Soluble reducing fracturing plugging tool

Abstract

The invention provides a soluble variable-diameter fracturing plugging tool. A guide short section is formed at the end of a pull tube; the push piece is sleeved on the pull tube; the pull tube is sleeved with the diameter changing mechanism, the diameter changing mechanism is provided with a first-stage diameter changing structure and a second-stage diameter changing structure which are sequentially arranged in the axial direction of the pull tube, the front end of the pushing piece is arranged between the first-stage diameter changing structure and the pull tube in a penetrating mode, and the front end of the first-stage diameter changing structure is arranged between the second-stage diameter changing structure and the pull tube in a penetrating mode; in the state that the pushing piece drives the first-stage reducing structure to move towards the guiding short section, the second-stage reducing structure can be arranged in an expanding mode in the radial direction of the pull pipe; and in the state that the pushing piece moves relative to the first-stage reducing structure, the first-stage reducing structure can expand in the radial direction of the pull pipe. By means of the reducing mechanism, the problems that in the technical field of oil and gas well exploitation, the device needs to adapt to damaged sleeves of various sizes and diameters, the traffic capacity in smaller sleeve damage space is improved, and the plugging capacity in damaged sleeves of large sizes and diameters is improved are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas well exploitation, and particularly to a soluble variable-diameter fracturing plugging tool. Background Technique

[0002] The description in this part only provides background information related to the disclosure of the present invention, and does not constitute prior art.

[0003] In recent years, in the technical field of oil and gas well exploitation, the exploitation of unconventional oil and gas wells such as shale gas has been increasing. Currently, hydraulic fracturing technology is generally used for shale gas exploitation. However, hydraulic fracturing technology is generally considered to be the main factor causing phenomena such as fracture sliding and geological migration. At the same time, it will also cause deformation of a large number of casings in shale gas wells, such as diameter reduction, offset, etc. In existing engineering construction, it is usually necessary to abandon sections to preserve the existing wellbore structure. Even more seriously, when the situation is more severe, the fracturing process cannot be carried out, and only the option of abandoning the well can be taken.

[0004] How to achieve fracturing in shale gas wells with large casing deformation and reduce the risk of well abandonment has become a problem that needs to be solved in the exploitation technology of unconventional oil and gas wells such as shale gas. Currently, in technical means, many deformable plugging tools have been designed. Through the design of the deformation structure of the plugging tool, the plugging tool can pass through a smaller casing damage space to reach the position that needs to be plugged. However, these plugging tools are restricted by the structure design, resulting in a still relatively large diameter after reduction and a still relatively small diameter after enlargement, and they cannot be applied to and be compatible with deformed casings of various sizes, and cannot achieve a large compatibility range.

[0005] It should be noted that the above introduction of the technical background is only for the convenience of clearly and completely explaining the technical solution of the present invention and facilitating the understanding of those skilled in the art. It cannot be considered that the above technical solutions are well-known to those skilled in the art just because these solutions are described in the background art part of the present invention. Summary of the Invention

[0006] The purpose of the present invention is to provide a soluble variable-diameter fracturing plugging tool, which solves the problems in the technical field of oil and gas well exploitation that it is necessary to adapt to damaged casings of various sizes, improve the passing ability in a smaller casing damage space, and improve the plugging ability in damaged casings with a large diameter.

[0007] The above implementation purpose of the present invention is mainly achieved by the following technical solutions:

[0008] The present invention provides a soluble variable-diameter fracturing plugging tool, including:

[0009] A pulling pipe, at the end of which a guiding short section is formed;

[0010] A pushing member, sleeved on the pulling pipe;

[0011] The diameter-changing mechanism is sleeved on the pulling pipe. The diameter-changing mechanism has a primary diameter-changing structure and a secondary diameter-changing structure arranged in sequence along the axial direction of the pulling pipe. The front end of the pushing member is inserted between the primary diameter-changing structure and the pulling pipe, and the front end of the primary diameter-changing structure is inserted between the secondary diameter-changing structure and the pulling pipe;

[0012] Wherein, when the pushing member drives the primary diameter-changing structure to move towards the guiding short section, the secondary diameter-changing structure can be expanded along the radial direction of the pulling pipe; when the pushing member moves relative to the primary diameter-changing structure, the primary diameter-changing structure can be expanded along the radial direction of the pulling pipe

[0013] In a specific embodiment, the primary diameter-changing structure has a connecting portion and an expanding portion connected to each other. The connecting portion is sleeved on the front end of the pushing member. The expanding portion has a plurality of slitting bodies arranged at intervals along its circumferential direction, and slits are formed between two adjacent slitting bodies.

[0014] In a specific embodiment, the connecting portion and the front end of the pushing member are connected by a primary locking mechanism. The primary locking mechanism includes a locking ball and a primary locking groove. The primary locking groove is formed on the peripheral wall of the front end of the pushing member. A radial through hole is provided on the connecting portion, and the locking ball is located in the radial through hole and is clamped in the primary locking groove.

