Test equipment, test method and system for plugging inner cavity of oil well pipe by alloy

Abstract

The invention discloses test equipment, a test method and a test system for an alloy plugging oil well pipe inner cavity. The test equipment comprises an alloy casting oil well pipe inner cavity device and a sealing performance test device, the alloy casting oil well pipe inner cavity device comprises an oil well pipe, a casting head, a lower connector, a first plug and a second plug. The casting head is connected with an oil well pipe and used for injecting liquid alloy into an inner cavity of the oil well pipe. The lower joint is connected with an oil well pipe; at least part of the first plug is embedded into an inner cavity of the oil well pipe, and the second plug is connected with the lower connector and limits the first plug. The sealing performance test device comprises a pressure test outer cylinder, an upper sealing head, a lower sealing head and a lower jacket. The oil well pipe is arranged in the accommodating cavity of the pressure testing outer cylinder; the upper sealing head is connected with the pressure test outer cylinder, and the upper sealing head is externally connected with pressing equipment; the lower sealing head sleeves the outer side of the oil well pipe, is positioned between the oil well pipe and the pressure test outer cylinder and is limited by the lower joint; and the lower jacket sleeves the lower end of the lower joint and limits the second plug so as to realize a sealing test.

Description

Technical Field

[0001] This invention relates to the field of novel well workover operations and related technologies, and in particular to a test device, test method and system for alloy plugging of the inner cavity of oil well pipes. Background Technology

[0002] In the later stages of oil and gas field development, as formation productivity declines, oil and gas well production decreases, and some wells become unprofitable, becoming abandoned wells. Although abandoned wells are nearing depletion of their production capacity, they still accumulate large amounts of flammable or toxic gases over time. Leaks from these wells can still cause significant environmental damage, necessitating permanent sealing. Furthermore, due to recent societal development and increased environmental awareness, some oil and gas wells are located within nature reserves or pose potential safety and environmental risks. These wells also require permanent sealing. Reliable permanent sealing has a significant impact on eliminating safety hazards, protecting formations, restoring topography, and protecting the environment.

[0003] Currently, permanent well sealing is mainly achieved by cementing the wellbore and related formations. However, there are no industry-wide standardized procedures or operational standards for permanent sealing technology, making it difficult to assess the effectiveness of permanent well sealing in oil and gas wells. Given the potential risks and environmental hazards posed by oil and gas leaks, the environmental impact of a failed or ultimately ineffective permanent well sealing operation is immeasurable.

[0004] Using low-melting-point alloys for wellbore cavitation plugging is a new technical approach. This involves using a low-melting-point alloy with a melting point higher than the downhole ambient temperature by a certain value. The alloy is then processed into a specific shape above the well according to operational requirements and used in conjunction with a downhole heater to form a set of downhole tools. Summary of the Invention

[0005] In order to test the sealing performance of the plugging effect of oil well tubing, especially to accurately and effectively test the sealing performance of the alloy plugged section of the oil well tubing, this invention provides a test device, test method and system for alloy plugging of the oil well tubing cavity.

[0006] In a first aspect, embodiments of the present invention provide a test device for sealing the inner cavity of an oil well pipe with an alloy, which may include: an alloy cast oil well pipe inner cavity device and a sealing performance test device;

[0007] The alloy casting oil well pipe inner cavity device is used for casting an alloy so that the alloy solidifies in the inner cavity of the oil well pipe; the alloy casting oil well pipe inner cavity device may include: an oil well pipe, a casting head, a lower connector, a first plug and a second plug; the casting head is detachably connected to one end of the oil well pipe for injecting liquid alloy into the inner cavity of the oil well pipe; the lower connector is connected to the other end of the oil well pipe; the first plug is at least partially embedded in the inner cavity of the oil well pipe, and the second plug is connected to the lower connector and limits the first plug;

[0008] The sealing performance testing device is used to accommodate the inner cavity device of the alloy cast oil well pipe to test the sealing performance of the alloy plug section of the inner cavity of the oil well pipe; the sealing performance testing device may include: a test pressure outer cylinder, an upper sealing head, a lower sealing head, and a lower outer sleeve; the oil well pipe is placed in the cavity of the test pressure outer cylinder; the upper sealing head is connected to one end of the test pressure outer cylinder, and the end of the upper sealing head away from the test pressure outer cylinder is connected to a pressure testing device; the lower sealing head is sleeved on the outside of the oil well pipe, located between the oil well pipe and the test pressure outer cylinder and limited by the lower connector; the lower outer sleeve is sleeved on the lower end of the lower connector and limits the second plug.

