An experimental device and method for simulating vibration of oil pipe string in annular pressure gas well

Abstract

The present invention discloses an experimental device and method for simulating vibration of annular pressure gas well tubing. Liquid is injected into the annulus of a cylinder to form annular pressure, and high-pressure gas is injected into a reservoir simulation unit. The high-pressure gas flows from the bottomhole simulation space of the reservoir simulation unit into a test tubing at the axis of the cylinder and is released through a high-pressure gas discharge pipeline. Different closing speeds of the solenoid valve are used to simulate different well shut-in times. The rapid closing of the solenoid valve generates pressure fluctuations, forming a water hammer effect, causing the test tubing to vibrate, thereby simulating tubing vibration. Stress and strain gauges can monitor the dynamic response process of the test tubing vibration and transmit the data to a computer for real-time storage. The device and method of the present invention can not only effectively simulate the vibration process of the tubing in annular pressure gas well tubing, but also quantitatively analyze the stress and strain conditions at different positions of the tubing during the vibration process. This breaks through the limitations of theoretical research and more realistically simulates the vibration of the tubing in annular pressure gas well tubing.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas development, and in particular to a device and method for simulating vibration of an oil pipe string in an annular pressure gas well. Background Art

[0002] With the continuous increase in natural gas consumption demand in my country in recent years and the further development of the natural gas industry, natural gas exploration and development are also advancing into deep, complex formations, and unconventional areas. Natural gas exploration and development in deep and complex formations faces increasingly demanding conditions. Annular pressure is becoming increasingly serious during the production of high-pressure, high-yield natural gas wells, increasing the risk of wellbore integrity failure. Some gas wells even experience simultaneous pressure in multiple layers of the annulus. Annular pressure, also known as sustained casing pressure, refers to the phenomenon in which the annular pressure of a gas well quickly returns to its pre-pressure level after pressure relief. During production, if high-pressure natural gas breaks through the wellbore integrity barrier and enters the annulus, it can seriously impact the safe production of the gas well. Excessive annular pressure can cause collapse and failure of tubing, casing, packers, wellhead equipment, and other components, posing a significant threat to the safe production of the gas well. When annular pressure is not obvious, pressure monitoring and pressure relief operations increase production costs and safety risks. In severe cases, it can lead to well closure or even the abandonment of the entire well. Once persistent annular pressure occurs, the treatment methods are very limited. It is difficult to remediate annular pressure gas wells. Well repair often requires pulling out the oil tubing and inspecting and treating the damaged oil tubing, and the cost of well repair is extremely high.

[0003] There are two main causes of annular pressure in gas wells. One is tubing string failure, typically caused by failure of the tubing string, casing, or downhole packer. This causes gas from the producing zone to flow into the annulus of the casing and accumulate at the wellhead, creating annular pressure. This type of annular pressure presents the greatest risk and is the primary cause of annular pressure. The other is cement sheath seal failure. Due to unique circumstances during the cement casting or cooling process, microscopic gaps form within the cement sheath. High-pressure gas from the downhole seeps through these gaps into the wellhead in the casing annulus, creating annular pressure. Downhole tubing string failure in gas wells has become a significant constraint on the stable development of many oil and gas fields in my country. During production in wells with annular pressure, downhole gas continuously accumulates in the annulus at the wellhead through crossflow, not only causing annular pressure buildup, but also, if the natural gas in the well contains corrosive gases such as CO2 and H2S, it can corrode the tubing string, weakening its strength and posing a direct threat to the integrity of the wellbore, impacting safe production.

[0004] For high-pressure, high-yield gas wells, production fluctuations and well opening and closing operations can cause natural gas flow instability. The transient pressure fluctuations of high-speed gas flow impose strong dynamic alternating loads on the tubing string, inducing vibration, resulting in stress fatigue damage, crack initiation, and eventual failure. Friction and wear between the tubing and the inner wall of the casing cause other forms of damage. If the tubing string is exposed to harsh production environments and is prone to corrosion, vibration can accelerate damage and failure, leading to even more demanding service environments.

[0005] Currently, research on tubing string chatter is mainly based on numerical model calculations. However, there are a lot of simplifications in the model processing process, and the assumptions of the calculation model differ from the actual wellbore environment, resulting in large deviations in the calculation results of the theoretical model of tubing string chatter.