[0015] In a specific embodiment, an adjusting member and an elastic member are provided in the radial through hole, and the elastic member is clamped between the locking ball and the adjusting member.

[0016] In a specific embodiment, a secondary locking groove is provided on the pushing member. When the primary locking mechanism is unlocked and the front end of the pushing member abuts against the guiding short section, the locking ball can be clamped in the secondary locking groove.

[0017] In a specific embodiment, the secondary diameter-changing structure has a sealing body and a plurality of diameter-changing slips arranged along the circumferential direction of the pulling pipe, and the sealing body is hermetically sleeved on the outside of the primary diameter-changing structure.

[0018] In a specific embodiment, the outer diameter of the primary diameter-changing structure gradually decreases along the direction close to the guiding short section; an axial guiding structure is provided between the secondary diameter-changing structure and the primary diameter-changing structure, and the secondary diameter-changing structure is slidably arranged on the primary diameter-changing structure through the axial guiding structure.

[0019] In a specific embodiment, the axial guiding structure includes an axially guiding rib and an axially guiding groove that are engaged with each other;

[0020] Wherein, the axial guiding rib is arranged on the inner wall of the variable-diameter slip of the secondary variable-diameter structure, and the axial guiding groove is opened on the outer wall of the diameter-expanding part of the primary variable-diameter structure; or, the axial guiding rib is arranged on the outer wall of the diameter-expanding part of the primary variable-diameter structure, and the axial guiding groove is opened on the inner wall of the variable-diameter slip of the secondary variable-diameter structure.

[0021] In a specific embodiment, a radial guiding structure is provided between the secondary variable-diameter structure and the guiding short section, and the secondary variable-diameter structure can be slidably arranged along the radial direction of the guiding short section through the radial guiding structure.

[0022] In a specific embodiment, the radial guiding structure includes a radially engaging guiding rib and a radially engaging guiding groove;

[0023] Wherein, the radially engaging guiding rib is arranged at the front end of the variable-diameter slip of the secondary variable-diameter structure, and the radially engaging guiding groove is opened at the rear end of the guiding short section; or, the radially engaging guiding rib is arranged at the rear end of the guiding short section, and the radially engaging guiding groove is opened at the front end of the variable-diameter slip of the secondary variable-diameter structure.

[0024] In a specific embodiment, at least one shear pin is connected between the guiding short section and the pulling pipe, and in a state where at least one of the shear pins is cut off, the guiding short section is separated from the end of the pulling pipe.

[0025] In a specific embodiment, a plurality of the primary variable-diameter structures are provided between the pushing member and the secondary variable-diameter structure, and in a state where two adjacent primary variable-diameter structures move relative to each other, the primary variable-diameter structure close to the guiding short section can be movably arranged along the radial direction of the pulling pipe.

[0026] Compared with the prior art, the technical solution of the present invention has the following characteristics and advantages:

[0027] The present invention can maintain the minimum diameter during passing through by arranging the pushing member and the variable-diameter mechanism on the pulling pipe, thereby improving the passing ability of the overall plugging tool in the damaged casing space; at the same time, when reaching the plugging position, the pushing member can be pushed by the passing pressure to be sleeved in the variable-diameter mechanism, so that the variable-diameter mechanism expands radially along the pulling pipe to realize the variable-diameter function, and further ensure setting and sealing in a larger-diameter casing; furthermore, the present invention can also increase the setting diameter by increasing the number of the primary variable-diameter structures in the variable-diameter mechanism, thereby improving the overall setting ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a sectional view of the soluble variable-diameter fracturing plugging tool of the present invention;

[0029] Figure 2 It is a sectional view of the first-stage locking mechanism of the soluble variable-diameter fracturing plugging tool of the present invention;

[0030] Figure 3 It is a structural diagram of the pusher of the soluble variable-diameter fracturing plugging tool of the present invention;

[0031] Figure 4 It is another structural diagram of the pusher of the soluble variable-diameter fracturing plugging tool of the present invention;

[0032] Figure 5 It is a schematic diagram of the expansion of the seal body of the soluble variable-diameter fracturing plugging tool of the present invention;

[0033] Figure 6 It is a structural diagram of the first-stage variable-diameter structure of the soluble variable-diameter fracturing plugging tool of the present invention;

[0034] Figure 7 It is a structural diagram of the variable-diameter slip of the soluble variable-diameter fracturing plugging tool of the present invention;

[0035] Figure 8 It is another structural diagram of the variable-diameter slip of the soluble variable-diameter fracturing plugging tool of the present invention;

[0036] Figure 9 It is a structural diagram of the guide nipple of the soluble variable-diameter fracturing plugging tool of the present invention;

[0037] Figure 10 It is a structural diagram of the shaft during the lowering process of the soluble variable-diameter fracturing plugging tool of the present invention;

[0038] Figure 11 It is a structural diagram of the shaft during the diameter-expanding process of the soluble variable-diameter fracturing plugging tool of the present invention;

[0039] Figure 12 It is a structural diagram of the diameter-expanding process of the soluble variable-diameter fracturing plugging tool of the present invention;

[0040] Figure 13 It is a structural diagram of the shaft during the process of dropping the plugging ball of the soluble variable-diameter fracturing plugging tool of the present invention;

[0041] Figure 14 It is a structural diagram of the process of dropping the plugging ball of the soluble variable-diameter fracturing plugging tool of the present invention;

[0042] Figure 15 It is a structural diagram of the shaft during the fracturing process of the soluble variable-diameter fracturing plugging tool of the present invention.

