Sleeve patching device and patching method

Abstract

The invention belongs to the technical field of petroleum well repair, and discloses a casing patching device and patching method. The casing patching device comprises a center rod, a hydraulic cylinder, a bottom plug, an expansion rod set, an expansion cone piece and an expansion pipe, the center rod is provided with a liquid flow channel in the axial direction of the center rod and used for introducing high-pressure liquid, the top end of the center rod is open, and the bottom end of the center rod is closed. The hydraulic cylinder is arranged on the center rod and is communicated with the liquid flow channel; the bottom plug is arranged on the center rod and fixedly connected with the center rod, and the bottom plug is located below the hydraulic cylinder; the two ends of the expansion rod set are rotationally connected to the hydraulic cylinder and the bottom plug correspondingly. The expansion conical sheet is rotationally connected with the expansion rod group; and the expansion pipe is sleeved on the outer side of the expansion cone sheet. The expansion pipe can be applied to patching of a casing pipe with an expanding section, the outer diameter change range of the expansion pipe is large, the expansion pipe can better adapt to the size change of an external casing pipe, and the application range of patching of the expansion pipe is widened; and in cooperation with a thin-wall expansion pipe, the expansion joint can be used in a small-size sleeve, and the drift diameter loss in the sleeve is reduced to the maximum extent.

Description

Technical Field

[0001] This invention relates to the field of oil well workover technology, and in particular to a casing patching device and patching method. Background Technology

[0002] As oilfield development progresses into its later stages, casing damage becomes increasingly common. Furthermore, large-scale volumetric fracturing during shale gas and shale oil extraction can lead to casing damage, deformation, and leakage. Expansion tube patching technology, with its advantages of a large inner diameter and high pressure-bearing capacity after patching, has become an effective means of repairing damaged casing.

[0003] An expansion tube patching tool typically consists of an expansion cone, a bottom plug, and an expansion tube. The expansion tube has a larger outer diameter at the bottom, where the expansion cone is placed. The expansion cone, bottom plug, and expansion tube together form a sealed cavity. By injecting high-pressure fluid into this cavity, the expansion cone is pushed upwards, causing the expansion tube to expand and fit tightly against the damaged outer casing. Combined with a rubber ring on the outside of the expansion tube, a reliable seal is formed, restoring the casing's internal sealing. In field implementation, if the inner diameter of the deformed section of the casing expands beyond the inner diameter of the upper casing, the expanded outer diameter of the expansion tube will be too small after the patching tool is inserted, preventing it from fitting snugly against the casing's inner wall. Furthermore, currently, expansion tube wall thicknesses are generally 6-10mm, resulting in a 12-20mm loss in inner diameter after patching. For small-sized damaged wells, this loss is significant, affecting the insertion of subsequent downhole tools. Conversely, if a thinner-walled expansion tube is used, it cannot withstand the high pressure of the fluid during expansion. Therefore, current expansion tube patching tools are limited by their implementation principle and structure, making it impossible to patch and repair the deformed and enlarged diameter section of the casing, and also unable to meet the needs of patching small-sized casings, thus having certain limitations. Summary of the Invention

[0004] The purpose of this invention is to provide a casing patching device and patching method for patching and repairing the deformed and enlarged diameter section of the casing, with minimal loss of inner diameter after patching.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A casing patching device for patching the inner wall of a casing; the casing patching device includes:

[0007] A central rod, wherein a liquid flow channel is provided along its axial direction for introducing high-pressure liquid, and the top end of the central rod is open and the bottom end is closed;

[0008] A liquid cylinder is mounted on the central rod and communicates with the liquid flow channel. The high-pressure liquid in the liquid flow channel can drive the liquid cylinder to move downward along the central rod.

[0009] A bottom plug is provided on the center rod and fixedly connected to the center rod, and the bottom plug is located below the hydraulic cylinder;

[0010] An expansion rod assembly, the two ends of which are rotatably connected to the hydraulic cylinder and the bottom plug, respectively. When the hydraulic cylinder moves downward, the expansion rod assembly rotates and expands along the radial direction of the central rod.