[0006] Therefore, it is necessary to conduct relevant experimental research to clarify the dynamic response of tubing string vibration. To address the above issues, it is necessary to analyze the vibration and stress distribution of tubing strings during gas production to provide a scientific basis for the safety of tubing strings in high-pressure, high-yield gas wells. By identifying the locations with the highest failure risk, preventive measures such as improved completion design can be taken to extend the service life of tubing strings, providing theoretical guidance for the safe and long-term service of tubing strings in oil fields. Summary of the Invention

[0007] In order to solve the problem of large deviation in the calculation results of the theoretical model of the above-mentioned oil tubing string vibration, the present invention proposes an experimental device and method for simulating the vibration of the oil tubing string in annular pressure gas wells, which can explore the vibration response law of the oil tubing string during gas production and provide scientific theoretical guidance for vibration reduction of the oil tubing string in high-pressure gas wells.

[0008] In the first aspect, an annulus pressurized gas well oil tubing string vibration simulation experimental device includes a high-pressure gas input pipeline, a high-pressure gas exhaust pipeline and a reservoir simulation unit, and also includes a barrel, a test string and a liquid input pipeline; the high-pressure gas input pipeline includes a nitrogen cylinder, a gas booster pump, a throttle valve and a gas flow meter; the nitrogen cylinder is connected to the gas booster pump, the throttle valve, the gas flow meter, the high-pressure gas input pipeline in sequence, and is connected to the reservoir simulation unit.

[0009] Specifically, the upper and lower ends of the cylinder are sealed by a cover plate and a base respectively, a test pipe string fixed by the cover plate and the base is set at the axis of the cylinder, and the base is connected to the reservoir simulation unit; the upper end of the test pipe string passes through the center of the cover plate at the upper end of the cylinder and is connected to the high-pressure gas exhaust pipeline; the cover plate is also connected to the liquid injection pipeline, the liquid injection pipeline is connected to the liquid delivery pump and communicates with the annulus in the cylinder; the high-pressure gas exhaust pipeline is connected to the pressure sensor, the solenoid valve and the gas discharge outlet in sequence.

[0010] Specifically, five stress strain gauges are connected to the outer wall of the test pipe string, namely stress strain gauge one, stress strain gauge two, stress strain gauge three, stress strain gauge four and stress strain gauge five; the five stress strain gauges are all connected to the data transmission line located in the annulus, the data transmission line is connected to the data transmission line connector, and the other end of the data transmission line connector is connected to the computer.

[0011] Specifically, the base is connected to the cylinder and the reservoir simulation unit through a flange connection. The test pipe string passes through the center of the base and is fixed by the base. Within a certain range, the base can fix different positions of the test pipe string. The area between the test pipe string and the inner wall of the cylinder is an annulus. A drain valve is provided on the wall of the base, and the drain valve is connected to the annulus. The length of the cylinder and the test pipe string can be adjusted according to experimental needs.

[0012] Specifically, the cover plate is fixed to the cylinder by bolts in a flange connection manner, and the cover plate includes an acoustic rangefinder, a data transmission line connector, a pressure relief valve three and a liquid input pipeline connector; the data transmission line connector is connected to the data transmission line inside the cylinder; the acoustic rangefinder is connected to the annulus; the pressure relief valve three is connected to the annulus; the liquid input pipeline connector is connected to the liquid input pipeline and is communicated with the annulus.

[0013] Specifically, five pressure sensors are provided on the cylinder wall at equal intervals, which are pressure sensor three, pressure sensor four, pressure sensor five, pressure sensor six, and pressure sensor seven from bottom to top.

[0014] Specifically, the gas input pipeline connector at the right end of the reservoir simulation unit is connected to the high-pressure gas input pipeline, and a pressure sensor and a pressure relief valve are provided at the right end of the reservoir simulation unit; a gap with a width of 1 mm and a seam plate assembly are provided in the seam plate assembly, and a cube-shaped bottom hole simulation space is provided at the left end of the seam plate assembly, the bottom hole simulation space is connected to the pressure sensor, and a pressure relief valve 2 is provided at the bottom end of the bottom hole simulation space.