[0043] Explanation of the reference numerals in the drawings:

[0044] 1. Pulling pipe;

[0045] 2. Guide nipple;

[0046] 3. Variable diameter mechanism; 31. Primary variable diameter structure; 311. Connection part; 3111. Radial perforation; 3112. Adjusting part; 3113. Elastic part; 312. Diameter expansion part; 3121. Slotted body; 313. Slit; 314. Primary locking mechanism; 3141. Locking ball; 3142. Primary locking groove; 32. Secondary variable diameter structure; 321. Sealing body; 322. Variable diameter slip; 3221. Protrusion; 33. Axial guiding structure; 331. Axial guiding rib; 332. Axial guiding groove;

[0047] 4. Pushing part; 41. Secondary locking groove;

[0048] 5. Radial guiding structure; 51. Radial guiding rib; 52. Radial guiding groove;

[0049] 6. Shearing pin;

[0050] 7. Casing;

[0051] 8. Plugging ball;

[0052] F. Axial direction of the pulling pipe;

[0053] D. Radial direction of the pulling pipe;

[0054] E. Axial direction of the primary variable diameter structure;

[0055] P. Radial direction of the guiding short joint. Detailed implementation manners

[0056] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0057] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only embodiments.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0059] As Figure 1 shown, the present invention provides a soluble variable-diameter fracturing plugging tool, comprising:

[0060] A pulling pipe 1, at the end of which a guiding short section 2 is formed;

[0061] A pushing member 4, sleeved on the pulling pipe 1;

[0062] A variable-diameter mechanism 3, sleeved on the pulling pipe 1, the variable-diameter mechanism 3 having a primary variable-diameter structure 31 and a secondary variable-diameter structure 32 sequentially arranged along the axial direction F of the pulling pipe 1. The front end of the pushing member 4 is disposed between the primary variable-diameter structure 31 and the pulling pipe 1, and the front end of the primary variable-diameter structure 31 is disposed between the secondary variable-diameter structure 32 and the pulling pipe 1;

[0063] Wherein, in a state where the pushing member 4 drives the primary variable-diameter structure 31 to move towards the guiding short section 2, the secondary variable-diameter structure 32 can be expanded and arranged along the radial direction D of the pulling pipe 1; in a state where the pushing member 4 moves relative to the primary variable-diameter structure 31, the primary variable-diameter structure 31 can be expanded and arranged along the radial direction D of the pulling pipe 1.

[0064] For the soluble variable-diameter fracturing plugging tool of the present invention, by sequentially arranging the pushing member 4, the variable-diameter mechanism 3, and the guiding short section 2 located at the end of the pulling pipe 1 along the axial direction F thereof, and with reference to Figure 10 shown, when the soluble variable-diameter fracturing plugging tool passes through the damaged area of the casing 7, it can pass through with the minimum diameter of each mechanism. At the same time, after passing through the damaged area and reaching the area that needs to be plugged and sealed, by pushing operation, the secondary variable-diameter structure 32 and the primary variable-diameter structure 31 can be expanded along the radial direction D of the pulling pipe 1 in sequence to realize the variable-diameter function. After the structure is expanded and variable-diameter, it can seal and plug a standard casing 7 with a diameter of 114.3 mm.

[0065] Specifically, the guiding short section 2 is arranged at the end of the pulling pipe 1. Along the axial direction F of the pulling pipe 1 and in the direction towards the end of the pulling pipe 1, a pushing member 4, a first-stage diameter-changing structure 31, and a second-stage diameter-changing structure 32 are sleeved in sequence. Among them, the front end of the pushing member 4 and the rear end of the first-stage diameter-changing structure 31, and the front end of the first-stage diameter-changing structure 31 and the rear end of the second-stage diameter-changing mechanism 3 are arranged in a penetrating manner in sequence. The pushing member 4 is generally a conical structure. Both the first-stage diameter-changing structure 31 and the second-stage diameter-changing structure 32 are sleeve structures with variable diameters. The pushing member 4 is movably sleeved on the pulling pipe 1. The axis of the pushing member 4 coincides with the axial direction F of the pulling pipe 1. The outer wall of the front end of the pushing member 4 is slidably connected to the inner wall of the rear end of the first-stage diameter-changing structure 31. The front outer wall of the first-stage diameter-changing structure 31, which is movably sleeved on the pulling pipe 1, is slidably connected to the inner wall of the rear end of the second-stage diameter-changing structure 32. The front end of the second-stage diameter-changing structure 32 is movably connected to the rear end of the guiding short section 2 along the radial direction P of the guiding short section 2 (that is, the radial direction D of the pulling pipe 1).

