Tail pipe blanking plug and production pipe column

Abstract

The invention relates to the field of unconventional oil and gas reservoir exploitation, in particular to a tail pipe blanking plug and a production pipe column, and aims to solve the technical problem that a core of an existing tail pipe blanking plug is dissolved in advance. The tail pipe blanking plug comprises a body, a soluble plugging core, an outer sleeve and a limiting piece. The body is in a cylinder shape with two open ends and is provided with a pressure transmitting hole penetrating through the side wall of the body. The multiple soluble plugging cores are arranged in the body at intervals in the axial direction of the body. The outer sleeve is arranged on the body in a sleeving mode and fixedly connected with the body through the shearing piece, and an annular cavity communicating with the pressure transmitting hole is formed between the outer sleeve and the body. The limiting piece is arranged on the body and connected with the soluble plugging core, and the limiting piece can unlock the soluble plugging core under the working condition that the outer sleeve slides in the axial direction of the body. According to the tail pipe blanking plug, series connection of a plurality of soluble plugging cores is achieved, after one core fails, other cores can still be sealed, and safe tripping-in of a production pipe column is effectively guaranteed; and all the soluble plugging cores can be removed through one-time pressing, and operation is easy and convenient.

Description

Technical Field

[0001] The invention relates to the field of unconventional oil and gas reservoir exploitation, and in particular to a tail pipe plugger and a production pipe string. Background Art

[0002] After large-scale fracturing construction using casing, in order to avoid reservoir contamination, the production string is often lowered under pressure. During the process of lowering the production string under pressure, a tail pipe plug is connected at the bottom of the tubing to achieve reservoir isolation. After the production string is in place, pressure is applied to the tubing to knock out the core in the tail pipe plug. After the core is knocked out, the reservoir is connected and production can be carried out. In order to ensure that there is no residue in the wellbore, the core is often made of soluble materials. However, during the process of lowering the tubing, the core slowly dissolves, resulting in sealing failure. Once the core seal fails, complex accidents such as blowouts will occur. Summary of the invention

[0003] The object of the present invention is to provide a tail pipe plug and a production pipe column to solve the technical problem of premature dissolution of the core in the existing tail pipe plug.

[0004] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0005] In a first aspect, the present invention provides a tail pipe plug, comprising: a body, a soluble plugging core, an outer sleeve and a stopper;

[0006] The main body is in the shape of a cylinder with two ends open, and is provided with a pressure transmission hole penetrating through its side wall;

[0007] The soluble plugging core is provided in plurality and is arranged in the body at intervals along the axial direction of the body and between one end of the body and the pressure transmission hole;

[0008] The outer sleeve is sleeved on the body and fixedly connected to the body through a shearing piece, and an annular cavity communicating with the pressure transmission hole is formed between the outer sleeve and the body;

[0009] The limiting member is arranged on the main body and connected to the soluble plugging core to lock the soluble plugging core to the main body. The limiting member can release the lock on the soluble plugging core when the outer sleeve slides axially along the main body.

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

[0011] The limiting member comprises a locking block, which is inserted into the positioning hole and plugged into the soluble plugging core, and one end of the locking block away from the soluble plugging core abuts against the outer sleeve;

[0012] An escape groove is provided on the inner wall of the outer sleeve, and the escape groove is configured to accommodate the locking block when the outer sleeve is in a sliding condition.

[0013] Furthermore, the position limiting members are provided in a plurality of groups, and the plurality of groups of the position limiting members correspond one to one with the soluble plugging core;

[0014] In each group of the limiting members, a plurality of the locking blocks are distributed at intervals along the circumference of the soluble plugging core.

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

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

[0017] Furthermore, the locking block is used to chamfer the end portion of the soluble plug;

[0018] The soluble plugging core is provided with an inserting groove matched with the locking block.

[0019] Furthermore, the shearing piece includes a plurality of shearing pins, and the plurality of shearing pins are distributed at intervals along the circumference of the outer sleeve.

[0020] Furthermore, the tail pipe plugger also includes a locking piece;

[0021] The locking member is disposed on the body, and can prevent the outer sleeve from sliding after the outer sleeve slides to the stop member to release the lock on the soluble plugging core.

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

[0023] The locking member comprises a C-shaped locking ring, which is arranged 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, and the locking groove is configured to accommodate the C-shaped locking ring when the outer sleeve is in a sliding condition.

