Tailpipe plug and production tubing

Abstract

This invention relates to the field of unconventional oil and gas reservoir development, and particularly to a tailpipe plugger and production tubing, aiming to solve the technical problem of premature dissolution of the plug core in existing tailpipe pluggers. The tailpipe plugger includes a body, a soluble plug core, an outer sleeve, and a limiting member. The body is a cylindrical shape with open ends and a pressure-transmitting hole penetrating its sidewalls. Multiple soluble plug cores are arranged axially and spaced within the body. The outer sleeve is fitted onto the body and fixedly connected to it via a shearing member, forming an annular cavity communicating with the pressure-transmitting hole between the outer sleeve and the body. The limiting member is located on the body and connected to the soluble plug cores, and can release the locking of the soluble plug cores when the outer sleeve slides axially along the body. This tailpipe plugger enables the series connection of multiple soluble plug cores; even if one core fails, the others can still seal, effectively ensuring the safe insertion of the production tubing. Furthermore, a single pressurization can remove all soluble plug cores, simplifying operation.

Description

Technical Field

[0001] This invention relates to the field of unconventional oil and gas reservoir development, and particularly to a tailpipe plug and production tubing. Background Technology

[0002] After large-scale fracturing operations using casing, to avoid reservoir contamination, production tubing is often run under pressure. During this process, a tailpipe plug is connected to the bottom of the tubing to isolate the reservoir. Once the production tubing is in place, pressure is applied to the tubing to remove the core from the tailpipe plug. Once the core is removed, the reservoir is connected and production can begin. To ensure no residue remains in the wellbore, the core is often made of a soluble material. However, during tubing installation, the core can slowly dissolve, leading to seal failure. Once the core seal fails, complex accidents such as blowouts can occur. Summary of the Invention

[0003] The purpose of this invention is to provide a tailpipe plug and a production tubing to solve the technical problem of premature dissolution of the core in existing tailpipe plugs.

[0004] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0005] In a first aspect, the present invention provides a tailpipe plug, comprising: a body, a soluble plug core, an outer sleeve, and a limiting member;

[0006] The main body is a cylindrical shape with open ends and is provided with pressure transmission holes that penetrate its side walls;

[0007] Multiple soluble plugs are provided and are spaced apart along the axial direction of the body, and are located between one end of the body and the pressure transmission hole.

[0008] The outer sleeve is fitted onto the body and is fixedly connected to the body by a shearing member, and an annular cavity communicating with the pressure transmission hole is formed between the outer sleeve and the body.

[0009] The limiting member is disposed on the body and connected to the soluble plug core to lock the soluble plug core to the body. The limiting member can release the locking of the soluble plug core when the outer sleeve slides along the axial direction of the body.

[0010] Furthermore, the body is also provided with a positioning hole penetrating its side wall;

[0011] The limiting member includes a locking block, which passes through the positioning hole and is inserted into the soluble plug core. The end of the locking block away from the soluble plug core abuts against the outer sleeve.

[0012] The inner wall of the outer sleeve is provided with a relief groove, which is configured to accommodate the locking block when the outer sleeve is sliding.

[0013] Furthermore, the limiting member is provided in multiple sets, and each set of the limiting member corresponds one-to-one with the soluble plug core;

[0014] In each set of limiting members, multiple locking blocks are distributed at circumferential intervals along the soluble plug core.

[0015] Furthermore, the soluble plugging core is fitted with a sealing ring, which abuts against the inner wall of the body.

[0016] Furthermore, each of the soluble plugging cores is provided with two sealing rings, which are distributed on both sides of the locking block.

[0017] Furthermore, the locking block is used to chamfer the end that is inserted into the soluble plug core;

[0018] The soluble plug core is provided with a plug groove that is adapted to the locking block.

[0019] Furthermore, the shearing element includes a plurality of shear studs, which are distributed at intervals along the circumference of the outer sleeve.

[0020] Furthermore, the tailpipe plug also includes a locking element;

[0021] The locking element is disposed on the body and is capable of preventing the outer sleeve from sliding after the outer sleeve slides to the point where the limiting element releases the lock on the soluble plug.

[0022] Furthermore, along the circumference of the body, the outer wall of the body is provided with a fixing groove;

[0023] The locking element includes a C-shaped locking ring, which is disposed in the fixing groove and abuts against the inner wall of the outer sleeve;

[0024] The inner wall of the outer sleeve is provided with a locking groove, which is configured to accommodate the C-shaped locking ring when the outer sleeve is sliding.

