An automatic detection and sealing device for the venting channel of an oil well casing

Abstract

This invention relates to the field of oil production engineering technology, and in particular to an automatic detection and sealing device for the venting channel of an oil well casing. The device includes: a main body; a locking mechanism located near one end of the main body, used to secure the main body within the venting channel of the oil well casing; the main body is hollow inside, with openings at both ends, wherein the portion of the main body near one end is cylindrical, and the portion near the other end is semi-circular; the end of the semi-circular cylinder has an inclined surface at a predetermined angle; an automatic sealing mechanism is installed on the non-arc side of the semi-circular cylinder near the end. This invention solves the problem that existing anti-theft oil switches require the use of tubing and heavy machinery for installation and use, making quick installation or disassembly difficult, resulting in high operating costs and increased labor intensity.

Description

Technical Field

[0001] This invention relates to the field of oil production engineering technology, and in particular to an automatic detection and sealing device for the venting channel of an oil well casing. Background Technology

[0002] The existing casing anti-theft switch is installed between the first and second tubing in the well and can prevent oil theft. However, the installation requires the use of a heavy crane or scaffold to move the tubing string, which is complicated and costly, greatly limiting its application in the field. Summary of the Invention

[0003] This invention proposes an automatic detection and sealing device for the venting channel of an oil well casing, which solves the problem that existing anti-theft switches require the use of tubing and heavy machinery during installation and use, making it difficult to install or disassemble quickly, resulting in high operating costs and increased labor intensity.

[0004] According to one aspect of the present invention, an automatic detection and sealing device for the venting channel of an oil well casing is provided, characterized in that it comprises: a main body;

[0005] A locking mechanism is provided near one end of the main body, and the locking mechanism is used to lock the main body in the oil well casing venting channel;

[0006] The interior of the main body is hollow, with openings at both ends. The part of the main body near one end is cylindrical, and the part of the main body near the other end is semi-circular.

[0007] The end of the semi-circular cylinder of the main body has an inclined surface at a predetermined angle;

[0008] An automatic sealing mechanism is installed on the non-arc side of the semi-circular cylinder of the main body near the end. The automatic sealing mechanism is used to automatically seal the opening at the other end of the main body when the liquid level in the venting channel reaches the other end of the main body, and / or to automatically open the opening at the other end of the main body when the liquid level in the venting channel moves away from the main body.

[0009] Preferably, the locking mechanism includes: a tightening screw, a locking tooth block, and a wrench;

[0010] The main body has a mounting hole near one end, and the expansion screw is fixed in the mounting hole by threaded engagement.

[0011] The portion of the expansion screw tube near one end of the main body has a tapered annular surface;

[0012] On the main body, a through hole is provided at a position corresponding to the conical ring face, and the locking tooth block is installed inside the through hole;

[0013] The internal shape of the tightening screw tube matches the external shape of the wrench.

[0014] Preferably, the body of the locking tooth block is an elliptical cylinder, the outer wall of the locking tooth block has a toothed structure, and the shape of the inner wall of the locking tooth block matches the shape of the conical annular surface of the expansion screw tube.

[0015] Preferably, the blocking mechanism includes: a flap gate and a float;

[0016] One end of the flap gate is axially connected to the end of the main body away from the locking mechanism;

[0017] The float is installed on the side of the flap gate away from the main body, and in its natural state, the flap gate is in a vertical position.

[0018] The float is a semi-circular cylinder with sloping ends.

[0019] Preferably, it further includes: a return sealing ring;

[0020] The outer wall of the locking tooth block and the main body has a communicating annular groove, and the return sealing ring is disposed inside the annular groove.

[0021] Preferably, it further includes: a protective plate;

[0022] The protective plate is installed on the inner wall of the cylindrical part of the main body, on the side near the semi-circular cylinder of the main body;

[0023] The body of the protective plate is semi-circular or semi-elliptical.

[0024] Preferably, the floating plate is made of EVA foam.

[0025] Preferably, it also includes: a safety sheath;

[0026] An L-shaped groove is provided on the outer wall surrounding the main body, and the side of the L-shaped groove away from the locking mechanism is open;

[0027] The safety sleeve is fitted over the outside of the L-shaped groove and is interference-fitted with the L-shaped groove;

[0028] The safety sleeve is made of nylon.