[0009] In one embodiment, the outer side of the test cylinder is provided with a first annular groove, the lower outer sleeve is cylindrical, and the outer side of the lower outer sleeve is provided with a second annular groove;

[0010] The sealing performance testing device may further include: an outer clamp and an outer sleeve; the outer clamp is a split structure in the shape of a cylinder, and is provided with inner grooves that respectively cooperate with the test outer cylinder and the lower outer sleeve, as well as a first inner boss that cooperates with the first annular groove and a second inner boss that cooperates with the second annular groove; the outer sleeve is nested on the outside of the outer clamp and the lower outer sleeve.

[0011] In another embodiment, the outer sleeve is cylindrical, the inner side of the outer sleeve is provided with a first step and an internal thread, and the outer side of the lower sleeve is provided with an external thread;

[0012] The outer sleeve is threadedly connected to the lower outer sleeve, and the first step limits the outer clamp.

[0013] In another embodiment, the inner side of the lower outer sleeve is provided with a second step, which abuts against the lower connector and limits the second plug.

[0014] In another embodiment, a sealing ring is provided between the upper sealing head and the outer test cylinder, a sealing ring is provided between the lower sealing head and the outer test cylinder, and a sealing ring is provided between the lower sealing head and the lower connector.

[0015] In another embodiment, a groove is provided on the lower end face of the upper sealing head to connect the inner cavity of the oil well pipe and the annular cavity between the oil well pipe and the test pressure outer cylinder.

[0016] In another embodiment, the lower connector is threaded to the other end of the well pipe, and the second plug is threaded to the lower connector.

[0017] In another embodiment, the casting head has a double-hole structure, and the end of the casting head away from the oil well pipe is flared.

[0018] Secondly, embodiments of the present invention provide a test method for alloy-sealed oil well pipe cavities, wherein the sealing performance of the alloy-sealed section of the oil well pipe cavity is tested using the test equipment for alloy-sealed oil well pipe cavities described in the first aspect.

[0019] Thirdly, embodiments of the present invention provide a test system for alloy plugging of the inner cavity of an oil well pipe, comprising: casting equipment, pressure testing equipment, and the test equipment for alloy plugging of the inner cavity of an oil well pipe as described in the first aspect;

[0020] The casting equipment is used to inject liquid alloy into the inner cavity of the oil well pipe in the alloy casting oil well pipe inner cavity device, so as to form an alloy blockage section in the inner cavity of the oil well pipe; the pressure testing equipment is used to pressurize the outer cylinder of the sealing performance testing device to test the sealing performance of the alloy blockage section in the inner cavity of the oil well pipe.

[0021] The beneficial effects of the above-mentioned technical solutions provided in the embodiments of the present invention include at least the following:

[0022] This invention provides a test device, test method, and system for alloy-sealed oil well pipe cavities. The test device has advantages such as simple structure, convenient manufacturing, no special processing parts, and low requirements for processing equipment. Furthermore, the device is highly adaptable, has good repeatability, and high reusability, and can be applied to sealing tests of related products. The device includes an oil well pipe and a test cylinder. The oil well pipe is seated or sealed inside the test cylinder. Each test verifies the sealing performance of the internal oil well pipe. If the oil well pipe is damaged, only the internal oil well pipe needs to be replaced.

[0023] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0024] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0025] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0026] Figure 1 This is a structural diagram of the alloy cast oil well pipe inner cavity device provided in an embodiment of the present invention;

[0027] Figure 2 This is a structural diagram of the sealing performance testing device provided in the embodiments of the present invention;

[0028] Figure 3 This is a structural diagram of the test equipment for alloy plugging of the inner cavity of an oil well pipe provided in an embodiment of the present invention;

[0029] Figure 4 This is a structural diagram of the external clamp provided in an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of the structure of the test system for sealing the inner cavity of an oil well pipe with alloy provided in an embodiment of the present invention;

[0031] Among them, 1-test equipment for alloy plugging of the inner cavity of oil well pipe; 2-casting equipment; 3-pressure testing equipment;

[0032] 11-Alloy cast oil well tubing inner cavity device; 12-Sealing performance testing device; 13-Sealing ring; 14-Annular cavity;

[0033] 111-Oil well tubing; 112-Casting head; 113-Lower connector; 114-First plug; 115-Second plug;