[0015] On the other hand, a method for simulating vibration of an oil tubing string in an annular pressure gas well is implemented based on an apparatus for simulating vibration of an oil tubing string in an annular pressure gas well, comprising the following steps:

[0016] Step S1: Experimental preparation, check the experimental device; keep the nitrogen bottle closed, close the pressure relief valve 1 and pressure relief valve 2 to keep the reservoir simulation unit in a closed state; close the pressure relief valve 3 and the drain valve to keep the annulus in a closed state; keep the solenoid valve open;

[0017] Step S2: injecting liquid into the annulus, starting the liquid delivery pump, inputting the liquid into the annulus, and after various pressures are stabilized, recording the pressure values ​​P3, P4, P5, P6, and P7 of pressure sensor 3, pressure sensor 4, pressure sensor 5, pressure sensor 6, and pressure sensor 7, respectively, starting the sonic rangefinder to measure the liquid level in the annulus, and then closing the one-way valve;

[0018] Step S3: Open the nitrogen bottle and inject gas into the experimental device; turn on the gas booster pump, control the throttle valve opening to maintain a certain value, and after the values ​​of each pressure sensor and gas flow meter are stable, record the flow value Q of the gas flow meter, and record the pressure values ​​P1, P2, and P8 of pressure sensor 1, pressure sensor 2, and pressure sensor 8 respectively.

[0019] Specifically, the following steps are also included:

[0020] Step S4: Setting a certain speed to close the solenoid valve, recording the dynamic changes of the values ​​of stress strain gauge 1, stress strain gauge 2, stress strain gauge 3, stress strain gauge 4, and stress strain gauge 5 through a computer, and drawing a transient change graph;

[0021] Step S5: changing the closing speed of the solenoid valve, and repeating steps S3 and S4;

[0022] Step S6: End the experiment, turn off the nitrogen gas cylinder and the gas booster pump; discharge the liquid in the annulus out of the cylinder of the experimental device through the drain valve; open the pressure relief valve 1, pressure relief valve 2 and pressure relief valve 3 to release the pressure.

[0023] The beneficial effects of the present invention are as follows: the present invention proposes an experimental device and method for simulating vibration of annular pressure gas well oil tubing string, wherein a liquid delivery pump injects liquid into the annulus of a cylinder to form annular pressure, and a gas booster pump injects high-pressure gas into a reservoir simulation unit, and the high-pressure gas flows from the bottom hole simulation space of the reservoir simulation unit into the test tubing string at the axis of the cylinder, and then is discharged through the high-pressure gas discharge pipeline; different closing speeds of the solenoid valve are used to simulate different well shut-in times, and the rapid closing of the solenoid valve generates pressure fluctuations, forming a water hammer effect, causing the test tubing string to vibrate to simulate oil tubing string vibration; the stress and strain gauges on the test tubing string can monitor the dynamic response process of the test tubing string vibration, and transmit the data to a computer for real-time storage. The device can not only effectively simulate the vibration process of the oil tubing string in an annular pressure gas well, but also quantitatively analyze the stress and strain conditions at different positions of the tubing string during the vibration process; it breaks through the limitations of theoretical research and more realistically simulates the vibration of the oil tubing string in annular pressure gas wells. It can simulate the problem of vibration of the oil tubing string in annular pressure gas wells, breaking through the limitations of theoretical mathematical model research; the solenoid valve in the present invention can be set to close at different speeds to simulate well shut-in for different lengths of time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1This is a front view of an annulus pressure gas well oil pipe string vibration simulation experimental device of the present invention;

[0025] Figure 2 This is a schematic AA cross-sectional view of an annular pressure gas well oil pipe string vibration simulation experimental device of the present invention;

[0026] Figure 3 This is a partial schematic diagram of the AA section of an annular pressure gas well oil pipe string vibration simulation experimental device of the present invention;

[0027] Figure 4 This is a top view of a cover plate of an annular pressure gas well oil pipe string vibration simulation experimental device of the present invention;

[0028] Figure 5 This is a CC section (orthogonal to the AA section) schematic diagram of an annulus pressure gas well oil pipe string vibration simulation experimental device of the present invention;

[0029] Figure 6 This is an axonometric view of the main part of an annular pressure gas well oil pipe string vibration simulation experimental device of the present invention;

[0030] Figure 7 This is a BB cross-sectional view of an annular pressure gas well oil pipe string vibration simulation experimental device of the present invention;