[0025] In summary, the technical effects achieved by the tailpipe plug provided by this invention are as follows:

[0026] The tailpipe plug provided by the present invention includes a body, a soluble plug core, an outer sleeve, and a limiting member; the body is a cylindrical shape with open ends and has a pressure transmission hole penetrating its side wall; multiple soluble plug cores are provided and are spaced apart along the axial direction of the body, and are located between one end of the body and the pressure transmission hole; the outer sleeve is sleeved on the body and is fixedly connected to the body by a shearing member, and an annular cavity communicating with the pressure transmission hole is formed between the outer sleeve and the body; the limiting member is provided on the body and connected to the soluble plug core to lock the soluble plug core in the body, and the limiting member can release the locking of the soluble plug core when the outer sleeve slides along the axial direction of the body.

[0027] In this tailpipe plugger, multiple soluble plugs are installed inside the main body to block the channels within the main body. Each soluble plug is independent of the others; if one fails, the others can still function. The soluble plugs do not affect each other, ensuring the safety and reliability of the tailpipe plugger during pressurized production of the tubing. When pressure is applied to the main body, the pressure enters the annular cavity through the pressure transmission hole. Under this pressure, the outer sleeve slides relative to the main body, thereby cutting off the shearing component. As a result, the limiting component releases the locking of the soluble plug, and under the pressure, the soluble plug is knocked off.

[0028] As can be seen, compared with the existing technology, this tailpipe plugger realizes the series connection of multiple soluble plugs, each of which works independently. If one plug fails, the others can still seal, effectively ensuring the safe insertion of the production tubing; and all soluble plugs can be removed with one pressurization, making the operation simple.

[0029] Secondly, the present invention provides a production string including an oil pipe and the tailpipe plug described above, wherein the oil pipe is connected to the body.

[0030] The beneficial effects of the production tubing provided by this invention are as follows:

[0031] The production tubing provided by this invention includes a tailpipe plugger. Therefore, the technical advantages and effects achieved by this production tubing also include the technical advantages and effects achieved by the aforementioned tailpipe plugger, which will not be repeated here. Attached Figure Description

[0032] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] Figure 1 A cross-sectional view of the tailpipe plug provided in an embodiment of the present invention;

[0034] Figure 2 and Figure 3 A cross-sectional view of the tailpipe plug provided in an embodiment of the present invention after one of the soluble plug cores has failed;

[0035] Figure 4 This is a cross-sectional view of the tailpipe plug provided in an embodiment of the present invention after the soluble plug core has been removed.

[0036] Icons: 100 - Body; 110 - Pressure transmission hole; 120 - Positioning hole;

[0037] 200-Soluble plugging core;

[0038] 300 - Outer sleeve; 310 - Clearance groove; 320 - Locking groove;

[0039] 400 - Limiting element; 500 - Shearing element; 600 - Ring cavity; 700 - Sealing ring; 800 - Locking element. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0042] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0043] After large-scale fracturing operations using casing, to avoid reservoir contamination, production tubing is often run under pressure. During this process, a tailpipe plug is connected to the bottom of the tubing to isolate the reservoir. Once the production tubing is in place, pressure is applied to the tubing to remove the core from the tailpipe plug. Once the core is removed, the reservoir is connected and production can begin. To ensure no residue remains in the wellbore, the core is often made of a soluble material. However, during tubing installation, the core can slowly dissolve, leading to seal failure. Once the core seal fails, complex accidents such as blowouts can occur.

[0044] In view of this, the present invention provides a tailpipe plugger, including a body 100, a soluble plug core 200, an outer sleeve 300, and a limiting member 400; the body 100 is a cylindrical shape with open ends and is provided with a pressure transmission hole 110 penetrating its side wall; multiple soluble plug cores 200 are provided and are spaced apart along the axial direction of the body 100 inside the body 100, and are located between one end of the body 100 and the pressure transmission hole 110; the outer sleeve 300 is sleeved on the body 100 and is fixedly connected to the body 100 by a shearing member 500, and an annular cavity 600 communicating with the pressure transmission hole 110 is formed between the outer sleeve 300 and the body 100; the limiting member 400 is provided on the body 100 and connected to the soluble plug core 200 to lock the soluble plug core 200 in the body 100, and the limiting member 400 can release the locking of the soluble plug core 200 when the outer sleeve 300 slides along the axial direction of the body 100.

