A dynamic damage evaluation device and method for metal sealing surface in a high temperature and high pressure corrosive environment

Abstract

The present invention relates to a device and method for evaluating dynamic damage of metal sealing surfaces in a high-temperature and high-pressure corrosion environment, including a high-temperature and high-pressure sealing autoclave assembly and a dynamic damage test assembly. The high-temperature and high-pressure sealing autoclave assembly and the dynamic damage test assembly can be used together to realize dynamic damage evaluation of metal sealing surfaces. The device and method use a high-temperature and high-pressure autoclave to simulate the high-temperature and high-pressure environment underground, use an exciter, a bending device, and a supporting screw to simulate dynamic damage conditions, use a gas detector and a second pressure gauge to detect the internal and external environmental gases and pressure changes of the threaded sealing pair to determine whether the sealing surface is damaged, and determine the degree of corrosion of the sealing surface through corrosion morphology and product analysis, thereby evaluating the performance of the metal sealing surface and obtaining the influence of various factors on the performance of the metal sealing surface.

Description

Technical Field

[0001] The present invention relates to the field of dynamic damage of metal sealing surfaces, and in particular to a device and method for evaluating dynamic damage of metal sealing surfaces in a high-temperature and high-pressure corrosive environment. Background Art

[0002] The downhole environment of oil and gas wells is usually a high-temperature, high-pressure, and corrosive environment. Downhole metal oil pipes are usually connected by threads. By loading the metal sealing surface with a load, the metal sealing surface is in close contact, deformed, and produces contact stress to obtain sealing ability. Such metal seals have the characteristics of high-temperature, high-pressure, and corrosion resistance, so they have been well applied in the sealing of downhole oil pipes in high-temperature and high-pressure oil and gas wells. However, when the downhole oil pipe is working, it is under certain dynamic stress damage conditions, and the metal sealing surface of the oil pipe will also be damaged due to the effect of corrosive media in the high-temperature and high-pressure environment, which leads to a series of downhole accidents.

[0003] The dynamic damage of the metal sealing surface of the downhole oil pipe is mainly reflected in the aspect of abrasive corrosion. The vibration of the oil pipe causes the metal contact sealing surface to repeatedly move slightly, thus causing the wear and corrosion of the metal matrix of the oil pipe. This slight movement not only wears off the oxide film on the surface of the metal matrix of the oil pipe, but also further oxidizes the exposed fresh metal surface, and overlaps with the friction of the worn oxide debris as additional abrasives, forming double abrasion.

[0004] Therefore, it is necessary to carry out dynamic damage behavior and sealing performance tests of metal oil pipes under the action of abrasive vibration corrosion in high temperature and high pressure corrosion environment, evaluate their sealing performance, optimize their sealing structure, and effectively control downhole tubing leakage accidents. Summary of the invention

[0005] The problem to be solved by the present invention is to provide a device and method for evaluating the dynamic damage of metal sealing surfaces in a high-temperature and high-pressure corrosion environment in response to the dynamic damage of abrasive vibration corrosion in downhole tubulars. The device and method simulate the high-temperature and high-pressure environment downhole to measure the degree of dynamic corrosion damage of different types of metal sealing surfaces, evaluate the sealing performance of the metal sealing surfaces, and provide guidance for the design of metal sealing structures for downhole tubulars.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A dynamic damage evaluation device for a metal sealing surface in a high-temperature and high-pressure corrosive environment, the dynamic damage evaluation device for a metal sealing surface comprising a high-temperature and high-pressure sealing kettle assembly and a dynamic damage test assembly;