[0011] An expansion cone is rotatably connected to the expansion rod assembly. When the expansion rod assembly rotates and expands, it drives the expansion cone to move along the radial direction of the central rod.

[0012] An expansion tube is sleeved on the outside of the expansion cone. When the expansion cone moves in the radial direction of the central rod, it can support the expansion tube to expand synchronously, so that the outer wall of the expansion tube abuts against the inner wall of the sleeve to support the sleeve.

[0013] In some embodiments, multiple liquid cylinders and multiple bottom plugs are provided, and the multiple liquid cylinders and multiple bottom plugs are alternately arranged along the axial direction of the central rod. An expansion rod assembly is rotatably arranged between any one of the liquid cylinders and one of the bottom plugs below it.

[0014] In some embodiments, the expansion cone is arranged parallel to the axial direction of the central rod, and each expansion cone is rotatably connected to a plurality of expansion rod groups along the axial direction.

[0015] In some embodiments, the central rod is provided with a limiting boss, and when the expansion rod assembly is in a retracted state, the hydraulic cylinder abuts against the limiting boss.

[0016] In some embodiments, an elastic element is provided between the limiting boss and the hydraulic cylinder. When the expansion rod assembly is in a contracted state, the hydraulic cylinder abuts against the limiting boss under the elastic force of the elastic element.

[0017] In some embodiments, the outer diameter of the bottom plug at the lowest point of the central rod is larger than the outer diameter of the expansion tube to support the bottom end of the expansion tube.

[0018] In some embodiments, the expansion rod assembly includes a first rod assembly and a second rod assembly, the top end of the first rod assembly is rotatably connected to the hydraulic cylinder, the bottom end of the first rod assembly is rotatably connected to the top end of the second rod assembly, and the bottom end of the second rod assembly is rotatably connected to the bottom plug.

[0019] In some embodiments, the first rod group and the second rod group each include a plurality of expansion rods, and the plurality of expansion rods are evenly spaced around the central rod in a circumferential manner.

[0020] In some embodiments, the expansion rod assembly includes a first rod assembly and a second rod assembly, the top end of the first rod assembly is rotatably connected to the hydraulic cylinder, the bottom end of the first rod assembly is rotatably connected to the expansion cone, the top end of the second rod assembly is rotatably connected to the expansion cone, and the bottom end of the second rod assembly is rotatably connected to the bottom plug.

[0021] A casing patching method, using the casing patching device provided by the present invention, the casing patching method includes the following steps:

[0022] S1, when the expansion rod assembly is in the retracted state, the expansion tube is sleeved on the outside of multiple expansion cones, and the bottom end of the expansion tube contacts the bottom plug at the bottommost end;

[0023] S2, the sleeve patching device is lowered into the patching position inside the sleeve;

[0024] S3, high-pressure liquid is introduced into the liquid flow channel of the central rod. The high-pressure liquid pushes the hydraulic cylinder to squeeze the expansion rod assembly to rotate and expand, and pushes the expansion cone to move along the radial direction of the central rod. The expansion tube expands and fits against the inner wall of the sleeve to cover the position to be covered inside the sleeve.

[0025] In some embodiments, the sleeve patching method further includes step S4: after the hydraulic cylinder is moved into place, the central rod is rotated and moved up and down to make the expansion tube fully expand; then the pressure is released to make the expansion rod assembly contract, and then the central rod is lifted to complete the patching.