[0045] In this tailpipe plugger, the main body 100 is equipped with multiple soluble plugs 200 to block the channels inside the main body 100. Each soluble plug 200 is independent of the others. If one fails, the others can still work. The soluble plugs 200 do not affect each other, ensuring the safety and reliability of the tailpipe plugger during the production of the tubing under pressure. When pressure is applied to the main body 100, the pressure will enter the annular cavity 600 through the pressure transmission hole 110. Under the action of this pressure, the outer sleeve 300 will slide relative to the main body 100, thereby cutting off the shearing element 500. As a result, the limiting element 400 will release the locking of the soluble plug 200. Under the action of pressure, the soluble plug 200 is knocked off.

[0046] As can be seen, compared with the existing technology, this tailpipe plugger realizes the series connection of multiple soluble plugs 200. Each soluble plug 200 works independently. After one plug fails, the other plugs can still seal, effectively ensuring the safe insertion of the production tubing. Moreover, all soluble plugs 200 can be removed by one pressurization, making the operation simple.

[0047] It should be noted here that the shearing element 500 is a shear pin, and multiple shear pins are distributed at intervals along the circumference of the outer sleeve 300. When the pressure is transmitted to the annular cavity 600, the shear pins are sheared, and the outer sleeve 300 slides.

[0048] The following combination Figures 1 to 4 The structure and shape of the tailpipe plug provided in this embodiment are described in detail below:

[0049] Further reference Figures 1 to 4The main body 100 is also provided with a positioning hole 120 penetrating its side wall; the limiting member 400 includes a locking block, which is inserted into the positioning hole 120 and engaged with the soluble plug core 200, and the end of the locking block away from the soluble plug core 200 abuts against the outer sleeve 300; the inner wall of the outer sleeve 300 is provided with a relief groove 310, which is configured to accommodate the locking block when the outer sleeve 300 is sliding.

[0050] Specifically, the limiting member 400 is provided in multiple sets, and each set of limiting members 400 corresponds one-to-one with the soluble plug core 200; in each set of limiting members 400, multiple locking blocks are distributed at intervals along the circumference of the soluble plug core 200; each soluble plug core 200 is fitted with two sealing rings 700, which are distributed on both sides of the locking block; the locking block has a chamfered end for inserting into the soluble plug core 200, and the soluble plug core 200 is provided with an insertion groove adapted to the locking block.

[0051] In the above design, the two sealing rings 700 ensure the sealing between the soluble plug 200 and the body 100, while preventing fluid from entering the insertion groove and affecting the downward sliding of the soluble plug 200. The cooperation between the soluble plug 200 and the locking block allows the locking block to easily move outward to the clearance groove 310 when the soluble plug 200 applies pressure, thus enabling the soluble plug 200 to be easily removed. (Reference) Figure 1 When pressure is applied into the tubing string, the pressure is transmitted to the outer sleeve 300 through the pressure transmission hole 110. The pressure pushes the outer sleeve 300 downward. During its downward movement, the outer sleeve 300 first shears off the shear pin. The clearance groove 310 on the outer sleeve 300 moves to the locking block, allowing the locking block to move freely. At this time, the locking block loses the support of the outer sleeve 300. When the pressure inside the tubing string pushes the soluble plug 200, the soluble plug 200 squeezes the locking block, causing the locking block to move outward. At this time, the soluble plug 200 loses the fixation of the locking block and falls into the well. Figure 4 As shown.

[0052] Further reference Figure 1 The tailpipe plug also includes a locking element 800; the locking element 800 is disposed on the body 100 and can prevent the outer sleeve 300 from sliding after the outer sleeve 300 slides to the limit element 400 to release the lock on the soluble plug core 200.

[0053] Specifically, along the circumference of the body 100, the outer wall of the body 100 is provided with a fixing groove; the locking member 800 includes a C-shaped locking ring, which is disposed in the fixing groove and abuts against the inner wall of the outer sleeve 300; the inner wall of the outer sleeve 300 is provided with a locking groove 320, which is configured to accommodate the C-shaped locking ring when the outer sleeve 300 is sliding.

[0054] After the outer sleeve 300 cuts the shear pin under pressure, it slides downward. When it slides to the locking groove 320 and is aligned with the C-shaped locking ring, the C-shaped locking ring returns to its original shape and is embedded in the locking groove 320, thereby locking the outer sleeve 300 onto the body 100 and preventing it from sliding again.