[0008] The high temperature and high pressure sealed kettle assembly comprises: a sealed kettle body, a sealed kettle cover, a corrosion test chamber, a heating sleeve, a fixing bolt, a fixing bolt gasket, a first sealing packing, a first air injection pump, a second air injection pump, a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a first air inlet, an air outlet, a first pressure gauge, a second pressure gauge, a gas detector, and a sealed kettle cover central sealing structure, wherein the sealed kettle cover central sealing structure is as follows: Figure 3 As shown, it includes: a hollow bolt, a hollow bolt washer, a circular washer, and a second sealing packing; the sealing kettle cover is fixed to the sealing kettle body by fixing bolts and fixing bolt washers, the sealing kettle cover presses the first sealing packing to form a seal, and the middle part of the sealing kettle cover presses the circular washer and the second sealing packing to form a seal through the hollow bolts; an air inlet is opened at the bottom of the sealing kettle body, and corrosive gas medium can be injected into the corrosion test chamber through the first air injection pump. At the same time, another pipeline is arranged at the bottom of the sealing kettle body to be connected with an external gas detector, a second pressure gauge and the second air injection pump, and the other end of the pipeline will be connected to the inner cavity of the threaded sealing pair; the sealing kettle cover is opened with an air outlet, and the air outlet is connected with the first pressure gauge, which can measure the gas pressure in the corrosion test chamber.

[0009] The dynamic damage test assembly includes: an exciter, a bracket, a push rod, a threaded seal male end, a threaded seal female end, a threaded seal inner cavity, a second air inlet, a spring, a metal hose connector, a support screw, a bending screw, a bending screw sleeve, a first hexagonal sleeve, and a second hexagonal sleeve; the threaded seal male end and the female end are connected by threads, such as Figure 2 As shown, the threaded connection forms a sealing surface, such as Figure 4 As shown, a seal is formed by a sealing surface; the exciter transmits vibration to the threaded sealing pair through a push rod; the bending screw and the bending sleeve form a bending device, such as Figure 5 As shown, both sides of the bending screw are threaded, and the threads on both sides are rotated in opposite directions. One side is connected to the right part of the sealing kettle body, and the other side is connected to the bending screw sleeve. The threaded connection between the bending screw and the screw sleeve has a self-locking function, which can stably load the bending moment. The bending screw and the screw sleeve are initially in a tightened state, at which time the bending screw sleeve does not contact the first hexagonal sleeve, which is convenient for the installation of the threaded sealing pair. The outside of the bending screw sleeve is a regular hexagonal column, and its left view is as shown in Figure 7As shown, it can be rotated by a wrench; the left end of the supporting screw is connected to the sealing kettle body by a thread, and this threaded connection also has self-locking ability. Initially, the right end of the supporting screw does not contact the second hexagonal sleeve on the female end of the threaded sealing pair, which is convenient for the installation of the threaded sealing pair. The supporting screw is unscrewed so that it is tightly connected with the second hexagonal sleeve. At this time, it can provide a good support for the female end of the threaded sealing pair; the bending device and the supporting screw can provide a variable bending moment for the threaded sealing pair; the first hexagonal sleeve and the second hexagonal sleeve are made of polytetrafluoroethylene, which is corrosion-resistant and has good outer ring smoothness and small roughness. They are respectively in plane-to-plane contact with the bending screw sleeve and the supporting screw, and their inner rings are tightly wrapped around the outer surfaces of the male end and the female end of the threaded sealing pair, with poor smoothness and large roughness; the two hexagonal sleeves have the same structure, and their inner rings are circular in the top view and regular hexagonal in the outer ring, as shown Figure 8 As shown, the hexagonal sleeve is very thin and its buffering effect on force can be ignored. The arrangement of the sleeve layer ensures that the bending effect of the threaded sealing pair always exists when the threaded sealing pair performs vibration movement and does not generate friction resistance to the threaded sealing pair.

[0010] Furthermore, a spring and a metal hose joint are arranged under the threaded sealing pair. When the threaded sealing pair performs up and down vibration movement, the spring provides it with a rebound force to maintain its up and down vibration movement. The spring is made of Hastelloy material and is corrosion-resistant. The metal hose joint is mainly composed of a bellows, a joint, a sealing ring and a mesh sleeve. It is connected to the lower pipe of the threaded sealing pair and can absorb the cyclic load of the up and down movement of the threaded sealing pair to compensate for the up and down displacement of the threaded sealing pair.