[0029] The present invention has at least the following beneficial effects:

[0030] This invention proposes an automatic detection and sealing device for the venting channel of an oil well casing. By setting a locking mechanism and an automatic sealing mechanism on the main body, it solves the problem of difficult installation of the casing anti-theft switch, reduces the cost of using the tubing string during operation, and allows the automatic detection and sealing device to be freely installed and removed in the channel without moving the oil well tubing string. When the fluid level rises automatically, it automatically closes the channel to block the liquid ejection, and when the fluid level drops, it automatically opens. Attached Figure Description

[0031] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present invention and, together with the specification, serve to explain the technical solutions of the present invention.

[0032] Figure 1 This diagram illustrates the structure of an automatic detection and sealing device for the venting channel of an oil well casing according to an embodiment of the present invention.

[0033] Figure 2 A schematic diagram of the main body according to an embodiment of the present invention is shown;

[0034] Figure 3 A schematic diagram of the structure of a wrench according to an embodiment of the present invention is shown;

[0035] Figure 4 A schematic diagram of the structure of the expansion screw tube according to an embodiment of the present invention is shown;

[0036] Figure 5 A schematic diagram of the structure of the locking tooth block according to an embodiment of the present invention is shown;

[0037] Figure 6 A schematic diagram of the structure of the protective plate according to an embodiment of the present invention is shown;

[0038] Figure 7 A schematic diagram of the structure of a flap gate according to an embodiment of the present invention is shown;

[0039] Figure 8 A schematic diagram of the structure of a float according to an embodiment of the present invention is shown;

[0040] Figure 9 A schematic diagram of the installation sleeve according to an embodiment of the present invention is shown.

[0041] In the diagram, 1-main body, 2-expansion screw tube, 3-locking tooth block, 4-wrench, 5-conical annular surface, 6-tooth structure, 7-flip valve, 8-float, 9-return sealing ring, 10-protective plate, 11-safety sleeve, 12-through hole. Detailed Implementation

[0042] Various exemplary embodiments, features, and aspects of the present invention will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0043] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0044] In this document, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" in this document means any combination of at least two of any one or more elements. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0045] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art will understand that the present invention can be practiced without certain specific details. In some instances, methods, means, elements, and circuits well known to those skilled in the art have not been described in detail in order to highlight the spirit of the invention.

[0046] Figure 1 This diagram illustrates the structure of an automatic detection and sealing device for the venting channel of an oil well casing according to an embodiment of the present invention. Figure 2 A schematic diagram of the main body according to an embodiment of the present invention is shown; Figure 3 A schematic diagram of the structure of a wrench according to an embodiment of the present invention is shown; Figure 4 A schematic diagram of the structure of the expansion screw tube according to an embodiment of the present invention is shown; Figure 5 A schematic diagram of the structure of the locking tooth block according to an embodiment of the present invention is shown; Figure 6 A schematic diagram of the structure of the protective plate according to an embodiment of the present invention is shown; Figure 7 A schematic diagram of the structure of a flap gate according to an embodiment of the present invention is shown; Figure 8 A schematic diagram of the structure of a float according to an embodiment of the present invention is shown; Figure 9 A schematic diagram of the mounting sleeve according to an embodiment of the present invention is shown. Figure 1-9As shown, an automatic detection and sealing device for an oil well casing venting channel includes: a main body 1; a locking mechanism is provided near one end of the main body 1, the locking mechanism being used to lock the main body 1 into the oil well casing venting channel; the interior of the main body 1 is hollow, with openings at both ends, wherein the portion of the main body 1 near one end is cylindrical, and the portion of the main body 1 near the other end is semi-circular cylindrical; the end of the semi-circular cylindrical part of the main body 1 has an inclined surface at a predetermined angle; an automatic sealing mechanism is installed on the non-arc side of the semi-circular cylindrical part of the main body 1 near the end, the automatic sealing mechanism being used to automatically seal the opening at the other end of the main body 1 when the liquid level in the venting channel reaches the other end of the main body 1, and / or to automatically open the opening at the other end of the main body 1 when the liquid level in the venting channel moves away from the main body 1.

[0047] In the embodiments of the present invention and Figure 1 , 2 In the design, the predetermined angle is 30 degrees. The upper half of the main body 1 is cylindrical, and starting from the middle left or right position, it tapers inward by half on one side, thus forming an upper cylindrical shape and a lower semi-circular cylindrical shape. The automatic sealing mechanism is installed at the lower end of the taper side of the main body 1. The other end of the main body 1 is an inclined surface, that is, the end of the semi-circular cylinder is designed with a 30-degree angled cut-out shape, and the shorter side of the cut-out is on the side where the diameter of the main body 1 tapers inward.