[0066] Refer to in conjunction with Figures 10 to 15 As shown, during the diameter-changing process, the ground uses a tool to push the pushing member 4 to move along the axial direction F of the pulling pipe 1 towards the end of the pulling pipe 1. The pushing member 4 drives the first-stage diameter-changing structure 31 to move along the axial direction F of the pulling pipe 1 towards the end of the pulling pipe 1. The second-stage diameter-changing structure 32 expands in diameter along the radial direction D of the pulling pipe 1. The inner wall of the rear end of the second-stage diameter-changing structure 32 slides along the outer wall of the first-stage diameter-changing structure 31. When the front end of the first-stage diameter-changing structure 31 abuts against the guiding short section 2, the second-stage diameter-changing structure 32 is sleeved outside the first-stage diameter-changing structure 31. In this state, continue to push the pushing member 4. The pushing member 4 moves towards the further end of the pulling pipe 1. The pushing member 4 and the first-stage diameter-changing structure 31 move relative to each other. Both the first-stage diameter-changing structure 31 and the second-stage diameter-changing structure 32 expand in diameter along the radial direction D of the pulling pipe 1. The inner wall of the rear end of the first-stage diameter-changing structure 31 slides along the outer wall of the pushing member 4. When the front end of the pushing member 4 abuts against the guiding short section 2, the first-stage diameter-changing structure 31 is sleeved outside the pushing member 4, and the second-stage diameter-changing structure 32 is sleeved outside the first-stage diameter-changing structure 31. The outer wall of the second-stage diameter-changing structure 32 abuts against and seals the inner wall of the casing 7 to complete the plugging.

[0067] As Figure 1 、 Figures 6 to 8 shown, in a specific embodiment, the first-stage diameter-changing structure 31 has a connected connecting portion 311 and a diameter-expanding portion 312. The connecting portion 311 is sleeved on the front end of the pushing member 4. The diameter-expanding portion 312 has a plurality of slit bodies 3121 arranged at intervals along its circumferential direction. A slit 313 is formed between two adjacent slit bodies 3121.

[0068] Through the arrangement of the connecting portion 311 and the diameter-expanding portion 312, the diameter-expanding portion 312 of the primary diameter-changing structure 31 can expand along the radial direction D of the pull tube 1 under the pushing action of the pushing member 4 to achieve the purpose of diameter change. At the same time, the connecting portion 311 is sleeved on the pushing member 4 to limit the connection relationship and relative movement mode between the primary diameter-changing structure 31 and the pushing member 4.

[0069] Specifically, the connecting portion 311 of the primary diameter-changing structure 31 is located at the tail end of the primary diameter-changing structure 31, and the diameter-expanding portion 312 of the primary diameter-changing structure 31 is located at the front end of the primary diameter-changing structure 31. A plurality of slotted bodies 3121 on the diameter-expanding portion 312 are arranged at intervals along the circumferential direction of the diameter-expanding portion 312. One end of each slotted body 3121 is connected to the connecting portion 311, and a slit 313 is formed between two adjacent slotted bodies 3121. In the state where the pushing member 4 moves relative to the primary diameter-changing structure 31, the front end of the pushing member 4 abuts against the inner wall of each slotted body 3121, and one end of each slotted body 3121 away from the connecting portion 311 expands along the radial direction D of the pull tube 1, and one end of each slotted body 3121 close to the connecting portion 311 is fixedly connected to the connecting portion 311.

[0070] As Figures 1 to 4 、 Figure 6 shown, in a specific embodiment, the connecting portion 311 and the front end of the pushing member 4 are connected by a primary locking mechanism 314. The primary locking mechanism 314 includes a locking ball 3141 and a primary locking groove 3142. The primary locking groove 3142 is opened on the peripheral wall of the front end of the pushing member 4. A radial through hole 3111 is provided on the connecting portion 311 of the primary diameter-changing structure 31. The locking ball 3141 is located in the radial through hole 3111 and is clamped in the primary locking groove 3142.

[0071] Through the arrangement of the locking ball 3141 and the primary locking groove 3142, the primary diameter-changing structure 31 sleeved outside the pushing member 4 can be locked and connected to the pushing member 4. At the same time, through the primary locking mechanism 314, the relative fixation between the two can be maintained when the pushing member 4 drives the primary diameter-changing structure 31 to move toward the guiding short section 2.

[0072] Specifically, the primary locking groove 3142 is arranged on the outer wall of the pushing member 4, and the primary locking groove 3142 is located at the front end of the pushing member 4. A radial through hole 3111 for accommodating the locking ball 3141 is opened on the connecting portion 311 of the primary diameter-changing structure 31. A device for abutting against the locking ball 3141 is provided at the opening of the end of the radial through hole 3111 away from the pushing member 4. The locking ball 3141 passes through the opening at the end of the radial through hole 3111 close to the pushing member 4 and is clamped in the primary locking groove 3142.