[0011] Furthermore, the power of the vibrator is adjustable, and its amplitude and frequency can be adjusted by adjusting its power; the vibrator is fixed to the sealed kettle cover through a bracket; the vibrator is stably connected to the top rod, and the top rod can well transmit the vibration output by the vibrator. The material of the top rod is Hastelloy, which is corrosion-resistant.

[0012] Furthermore, the first and second sealing packings are made of polytetrafluoroethylene and are corrosion-resistant; the fixing bolt gasket and the annular gasket are made of Hastelloy; a plane-to-plane sealing method is adopted between the second sealing packing and the annular gasket; there is a circular hole in the center of the hollow bolt, such as Figure 6 As shown, the push rod passes through its circular hole and is connected to the vibrator and the threaded sealing male end, and the hollow bolt and the sealing kettle cover are connected by airtight threads.

[0013] Furthermore, the male end of the threaded sealing pair and the female end of the threaded sealing pair are interference fit, the outer portion of the threaded sealing pair is generally cylindrical, and its material is the metal material used for downhole oil pipes. The metal sealing surface is in the form of a combination of two of the same or different surfaces of a plane, a conical surface, and a spherical surface. The material or surface quality or surface roughness or contact stress or effective sealing area that affects the performance of the sealing surface is variable.

[0014] Furthermore, the high temperature and high pressure environment is created by a heating jacket and an air injection pump. The heating jacket can heat and keep the sealed kettle warm. The air injection pump can inject a constant ratio of corrosive gas medium into the corrosion test chamber and the inner cavity of the threaded sealing pair. The pressure gauge can measure the gas pressure values ​​of the corrosion test chamber and the inner cavity of the threaded sealing pair. The gas detector can detect the corrosive gas medium in the inner cavity of the threaded sealing pair.

[0015] Furthermore, after the dynamic damage test is completed, the threaded sealing pair is taken out, and the corrosion morphology and corrosion products of the sealing surface are tested and analyzed to determine the degree of corrosion of the metal sealing surface. By adopting the above technical solution, the beneficial effects of the present invention are:

[0016] The device and method can well simulate the underground high-temperature and high-pressure corrosion environment and dynamic stress conditions. By detecting whether the metal sealing surface is damaged and the corrosion morphology and corrosion products of the metal sealing surface, the sealing performance of the metal sealing surface under dynamic damage can be determined. By changing the material of the threaded sealing pair and the factors affecting the sealing surface performance, the influence of various factors on the performance of the metal sealing surface can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the following briefly introduces the drawings required in the description of the embodiment. The drawings in the following description are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 This is a diagram of the device in the corrosion experiment chamber of the present invention;

[0020] Figure 3 This is a schematic diagram of the central sealing structure of the sealed kettle cover in the present invention;

[0021] Figure 4 A schematic diagram of a sealing surface formed by a threaded sealing pair connection in the present invention;

[0022] Figure 5 It is a schematic diagram of the bending moment loader in the present invention;

[0023] Figure 6 is a top view of the hollow bolt in the present invention;

[0024] Figure 7 It is a left view of the thread sleeve for bending in the present invention;

[0025] Figure 8 It is a schematic diagram of a hexagonal sleeve in the present invention;

[0026] Fig. 9 This is the corrosion morphology of the sealing surface of Example 1;

[0027] Fig.10 This is the corrosion product diagram of the sealing surface of Example 1;

[0028] Fig.11 This is the corrosion morphology of the sealing surface of Example 2;

[0029] Fig.12 This is the corrosion product diagram of the sealing surface of Example 2.