[0026] The beneficial effects of this invention are:

[0027] The casing patching device provided by this invention, by rotatably connecting the two ends of the expansion rod assembly between the hydraulic cylinder and the bottom plug respectively, allows for a wide range of changes in the outer diameter of the expansion tube. It can be applied to patching damaged wells with expanded diameter sections, better adapting to changes in the size of the external casing and expanding the application range of expansion tube patching. Combined with a thin-walled expansion tube, it can be used with small-sized casings, minimizing casing inner diameter loss. The casing patching requires low construction pressure, is simple to operate, and eliminates the safety hazards of high-pressure construction in conventional expansion tube patching. The casing patching device of this invention has strong applicability; it can be applied to various types of casing patching without changing the structure or size. By controlling the high-pressure pump on the ground, the outer diameter of the expansion tool can be changed. Using an independent hydraulic cylinder, it does not rely on the cavity formed by the expansion tube and expansion cone, greatly reducing damage to the expansion tube from high-pressure liquid. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the expanded state structure of the sleeve patching device provided in an embodiment of the present invention;

[0029] Figure 2This is a schematic diagram of the sleeve patching device in its contracted state according to an embodiment of the present invention.

[0030] In the picture:

[0031] 1. Center rod; 11. Limiting boss; 2. Hydraulic cylinder; 3. Bottom plug; 4. Expansion rod assembly; 41. Expansion rod; 5. Expansion cone; 6. Expansion tube; 7. Elastic element. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0033] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0035] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0036] The purpose of this invention is to provide a casing patching device for patching the inner wall of a casing; such as Figure 1 and Figure 2As shown, the sleeve compensation device includes a central rod 1, a hydraulic cylinder 2, a bottom plug 3, an expansion rod assembly 4, an expansion cone 5, and an expansion tube 6. The central rod 1 has a liquid flow channel along its axial direction for introducing high-pressure liquid. The top of the central rod 1 is open and the bottom is closed. Specifically, the central rod 1 adopts a tube structure. The hydraulic cylinder 2 is mounted on the central rod 1 and connected to the liquid flow channel. The high-pressure liquid in the liquid flow channel can drive the hydraulic cylinder 2 to move downward along the central rod 1. The bottom plug 3 is mounted on the central rod 1 and fixedly connected to the central rod 1. The bottom plug 3 is located on the central rod 1 below the hydraulic cylinder 2. The two ends of the expansion rod assembly 4 are rotatably connected to the hydraulic cylinder 2 and the bottom plug 3, respectively. When the hydraulic cylinder 2 moves downward, the expansion rod assembly 4 rotates and expands in the radial direction of the central rod 1. The expansion cone 5 is rotatably connected to the expansion rod assembly 4. When the expansion rod assembly 4 rotates and expands, it drives the expansion cone 5 to move in the radial direction of the central rod 1. The expansion tube 6 is sleeved on the outside of the expansion cone 5. When the expansion cone 5 moves in the radial direction of the central rod 1, it can support the expansion tube 6 to expand synchronously, so that the outer wall of the expansion tube 6 abuts against the inner wall of the sleeve to supplement the sleeve.

[0037] The casing patching device provided by this invention connects the two ends of the expansion rod assembly 4 rotatably between the hydraulic cylinder 2 and the bottom plug 3, respectively. The hydraulic cylinder 2 drives the expansion rod assembly 4 to rotate and expand. Compared to the prior art using an expansion cone, this invention allows for a wider range of outer diameter variation in the expansion tube 6, making it applicable to patching damaged areas inside casings with expansion sections. It better adapts to changes in the size of the outer casing, expanding the application range of the expansion tube 6. It can be understood that the axial length of the expansion tube 6 is preset based on the length of the section to be patched within the casing with expansion characteristics to ensure patching is completed in one operation. When the length to be patched is large, multiple insertions can be used for patching.

[0038] The casing patching device provided in this embodiment of the invention, in conjunction with a thin-walled expansion tube 6, can be used in casings with small diameter orifices, minimizing the loss of inner diameter of the casing. This casing patching device uses high-pressure liquid as a power source through a hydraulic channel provided by the central rod 1, requiring low construction pressure and simple operation, eliminating the safety hazards of high-pressure construction during conventional expansion tube 6 patching. The casing patching device of this invention has strong applicability; it does not require changes to the structure or size. The radial expansion degree of the expansion rod assembly 4 driven by the hydraulic cylinder 2 can be applied to various types of casing patching, greatly improving its versatility. By controlling the high-pressure pump on the ground to inject high-pressure liquid into the hydraulic channel, the expansion outer diameter of the expansion rod assembly 4 can be changed. The positions of both ends of the expansion rod assembly 4 are controlled using an independent hydraulic cylinder 2 and a bottom plug 3, without relying on the cavity formed by the expansion tube 6 and the expansion cone, greatly reducing the damage of high-pressure liquid to the expansion tube 6, resulting in a smaller loss of inner diameter after patching.

