two ends will inevitably generate elastic force towards the outside of the piston 1, so that the two ends of the steel bar 3 are tightly attached to the inner annular groove 11. The retaining groove 13 is opened on the side wall of the inner annular groove 11, so the end of the steel bar 3 will inevitably be stuck in the retaining groove 13. In this way, the end face of the retaining groove 13 can be used to block the end of the steel bar 3 to prevent the steel bar 3 from exiting from the insertion hole 12.

[0032] Preferred, such as Figure 2 , Figure 5 As shown, the outer end of the insertion hole 12 is coaxially provided with a threaded hole 14, and a threaded plug 4 is provided in the threaded hole 14 to prevent the steel bar 3 from exiting the insertion hole 12.

[0033] Further optimized, combined Figure 2 , Figure 5 As shown, the outer end of the steel bar 3 is coaxially provided with a screw part 31. The outer diameter of the screw part 31 is smaller than the outer diameter of the steel bar 3. The inner end of the threaded plug 4 is provided with an internal threaded hole for connecting the screw part 31. The external thread of the threaded plug 4 has the same pitch as the internal threaded hole to facilitate the smooth rotation of the threaded plug 4. After the threaded plug 4 is installed, the screw part 31 is inserted into the internal threaded hole, and the outer end of the screw part 31 protrudes out of the threaded hole 14. The above structural design helps to pull out the steel bar 3 smoothly. During the pulling operation, first loosen the threaded plug 4 to separate it from the threaded hole 14. Because the outer end of the screw part 31 protrudes out of the threaded hole 14 during assembly, when the threaded plug 4 is separated from the threaded hole 14, the screw part 31 is still connected to the internal threaded hole. By connecting the nut connector of the threaded pin puller to the exposed threaded plug 4, the steel bar 3 can be pulled out by the threaded pin puller.

[0034] Preferably, the screw portion 31 is integrally formed using the material of the steel bar 3 itself. As a further preferred embodiment, to prevent the threaded plug 4 from protruding beyond the outside of the piston 1, a stepped groove 15 is provided on the outer wall of the piston 1 at the position corresponding to the threaded hole 14 to accommodate the outer end of the threaded plug 4.

[0035] Preferred, such as Figure 3 As shown, the side wall of the piston 1 is provided with an observation hole 16 that communicates with the inner annular groove 11, which is used to determine the relative position of the inner annular groove 11 and the outer annular groove 21, so as to determine whether the two are aligned along the axial direction. More preferably, the axis of the observation hole 16 intersects the axis of the piston 1 perpendicularly.

[0036] Example 2

[0037] A packer including the piston mounting structure described in Example 1.

[0038] Example 3

[0039] An installation tool is used to assemble the piston mounting structure described in Embodiment 1, such as... Figure 6 , Figure 7 As shown, the installation tool includes a guide tube 5 and a push rod 6. The front end of the guide tube 5 is connected to the threaded hole 14 through a threaded structure. The inner diameter of the guide tube 5 is larger than the outer diameter of the steel strip 3. The push rod 6 is detachably inserted into the end of the guide tube 5. During installation, the position of the piston 1 on the central tube 2 is adjusted so that the inner annular groove 11 and the outer annular groove 21 are aligned. The front end of the guide tube 5 is fixed in the threaded hole 14, and then the steel strip 3 is inserted into the guide tube 5. The push rod 6 is inserted from the end of the guide tube 5 and the steel strip 3 is pushed forward. The pressure generated by the push rod 6 is used to insert the steel strip 3 between the inner annular groove 11 and the outer annular groove 21. Pushing the steel strip 3 with the installation tool can effectively prevent the steel strip 3 from bending, and the end is stressed, so the steel strip can be pushed more smoothly.

[0040] Preferably, the push rod 6 is a screw structure, and the inner wall of the conduit 5 has internal threads on the whole or at the end for connecting the push rod 6. By rotating the push rod 6, it can be moved along the axial direction of the conduit 5. The steel bar 3 can be pushed by the threaded transmission, which makes it easier to insert the steel bar 3 between the inner annular groove 11 and the outer annular groove 21. Moreover, the thread direction of the push rod 6 is consistent with the thread direction of the threaded hole 14, which can prevent the conduit 5 from falling out of the threaded hole 14 during the process of pushing the steel bar 3.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to be the only or limiting of the invention. Those skilled in the art should understand that various changes or equivalent substitutions made to the present invention without departing from its scope are all within the protection scope of the present invention.

Claims

1. An installation tool for installing a piston mounting structure; said piston mounting structure for defining the axial position of a piston (1) on a central tube (2), characterized in that, The outer annular groove (21) is provided on the outside of the central tube (2), and the piston (1) is coaxially sleeved on the outside of the central tube (2). The inner annular groove (11) is provided on the inner wall of the piston (1), and the side wall of the piston (1) is provided with an insertion hole (12) communicating with the inner annular groove (11). The axis of the insertion hole (12) and the axis of the piston (1) are spaced apart. A steel bar (3) is inserted through the insertion hole (12) between the inner annular groove (11) and the outer annular groove (21). A part of the cross section of the steel bar (3) is embedded in the inner annular groove (11), and the other part is embedded in the outer annular groove (21). The outer end of the insertion hole (12) is coaxially provided with a threaded hole (14), and a threaded plug (4) is provided inside the threaded hole (14). The installation tool includes a conduit (5) and a push rod (6). The front end of the conduit (5) is connected to the threaded hole (14) through a threaded structure. The inner diameter of the conduit (5) is larger than the outer diameter of the steel bar (3). The push rod (6) is detachably inserted into the end of the conduit (5). The push rod (6) is a screw structure. The entire inner wall or the end of the conduit (5) has internal threads for connecting the push rod (6). The thread direction of the push rod (6) is consistent with the thread direction of the threaded hole (14).

2. The installation tool according to claim 1, characterized in that, The insertion hole (12) is tangent to the inner annular groove (11).

3. The installation tool according to claim 1, characterized in that, The inner annular groove (11) and the outer annular groove (21) both have semi-circular cross-sections and the same cross-sectional radius. The inner annular groove (11) and the outer annular groove (21) have the same annular radius.

4. An installation tool according to claim 1, characterized in that, The inner annular groove (11) has a backstop groove (13) at the junction of the side wall and the insertion hole (12). After the steel bar (3) is inserted into the inner annular groove (11), its end is located in the backstop groove (13).

5. An installation tool according to claim 1, characterized in that, The outer end of the steel bar (3) is coaxially provided with a screw part (31). The outer diameter of the screw part (31) is smaller than the outer diameter of the steel bar (3). The inner end of the threaded plug (4) is provided with an internal threaded hole for connecting the screw part (31). The external thread of the threaded plug (4) has the same pitch as the internal threaded hole. After the threaded plug (4) is installed, the screw part (31) is inserted into the internal threaded hole, and the outer end of the screw part (31) protrudes out of the threaded hole (14).

6. An installation tool according to claim 1, characterized in that, The piston (1) has an observation hole (16) on its side wall that communicates with the inner annular groove (11).

7. A packer, characterized in that, Includes a piston mounting structure; the piston mounting structure is installed using an installation tool as described in any one of claims 1-6.

Images