[0030] In the figure: 1- bracket, 2- vibrator, 3- push rod, 4- sealing kettle center sealing structure, 5- fixing bolt, 6- fixing bolt gasket, 7- sealing kettle cover, 8- first sealing packing, 9- sealing kettle body, 10- supporting screw, 11- heating sleeve, 12- spring, 13- first air inlet, 14- metal hose connector, 15- first air injection pump, 16- first valve, 17- first pressure gauge, 18- second valve, 19- air outlet, 20- screw sleeve for bending, 21- screw for bending , 22-first hexagonal sleeve, 23-threaded sealing male end, 24-threaded sealing female end, 25-second hexagonal sleeve, 26-second vent, 27-second pressure gauge, 28-gas detector, 29-third valve, 30-fourth valve, 31-fifth valve, 32-second air injection pump, 33-corrosion test chamber, 34-threaded sealing chamber, 35-sealing surface, 401-hollow bolt, 402-hollow bolt washer, 403-ring washer, 404-second sealing packing. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0032] Example 1

[0033] The corrosion test chamber is at high temperature and high pressure, with gaseous corrosive media but no liquid corrosive media:

[0034] Step 1: Connect the inlet and outlet gas pipelines, and check whether the first gas injection pump (15), the second gas injection pump (32), the first pressure gauge (17), the second pressure gauge (27) and the gas detector (28) are working properly;

[0035] Step 2: Assemble the bending screw (21), the bending screw sleeve (20) and the supporting screw (10), at which time the bending screw sleeve and the supporting screw are both in a tightened state, which is convenient for installing the threaded sealing pair;

[0036] Step 3: The prepared threaded sealing male end (23) and female end (24) are made of 3Cr, connected by threads and loaded and fastened. Figure 2 As shown, a sealing surface (35) is formed, such as Figure 4 As shown; the male end and the female end of the threaded sealing pair are respectively wrapped with a first hexagonal sleeve (22) and a second hexagonal sleeve (25);

[0037] Step 4: Place the spring (12) at the bottom center of the sealed kettle body (9), place the threaded seal pair in the corrosion test chamber (33), the female end (24) of the threaded seal pair is provided with a second vent (26) and a matching vent pipe, the vent pipe passes through the spring and is connected to the metal hose connector (14) at the bottom of the sealed kettle body, the metal hose connector can absorb the cyclic load of the threaded seal pair moving up and down, and compensate for the up and down displacement of the threaded seal pair;

[0038] Step 5: Unscrew the support screw (10) to make it contact with the second hexagonal sleeve (25) plane to plane, and then unscrew the bending screw sleeve (20) to make it contact with the first hexagonal sleeve (22) plane to plane, and then continue to unscrew the bending screw sleeve (20) by 0.1 cm to obtain the corresponding bending moment;

[0039] Step 6: Insert the first sealing packing (8) into the sealing kettle cover (7), insert the second sealing packing (404) into the sealing kettle cover, then insert the annular gasket (403) and the hollow bolt gasket (402), screw the hollow bolt (401) into the sealing kettle cover, there is a round hole in the middle of the hollow bolt for the push rod (3) to pass through, do not tighten the hollow bolt at this time;

[0040] Step 7: Cover the sealed kettle body (9) with a sealed kettle cover (7), and fix the sealed kettle cover and the sealed kettle body tightly with fixing bolts (5) and fixing bolt washers (6); the sealed kettle cover is connected to the air outlet (19), and the air outlet is connected to a first pressure gauge (17), and the first pressure gauge can measure the pressure in the corrosion test chamber (33);

[0041] Step 8: Pass the push rod (3) through the hollow bolt (401) and make close contact with the top of the threaded sealing male end (23). At this time, tighten the hollow bolt, and the hollow bolt presses the annular gasket (403) and the second sealing packing (404) to form a seal. This sealing component is as follows: Figure 3 As shown;

[0042] Step 9: Connect the push rod (3) to the vibrator (2). The vibrator is supported by the bracket (1). The bracket is fixed on the sealing kettle cover (7). The vibrator applies vibration to the threaded sealing pair through the push rod. At this time, all components are installed. The whole device is as follows: Figure 1 As shown;