[0025] In summary, the technical effects that can be achieved by the tail pipe plug provided by the present invention are:

[0026] The tail pipe plugger provided by the present invention includes a main body, a soluble plugging core, an outer sleeve and a limit piece; the main body is in a cylindrical shape with both ends open, and is provided with a pressure transmission hole penetrating its side wall; a plurality of soluble plugging cores are provided, and are arranged in the main body at intervals along the axial direction of the main body, and are located between one end of the main body and the pressure transmission hole; the outer sleeve is sleeved on the main body, and is fixedly connected to the main body by a shear piece, and an annular cavity connected to the pressure transmission hole is formed between the outer sleeve and the main body; the limit piece is arranged on the main body, and is connected to the soluble plugging core to lock the soluble plugging core to the main body, and the limit piece can release the lock of the soluble plugging core when the outer sleeve slides axially along the main body.

[0027] In the tail pipe plugger, a plurality of soluble plugging cores are arranged in the main body to realize the plugging of the channels in the main body, and each soluble plugging core is independent of each other. If one soluble plugging core fails, the other soluble plugging cores can still work, and the soluble plugging cores do not affect each other, thereby ensuring the safety and reliability of the tail pipe plugger during the production of the tubing string under pressure. When pressure is applied to the main body, the pressure will enter the annular cavity through the pressure transmission hole. Under the action of the pressure, the outer sleeve will slide relative to the main body, thereby cutting off the shear piece. In this way, the limit piece will release the lock on the soluble plugging core, and the soluble plugging core will be knocked off under the action of pressure.

[0028] It can be seen that compared with the existing technology, the tail pipe plugger realizes the series connection of multiple soluble plugging cores, each soluble plugging core works independently of each other, after one core fails, the other cores can still be sealed, effectively ensuring the safe lowering of the production tubing; and all soluble plugging cores can be knocked out by one pressure, which is easy to operate.

[0029] In a second aspect, the present invention provides a production tubing string, comprising an oil pipe and the above-mentioned tail pipe plug, wherein the oil pipe is connected to the body.

[0030] The beneficial effects of a production string provided by the present invention are:

[0031] The production tubing string provided by the present invention includes a tail pipe plug. Therefore, the technical advantages and effects achieved by the production tubing string also include the technical advantages and effects achieved by the above-mentioned tail pipe plug, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 A cross-sectional view of a tail pipe plug provided by an embodiment of the present invention;

[0034] Figure 2 and Figure 3 A cross-sectional view of a tail pipe plug provided by an embodiment of the present invention after one of the soluble plugging cores has failed;

[0035] Figure 4 A cross-sectional view of the tail pipe plug provided by an embodiment of the present invention after the soluble plugging core is removed.

[0036] Icon: 100-main body; 110-pressure transmission hole; 120-positioning hole;

[0037] 200-soluble plugging core;

[0038] 300-outer sleeve; 310-avoidance groove; 320-locking groove;

[0039] 400-limiting piece; 500-shearing piece; 600-ring cavity; 700-sealing ring; 800-locking piece. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0043] After large-scale fracturing construction using casing, in order to avoid reservoir contamination, the production string is often lowered under pressure. During the process of lowering the production string under pressure, a tail pipe plug is connected at the bottom of the tubing to achieve reservoir isolation. After the production string is in place, pressure is applied to the tubing to knock out the core in the tail pipe plug. After the core is knocked out, the reservoir is connected and production can be carried out. In order to ensure that there is no residue in the wellbore, the core is often made of soluble materials. However, during the process of lowering the tubing, the core slowly dissolves, resulting in sealing failure. Once the core seal fails, complex accidents such as blowouts will occur.

[0044] In view of this, the present invention provides a tail pipe plugger, including a main body 100, a soluble plugging core 200, an outer sleeve 300 and a limiter 400; the main body 100 is in a cylindrical shape with both ends open, and is provided with a pressure transmission hole 110 running through its side wall; a plurality of soluble plugging cores 200 are provided, and are arranged in the main body 100 at intervals along the axial direction of the main body 100, and are located between one end of the main body 100 and the pressure transmission hole 110; the outer sleeve 300 is sleeved on the main body 100, and is fixedly connected to the main body 100 through a shear piece 500, and an annular cavity 600 connected to the pressure transmission hole 110 is formed between the outer sleeve 300 and the main body 100; the limiter 400 is arranged on the main body 100, and is connected to the soluble plugging core 200 to lock the soluble plugging core 200 to the main body 100, and the limiter 400 can release the lock on the soluble plugging core 200 when the outer sleeve 300 slides axially along the main body 100.