[0034] 121-Test pressure outer cylinder; 122-Upper sealing head; 123-Lower sealing head; 124-Lower outer sleeve; 125-Outer clamp; 126-Outer sleeve;

[0035] 1211 - First annular groove; 1221 - Groove; 1241 - Second annular groove; 1242 - External thread; 1243 - Second step; 1251 - Internal groove; 1252 - First internal boss; 1253 - Second internal boss; 1261 - First step; 1262 - Internal thread. Detailed Implementation

[0036] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0037] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "far," "near," "front," and "rear," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] Alloy downhole plugging technology is a novel downhole operation technology in the industry. If a permanently plugged abandoned oil and gas well has a leak, the leak point is connected to the wellbore cavity. An alloy and heater combination downhole tool is lowered to a predetermined location (e.g., above the leak point). The heater heats the alloy, causing it to melt and flow through the wellbore into the leak point or fill the cavity of the well casing (tubing or casing) above the leak point. The alloy solidifies, sealing both the leak point and the wellbore cavity. Before application in the well, the alloy needs to undergo various performance tests on the surface. Therefore, surface simulation testing is essential to ensure the reliability and feasibility of alloy downhole plugging. The inventors have found no relevant literature documenting surface testing of alloy plugging performance. In view of the above problems, this invention proposes a testing device, method, and system for alloy plugging of well casing cavities to overcome or at least partially solve the above problems.

[0040] This invention provides a test device for sealing the inner cavity of an oil well pipe with an alloy, referring to... Figures 1-3As shown, the test equipment 1 for sealing the inner cavity of an oil well pipe with an alloy may include: an alloy casting oil well pipe inner cavity device 11 and a sealing performance test device 12; the alloy casting oil well pipe inner cavity device 11 is used to cast the alloy so that the alloy solidifies in the inner cavity of the oil well pipe; the alloy casting oil well pipe inner cavity device 11 may include: an oil well pipe 111, a casting head 112, a lower connector 113, a first plug 114 and a second plug 115; the casting head 112 is detachably connected to one end of the oil well pipe 111 and is used to inject liquid alloy into the inner cavity of the oil well pipe 111; the lower connector 113 is connected to the other end of the oil well pipe 111; at least a portion of the first plug 114 is embedded in the inner cavity of the oil well pipe 111, and the second plug 115 is connected to the lower connector 113 and performs sealing tests on the first plug 114. The sealing performance testing device 12 is used to accommodate the inner cavity device 11 of the alloy cast oil well pipe to test the sealing performance of the alloy plug section of the inner cavity of the oil well pipe 111. The sealing performance testing device 12 may include: a test pressure outer cylinder 121, an upper sealing head 122, a lower sealing head 123, and a lower outer sleeve 124. The oil well pipe 111 is placed in the cavity of the test pressure outer cylinder 121. The upper sealing head 122 is connected to one end of the test pressure outer cylinder 121, and the end of the upper sealing head 122 away from the test pressure outer cylinder 121 is connected to the external pressure testing device 3. The lower sealing head 123 is sleeved on the outside of the oil well pipe 111, located between the oil well pipe 111 and the test pressure outer cylinder 121, and is limited by the lower connector 113. The lower outer sleeve 124 is sleeved on the lower end of the lower connector 113 and limits the second plug 115.

[0041] The experimental equipment for sealing the inner cavity of an oil well pipe with the aforementioned alloy provided in this embodiment of the invention is used to test the sealing performance of the alloy-plugged section after the inner cavity of the oil well pipe is sealed with a fusible alloy. The test process mainly consists of two steps: the first step is to inject the molten alloy into the oil well pipe (tubing or casing), and after the alloy solidifies in the inner cavity of the oil well pipe, the second step is to perform the sealing performance test; the second step is to perform a pressure test on the oil well pipe after alloy plugging using a pressure testing device (pressure pump, etc.), thereby testing the sealing performance of the alloy in sealing the inner cavity of the oil well pipe.

[0042] In this embodiment, the alloy casting well pipe inner cavity device 11 serves as a tooling for injecting liquid alloy into the test well pipe 111 and allowing it to cool and solidify. The alloy casting process can involve heating the alloy into a liquid state in a crucible clamp, injecting it into the inner cavity of the well pipe 111 through the casting head 112, and allowing the alloy to naturally cool and solidify, thus sealing the inner cavity of the well pipe 111 and forming an alloy plug section. In this embodiment, the lower end of the well pipe 111 is connected via a lower connector 113. The lower connector 113 contains a first plug 114 (inner plug) and a second plug 115 (dead plug). The first plug 114 separates the alloy from the second plug 115, facilitating the removal and replacement of the second plug 115 after the alloy solidifies. It should be noted that the second plug 115 in this embodiment has a central hole. When the alloy plug section fails to seal during a pressure test, seeping water can flow out through the central hole of the second plug, allowing for easy observation of the sealing condition of the alloy plug section.