[0043] Step 10: Open the first valve (16) and the second valve (18), and use the first gas injection pump (15) to introduce H2S and N2 gases in a ratio of 1:5 into the corrosion test chamber (33), and continue to inject for 10 minutes to ensure that the air in the corrosion test chamber is completely expelled, and then close the second valve;

[0044] Step 11: Open the heating jacket (11) for heating, and continuously introduce H2S and N2 gases in a ratio of 1:7. When the pressure reaches 60 MPa and the temperature reaches 80°C, open the fourth valve (30). It is found that the gas detector (28) detects that a corrosive mixed gas has been introduced into the inner cavity (34) of the threaded sealing pair, indicating that the sealing surface (35) of the threaded sealing pair has poor sealing performance. Take out the threaded sealing pair for sealing optimization, and repeat the above steps. It is observed that the gas detector cannot detect the introduced gas, which indicates that the sealing performance of the sealing surface of the threaded sealing pair is normal.

[0045] Step 12: Turn on the vibration exciter (2), set the power to 80W, and transmit vibration to the threaded sealing pair through the push rod (3); observe that the gas detector (28) does not detect the introduced gas, indicating that the sealing performance of the metal sealing surface (35) is normal;

[0046] Step 13: After the friction-vibration corrosion test is completed, the threaded seal pair is taken out and the corrosion morphology and products of the sealing surface (35) are analyzed. Fig. 9 and Fig.10 As shown, no obvious local corrosion marks were found on the sealing surface, and no obvious corrosion product accumulation was found, indicating that the sealing surface was slightly corroded and the sealing performance was good;

[0047] Step 14: After the inspection, replace the thread sealing surface and conduct the next set of experiments. Perform multiple experiments to measure the sealing performance of the thread sealing surface under the influence of different thread sealing pair materials and different thread sealing surface couplings, so as to select the combination of thread sealing pair materials and sealing surface forms with stronger sealing performance.

[0048] Example 2

[0049] The corrosion test chamber has a high temperature environment, liquid corrosive media, and high-pressure corrosive gas in the inner cavity of the threaded seal pair:

[0050] Step 1: Connect the inlet and outlet gas pipelines, and check whether the first gas injection pump (15), the second gas injection pump (32), the first pressure gauge (17), the second pressure gauge (27) and the gas detector (28) are working properly;

[0051] Step 2: Assemble the bending screw (21), the bending screw sleeve (20) and the supporting screw (10), at which time the bending screw sleeve and the supporting screw are both in a tightened state, which is convenient for installing the threaded sealing pair;

[0052] Step 3: The prepared threaded sealing male end (23) and female end (24) are made of N80 material, connected by threads and loaded and fastened. Figure 2 As shown, a sealing surface (35) is formed, such as Figure 4 As shown; the male end and the female end of the threaded sealing pair are respectively wrapped with a first hexagonal sleeve (22) and a second hexagonal sleeve (25);

[0053] Step 4: Place the spring (12) at the bottom center of the sealed kettle body (9), place the threaded seal pair in the corrosion test chamber (33), the female end (24) of the threaded seal pair is provided with a second vent (26) and a matching vent pipe, the vent pipe passes through the spring and is connected to the metal hose connector (14) at the bottom of the sealed kettle body, the metal hose connector can absorb the cyclic load of the threaded seal pair moving up and down, and compensate for the up and down displacement of the threaded seal pair;

[0054] Step 5: Unscrew the support screw (10) to make it contact with the second hexagonal sleeve (25) plane to plane, and then unscrew the bending screw sleeve (20) to make it contact with the first hexagonal sleeve (22) plane to plane, and then continue to unscrew the bending screw sleeve (20) by 0.15 cm to obtain the corresponding bending moment;

[0055] Step 6: Inject the prepared simulated formation water into the corrosion test chamber (33) to cover the connection between the male end (23) and the female end (24) of the threaded seal by 10 cm, ensuring that the metal sealing surface (35) is always in the corrosive liquid when vibrating;