[0073] As Figure 1 and Figure 2As shown, in a specific embodiment, an adjusting member 3112 and an elastic member 3113 are provided in the radial through hole 3111, and the elastic member 3113 is clamped between the locking ball 3141 and the adjusting member 3112.

[0074] Through the elastic member 3113, the locking ball 3141 can be elastically clamped in the first-stage locking groove 3142. At the same time, through the adjusting member 3112, the compression amount of the elastic member 3113 can be adjusted, and the abutting force between the locking ball 3141 and the first-stage locking groove 3142 can be adjusted, so as to avoid the unlocking of the locking ball 3141 and the first-stage locking groove 3142 and the relative movement between the first-stage variable diameter structure 31 and the driving member 4 when the driving member 4 drives the first-stage variable diameter structure 31 to move towards the guiding short section 2 due to the too small elastic force provided by the elastic member 3113. Specifically, in this embodiment, the adjusting member 3112 is arranged at the opening of the radial through hole 3111 away from the driving member 4, the position of the adjusting member 3112 in the radial through hole 3111 is adjustable, one end of the elastic member 3113 is connected to the adjusting member 3112, and the other end thereof is connected to the locking ball 3141.

[0075] As Figures 1 to 4 shown, in a specific embodiment, a second-stage locking groove 41 is provided on the driving member 4. When the first-stage locking mechanism 314 is unlocked and the front end of the driving member 4 abuts against the guiding short section 2, the locking ball 3141 can be clamped in the second-stage locking groove 41.

[0076] Through the cooperation setting of the second-stage locking groove 41 and the locking ball 3141, the soluble variable diameter fracturing plugging tool can lock the configuration in the fully expanded state, avoiding the structural deformation caused by the pressure change and further avoiding the plugging failure.

[0077] Specifically, the secondary locking groove 41 is provided at the rear end of the pushing member 4 and is also located on the outer wall of the pushing member 4. When the pushing member 4 drives the primary diameter-changing structure 31 to move towards the guiding short section 2, the locking ball 3141 is located in the primary locking groove 3142. When the primary diameter-changing structure 31 contacts one end of the guiding short section 2, continue to push the pushing member 4, and the primary locking mechanism 314 is unlocked, that is, the primary locking groove 3142 is separated from the locking ball 3141. When the pushing member 4 moves relative to the primary diameter-changing structure 31, the locking ball 3141 rolls and moves along the outer wall of the pushing member 4. When the front end of the pushing member 4 abuts against the guiding short section 2, the locking ball 3141 snaps into the secondary locking groove 41. In this embodiment, when the secondary locking groove 41 is locked with the locking ball 3141, the force required for the locking ball 3141 to be unlocked in the axial direction F of the pulling pipe 1 is greater than the force required for the locking ball 3141 to be unlocked in the axial direction F of the pulling pipe 1 when the primary locking groove 3142 is locked with the locking ball 3141, so as to prevent the locking ball 3141 from slipping out of the secondary locking groove 41 during the fracturing operation. In other embodiments, the secondary locking groove 41 can also adopt other groove structures to limit the slipping out of the locking ball 3141.

[0078] As Figure 1 , Figure 5 , Figures 7 to 9 shown, in a specific embodiment, the secondary diameter-changing structure 32 has a connected sealing body 321 and a plurality of diameter-changing slips 322 arranged along the circumferential direction of the pulling pipe 1. The sealing body 321 is sealingly sleeved outside the primary diameter-changing structure 31.

[0079] The soluble diameter-changing fracturing plugging tool can be set in the casing 7 through the diameter-changing slips 322, and the gap between the soluble diameter-changing fracturing plugging tool and the inner wall of the casing 7 can be sealed through the sealing body 321, achieving a sealing effect and preventing the fracturing fluid from leaking from the soluble diameter-changing fracturing plugging tool.

[0080] In this embodiment, the diameter-changing slip 322 is a tile-shaped structure. The outer wall of the diameter-changing slip 322 is provided with bumps 3221 for increasing friction. The front end of the diameter-changing slip 322 is connected to the guiding short section 2. The rear end of the diameter-changing slip 322 is sleeved outside the front end of the primary diameter-changing structure 31. The front end of the sealing body 321 is connected to the rear end of the diameter-changing slip 322. The rear end of the sealing body 321 is sleeved outside the primary diameter-changing structure 31. When the primary diameter-changing structure 31 moves towards the guiding short section 2, the front end of the diameter-changing slip 322 expands in the radial direction D of the pulling pipe 1, the rear end of the diameter-changing slip 322 slides along the outer wall of the primary diameter-changing structure 31, and the rear end of the sealing body 321 also slides along the outer wall of the primary diameter-changing structure 31.

[0081] As Figure 1 ,Figure 6 , Figures 7 to 9 As shown in Figures 7 to 9 , in a specific embodiment, the outer diameter of the first-stage diameter-changing structure 31 gradually decreases in the direction close to the guiding short section 2; an axial guiding structure 33 is provided between the second-stage diameter-changing structure 32 and the first-stage diameter-changing structure 31, and the second-stage diameter-changing structure 32 is slidably arranged on the first-stage diameter-changing structure 31 through the axial guiding structure 33.