[0039] In some embodiments, multiple liquid cylinders 2 and multiple bottom plugs 3 are provided, and multiple liquid cylinders 2 and multiple bottom plugs 3 are alternately arranged along the axial direction of the central rod 1. An expansion rod group 4 is rotatably arranged between any liquid cylinder 2 and a bottom plug 3 below it.

[0040] by Figure 1 and Figure 2 In this embodiment, two hydraulic cylinders 2 and two bottom plugs 3 are provided, corresponding to the installation of two expansion rod assemblies 4. Specifically, the first expansion rod assembly 4 is rotatably connected between the first adjacent hydraulic cylinder 2 and the first bottom plug 3 on the central rod 1, and the second expansion rod assembly 4 is rotatably connected between the second hydraulic cylinder 2 and the second bottom plug 3. Through the two spaced expansion rod assemblies 4, stable and balanced support can be achieved for the expansion tube 6 during expansion. When the expansion tube 6 is long, more than one hydraulic cylinder 2, bottom plug 3, and expansion rod assembly 4 can be added to form multi-point support, which is beneficial for the balanced expansion of the expansion tube 6.

[0041] In some embodiments, the expansion cone 5 is arranged parallel to the axial direction of the central rod 1, and each expansion cone 5 is rotatably connected to multiple expansion rod groups 4 in the axial direction.

[0042] like Figure 1 As shown, multiple expansion cones 5 are arranged circumferentially around the expansion rod assembly 4. Each expansion cone 5 is rotatably connected to the expansion rod assembly 4. When the expansion rod assembly 4 expands, it drives the expansion cones 5 to move radially to better support the inner wall of the expansion tube 6 and deform it. In some embodiments, when multiple expansion rod assemblies 4 are provided, a set of expansion cones 5 is provided around each expansion rod assembly 4 respectively; in a more preferred embodiment, two or more sets of expansion rod assemblies 4 arranged coaxially are rotatably connected to the same expansion cone 5 at the same radial angular position, such as... Figure 1 The expansion cone 5 is rotatably connected to two expansion rod assemblies 4 at both ends, thus providing a balanced axial force across the entire length of the expansion tube 6, which facilitates uniform deformation and expansion of the expansion tube 6, thereby improving the patching effect and efficiency. When the expansion rod assembly 4 is in the contracted state, the expansion cone 5 covers the outside of the expansion rod assembly 4, and the edges of multiple expansion cone 5 are in contact with each other, which facilitates the inclusion of the expansion rod assembly 4 during the insertion process, and the arrangement of the expansion cone 5 facilitates the installation and fitting of the expansion tube 6.

[0043] In some embodiments, the center rod 1 is provided with a limiting boss 11, and when the expansion rod assembly 4 is in the retracted state, the hydraulic cylinder 2 abuts against the limiting boss 11.

[0044] like Figure 2As shown, when the expansion rod assembly 4 is in the retracted state, the first hydraulic cylinder 2 on the central rod 1 can abut against the limiting boss 11. By setting a positioning detection switch, the depressurization state of the hydraulic cylinder 2 can be judged to ensure that depressurization is completed after the adjustment and the expansion rod assembly 4 is fully retracted, so as to smoothly lift the central rod 1. The limiting boss 11 is a large-diameter section set on the outer peripheral wall of the central rod 1. The outer diameter of the limiting boss 11 is larger than the outer diameter of the hydraulic cylinder 2, which can protect the hydraulic cylinder 2 during the lifting of the central rod 1.