[0056] Step 7: Insert the first sealing packing (8) into the sealing kettle cover (7), insert the second sealing packing (404) into the sealing kettle cover, then insert the annular gasket (403) and the hollow bolt gasket (402), screw the hollow bolt (401) into the sealing kettle cover, there is a round hole in the middle of the hollow bolt for the push rod (3) to pass through, do not tighten the hollow bolt at this time;

[0057] Step 8: Cover the sealed kettle body (9) with the sealed kettle cover (7), and fix the sealed kettle cover and the sealed kettle body tightly with the fixing bolts (5) and the fixing bolt washers (6); this experiment does not require the air outlet (19), so close the second valve (18);

[0058] Step 9: Pass the push rod (3) through the hollow bolt (401) and make close contact with the top of the threaded sealing male end (23). At this time, tighten the hollow bolt, and the hollow bolt presses the annular gasket (403) and the second sealing packing (404) to form a seal. This sealing component is as follows: Figure 3 As shown;

[0059] Step 10: Connect the push rod (3) to the vibrator (2). The vibrator is supported by the bracket (1). The bracket is fixed on the sealing kettle cover (7). The vibrator applies vibration to the threaded sealing pair through the push rod. At this time, all components are installed. The whole device is as follows: Figure 1 As shown;

[0060] Step 11: Open the fifth valve (31) and the third valve (29), use the second air injection pump (32) to introduce 10MPa H2S and 70MPa N2 into the inner cavity (34) of the threaded seal pair, close the fifth valve, observe the inner cavity pressure of the threaded seal pair detected by the second pressure gauge (27), and find that the pressure continues to decrease, indicating that the sealing performance of the sealing surface (35) of the threaded seal pair is poor. Take out the threaded seal pair for sealing optimization, repeat the above steps, and observe that the value of the second pressure gauge is stable, which indicates that the sealing performance of the sealing surface of the threaded seal pair is normal;

[0061] Step 12: Turn on the heating sleeve (11) to heat. When the temperature reaches 120°C, turn on the vibrator (2) and set the power to 100W to transmit vibration to the threaded sealing pair through the push rod (3); the pressure in the inner cavity of the threaded sealing pair detected by the second pressure gauge (27) is found to be unstable and continuously decreasing, indicating that the sealing surface is damaged;

[0062] Step 13: After the friction-vibration corrosion test is completed, the threaded seal pair is taken out and the corrosion morphology and products of the sealing surface (35) are analyzed. Fig.11 and Fig.12 As shown, a large number of corrosion products cross the sealing surface, the corrosion products are unevenly distributed and not tight, and there are pitting pits on the sealing surface, indicating that the sealing surface is seriously corroded;

[0063] Step 14: After the inspection, replace the thread sealing surface and conduct the next set of experiments. Perform multiple experiments to measure the sealing performance of the thread sealing surface under the influence of different thread sealing pair materials and different thread sealing surface couplings, so as to select the combination of thread sealing pair materials and sealing surface forms with stronger sealing performance.