[0048] When using it, first release the casing pressure in the oil well. For wells with high casing pressure, well flushing should be performed to kill the well. Then, remove the clamp screws of the casing gate valve and remove the casing gate valve.

[0049] The main body 1 is slowly inserted into the well casing venting channel, i.e., the large four-way outlet channel, from the other end. At this time, the automatic sealing mechanism keeps the other end of the main body 1 open, and the internal channel of the semi-circular cylinder of the main body 1 is in a state of communication with the inside of the casing venting channel. The main body 1 is then locked onto the inner wall of the casing venting channel by the locking mechanism, thus completing the installation.

[0050] When the liquid level in the casing reaches the outlet of the large four-way valve, the automatic sealing mechanism detects that the liquid level has reached the other end of the main body 1, i.e., below the main body 1. It then automatically seals the other end of the main body 1, i.e., the end of the semi-circular cylinder furthest from the locking mechanism, completely closing the channel and preventing oil and gas from escaping. This automatic shut-off action prevents production losses and environmental pollution caused by oil theft and leakage. When the liquid level in the casing drops, the automatic sealing mechanism automatically opens the other end of the main body 1, enabling operations such as lowering equipment.

[0051] In this invention, the locking mechanism includes: a tightening screw tube 2, a locking tooth block 3, and a wrench 4; the main body 1 has an installation hole near one end, and the tightening screw tube 2 is fixed in the installation hole by threaded engagement; the portion of the tightening screw tube 2 near one end of the main body 1 has a tapered annular surface 5; a through hole 12 is provided on the main body 1 at a position corresponding to the tapered annular surface 5, and the locking tooth block 3 is installed inside the through hole 12; the internal shape of the tightening screw tube 2 matches the external shape of the wrench 4.

[0052] In the embodiments of the present invention and Figure 3 , 4 In part 5, there are three through holes 12, which are evenly distributed along the circumference of the side wall of the main body 1. Each through hole 12 is fitted with a locking tooth block 3. The two ends of the mounting hole are open and communicate with the inside of the cylinder of the main body 1. The side wall of the mounting hole has internal threads.

[0053] exist Figure 4 In the diagram, Figure a is the front view of the expansion screw tube 2, and Figure b is the left view of the expansion screw tube 2; as shown... Figure 4 As shown, the expansion screw tube 2 is hollow inside, with open ends. The end furthest from the main body 1 is cylindrical, and the end closest to the main body 1 is conical. The internal shape of the expansion screw tube 2 is elliptical. The expansion screw tube 2 has external threads that match the internal threads of the mounting hole. The internal shape of the mounting hole matches the external shape of the expansion screw tube 2. The expansion screw tube 2 is rotated and fixed inside the mounting hole of the main body 1 through the threaded structure. In the initial state, the expansion screw tube 2 is located at the end furthest from the main body 1 inside the mounting hole; the side of the locking tooth block 3 closest to the main body 1 is in contact with the conical annular surface 5 of the expansion screw tube 2 at the end closest to the main body 1, i.e., the sidewall of the conical portion.

[0054] The body of the wrench 4 is T-shaped or L-shaped, and the shape of one end of the wrench 4 matches the internal shape of the tightening screw tube 2, that is, it is an elliptical cylinder.

[0055] In use, the main body 1 is placed into the sleeve venting channel, and one end of the wrench 4 is inserted into the hollow interior of the tightening screw tube 2. The other end of the wrench 4 is rotated clockwise, thereby causing the tightening screw tube 2 to rotate along the axis. When the tightening screw tube 2 rotates, it moves towards the center of the main body 1 through the threaded engagement with the mounting hole. Because one end of the tightening screw tube 2 is a conical annular surface 5, during the movement into the main body 1, it pushes the locking tooth block 3 outward, thereby causing the locking tooth block 3 to move towards the inner wall of the sleeve venting channel. The side of the locking tooth block 3 away from the main body 1 is pressed tightly against the inner wall of the sleeve venting channel, thus fixing the main body 1 inside the sleeve venting channel.

[0056] During disassembly, insert one end of the wrench 4 into the hollow interior of the expansion screw tube 2 and rotate the other end of the wrench 4 in the opposite direction, so that the expansion screw tube 2 moves away from the main body 1, thereby no longer applying a pushing force to the locking tooth block 3. The pressure of the locking tooth block 3 on the inner wall of the sleeve venting channel is reduced, and the main body 1 can then be removed.