[0082] By changing the outer diameter size, the second-stage diameter-changing structure 32 can slide on the first-stage diameter-changing structure 31 to achieve the purpose of expanding along the radial direction D of the pulling pipe 1. At the same time, by setting the axial guiding structure 33, the moving path of the second-stage diameter-changing structure 32 on the first-stage diameter-changing structure 31 can be limited, making the entire diameter-changing process more orderly. In this embodiment, the first-stage diameter-changing structure 31 is generally in the shape of a tapered barrel, and the outer diameter of the front end of the first-stage diameter-changing structure 31 is smaller than the outer diameter of the rear end of the first-stage diameter-changing structure 31. In other embodiments, the specific shape of the first-stage diameter-changing structure 31 can also be set to other shapes, and no specific limitation is made thereto.

[0083] With reference to Figures 6 to 8 As shown in Figures 6 to 8 , in a specific embodiment, the axial guiding structure 33 includes an axially guiding convex rib 331 and an axially guiding groove 332 that are engaged with each other. Among them, the axially guiding convex rib 331 is provided on the inner wall of the diameter-changing chuck 322 of the second-stage diameter-changing structure 32, and the axially guiding groove 332 is opened on the outer wall of the diameter-expanding portion 312 of the first-stage diameter-changing structure 31; alternatively, the axially guiding convex rib 331 is provided on the outer wall of the diameter-expanding portion 312 of the first-stage diameter-changing structure 31, and the axially guiding groove 332 is opened on the inner wall of the diameter-changing chuck 322 of the second-stage diameter-changing structure 32.

[0084] By providing the axially guiding convex rib 331 and the axially guiding groove 332, the first-stage diameter-changing structure 31 and the second-stage diameter-changing structure 32 can be slidably connected together to achieve the purpose of restricting their moving directions.

[0085] Specifically, the axially guiding convex rib 331 is generally a raised cubic structure, and the axially guiding groove 332 is arranged in cooperation with the axially guiding convex rib 331. In other embodiments, the axially guiding convex rib 331 can also be a raised inverted trapezoidal structure, and no specific limitation is made thereto; in a specific embodiment, the axially guiding groove 332 is generally arranged on the outer wall of the diameter-expanding portion 312 of the first-stage diameter-changing structure 31 along the axial direction E of the first-stage diameter-changing structure 31, and the axially guiding convex rib 331 is provided on the inner wall of the rear end of the diameter-changing chuck 322. The number of axially guiding grooves 332 and the number of axially guiding convex ribs 331 correspond to the number of diameter-changing chucks 322. In another embodiment, the axially guiding groove 332 is generally arranged on the inner wall of the diameter-changing chuck 322 along the axial direction F of the pulling pipe 1, and the axially guiding convex rib 331 is provided on the outer wall of the front end of the first-stage diameter-changing structure 31.

[0086] As Figure 1 , Figures 7 to 9 shown, in a specific embodiment, a radial guiding structure 5 is provided between the secondary diameter-changing structure 32 and the guiding short section 2, and the secondary diameter-changing structure 32 can be slidably arranged along the radial direction P of the guiding short section 2 through the radial guiding structure 5. Through the radial guiding structure 5, the secondary diameter-changing structure 32 and the guiding short section 2 can be slidably connected together, achieving the purpose of restricting the secondary diameter-changing structure 32 to only move radially towards the guiding short section 2.

[0087] In a specific embodiment, the radial guiding structure 5 includes a radially guiding rib 51 and a radially guiding groove 52 that are engaged with each other; wherein, the radially guiding rib 51 is arranged at the front end of the diameter-changing slip 322 of the secondary diameter-changing structure 32, and the radially guiding groove 52 is opened at the rear end of the guiding short section 2; alternatively, the radially guiding rib 51 is arranged at the rear end of the guiding short section 2, and the radially guiding groove 52 is opened at the front end of the diameter-changing slip 322 of the secondary diameter-changing structure 32.

[0088] Through the cooperative setting of the radially guiding rib 51 and the radially guiding groove 52, the restricting effect can be achieved; specifically, the radially guiding rib 51 is generally a convex inverted trapezoidal structure, and the cross-section of the radially guiding groove 52 is a concave inverted trapezoid. In other embodiments, the axially guiding rib 331 can also be a convex cubic structure, and no specific limitation is made thereto; in one embodiment, the radially guiding groove 52 is generally arranged along the radial direction P of the guiding short section 2 at the rear end of the guiding short section 2, and the radially guiding rib 51 is arranged at the front end of the diameter-changing slip 322. In another embodiment, the radially guiding groove 52 is generally arranged along the radial direction P of the guiding short section 2 at the front end of the diameter-changing slip 322, and the radially guiding rib 51 is arranged at the rear end of the guiding short section 2.