[0043] In this embodiment, the sealing performance testing device 12 is used to test the sealing effect of the alloy plug section on the inner cavity of the oil well pipe 111. The testing process can be as follows: the upper sealing head 122 is connected to an external pressure testing device 3 (e.g., a pressure pump, etc.). Figure 2 and Figure 3 The location indicated by the pressure testing device 3 can be the pressure pump or the joint of its connecting pipeline (those skilled in the art should not misunderstand this). The pressure pump is energized and pressurizes until liquid leaks from the bottom of the test device 1 (second plug 115 and lower outer sleeve 124) of the alloy-sealed oil well pipe cavity. The pressure value at the time of leakage is the sealing pressure of the alloy plug section. In this embodiment, the function of the alloy plug section is sealing and it cannot withstand axial force. The hydraulic axial force generated by the pressure test is borne by the second plug 115, which is connected to the lower joint 113 to transmit the hydraulic axial force to the lower outer sleeve 124.

[0044] The testing equipment provided in this embodiment has the advantages of simple structure, convenient processing and manufacturing, no special processing parts, and low requirements for processing equipment. Furthermore, the equipment has strong adaptability, good repeatability, and high reusability, and can be used for sealing tests of related products. The device includes an oil well pipe (inner test pipe) and a pressure testing outer cylinder (outer pressure-bearing thick-walled pipe). The oil well pipe is set or sealed inside the pressure testing outer cylinder. Each time, the sealing performance of the internal oil well pipe is tested. If the oil well pipe is damaged, only the internal oil well pipe needs to be replaced.

[0045] Furthermore, this testing equipment can conduct tests on the sealing performance of various packers, bridge plugs, packer sleeves, cement, organic sealants, etc., used to seal or plug oil well pipes.

[0046] In an optional embodiment, refer to Figures 2-4As shown, the outer cylinder 121 of the test pressure is provided with a first annular groove 1211 on its outer side, the lower outer sleeve 124 is cylindrical, and the outer side of the lower outer sleeve 124 is provided with a second annular groove 1241; the sealing performance test device 12 may also include: an outer clamp 125 and an outer sleeve 126; the outer clamp 125 is a split structure and is cylindrical in shape, and is provided with an inner groove 1251 that respectively cooperates with the outer cylinder 121 and the lower outer sleeve 124, as well as a first inner boss 1252 that cooperates with the first annular groove 1211 and a second inner boss 1253 that cooperates with the second annular groove 1241; the outer sleeve 126 is nested on the outer side of the outer clamp 125 and the lower outer sleeve 124.

[0047] In this embodiment of the invention, annular grooves are provided on the outer circular surfaces of both the outer test cylinder 121 and the lower outer sleeve 124, which cooperate with the annular protrusions on the inner side of the outer clamp 125 to facilitate the connection of the outer test cylinder 121 and the lower outer sleeve 124. In a specific implementation, the aforementioned outer clamp 125 is a split structure, combined with... Figure 4 As shown, it can be processed into two parts (semicircle) or three parts, etc., and this embodiment does not specifically limit this. In this embodiment, the above structure can ensure that the axial pressure generated during the pressure test is borne by the outer clamp 125, that is, the axial pressure of the lower outer sleeve 124 is ultimately transmitted to the outer clamp 125. Therefore, the upward and downward axial forces of the pressure test are borne by the outer clamp 125. In this embodiment, due to the use of the clamp groove force-bearing structure of the outer clamp, the test fixture structure has good manufacturability, is easy to disassemble and assemble, and generally only requires two people to easily disassemble and assemble to complete the test.

[0048] In another alternative embodiment, refer to Figure 2 and Figure 3 As shown, the outer retaining sleeve 126 is cylindrical. The inner side of the outer retaining sleeve 126 has a first step 1261 and an internal thread 1262, while the outer side of the lower outer sleeve 124 has an external thread 1242. The outer retaining sleeve 126 and the lower outer sleeve 124 are threadedly connected, and the first step 1261 limits the movement of the outer clamp 125. The advantage of this structure is that the outer retaining sleeve 126 only serves to fix the outer clamp 125; the threaded connection is not subjected to force, avoiding easy damage to the threads under stress. That is, even under very large axial forces generated during pressure testing, the axial force has no effect on the threads, preventing thread deformation.