[0057] In this invention, the body of the locking tooth block 3 is an elliptical cylinder, the outer side wall of the locking tooth block 3 has a tooth structure 6, and the shape of the inner side wall of the locking tooth block 3 matches the shape of the conical annular surface 5 of the expansion screw tube 2.

[0058] In the embodiments of the present invention and Figure 5 Figure a shows the front view of the locking tooth block 3, and Figure b shows the bottom view of the locking tooth block 3. The side of the locking tooth block 3 away from the main body 1 has a toothed structure 6, the top of which is triangular with the tip pointing upwards. The side of the locking tooth block 3 closest to the expansion screw tube 2 has an inclination angle that matches the conical annular surface 5 of the expansion screw tube 2, and also has an arc-shaped concave surface that matches the conical sidewall of the expansion screw tube 2. When the locking tooth block 3 is inside the mounting hole, its side closest to the main body 1 is in close contact with the sidewall of the expansion screw tube 2.

[0059] In this invention, the sealing mechanism includes: a flap valve 7 and a float 8; one end of the flap valve 7 is axially connected to the end of the main body 1 away from the locking mechanism; the float 8 is installed on the side of the flap valve 7 away from the main body 1, and in its natural state, the flap valve 7 is in a vertical state; the body of the float 8 is a semi-circular cylinder with inclined slopes at both ends.

[0060] In this invention, the floating plate is made of EVA foam.

[0061] In the embodiments of the present invention and Figure 7 , 8 In the design, the flap gate 7 is a semi-elliptical tongue shape, matching the shape of the opening at the other end of the main body 1. The straight bottom edge of the semi-elliptical flap gate 7 is connected to the straight bottom edge of the semi-circular cylindrical end of the main body 1 via a hinge shaft. The float 8 needs to have a density less than water and can be made of EVA foam rods. One side of the float 8 is connected to the side of the flap gate 7 away from the main body 1, and the length of the side of the float 8 connected to the flap gate 7 is greater than the length of the other side, thus making the whole structure roughly boat-shaped.

[0062] The main function of float 8 is to sense the buoyancy brought by the liquid. When the liquid in the sleeve rises to the bottom of float 8, float 8 drives flap valve 7 to rotate upward along the axis of the connection with the main body 1 through the buoyancy of the liquid. When flap valve 7 rotates to fit with the end of the semi-circular cylinder of the main body 1, flap valve 7 completely covers the opening at the other end of the main body 1, so that the liquid cannot enter the main body 1, thus realizing automatic sealing of the internal channel of the main body 1.

[0063] A portion of the main body 1 is designed as a semi-circular cylinder, so that the half-space formed after it contracts inward can accommodate the float 8 and the flap valve 7, allowing the flap valve 7 to remain vertical in its natural state. The other end of the main body 1 can be fully opened, and at this time, the side of the float 8 away from the flap valve 7 is in contact with the inner wall of the sleeve. When the liquid rises to the float 8 and the flap valve 7, the contact between the float 8 and the inner wall of the sleeve acts as a limit, so even if the liquid flow rate and pressure are high, the flap valve 7 will not be pushed towards the inner wall of the sleeve on the side closer to the float 8, preventing the flap valve 7 from opening too wide, which would cause the float 8 to fail to float properly and the flap valve 7 to fail to close properly.

[0064] The invention also includes: a return sealing ring 9; and an annular groove that communicates with the outer side wall of the locking tooth block 3 and the main body 1, wherein the return sealing ring 9 is disposed inside the annular groove.

[0065] In this embodiment of the invention, there are two return sealing rings 9, respectively located near both ends of the locking tooth block 3. The return sealing rings are O-rings, and have two main functions: first, to tighten and fix the locking tooth block, preventing it from falling out of the mounting hole; second, because the expansion screw tube 2 pushes the locking tooth block 3 away from the main body 1, the return sealing ring 9 will be stretched and deformed. When the main body 1 needs to be removed, the expansion screw tube 2 no longer applies a pushing force to the locking tooth block 3, and the return sealing ring 9 can pull the locking tooth block back into the mounting hole of the main body 1 by rebounding.

[0066] In this invention, it also includes: a protective plate 10; the protective plate 10 is installed on the inner wall of the cylindrical part of the main body 1, on the side close to the semi-circular cylinder of the main body 1; the body of the protective plate 10 is semi-circular or semi-elliptical.