[0089] As Figure 1 , Figures 9 to 12 shown, in a specific embodiment, at least one shear pin 6 is connected between the guiding short section 2 and the pulling pipe 1, and in a state where at least one shear pin 6 is cut off, the guiding short section 2 is separated from the end of the pulling pipe 1.

[0090] Through the setting manner of the shear pin 6, it is possible to break the connection between the guiding short section 2 and the pulling pipe 1 by pulling the pulling pipe 1, complete the recovery work of the pulling pipe 1, and provide a construction environment for the injection of fracturing fluid.

[0091] Specifically, the shear pin 6 is inserted through the guiding short section 2. One end of the shear pin 6 penetrates through the inner wall of the guiding short section 2 and is connected to the pulling pipe 1. In a specific embodiment, the number of shear pins 6 is two, and the two shear pins 6 are connected between the guiding short section 2 and the pulling pipe 1 at a certain angle to provide a more stable connection relationship and prevent the shear pins 6 from being easily pulled off. In other embodiments, there are no specific restrictions on the number and arrangement of the shear pins 6 and the structure of the guiding short section 2. In this embodiment, after the pulling pipe 1 is withdrawn from the soluble variable-diameter fracturing plugging tool and then withdrawn from the shaft, the plugging ball 8 can be pushed into the wellhead from the wellhead. The plugging ball 8 plugs the rear end of the pushing member 4, and can plug the space of the original pulling pipe 1, so that the soluble variable-diameter fracturing plugging tool can achieve the effect of sealing and plugging as a whole. In other embodiments, other plugging tools can also be used, and there are no restrictions on this.

[0092] In a specific embodiment, a plurality of first-stage variable-diameter structures 31 are provided between the pushing member 4 and the second-stage variable-diameter structure 32. In a state where two adjacent first-stage variable-diameter structures 31 move relative to each other, the first-stage variable-diameter structure 31 close to the guiding short section 2 can move along the radial direction D of the pulling pipe 1.

[0093] By providing a plurality of first-stage variable-diameter structures 31, the variable-diameter ability of the soluble variable-diameter fracturing plugging tool can be further expanded to plug damaged casings 7 with a larger diameter.

[0094] Specifically, in an embodiment, there are two first-stage variable-diameter structures 31. The first-stage variable-diameter structure 31 close to the second-stage variable-diameter structure 32 is the first variable-diameter member, and the first-stage variable-diameter structure 31 close to the pushing member 4 is the second variable-diameter member. The front end of the first variable-diameter member is inserted between the second-stage variable-diameter structure 32 and the pulling pipe 1, the front end of the second variable-diameter member is inserted between the first variable-diameter member and the pulling pipe 1, and the front end of the pushing member 4 is inserted between the second variable-diameter member and the pulling pipe 1. Among them, in a state where the pushing member 4 drives the first variable-diameter member and the second variable-diameter member to move towards the guiding short section 2, the second-stage variable-diameter structure 32 can expand along the radial direction D of the pulling pipe 1; in a state where the pushing member 4 and the second variable-diameter member move relative to the first variable-diameter member, the first variable-diameter member can expand along the radial direction D of the pulling pipe 1; in a state where the pushing member 4 moves relative to the second variable-diameter member, the second variable-diameter member can expand along the radial direction D of the pulling pipe 1.

[0095] In this application, at least some components of the soluble variable-diameter fracturing plugging tool are made of soluble materials. In a specific embodiment, the pushing member 4, the first-stage variable-diameter structure 31 (including the connecting portion 311 and the diameter-expanding portion 312 in an embodiment), the locking ball 3141, the second-stage variable-diameter structure 32 (including the variable-diameter slip 322 and the sealing body 321 in an embodiment), and the guiding short section 2 are made of soluble materials. Thus, after the fracturing process is completed, the soluble variable-diameter fracturing plugging tool can be dissolved in the casing 7 by pickling.

[0096] In the embodiments of the present application, the dissolvable material may include dissolvable metals, dissolvable rubbers, etc. In practical applications, the corresponding dissolvable material can be selected according to the dissolution rate, the required material strength, etc. In some embodiments, the pusher 4, the guiding short joint 2, and the first-stage diameter-changing structure 31 (including a connecting portion 311 and a diameter-expanding portion 312 in some embodiments) are made of dissolvable metal materials, and the locking balls 3141 and the second-stage diameter-changing structure 32 (including a diameter-changing slip 322 and a sealing body 321 in some embodiments) are made of dissolvable rubber materials, but are not limited thereto. Referring to the related art, the connecting portion 311 and the diameter-expanding portion 312 can also be made of dissolvable rubber materials, and other components of the dissolvable diameter-changing fracturing plugging tool can also be made of dissolvable rubber materials, etc.

[0097] In some embodiments, the dissolvable material includes: an active metal selected from aluminum, calcium, and magnesium; and alloying elements, where the alloying elements include one of lithium, gallium, indium, zinc, bismuth, aluminum in the case where aluminum is not an active metal, calcium in the case where calcium is not an active metal, and magnesium in the case where magnesium is not an active metal. In addition, the dissolvable material further includes one of reinforcing fibers and microparticles.