[0045] In some embodiments, an elastic element 7 is provided between the limiting boss 11 and the hydraulic cylinder 2. When the expansion rod assembly 4 is in a contracted state, the hydraulic cylinder 2 abuts against the limiting boss 11 under the elastic force of the elastic element 7.

[0046] The specific connection relationship of the elastic element 7 is not marked in the figure. It can be understood that the elastic element 7 is set between the limiting boss 11 and the hydraulic cylinder 2. Considering the characteristics of downhole tools such as casing, the elastic force of the elastic element 7 can be achieved by fitting a spring on the central rod 1. The two ends of the spring abut against the top of the limiting boss 11 and the outer sleeve of the hydraulic cylinder 2, respectively. The top of the outer sleeve fits onto the top of the spring, so that the hydraulic cylinder 2 is always in the state of abutting the limiting boss 11 under the elastic force of the spring. When the casing subsidy device is lowered into the downhole to be subsidyd position and high-pressure fluid is introduced, the pressure of the high-pressure fluid overcomes the elastic force of the spring, thereby driving the hydraulic cylinder 2 to move down and drive the expansion rod assembly 4 to rotate and expand its diameter, thus achieving subsidy. When the high-pressure fluid is stopped and the pressure is released, the hydraulic cylinder 2 automatically returns to abutting the limiting boss 11 under the elastic force of the spring. The expansion rod assembly 4 and the expansion cone 5 are both contracted to the minimum outer diameter state. Only at this time can the lifting and recovery action be performed to ensure smooth and safe recovery.

[0047] In some embodiments, the outer diameter of the bottom plug 3 at the bottommost end of the central rod 1 is larger than the outer diameter of the expansion tube 6 to support the bottom end of the expansion tube 6.

[0048] like Figure 2 As shown, the bottom plug 3, which is set at the bottom of the center rod 1, is used to support the bottom of the lowest expansion rod group 4. At the same time, after the expansion tube 6 is installed, it can support the expansion tube 6 when the sleeve subsidy device is lowered, so as to facilitate the positioning of the lowering position of the expansion tube 6.

[0049] In some embodiments, the expansion rod assembly 4 and the expansion cone 5 are connected in two ways:

[0050] The first type: the expansion rod assembly 4 includes a first rod assembly and a second rod assembly. The top end of the first rod assembly is rotatably connected to the hydraulic cylinder 2, and the bottom end of the first rod assembly is rotatably connected to the top end of the second rod assembly. The bottom end of the second rod assembly is rotatably connected to the bottom plug 3. The first rod assembly and the second rod assembly are rotatably connected, and then the expansion cone 5 is rotatably connected to them.

[0051] In some embodiments, the first rod group and the second rod group each include a plurality of expansion rods 41, and the plurality of expansion rods 41 are evenly spaced around the central rod 1 in a circumferential manner.

[0052] Combination Figure 1 The first and second rod groups each contain the same number of expansion rods 41, which are connected one-to-one to form a rod assembly. This embodiment uses four expansion rods 41 in each of the first and second rod groups as an example. The four expansion rods 41 in the first rod group are evenly spaced around the central rod 1. When the hydraulic cylinder 2 moves downward, because the bottom plug 3 is fixed, the hydraulic cylinder 2 drives the top ends of the four expansion rods 41 downward, and the bottom ends of the expansion rods 41 move away from the central rod 1. Simultaneously, this drives the top ends of the corresponding expansion rods 41 in the second rod group to move, thereby achieving rotational expansion. The hinged joints of the two rotatably connected expansion rods 41 in the first and second rod groups are rotatably connected to expansion cones 5, thus driving the expansion cones 5. The four expansion rods 41 in the two expansion rod groups 4 are rotatably connected to the four expansion cones 5 respectively. When the expansion rod group 4 is in the contracted state, as... Figure 2 The four expansion cones 5 contact each other to form a cylindrical shape, which can protect the expansion rod assembly 4 and facilitate the installation of the expansion tube 6.