[0067] In the embodiments of the present invention and Figure 6 In the middle, the protective plate 10 is installed in the cylindrical channel of the main body 1, and is positioned above the semi-circular column. Its function is to block objects floating upward with the liquid in the sleeve from entering the main body 1 and to seal one end of the outlet of the main body 1.

[0068] The invention also includes: a safety sleeve 11; an L-shaped groove is provided on the outer side wall of the main body 1 around its perimeter, and the side of the L-shaped groove away from the locking mechanism is open; the safety sleeve 11 is fitted over the L-shaped groove and is interference-fitted with the L-shaped groove; wherein the safety sleeve 11 is made of nylon.

[0069] In the embodiments of the present invention and Figure 9 Figure a shows the front view of the safety sleeve 11, and Figure b shows the left view of the safety sleeve 11. The safety sleeve 11 is cylindrical in shape and is tightly fitted to the main body 1 with an interference fit. The diameter of the cylindrical part of the main body 1 at the L-shaped groove is 52mm, and the outer diameter of the safety sleeve 11 after being fitted into the L-shaped groove is 61mm.

[0070] The function of the safety sleeve 11 is to limit the insertion depth of the automatic detection and closure device in the venting channel of the oil well casing. That is, the part of the main body 1 with the safety sleeve 11 is inserted into the inside of the casing four-way valve and fits tightly against the inner wall of the casing to prevent shaking. The diameter of the part of the main body 1 outside the safety sleeve 11 is larger than the inner diameter of the casing, so it is stuck outside the casing. In addition, the safety sleeve 11 can also protect the flap valve 7 and the float 8 to prevent deformation or damage caused by bumps or collisions during transportation.

[0071] During installation, first remove the clamp screws of the casing gate and dismantle the casing gate. Then, place the prepared main body 1 into the large four-way outlet channel, keeping the flap valve 7 and float 8 vertically downward, and the semi-circular through hole 12 of the column in a through state. Insert the elliptical part of the special wrench 4 into the expansion screw tube 2, and rotate the special wrench 4 with force to drive the expansion screw tube 2. The conical annular surface at the front end of the expansion screw tube 2 pushes the locking tooth block 3 to move vertically along the axis, pushing the locking tooth block 3 out of the main body 1. After it makes tight contact with the inner annular surface of the casing channel, remove the special wrench 4, and the installation work is completed.

[0072] When the liquid level in the casing reaches its large four-way outlet, the float 8 drives the flap valve 7 to rotate through buoyancy. As the buoyancy increases, the flap valve 7 flips upward to achieve automatic control until the entire main body 1 channel is completely closed and oil and gas cannot be ejected, thus achieving automatic closing. When the liquid level in the casing drops, the buoyancy gradually disappears, and the flap valve 7 flips downward under its own weight, thus automatically opening the channel.

[0073] It is understood that the various embodiments mentioned above in this invention can be combined with each other to form combined embodiments without violating the principle and logic. Due to space limitations, this invention will not elaborate further.

[0074] The overall structural design of this invention is novel and unique. The main body 1 has a cylindrical barrel shape. The expansion screw tube 2 pushes the locking tooth block 3 to achieve the anchoring function, and the return sealing ring 9 realizes the function of retracting the locking tooth block 3. The transition from a cylindrical design in the front half to a semi-circular cylindrical design in the middle and rear sections ensures sufficient flow area, while also ensuring design space for the anchoring structure and a unique outlet shape. The end of the main body 1 is cut at a 30-degree angle to form a slanted outlet shape, which is conducive to the installation of the flap valve 7 and the float 8.

[0075] The anti-theft component of this invention uses a special wrench 4 and a matching expansion screw tube 2. The joint between the two has an elliptical shape, which provides excellent anti-theft functionality. The conical annular surface at the front end of the expansion screw tube 2 pushes the locking tooth block 3 out, which engages with the inner annular surface of the sleeve channel and tightens. Under the action of the locking tooth block 3, an interference fit is generated, making the anchoring safer and more reliable. The "O"-shaped return sealing ring 9 is used as a spring, saving a lot of design space. The cylindrical channel of the main body 1 is designed with a protective plate 10, which can cover the semi-circular channel behind it and effectively prevent the damage caused by the entry of foreign objects.