[0045] In the tail pipe plugger, a plurality of soluble plugging cores 200 are arranged in the main body 100 to realize the plugging of the channel in the main body 100, and each soluble plugging core 200 is independent of each other. If one fails, the other soluble plugging cores 200 can still work, and the soluble plugging cores 200 do not affect each other, thereby ensuring the safety and reliability of the tail pipe plugger during the production of the tubing string 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, and under the action of the pressure, the outer sleeve 300 will slide relative to the main body 100, thereby cutting off the shear piece 500, and in this way, the limit piece 400 will release the lock on the soluble plugging core 200, and under the action of pressure, the soluble plugging core 200 will be knocked off.

[0046] It can be seen that compared with the prior art, the tail pipe plugger realizes the series connection of multiple soluble plugging cores 200, each soluble plugging core 200 works independently of each other, after one core fails, the other cores can still be sealed, effectively ensuring the safe lowering of the production tubing; and all soluble plugging cores 200 can be knocked out by one pressure, which is easy to operate.

[0047] It should be noted that the shearing member 500 is a shearing nail, and a plurality of shearing nails are distributed at intervals along the circumference of the outer sleeve 300. When the pressure is transmitted to the annular cavity 600, the shearing nails are sheared and the outer sleeve 300 slides.

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

[0049] For further reference, Figures 1 to 4The main body 100 is also provided with a positioning hole 120 passing through its side wall; the limiting member 400 includes a locking block, which is passed through the positioning hole 120 and is plugged into and matched with the soluble plugging core 200, and the end of the locking block away from the soluble plugging core 200 abuts against the outer sleeve 300; the inner wall of the outer sleeve 300 is provided with an avoidance groove 310, and the avoidance groove 310 is configured to accommodate the locking block when the outer sleeve 300 is in a sliding condition.

[0050] Specifically, there are multiple groups of limit members 400, and the multiple groups of limit members 400 correspond to the soluble plugging core 200 one by one; in each group of limit members 400, multiple locking blocks are distributed at intervals along the circumference of the soluble plugging core 200; each soluble plugging core 200 is provided with two sealing rings 700, and the two sealing rings 700 are distributed on both sides of the locking block; the locking block is used for the end chamfer of the soluble plugging core 200, and the soluble plugging core 200 is provided with a plug-in 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, and prevent the fluid from entering the plug slot and affecting the downward sliding of the soluble plug 200; the cooperation between the soluble plug 200 and the locking block makes it easy for the locking block to move outward to the avoidance groove 310 when the soluble plug 200 applies pressure to the locking block, so that the soluble plug 200 can be removed smoothly. Figure 1 When the pressure is applied to the pipe column, the pressure is transmitted to the outer sleeve 300 through the pressure transmission hole 110, and the pressure pushes the outer sleeve 300 to move downward. During the downward movement, the outer sleeve 300 first cuts off the shear nails, and the avoidance groove 310 on the outer sleeve 300 moves to the locking block, giving up the travel of the locking block. At this time, the locking block loses the support of the outer sleeve 300; when the pressure in the pipe column pushes the soluble plugging core 200, the soluble plugging core 200 squeezes the locking block, causing the locking block to move outward. At this time, the soluble plugging core 200 loses the fixation of the locking block and falls into the well. Figure 4 shown.

[0052] For further reference, Figure 1 The tail pipe plugger also includes a locking member 800 ; the locking member 800 is disposed on the body 100 , and can prevent the outer sleeve 300 from sliding after the outer sleeve 300 slides to the stop member 400 to release the lock on the soluble plugging core 200 .

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

[0054] After the outer sleeve 300 cuts off the shear nails under the action of pressure, it slides downward. When it slides to the locking groove 320 and is opposite to the C-shaped locking ring, the C-shaped locking ring returns to its original state and is embedded in the locking groove 320, thereby locking the outer sleeve 300 to the main body 100 to prevent it from sliding further.