[0098] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A soluble variable-diameter fracturing plugging tool, Characterized in that, Comprising: A pulling pipe, with a guiding short section formed at its end; A pushing member, sleeved on the pulling pipe; A variable-diameter mechanism, sleeved on the pulling pipe, the variable-diameter mechanism having a first-stage variable-diameter structure and a second-stage variable-diameter structure arranged in sequence along the axial direction of the pulling pipe, the front end of the pushing member being inserted between the first-stage variable-diameter structure and the pulling pipe, and the front end of the first-stage variable-diameter structure being inserted between the second-stage variable-diameter structure and the pulling pipe; Wherein, in a state where the pushing member drives the first-stage variable-diameter structure to move towards the guiding short section, the second-stage variable-diameter structure can be expanded and arranged along the radial direction of the pulling pipe; in a state where the pushing member moves relative to the first-stage variable-diameter structure, the first-stage variable-diameter structure can be expanded and arranged along the radial direction of the pulling pipe.

2. The soluble variable-diameter fracturing plugging tool according to claim 1, Characterized in that, The first-stage variable-diameter structure has a connected connecting part and an expanding part, the connecting part being sleeved on the front end of the pushing member, and the expanding part having a plurality of slotted bodies arranged at intervals along its circumferential direction, with slits formed between two adjacent slotted bodies.

3. The soluble variable-diameter fracturing plugging tool according to claim 2, Characterized in that, The connecting part is connected to the front end of the pushing member through a first-stage locking mechanism, the first-stage locking mechanism including a locking ball and a first-stage locking groove, the first-stage locking groove being opened on the circumferential wall of the front end of the pushing member, the connecting part being provided with a radial through-hole, and the locking ball being located in the radial through-hole and clamped in the first-stage locking groove.

4. The soluble variable-diameter fracturing plugging tool according to claim 3, Characterized in that, An adjusting member and an elastic member are provided in the radial through-hole, and the elastic member is clamped between the locking ball and the adjusting member.

5. The soluble variable-diameter fracturing plugging tool according to claim 3, Characterized in that, A second-stage locking groove is provided on the pushing member, and in a state where the first-stage locking mechanism is unlocked and the front end of the pushing member abuts against the guiding short section, the locking ball can be clamped in the second-stage locking groove.

6. The soluble variable-diameter fracturing plugging tool according to any one of claims 2 to 5, Characterized in that, The second-stage variable-diameter structure has a connected sealing body and a plurality of variable-diameter slips arranged along the circumferential direction of the pulling pipe, the sealing body being hermetically sleeved on the outside of the first-stage variable-diameter structure.

7. The soluble variable-diameter fracturing plugging tool according to claim 6, Characterized in that, The outer diameter of the first-stage variable-diameter structure gradually decreases in a direction close to the guiding short section; an axial guiding structure is provided between the second-stage variable-diameter structure and the first-stage variable-diameter structure, and the second-stage variable-diameter structure is slidably arranged on the first-stage variable-diameter structure through the axial guiding structure.

8. The soluble variable-diameter fracturing plugging tool according to claim 7, Characterized in that, The axial guiding structure includes an axially guiding rib and an axially guiding groove that are mutually clamped; Wherein, the axial guiding rib is arranged on the inner wall of the variable-diameter slip of the secondary variable-diameter structure, and the axial guiding groove is opened on the outer wall of the diameter-expanding part of the primary variable-diameter structure; or, the axial guiding rib is arranged on the outer wall of the diameter-expanding part of the primary variable-diameter structure, and the axial guiding groove is opened on the inner wall of the variable-diameter slip of the secondary variable-diameter structure.

9. The soluble variable-diameter fracturing plugging tool according to claim 6, characterized in that a radial guiding structure is provided between the secondary variable-diameter structure and the guiding short section, and the secondary variable-diameter structure can be slidably arranged along the radial direction of the guiding short section through the radial guiding structure.

10. The soluble variable-diameter fracturing plugging tool according to claim 9, characterized in that the radial guiding structure includes a radially guiding rib and a radially guiding groove that are engaged with each other; wherein, the radially guiding rib is arranged at the front end of the variable-diameter slip of the secondary variable-diameter structure, and the radially guiding groove is opened at the rear end of the guiding short section; or, the radially guiding rib is arranged at the rear end of the guiding short section, and the radially guiding groove is opened at the front end of the variable-diameter slip of the secondary variable-diameter structure.

11. The soluble variable-diameter fracturing plugging tool according to claim 1, characterized in that at least one shear pin is connected between the guiding short section and the pulling pipe, and in a state where at least one of the shear pins is cut off, the guiding short section is separated from the end of the pulling pipe.

12. The soluble variable-diameter fracturing plugging tool according to claim 1, characterized in that a plurality of the primary variable-diameter structures are provided between the pushing member and the secondary variable-diameter structure, and in a state where two adjacent primary variable-diameter structures move relative to each other, the primary variable-diameter structure close to the guiding short section can be movably arranged along the radial direction of the pulling pipe.

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