[0076] The flap valve 7 of this invention achieves automatic anti-theft closing. The float 8 is made of EVA foam rod and has a semi-circular shape. It is installed below the flap valve 7 and its main function is to sense the buoyancy brought by the liquid, thereby driving the flap valve 7 to move and realize the automatic closing of the semi-circular channel of the main body 1. The flap valve 7 is a tongue-shaped body and is installed at the semi-circular outlet of the main body 1. The lower part of the flap valve 7 is connected to the column in a hinge shaft manner. Under the action of external force on the float 8, the flap valve 7 can rotate around the axis to realize the automatic opening or closing of the channel of the main body 1.

[0077] During its development, this invention was tested on 60 sets at pumping wells in multiple operating areas, achieving excellent anti-theft performance. It can be freely installed and removed within the channel without moving the well tubing. When the fluid level rises, the valve automatically closes the channel to block fluid ejection; when the fluid level drops, the channel automatically opens, solving the problems of oil theft through casing and environmental pollution. Since its experimental application, it has cumulatively reduced crude oil losses by 630 tons, resulting in a net profit increase of 2.411 million yuan, demonstrating significant economic and social benefits and promising prospects for widespread application.

[0078] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. An automatic detection and sealing device for the venting channel of an oil well casing, characterized in that, include: Main body (1); The main body (1) is provided with a locking mechanism near one end, which is used to lock the main body (1) in the well casing venting channel; The interior of the main body (1) is hollow and open at both ends. The part of the main body (1) near one end is cylindrical and the part of the main body (1) near the other end is semi-circular. The end of the semi-circular cylinder of the main body (1) has an inclined surface at a predetermined angle; An automatic sealing mechanism is installed on the non-arc side of the semi-circular cylinder of the main body (1) near the end. The automatic sealing mechanism is used to automatically seal the other end opening of the main body (1) when the liquid level in the venting channel reaches the other end of the main body (1) upward, and / or automatically open the other end opening of the main body (1) when the liquid level in the venting channel moves away from the main body (1). The automatic sealing mechanism includes: a flap valve (7) and a float (8); one end of the flap valve (7) is axially connected to the end of the main body (1) away from the locking mechanism; the float (8) is installed on the flap valve (7) on the side away from the main body (1), and in its natural state, the flap valve (7) is in a vertical state; the body of the float (8) is a semi-circular cylinder with inclined slopes at both ends.

2. The automatic detection and sealing device for the venting channel of an oil well casing according to claim 1, characterized in that, The locking mechanism includes: a tightening screw tube (2), a locking tooth block (3), and a wrench (4); The main body (1) has an installation hole inside near one end, and the expansion screw (2) is fixed in the installation hole by threaded engagement; The portion of the expansion screw (2) near the end of the main body (1) has a tapered annular surface (5); On the main body (1), a through hole (12) is provided at a position corresponding to the conical annular surface (5), and the locking tooth block (3) is installed inside the through hole (12); The internal shape of the tightening screw (2) matches the external shape of the wrench (4).

3. The automatic detection and sealing device for the venting channel of an oil well casing according to claim 2, characterized in that: The main body of the locking tooth block (3) is an elliptical cylinder. The outer side wall of the locking tooth block (3) has a toothed structure (6). The shape of the inner side wall of the locking tooth block (3) matches the shape of the conical annular surface (5) of the expansion screw tube (2).

4. The automatic detection and sealing device for the venting channel of an oil well casing according to claim 2, characterized in that, Also includes: Return sealing ring (9); The outer sidewalls of the locking tooth block (3) and the main body (1) have communicating annular grooves, and the return sealing ring (9) is provided inside the annular grooves.

5. The automatic detection and sealing device for the venting channel of an oil well casing according to claim 1, characterized in that, Also includes: Protective plate (10); Inside the cylindrical portion of the main body (1), on the inner wall of the side of the semi-circular cylinder near the main body (1), the protective plate (10) is installed. The body of the guard plate (10) is semi-circular or semi-elliptical.

6. The automatic detection and sealing device for the venting channel of an oil well casing according to claim 1, characterized in that: The float material is EVA foam.

7. The automatic detection and sealing device for the venting channel of an oil well casing according to any one of claims 1-6, characterized in that, Also includes: Safety sheath (11); An L-shaped groove is provided on the outer side wall around the main body (1), and the side of the L-shaped groove away from the locking mechanism is open; The safety sleeve (11) is fitted over the outside of the L-shaped groove and is in an interference fit with the L-shaped groove; The safety sleeve (11) is made of nylon.

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