[0049] In another alternative embodiment, refer to Figure 2 and Figure 3As shown, the inner side of the lower outer sleeve 124 is provided with a second step 1243, which abuts against the lower connector 113 and limits the movement of the second plug 115. In this embodiment, since the lower outer sleeve 124 and the pressure testing outer cylinder 121 are fixed by the cooperation of the outer clamp 125, the position of the lower outer sleeve 124 can be fixed. The lower outer sleeve 124 abuts against the lower connector 113 through the second step 1243, which can also limit the stroke of the second plug 115. More specifically, the lower outer sleeve 124 abuts against the bottom of the pressure testing outer cylinder 121, which makes it easier for the lower outer sleeve 124 and the pressure testing outer cylinder 121 to be fixed by the cooperation of the outer clamp 125.

[0050] In another alternative embodiment, refer to Figure 2 and Figure 3 As shown, a sealing ring 13 is provided between the upper sealing head 122 and the test pressure outer cylinder 121, a sealing ring 13 is provided between the lower sealing head 123 and the test pressure outer cylinder 121, and a sealing ring 13 is provided between the lower sealing head 123 and the lower connector 113. The sealing rings are provided in this embodiment to ensure the sealing performance at the connection between adjacent components, thus making the sealing performance test of the alloy blockage section more accurate.

[0051] In another alternative embodiment, refer to Figure 2 and Figure 3 As shown, a groove 1221 is provided on the lower end face of the upper sealing head 122 to connect the inner cavity of the oil well pipe 111 and the annular cavity 14 between the oil well pipe 111 and the test outer cylinder 121. In this embodiment, the groove 1221 on the lower end face of the upper sealing head 122 can connect the inside and outside of the oil well pipe 111. The purpose is to ensure that the pressure balance between the inner cavity of the oil well pipe 111 and the outer annular cavity 14 is achieved during the pressure test. This will prevent the oil well pipe 111 from deforming under high pressure and ensure that the solidified alloy adheres to the inner wall of the oil well pipe 111 without being affected by the pressure test. The pressure test value is the true pressure bearing capacity of the alloy blockage section.

[0052] In another alternative embodiment, refer to Figure 1 and Figure 3 As shown, the lower connector 113 is threaded to the other end of the oil well pipe 111, and the second plug 115 is threaded to the lower connector 113. In this embodiment, the lower connector 113 is threaded to the other end of the oil well pipe 111. In actual implementation, the connection is made through the oil pipe thread, which ensures both connection strength and sealing. The threaded connection between the second plug 115 (a dead plug) and the lower connector 113, during the alloy casting process, forms a seal at the lower end of the inner cavity of the oil well pipe 111.

[0053] In another alternative embodiment, refer to Figure 1 and Figure 3As shown, the casting head 112 has a double-hole structure, and the end of the casting head 112 away from the oil well pipe 111 is flared. In this embodiment, the casting head 112 is designed with a double-hole structure. The large hole is the inlet for pouring liquid alloy, and the upper end is flared (outwardly flared flared mouth) to facilitate alloy pouring. The bypass irregularly shaped small hole is a breathing hole to balance the pressure inside and outside the pouring chamber during the alloy pouring process.

[0054] Based on the same inventive concept, this invention also provides a test method for alloy-sealed oil well pipe cavities. The method involves testing the sealing performance of the alloy-sealed section of the oil well pipe cavity using the aforementioned test equipment.

[0055] Based on the same inventive concept, this invention also provides a test system for alloy plugging of the inner cavity of oil well pipes, referring to... Figure 5 As shown, the system may include: a casting device 2, a pressure testing device 3, and a test device 1 for sealing the inner cavity of the oil well pipe with the aforementioned alloy; wherein, the casting device 2 is used to inject liquid alloy into the inner cavity of the oil well pipe 111 in the alloy casting oil well pipe inner cavity device 11, so that an alloy plugging section is formed in the inner cavity of the oil well pipe 111; the pressure testing device 3 is used to pressurize the test pressure outer cylinder 121 in the sealing performance test device 12, so as to test the sealing performance of the alloy plugging section in the inner cavity of the oil well pipe 111.