Claims

1. A dynamic damage evaluation device for metal sealing surfaces in a high temperature and high pressure corrosive environment, characterized in that: The metal sealing surface dynamic damage evaluation device comprises a high temperature and high pressure sealing kettle assembly and a dynamic damage test assembly; The high-temperature and high-pressure sealed kettle assembly comprises: a sealed kettle body (9), a sealed kettle cover (7), a corrosion test chamber (33), a heating jacket (11), a fixing bolt (5), a fixing bolt washer (6), a first sealing packing (8), a first air injection pump (15), a second air injection pump (32), a first valve (16), a second valve (18), a third valve (29), a fourth valve (30), a fifth valve (31), a first air inlet (13), an air outlet (19), a first pressure gauge (17), a second pressure gauge (27), a gas detector (28), and a sealed kettle cover central sealing structure (4), wherein the sealed kettle cover central sealing structure comprises: a hollow bolt (401), a hollow bolt washer (402), a circular washer (403), and a cylindrical washer (404). 03), the second sealing packing (404); the sealing kettle cover (7) is fixed to the sealing kettle body (9) by fixing bolts (5) and fixing bolt washers (6), the sealing kettle cover (7) presses the first sealing packing (8) to form a seal, and the middle part of the sealing kettle cover (7) presses the annular washer (403) and the second sealing packing (404) to form a seal through the hollow bolt (401); the bottom of the sealing kettle body (9) is provided with a first air inlet (13), and another pipeline is connected to the external gas detector (28), the second pressure gauge (27) and the second air injection pump (32), and the other end of the pipeline will be connected to the inner cavity (34) of the threaded sealing pair; the sealing kettle cover (7) is provided with an air outlet (19), and the air outlet is connected to the first pressure gauge (17); The dynamic damage test assembly comprises: an exciter (2), a bracket (1), a push rod (3), a male end of a threaded seal pair (23), a female end of a threaded seal pair (24), an inner cavity of a threaded seal pair (34), a second vent (26), a spring (12), a metal hose connector (14), a supporting screw (10), a bending screw (21), a bending screw sleeve (20), a first hexagonal sleeve (22), and a second hexagonal sleeve (25); a sealing surface (35) is formed between the male end (23) and the female end (24) of the threaded seal pair through a threaded connection, and a seal is formed by the sealing surface; the exciter (2) transmits vibration to the threaded seal pair through the push rod (3); the metal hose connector (14) mainly comprises The invention relates to a bending device, comprising a bellows, a joint, a sealing ring and a mesh sleeve, which is connected to the lower pipe of the threaded sealing pair; the bending screw (21) and the bending screw sleeve (20) form a bending device, the bending screw (21) has threads on both sides, and the threads on both sides rotate in opposite directions, one side is connected to the right part of the sealing kettle body (9), and the other side is connected to the bending screw sleeve (20), and the left end of the supporting screw (10) is connected to the sealing kettle body (9) through a thread; the outer rings of the first hexagonal sleeve (22) and the second hexagonal sleeve (25) have good smoothness and small roughness, and are respectively in plane-to-plane contact with the bending screw sleeve (20) and the supporting screw (10), and their inner rings are tightly wrapped around the outer surfaces of the threaded sealing pair male end (23) and the threaded sealing pair female end (24).

2. The dynamic damage evaluation device for metal sealing surface in high temperature and high pressure corrosion environment according to claim 1 is characterized in that: A plane-to-plane sealing method is adopted between the second sealing packing (404) and the annular gasket (403); a circular hole is provided at the center of the hollow bolt (401), and the push rod (3) passes through the circular hole to be connected to the vibrator (2) and the threaded sealing secondary male end (23); the hollow bolt (401) and the sealing kettle cover (7) are connected by airtight threads.

3. The dynamic damage evaluation device for metal sealing surface in high temperature and high pressure corrosion environment according to claim 1 is characterized in that: The threaded sealing male end (23) and the threaded sealing female end (24) are interference fit, the sealing surface is a combination of two identical or different surfaces of a plane, a conical surface and a spherical surface, and the material, surface quality, surface roughness, contact stress or effective sealing area that affect the performance of the sealing surface can be changed.