[0031] In the figure, 1-nitrogen cylinder, 2-gas booster pump, 3-throttle valve, 4-gas flow meter, 5-high-pressure gas input pipeline, 6-pressure sensor 1, 7-pressure relief valve 1, 8-reservoir simulation unit, 9-pressure relief valve 2, 10-pressure sensor 2, 11-base, 12-drain valve, 13-cylinder, 14-pressure sensor 3, 15-pressure sensor 4, 16-pressure sensor 5, 17-pressure sensor 6, 18-pressure sensor 7, 19-sonic rangefinder, 20-data transmission line connector, 21-cover, 22-pressure sensor 8, 23-high High-pressure gas discharge pipeline, 24-solenoid valve, 25-gas discharge outlet, 26-check valve, 27-liquid input pipeline, 28-liquid delivery pump, 29-computer, 30-data transmission line, 31-pressure relief valve three, 32-stress strain gauge one, 33-test string, 34-annulus, 35-stress strain gauge two, 36-stress strain gauge three, 37-stress strain gauge four, 38-stress strain gauge five, 39-bottomhole simulation space, 40-liquid input pipeline joint, 41-bolt, 42-gas input pipeline joint, 43-seam plate assembly, 44-gap. DETAILED DESCRIPTION

[0032] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0033] The present invention proposes a device and method for simulating vibration of oil pipe string in annular pressure gas well. Figure 1 、 Figure 2 and Figure 5 As shown, the annulus pressure gas well oil pipe string vibration simulation experimental device includes a high-pressure gas input pipeline 5, a reservoir simulation unit 8, a barrel 13 of the experimental device, a high-pressure gas discharge pipeline 23, and a liquid input pipeline 27; the high-pressure gas input pipeline 26 is connected to the reservoir simulation unit 8, and the upper and lower ends of the barrel 13 are respectively sealed by a cover plate 21 and a base 11 in a flange connection manner, and the lower end of the base 11 is connected to the reservoir simulation unit 8; the test string 33 is located at the axis of the barrel 13, passing through the base 11 and the cover plate 21; an annulus 34 is between the test string 33 and the inner wall of the barrel 13; the liquid injection pipeline 27 is connected to the annulus 34, and the high-pressure gas discharge pipeline 23 is connected to the outlet end of the test string 33.

[0034] On the high-pressure gas input pipeline 5, the gas released after the nitrogen cylinder 1 is opened forms high-pressure gas after passing through the gas booster pump 2, and enters the reservoir simulation unit 8 after flowing through the throttle valve 3 and the gas flowmeter 4; the high-pressure gas in the reservoir simulation unit 8 will flow into the test pipe string 33 located at the axis of the cylinder 13 in the bottom hole simulation space 39. Due to the sealing performance of the base 11, the gas will not flow into the annulus 34; the high-pressure gas flows out of the test pipe string 33, enters the high-pressure gas discharge pipeline 23, and flows out of the entire experimental device system through the gas discharge port 25. The solenoid valve 24 can be set with different valve closing speeds; the liquid delivery pump 28 injects liquid into the annulus 34 through the liquid input pipeline 27. After the liquid is injected, closing the one-way valve 26 can keep the pressure of the annulus 34 stable. Since the original gas in the annulus 34 is subjected to the pressure of the liquid, annulus pressure will be formed.

[0035] In this embodiment, if Figure 2 and Figure 3 As shown, five stress strain gauges are set at equal intervals on the wall of the test pipe string 33, namely stress strain gauge 1 32, stress strain gauge 2 35, stress strain gauge 36, stress strain gauge 4 37 and stress strain gauge 5 37. The data of the test pipe string 33 collected by the five stress strain gauges are transmitted through the data transmission line 30 and the data transmission line connector 20; five pressure sensors are set at equal intervals on the wall of the cylinder 13 to monitor the pressure at different positions in the annulus 34, namely pressure sensor 3 14, pressure sensor 4 15, pressure sensor 5 16, pressure sensor 6 17 and pressure sensor 7 18.

[0036] like Figure 3 and Figure 4 As shown, the cover plate 21 is provided with an acoustic rangefinder 19 , a data transmission line connector 20 , a pressure relief valve 31 , and a liquid input pipeline connector 40 , and a test pipe column 33 passes through the center of the cover plate 21 .

[0037] like Figure 6 As shown, pressure sensor 1 6 and pressure sensor 2 10 are respectively provided at the inlet and outlet ends of the reservoir simulation unit 8 ; a drain valve 12 communicating with the annulus 34 is provided on the wall of the base 11 .

[0038] like Figure 6 and Figure 7 As shown, gas enters the reservoir simulation unit 8 through the gas input pipeline joint 42 and passes through the slit plate assembly 43. A 1 mm wide slit 44 is set in the center of the slit plate assembly 43 to simulate reservoir fractures.