[0053] The second type: the expansion rod assembly 4 includes a first rod assembly and a second rod assembly. The top end of the first rod assembly is rotatably connected to the hydraulic cylinder 2, and the bottom end of the first rod assembly is rotatably connected to the expansion cone 5. The top end of the second rod assembly is rotatably connected to the expansion cone 5, and the bottom end of the second rod assembly is rotatably connected to the bottom plug 3.

[0054] In this method, the first and second rod groups are rotatably connected to the expansion cone 5, which increases the connection points between the expansion rod group 4 and the expansion cone 5, thereby increasing the support strength of the expansion cone 5 in the axial direction and improving the subsidy effect.

[0055] Using the casing patching device provided by this invention, this invention also provides a casing patching method, comprising the following steps:

[0056] S1, when the expansion rod assembly 4 is in the contracted state, the expansion tube 6 is sleeved on the outside of the multiple expansion cones 5, and the bottom end of the expansion tube 6 contacts the bottom plug 3 at the bottommost end.

[0057] S2, lower the casing subsidy device into the position to be subsidized inside the casing;

[0058] S3, high-pressure liquid is introduced into the fluid flow channel of the central rod 1. The high-pressure liquid pushes the hydraulic cylinder 2 to squeeze the expansion rod assembly 4 to rotate and expand, and pushes the expansion cone 5 to move radially along the central rod 1. The expansion tube 6 expands and fits against the inner wall of the casing to patch the area to be patched inside the casing. The expansion tube 6 can effectively seal the leak point on the casing and restore the integrity of the casing. In conjunction with the thin-walled expansion tube 6, it is applicable to small-size casing patching, short-section patching, and casing patching with low pressure resistance requirements. This invention has the significant advantage of small inner diameter loss. It should be noted that before patching, the location, length, and type of casing damage should be determined by logging and leak testing, thereby determining the length and wall thickness of the expansion tube 6 to be used. Before running the casing patching device, it is best to trim the area 10-20cm above and below the leak point on the casing to provide the casing inner wall conditions for patching and improve the patching effect.

[0059] In some embodiments, the sleeve patching method further includes step S4: after the hydraulic cylinder 2 moves into place, the center rod 1 is rotated and moved up and down to make the expansion tube 6 fully expand; then the pressure is released to make the expansion rod assembly 4 contract, and then the center rod 1 is pulled up to complete the patching.

[0060] By monitoring the verticality of the high-pressure pump, when the design value or critical value is reached, it indicates that the hydraulic cylinder 2 has been fully positioned. At this time, rotating the drill bit will drive the central rod 1 and its expansion cone 5 to rotate and move up and down, which can make the expansion tube 6 expand more completely.

[0061] If other leaks still exist inside the casing after the subsidy, the casing subsidy method and steps described above can be repeated until the entire casing is fully subsidized.

[0062] The casing patching method provided by the embodiments of the present invention has strong applicability and can be applied to various types of casing patches without changing the structure and size. By controlling the high-pressure pump on the ground to provide high-pressure liquid, the outer diameter of the expansion tube 6 can be changed. Each expansion rod assembly 4 is driven by an independent hydraulic cylinder 2, which greatly reduces the damage of high-pressure liquid to the expansion tube 6.

[0063] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A casing patching device for patching the inner wall of a casing; characterized in that, The sleeve patching device includes: A central rod (1) is provided with a liquid flow channel along its axial direction. The liquid flow channel is used to introduce high-pressure liquid. The top end of the central rod (1) is open and the bottom end is closed. A liquid cylinder (2) is mounted on the central rod (1) and communicates with the liquid flow channel. The high-pressure liquid in the liquid flow channel can drive the liquid cylinder (2) to move downward along the central rod (1). Bottom plug (3), the bottom plug (3) is disposed on the center rod (1) and fixedly connected to the center rod (1), the bottom plug (3) is located below the liquid cylinder (2); An expansion rod assembly (4) is rotatably connected at both ends to the liquid cylinder (2) and the bottom plug (3). When the liquid cylinder (2) moves downward, the expansion rod assembly (4) rotates and expands along the radial direction of the central rod (1). An expansion cone (5) is rotatably connected to the expansion rod assembly (4). When the expansion rod assembly (4) rotates and expands, it drives the expansion cone (5) to move along the radial direction of the central rod (1). An expansion tube (6) is sleeved on the outside of the expansion cone (5). When the expansion cone (5) moves in the radial direction of the central rod (1), it can support the expansion tube (6) to expand synchronously, so that the outer wall of the expansion tube (6) abuts against the inner wall of the sleeve to subdue the sleeve.