4. A method for evaluating dynamic damage of a metal sealing surface in a high-temperature and high-pressure corrosive environment, using the device for evaluating dynamic damage of a metal sealing surface in a high-temperature and high-pressure corrosive environment as claimed in any one of claims 1 to 3, characterized in that: The specific implementation steps are as follows: Step 1: Connect the inlet and outlet gas pipelines, and check whether the first gas injection pump (15), the second gas injection pump (32), the first pressure gauge (17), the second pressure gauge (27) and the gas detector (28) are working properly; Step 2: Assemble the bending screw (21), the bending screw sleeve (20) and the supporting screw (10), at which time the bending screw sleeve and the supporting screw are both in a tightened state; Step 3: The prepared threaded sealing pair male end (23) and threaded sealing pair female end (24) are connected by threads and loaded and fastened to form a sealing surface (35); the male end and the female end of the threaded sealing pair are respectively wrapped with a first hexagonal sleeve (22) and a second hexagonal sleeve (25); Step 4: Place the spring (12) at the center of the bottom of the sealed kettle body (9), place the threaded seal pair in the corrosion test chamber (33), the female end (24) of the threaded seal pair is provided with a second vent (26) and a matching vent pipe, the vent pipe passes through the spring and is connected to the metal hose connector (14) at the bottom of the sealed kettle body (9); Step 5: Unscrew the supporting screw rod (10) to make it contact with the second hexagonal sleeve (25) in a plane-to-plane manner to provide support, then unscrew the bending screw sleeve (20) to make it contact with the first hexagonal sleeve (22) in a plane-to-plane manner, and then adjust the advance to control the applied bending moment force; Step 6: As required, inject the prepared simulated formation water into the corrosion test chamber (33) so that it covers the connection between the male end (23) and the female end (24) of the threaded seal pair, ensuring that the sealing surface is always in the corrosive liquid when vibrating; Step 7: Insert the first sealing packing (8) into the sealing kettle cover (7), insert the second sealing packing (404) into the sealing kettle cover, then insert the annular gasket (403) and the hollow bolt gasket (402), screw the hollow bolt (401) into the sealing kettle cover, and do not tighten the hollow bolt at this time; Step 8: Cover the sealed kettle body (9) with the sealed kettle cover (7), and fix the sealed kettle cover and the sealed kettle body tightly with the fixing bolts (5) and the fixing bolt washers (6); connect the sealed kettle cover to the air outlet (19), the air outlet is connected to the first pressure gauge (17), and close the second valve (18); Step nine: Pass the push rod (3) through the hollow bolt (401) and make close contact with the top of the threaded sealing male end (23). At this time, tighten the hollow bolt, and the hollow bolt presses the annular gasket (403) and the second sealing packing (404) to form a seal; Step 10: Connect the push rod (3) to the vibrator (2), the vibrator is supported by the bracket (1), the bracket is fixed on the sealing kettle cover (7), and the vibrator applies vibration to the threaded sealing pair through the push rod. At this time, the installation of all components is completed; Step 11: A certain proportion of corrosive mixed gas is introduced into the corrosion test chamber (33) or the inner cavity (34) of the threaded seal pair, and the heating sleeve (11) is turned on for heating. After the pressure and temperature reach the specified values, observe whether the gas detector (28) detects that there is corrosive mixed gas introduced into the inner cavity (34) of the threaded seal pair or whether the pressure of the inner cavity (34) of the threaded seal pair detected by the second pressure gauge (27) is stable, so as to determine the sealing performance of the metal sealing surface (35) of the threaded seal pair when it is not dynamically damaged. If the sealing performance of the metal sealing surface of the threaded seal pair is poor, remove the threaded seal pair for sealing optimization, and repeat the above steps until the sealing performance of the sealing surface (35) of the threaded seal pair is normal, and then proceed to the next step; Step 12: Turn on the vibration exciter (2) and transmit vibration to the threaded seal pair through the push rod (3); observe whether the gas detector (28) detects that a corrosive mixed gas has been introduced into the inner cavity (34) of the threaded seal pair or whether the pressure of the inner cavity (34) of the threaded seal pair detected by the second pressure gauge (27) is stable, thereby determining whether the sealing performance of the metal sealing surface (35) of the threaded seal pair is damaged; Step 13: After the dynamic damage test is completed, the threaded sealing pair is taken out, and the corrosion morphology and products of the metal sealing surface (35) are analyzed to determine the corrosion degree, and the integrity of the metal sealing surface is determined according to the corrosion degree; Step 14: After the test, the metal sealing surface (35) is replaced and the next group of experiments are carried out. The sealing performance of the metal sealing surface under the influence of different thread sealing pair materials and different thread sealing surface coupling is measured through multiple experiments, so as to optimize the thread sealing pair material and sealing surface form combination with stronger sealing performance.

Images