[0055] The working process of the tailpipe plug provided in this embodiment is as follows:

[0056] When running tubing under pressure, the tailpipe plug (taking two soluble plug cores 200 connected in series as an example) is installed at the bottom of the tubing string. After reaching the designed position, pressure is applied into the tubing string. The pressure is transmitted to the outer sleeve 300 through the pressure transmission hole 110. The pressure pushes the outer sleeve 300 downward. During its downward movement, the outer sleeve 300 first shears off the shear pin. When the locking groove 320 on the outer sleeve 300 moves to the C-type locking ring, the C-type locking ring returns to its original position, locking the outer sleeve 300 onto the body 100. When the outer sleeve 300 is locked onto the body 100, the other two clearance grooves 310 on the outer sleeve 300 move to the two locking blocks respectively, allowing the locking blocks to travel. At this time, the two locking blocks lose the support of the outer sleeve 300. When the pressure inside the tubing string pushes the soluble plug core 200, the soluble plug core 200 squeezes the locking blocks outward, losing the fixation of the locking blocks, and thus falls into the well. Figure 4 As shown.

[0057] This invention also provides a production string, including an oil pipe and a tailpipe plug, with the oil pipe connected to the body 100. After the soluble plug 200 is removed, the inner cavity of the body 100 has a multi-beveled chamfered structure, which facilitates the removal of testing tools. Furthermore, since the production string provided by this invention includes a tailpipe plug, the technical advantages and effects achieved by this production string also include those achieved by the aforementioned tailpipe plug, which will not be elaborated further here.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tailpipe plug, characterized in that, include: Body (100), soluble plug (200), outer sleeve (300) and limiting component (400); The body (100) is a cylindrical shape with open ends and is provided with a pressure transmission hole (110) penetrating its side wall; Multiple soluble plugs (200) are provided and are spaced apart along the axial direction of the body (100) within the body (100), and are located between one end of the body (100) and the pressure transmission hole (110). The outer sleeve (300) is fitted onto the body (100) and is fixedly connected to the body (100) by a shearing member (500), and an annular cavity (600) is formed between the outer sleeve (300) and the body (100) that communicates with the pressure transmission hole (110); The limiting member (400) is disposed on the body (100) and connected to the soluble plug (200) to lock the soluble plug (200) to the body (100). The limiting member (400) can release the locking of the soluble plug (200) when the outer sleeve (300) slides along the axial direction of the body (100).

2. The tailpipe plug according to claim 1, characterized in that, The body (100) is also provided with a positioning hole (120) penetrating its side wall; The limiting member (400) includes a locking block, which passes through the positioning hole (120) and is inserted into the soluble plug (200). The end of the locking block away from the soluble plug (200) abuts against the outer sleeve (300). The inner wall of the outer sleeve (300) is provided with a relief groove (310), which is configured to accommodate the locking block when the outer sleeve (300) is sliding.

3. The tailpipe plug according to claim 2, characterized in that, The limiting member (400) is provided in multiple sets, and each set of the limiting member (400) corresponds one-to-one with the soluble plug (200); In each set of limiting members (400), a plurality of locking blocks are distributed circumferentially at intervals along the soluble plug core (200).

4. The tailpipe plug according to claim 3, characterized in that, The soluble plug (200) is fitted with a sealing ring (700), which abuts against the inner wall of the body (100).

5. The tailpipe plug according to claim 4, characterized in that, Each of the soluble plug cores (200) is fitted with two sealing rings (700), which are distributed on both sides of the locking block.

6. The tailpipe plug according to claim 2, characterized in that, The locking block is used for chamfering the end of the plug that is inserted into the soluble plug (200); The soluble plug (200) is provided with a plug groove that is adapted to the locking block.

7. The tailpipe plug according to claim 1, characterized in that, The shearing element (500) includes a plurality of shear pins, which are distributed circumferentially along the outer sleeve (300).

8. The tailpipe plug according to any one of claims 1 to 7, characterized in that, The tailpipe plug also includes a locking element (800); The locking member (800) is disposed on the body (100) and is able to prevent the outer sleeve (300) from sliding after the outer sleeve (300) slides to the point where the limiting member (400) releases the lock on the soluble plug (200).

9. The tailpipe plug according to claim 8, characterized in that, Along the circumference of the body (100), the outer wall of the body (100) is provided with a fixing groove; The locking member (800) includes a C-shaped locking ring, which is disposed in the fixing groove and abuts against the inner wall of the outer sleeve (300); The inner wall of the outer sleeve (300) is provided with a locking groove (320), which is configured to accommodate the C-shaped locking ring when the outer sleeve (300) is sliding.

10. A production tubular column, characterized in that, It includes an oil pipe and a tailpipe plug as described in any one of claims 1 to 9, wherein the oil pipe is connected to the body (100).

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