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

[0056] When the oil pipe is lowered under pressure, the tail pipe plugger (taking two soluble plugging cores 200 connected in series as an example) is installed at the lowest end of the pipe string. After it reaches the designed position, pressure is applied to the pipe string, and the pressure is transmitted to the outer sleeve 300 through the pressure transmission hole 110. The pressure pushes the outer sleeve 300 to move downward. The outer sleeve 300 first cuts the shear nails during the downward movement. 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 state and locks the outer sleeve 300 to the body 100; when the outer sleeve 300 is locked to the body 100, the other two avoidance grooves 310 on the outer sleeve 300 move to the two locking blocks respectively to give way to the travel of the locking blocks. At this time, the two locking blocks lose the support of the outer sleeve 300; when the pressure in the pipe string pushes the soluble plugging core 200, the soluble plugging core 200 squeezes the locking block to move outward, loses the fixation of the locking block, and thus falls into the well, as shown in FIG. Figure 4 shown.

[0057] The present invention also provides a production string, including an oil pipe and a tail pipe plugger, wherein the oil pipe is connected to a body 100. After the soluble plugging core 200 is removed, the inner cavity of the body 100 has a multi-bevel chamfer structure, which is beneficial for the lifting and lowering of the test tool. In addition, since the production string provided by the present invention includes a tail pipe plugger, the technical advantages and effects achieved by the production string also include the technical advantages and effects achieved by the above-mentioned tail pipe plugger, which will not be repeated here.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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 tail pipe plug, characterized in that: include: A body (100), a soluble plugging core (200), an outer sleeve (300) and a stopper (400); The main body (100) is in the shape of a cylinder with both ends open, and is provided with a pressure transmission hole (110) penetrating its side wall; The soluble plugging core (200) is provided in plurality and is arranged in the body (100) at intervals along the axial direction of the body (100) and is 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 fixedly connected to the body (100) via a shearing piece (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 arranged on the main body (100) and is connected to the soluble plugging core (200) so as to lock the soluble plugging core (200) to the main body (100). The limiting member (400) can release the lock on the soluble plugging core (200) when the outer sleeve (300) slides axially along the main body (100).

2. The tail pipe plug according to claim 1, characterized in that: The body (100) is also provided with a positioning hole (120) penetrating through its side wall; The limiting member (400) comprises a locking block, which is inserted into the positioning hole (120) and is plugged into the soluble plugging core (200), and one end of the locking block away from the soluble plugging core (200) is in contact with the outer sleeve (300); An escape groove (310) is provided on the inner wall of the outer sleeve (300), and the escape groove (310) is configured to accommodate the locking block when the outer sleeve (300) is in a sliding condition.

3. The tail pipe plug according to claim 2, characterized in that: The limiting members (400) are provided in multiple groups, and the multiple groups of limiting members (400) correspond to the soluble plugging cores (200) one by one; In each group of the limiting members (400), a plurality of the locking blocks are distributed at intervals along the circumference of the soluble plugging core (200).

4. The tail pipe plug according to claim 3, characterized in that: The outer shell of the soluble plugging core (200) is provided with a sealing ring (700), and the sealing ring (700) abuts against the inner wall of the body (100).

5. The tail pipe plug according to claim 4, characterized in that: Each of the soluble plugging cores (200) is provided with two sealing rings (700) on its outer sleeve, and the two sealing rings (700) are distributed on both sides of the locking block.

6. The tail pipe plug according to claim 2, characterized in that: The locking block is used to chamfer the end portion of the soluble plugging core (200) for insertion; The soluble plugging core (200) is provided with an inserting groove adapted to the locking block.

7. The tail pipe plug according to claim 1, characterized in that: The shearing piece (500) comprises a plurality of shearing pins, and the plurality of shearing pins are distributed at intervals along the circumference of the outer sleeve (300).

8. The tail pipe plug according to any one of claims 1 to 7, characterized in that: The tail pipe plugger further comprises a locking member (800); The locking member (800) is arranged on the main body (100), and can prevent the outer sleeve (300) from sliding after the outer sleeve (300) slides to the stop member (400) to release the lock on the soluble plugging core (200).

9. The tail pipe plug according to claim 8, characterized in that: A fixing groove is provided on the outer wall of the body (100) along the circumference of the body (100); The locking member (800) comprises a C-shaped locking ring, which is arranged 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), and the locking groove (320) is configured to accommodate the C-shaped locking ring when the outer sleeve (300) is in a sliding condition.

10. A production string, characterized in that: It comprises an oil pipe and the tail pipe plug according to any one of claims 1 to 9, wherein the oil pipe is connected to the body (100).

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