2. The sleeve patching device according to claim 1, characterized in that, Multiple liquid cylinders (2) and multiple bottom plugs (3) are provided respectively. Multiple liquid cylinders (2) and multiple bottom plugs (3) are alternately arranged along the axial direction of the central rod (1). An expansion rod group (4) is rotatably arranged between any liquid cylinder (2) and one of the bottom plugs (3) below it.

3. The casing patching device according to claim 1, characterized in that, The expansion cone (5) is arranged parallel to the axial direction of the central rod (1), and each expansion cone (5) is rotatably connected to multiple expansion rod groups (4) along the axial direction.

4. The casing patching device according to claim 1, characterized in that, The center rod (1) is provided with a limiting boss (11). When the expansion rod assembly (4) is in the contracted state, the hydraulic cylinder (2) abuts against the limiting boss (11).

5. The casing patching device according to claim 4, characterized in that, An elastic element (7) is provided between the limiting boss (11) and the hydraulic cylinder (2). When the expansion rod assembly (4) is in a contracted state, the hydraulic cylinder (2) abuts against the limiting boss (11) under the elastic force of the elastic element (7).

6. The casing patching device according to claim 1, characterized in that, The outer diameter of the bottom plug (3) at the bottommost end of the central rod (1) is larger than the outer diameter of the expansion tube (6) to support the bottom end of the expansion tube (6).

7. The casing patching device according to claim 1, characterized in that, The expansion rod assembly (4) includes a first rod assembly and a second rod assembly. The top end of the first rod assembly is rotatably connected to the hydraulic cylinder (2), the bottom end of the first rod assembly is rotatably connected to the top end of the second rod assembly, and the bottom end of the second rod assembly is rotatably connected to the bottom plug (3).

8. The casing patching device according to claim 7, characterized in that, The first rod group and the second rod group each include a plurality of expansion rods (41), and the plurality of expansion rods (41) are evenly spaced around the central rod (1) in the circumferential direction.

9. The casing patching device according to claim 1, characterized in that, The expansion rod assembly (4) includes a first rod assembly and a second rod assembly. The top end of the first rod assembly is rotatably connected to the hydraulic cylinder (2), and the bottom end of the first rod assembly is rotatably connected to the expansion cone (5). The top end of the second rod assembly is rotatably connected to the expansion cone (5), and the bottom end of the second rod assembly is rotatably connected to the bottom plug (3).

10. A casing patching method, characterized in that, The casing patching device according to any one of claims 1-9, wherein the casing patching method comprises the following steps: S1, when the expansion rod assembly (4) is in the contracted state, the expansion tube (6) is sleeved on the outside of multiple expansion cones (5), and the bottom end of the expansion tube (6) contacts the bottom plug (3) at the bottommost end; S2, the sleeve patching device is lowered into the patching position inside the sleeve; S3, high-pressure liquid is introduced into the liquid flow channel of the central rod (1). The high-pressure liquid pushes the liquid cylinder (2) to squeeze the expansion rod assembly (4) to rotate and expand, and pushes the expansion cone (5) to move in the radial direction of the central rod (1). The expansion tube (6) expands and fits against the inner wall of the sleeve to subsidize the position to be subsidized in the sleeve.

11. The casing patching method according to claim 10, characterized in that, The process also includes step S4, where after the cylinder (2) is moved into place, the center rod (1) is rotated and moved up and down to allow the expansion tube (6) to expand fully; then the pressure is released to allow the expansion rod assembly (4) to contract, and then the center rod (1) is lifted to complete the patching.

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