[0039] A method for simulating vibration of an oil pipe string in an annulus pressure gas well comprises the following steps:

[0040] Step 1: Prepare for the experiment and check the experimental equipment. Keep the nitrogen cylinder closed and close pressure relief valves 1 and 2 to keep the reservoir simulation unit sealed. Close pressure relief valve 3 and the drain valve to keep the annulus sealed. Keep the solenoid valve open.

[0041] Step 2: Inject liquid into the annulus, start the liquid delivery pump, and input the liquid into the annulus. After the pressures stabilize, record the pressure values ​​P3, P4, P5, P6, and P7 of pressure sensor three, pressure sensor four, pressure sensor five, pressure sensor six, and pressure sensor seven respectively, and start the sonic rangefinder to measure the liquid level in the annulus; then close the one-way valve.

[0042] Step 3: Open the nitrogen cylinder and fill the experimental apparatus with gas. Turn on the gas booster pump and maintain a constant throttle valve opening. After the pressure sensor and gas flow meter readings stabilize, record the flow rate Q on the gas flow meter and the pressure values ​​P1, P2, and P8 on pressure sensor 1, pressure sensor 2, and pressure sensor 8, respectively.

[0043] Step 4: Set a certain speed to close the solenoid valve, and use a computer to record the dynamic changes in the values ​​of stress strain gauge 1, stress strain gauge 2, stress strain gauge 3, stress strain gauge 4, and stress strain gauge 5, and draw a graph.

[0044] Step 5: Change the closing speed of the solenoid valve and repeat steps 3 and 4.

[0045] Step six, end the experiment, turn off the nitrogen bottle and gas booster pump; discharge the liquid in the annulus out of the cylinder of the experimental device through the drain valve; open pressure relief valve one, pressure relief valve two, and pressure relief valve three to release the pressure.

[0046] The present invention proposes an experimental device and method for simulating vibration of annular pressure gas well tubing strings. Liquid is injected into the annulus of the cylinder to form annular pressure, and high-pressure gas is injected into the reservoir simulation unit. The high-pressure gas flows from the bottomhole simulation space of the reservoir simulation unit into the test tubing string at the axis of the cylinder and is released through the high-pressure gas discharge pipeline. Different closing speeds of the solenoid valve are used to simulate different well shut-in times. The rapid closing of the solenoid valve generates pressure fluctuations, forming a water hammer effect, causing the test tubing string to vibrate, thereby simulating tubing string vibration. Stress and strain gauges can monitor the dynamic response process of the test tubing string vibration and transmit the data to a computer for real-time storage. The device and method of the present invention can not only effectively simulate the vibration process of the tubing string in annular pressure gas well tubing strings, but also quantitatively analyze the stress and strain conditions at different positions of the tubing string during vibration. It breaks through the limitations of theoretical research and more realistically simulates the vibration of the tubing string in annular pressure gas well tubing strings.