[0056] The test method and test system for alloy-sealed oil well tubing cavities described in the embodiments of the present invention, as well as their beneficial effects, can be found in the detailed description of the test equipment for alloy-sealed oil well tubing cavities described above. These descriptions will not be repeated here.

[0057] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. This disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims. Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A test device for alloy plugging of the inner cavity of an oil well pipe, characterized in that, include: Alloy-cast oil well tubing internal cavity device and sealing performance testing device; The alloy casting well pipe inner cavity device is used to cast the alloy so that the alloy solidifies in the well pipe inner cavity. The alloy-cast oil well pipe inner cavity device includes: an oil well pipe, a casting head, a lower connector, a first plug, and a second plug; the casting head is detachably connected to one end of the oil well pipe for injecting liquid alloy into the inner cavity of the oil well pipe; the lower connector is connected to the other end of the oil well pipe; the first plug is at least partially embedded in the inner cavity of the oil well pipe, and the second plug is connected to the lower connector and limits the position of the first plug; The sealing performance testing device is used to accommodate the inner cavity device of the alloy cast oil well pipe to test the sealing performance of the alloy plug section of the inner cavity of the oil well pipe; the sealing performance testing device includes: a test pressure outer cylinder, an upper sealing head, a lower sealing head, and a lower outer sleeve; the oil well pipe is placed in the cavity of the test pressure outer cylinder; the upper sealing head is connected to one end of the test pressure outer cylinder, and the end of the upper sealing head away from the test pressure outer cylinder is connected to a pressure testing device; the lower sealing head is sleeved on the outside of the oil well pipe, located between the oil well pipe and the test pressure outer cylinder and limited by the lower connector; the lower outer sleeve is sleeved on the lower end of the lower connector and limits the second plug.

2. The device according to claim 1, characterized in that, The outer side of the test cylinder is provided with a first annular groove, the lower outer sleeve is cylindrical, and the outer side of the lower outer sleeve is provided with a second annular groove; The sealing performance testing device further includes: an outer clamp and an outer sleeve; the outer clamp is a split structure in the shape of a whole cylinder, and is provided with inner grooves that respectively cooperate with the test pressure outer cylinder and the lower outer sleeve, as well as a first inner boss that cooperates with the first annular groove and a second inner boss that cooperates with the second annular groove; the outer sleeve is nested on the outside of the outer clamp and the lower outer sleeve.

3. The device according to claim 2, characterized in that, The outer sleeve is cylindrical, and the inner side of the outer sleeve is provided with a first step and an internal thread, while the outer side of the lower sleeve is provided with an external thread. The outer sleeve is threadedly connected to the lower outer sleeve, and the first step limits the outer clamp.

4. The device according to claim 1, characterized in that, The inner side of the lower jacket is provided with the first The second step abuts against the lower connector and limits the position of the second plug.

5. The device according to any one of claims 1 to 4, characterized in that, A sealing ring is provided between the upper sealing head and the outer cylinder of the test pressure, a sealing ring is provided between the lower sealing head and the outer cylinder of the test pressure, and a sealing ring is provided between the lower sealing head and the lower connector.

6. The device according to any one of claims 1 to 4, characterized in that, A groove is provided on the lower end face of the upper sealing head to connect the inner cavity of the oil well pipe and the annular cavity between the oil well pipe and the test pressure outer cylinder.

7. The device according to any one of claims 1 to 4, characterized in that, The lower connector is threaded to the other end of the oil well pipe, and the second plug is threaded to the lower connector.

8. The device according to any one of claims 1 to 4, characterized in that, The casting head has a double-hole structure, and the end of the casting head away from the oil well pipe is flared.

9. A test method for sealing the inner cavity of an oil well pipe with an alloy, characterized in that, The test equipment for alloy plugging of the inner cavity of oil well pipe according to any one of claims 1 to 8 is used to test the sealing performance of the alloy plugging section in the inner cavity of the oil well pipe.

10. A test system for sealing the inner cavity of an oil well pipe with an alloy, characterized in that, include: Casting equipment, pressure testing equipment, and testing equipment for alloy plugging of the inner cavity of oil well pipes as described in any one of claims 1 to 8; The casting equipment is used to inject liquid alloy into the inner cavity of the oil well pipe in the alloy casting oil well pipe inner cavity device, so as to form an alloy blockage section in the inner cavity of the oil well pipe; the pressure testing equipment is used to pressurize the outer cylinder of the sealing performance testing device to test the sealing performance of the alloy blockage section in the inner cavity of the oil well pipe.

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