[0047] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. An experimental device for simulating vibration of oil pipe string in annular pressure gas well, characterized by: The invention comprises a high-pressure gas input pipeline (5), a high-pressure gas discharge pipeline (23) and a reservoir simulation unit (8), and also comprises a cylinder (13), a test pipe string (33) and a liquid input pipeline (27); the high-pressure gas input pipeline (5) comprises a nitrogen cylinder (1), a gas booster pump (2), a throttle valve (3) and a gas flow meter (4); the nitrogen cylinder (1) is sequentially connected to the gas booster pump (2), the throttle valve (3), the gas flow meter (4), the high-pressure gas input pipeline (5), and is connected to the reservoir simulation unit (8); The upper and lower ends of the cylinder (13) are sealed with the base (11) through the cover plate (21) respectively. A test pipe string (33) fixed by the cover plate (21) and the base (11) is set at the axis of the cylinder (13), and the base (11) is connected to the reservoir simulation unit (8); the upper end of the test pipe string (33) passes through the center of the cover plate (21) at the upper end of the cylinder (13) and is connected to the high-pressure gas discharge pipeline (23); the cover plate (21) is also connected to the liquid input pipeline (27), the liquid input pipeline (27) is connected to the liquid delivery pump (28) and communicates with the annulus (34) in the cylinder (13); the high-pressure gas discharge pipeline (23) is connected to the pressure sensor (22), the solenoid valve (24), and the gas discharge outlet (25) in sequence; Five stress strain gauges are connected to the outer wall of the test pipe string (33), namely stress strain gauge 1 (32), stress strain gauge 2 (35), stress strain gauge 3 (36), stress strain gauge 4 (37) and stress strain gauge 5 (38); the five stress strain gauges are all connected to the data transmission line (30) located in the annulus (34), the data transmission line (30) is connected to the data transmission line connector (20), and the other end of the data transmission line connector (20) is connected to the computer (29); The base (11) is connected to the cylinder (13) and the reservoir simulation unit (8) by a flange connection. The test pipe string (33) passes through the center of the base (11) and is fixedly constrained by the base (11). Within a certain range, the base (11) can fix different positions of the test pipe string (33); the area between the test pipe string (33) and the inner wall of the cylinder (13) is an annulus (34), and a drain valve (12) is provided on the wall of the base (11), and the drain valve (12) is communicated with the annulus (34); the lengths of the cylinder (13) and the test pipe string (33) are adjusted according to experimental needs; The cover plate (21) is fixedly connected to the cylinder (13) by bolts (41) in a flange connection manner. The cover plate (21) includes an acoustic rangefinder (19), a data transmission line connector (20), a third pressure relief valve (31) and a liquid input pipeline connector (40); the data transmission line connector (20) is connected to the data transmission line (30) inside the cylinder (13); the acoustic rangefinder (19) is communicated with the annulus (34); the third pressure relief valve (31) is communicated with the annulus (34); the liquid input pipeline connector (40) is connected to the liquid input pipeline (27) and is communicated with the annulus (34); Five pressure sensors are provided on the wall of the cylinder (13) at equal intervals, which are pressure sensor three (14), pressure sensor four (15), pressure sensor five (16), pressure sensor six (17) and pressure sensor seven (18) from bottom to top; The gas input pipeline joint (42) at the right end of the reservoir simulation unit (8) is connected to the high-pressure gas input pipeline (5), and a pressure sensor (6) and a pressure relief valve (7) are provided at the right end of the reservoir simulation unit (8); a gap (44) with a width of 1 mm and a slit plate assembly (43) are provided in the slit plate assembly (43), and a cube-shaped bottom hole simulation space (39) is provided at the left end of the slit plate assembly (43), the bottom hole simulation space (39) is connected to the pressure sensor (10), and a pressure relief valve (9) is provided at the bottom end of the bottom hole simulation space (39).

2. A method for simulating vibration of an oil pipe string in an annular pressure gas well, based on the apparatus for simulating vibration of an oil pipe string in an annular pressure gas well according to claim 1, characterized in that: The following steps are involved: Step S1: Experimental preparation, check the experimental device; keep the nitrogen bottle (1) closed, close the pressure relief valve 1 (7) and the pressure relief valve 2 (9), so that the reservoir simulation unit (8) remains in a sealed state; close the pressure relief valve 3 (31) and the drain valve (12), so that the annulus (34) remains in a sealed state; the solenoid valve (24) remains in an open state; Step S2: inject liquid into the annulus (34), start the liquid delivery pump (28), input the liquid into the annulus (34), wait for the various pressures to stabilize, record the pressure values ​​P3, P4, P5, P6 and P7 of the pressure sensor 3 (14), the pressure sensor 4 (15), the pressure sensor 5 (16), the pressure sensor 6 (17) and the pressure sensor 7 (18), respectively, start the sonic rangefinder (19) to measure the liquid level in the annulus (34), and then close the one-way valve (26); Step S3: Open the nitrogen bottle (1) and inject gas into the experimental device; open the gas booster pump (2), control the throttle valve (3) to maintain a certain opening, and after the values ​​of each pressure sensor and gas flow meter (4) are stable, record the flow value Q of the gas flow meter (4), and record the pressure values ​​P1, P2 and P8 of pressure sensor 1 (6), pressure sensor 2 (10) and pressure sensor 8 (22) respectively.

3. The method for simulating vibration of annular pressure gas well tubing string according to claim 2, characterized in that: The following steps are also included: Step S4: Setting a certain speed to close the electromagnetic valve (24), recording the dynamic change process of the values ​​of the stress strain gauge 1 (32), the stress strain gauge 2 (35), the stress strain gauge 3 (36), the stress strain gauge 4 (37) and the stress strain gauge 5 (38) through the computer (29), and drawing a transient change graph; Step S5: changing the closing speed of the solenoid valve (24), and repeating steps S3 and S4; Step S6: End the experiment, close the nitrogen gas cylinder (1) and the gas booster pump (2); discharge the liquid in the annulus (34) out of the experimental device cylinder (13) through the drain valve (12); open the pressure relief valve 1 (7), pressure relief valve 2 (9) and pressure relief valve 3 (31) to release the pressure.

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