A visual simulation experimental test device and method for oil sleeve ring air-carrying liquid

Abstract

The present invention provides a visual simulation experimental test device and method for air-liquid carrying in an oil casing annulus, which belongs to the technical field of oil and natural gas extraction, and includes an oil casing annulus body and a fluid circulation system. A constant liquid level pipe is arranged next to the oil casing annulus body, and the equal liquid level principle is used to ensure that the bottom space pressure remains unchanged, thereby realizing a stable liquid carrying flow test; the influence of the oil pipe coupling on the gas-liquid carrying in the annulus pipe is measured, and it can be used to test the flow pattern characteristics and liquid carrying characteristics of the fluid in the annulus pipe under different liquid flow rates and gas flow rates of the gas-liquid two-phase, and analyze its influencing factors, and can simultaneously measure the bottom space pressure, the pressure difference on both sides of the oil pipe coupling, and the pressure difference in the vertical section of the annulus pipe. The present invention is of great significance for studying the flow mode of air-liquid carrying in the oil casing annulus, the oil casing annulus air-liquid two-phase flow pattern, the pressure difference, and realizing the integration of gas well drainage and gas production, and has a good application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and natural gas exploitation, and in particular relates to a visual simulation experimental test device and method for an oil casing ring air-carrying liquid. Background Art

[0002] In gas well production, velocity pipes or tubing are usually used. If it is necessary to switch to mechanical pumping, it is necessary to re-operate and lower the pump and lift string, which not only increases the operating cost, but also easily causes reservoir pollution and reduces the production capacity of the gas well. If it is possible to produce air-carrying liquid in the oil-casing annulus, when it is converted to mechanical pumping water drainage and pressure reduction production mode, it is only necessary to lower the sucker rod string to complete the conversion, which will greatly reduce operating costs and reservoir pollution and extend the life cycle of the gas well. Similarly, inserting a continuous tubing into the original production tubing for gas injection and gas lift is also commonly used for drainage production of liquid-producing gas wells, especially for dealing with the problem of liquid accumulation at the bottom of the well. Whether it is mechanical pumping or lowering a continuous tubing for gas lift, there is a problem of air-carrying liquid in the annulus.

[0003] However, there is currently a lack of simulation experimental testing equipment and methods for the flow mode of annular air carrying liquid, and it is impossible to determine the annular air carrying liquid mode and conditions. Summary of the invention

[0004] The problem to be solved by the present invention is to provide a visual simulation experimental test device and method for air-liquid carrying in an oil sleeve ring.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a visual simulation experiment test device for air-carrying liquid in an oil casing annulus, comprising an oil casing annulus body and a fluid circulation system, wherein the oil casing annulus body is vertically arranged, the oil casing annulus body comprises a simulated casing and a simulated oil pipe, the simulated oil pipe is installed in the simulated casing, the simulated oil pipe and the simulated casing are coaxially arranged, and an annulus pipe is formed between the side wall of the simulated oil pipe and the side wall of the simulated casing; the top of the simulated casing is closed; the top of the simulated oil pipe is an air inlet, which extends out of the simulated casing, the bottom of the simulated oil pipe is connected to the simulated casing, a bottom space is formed between the bottom of the simulated oil pipe and the bottom of the simulated casing, and the annulus pipe is connected to the bottom space; a fluid outlet is arranged near the top of the side wall of the simulated casing, and the fluid outlet is connected to a liquid storage tank for collecting the discharged liquid and performing liquid carrying analysis, so as to test the stable liquid carrying amount; the fluid circulation system comprises an air supply system and a liquid supply system, and the air supply system comprises an air compressor, a high-pressure gas storage tank, a gas flow The air compressor, the high-pressure gas storage tank, the gas flow meter, the gas flow valve and the air inlet of the simulated oil pipe are connected in sequence through the gas transmission pipeline. The air compressor pressurizes the air and enters the high-pressure gas storage tank. The air is measured by the gas flow meter and then injected through the air inlet of the simulated oil pipe. After mixing with the liquid in the bottom space, it enters the annular tube upward to observe the flow law of the air and liquid in the annular tube. The gas and liquid flow out through the fluid outlet, the liquid enters the liquid storage tank, and the gas is directly vented; the liquid supply system includes a water tank, a liquid flow meter, a liquid flow valve and a constant liquid level pipe. The constant liquid level pipe is vertically arranged on one side of the oil casing annular body. The water pump, the liquid flow meter, the bottom connecting part of the constant liquid level pipe and the bottom space of the water tank are connected in sequence through the infusion pipeline. The water tank is also connected to the control ball valve at the top of the constant liquid level pipe through the infusion pipeline. The constant liquid level pipe can ensure that the pressure of the bottom space is constant under a certain state, avoid the increase of the bottom space pressure causing the liquid to flow out, so that the liquid carrying capacity under a certain state cannot be accurately tested, and ensure that the liquid carrying flow under a certain state is not affected by the change of the bottom space pressure.

[0006] Furthermore, the oil casing annulus body is made of transparent material to facilitate observation of fluid flow in the annulus pipe, and the simulated casing and simulated tubing of the oil casing annulus body have adjustable diameters and lengths to meet different testing requirements.

[0007] Furthermore, a tubing coupling is provided on the simulated tubing, and the tubing coupling can be provided at different positions of the simulated tubing.

[0008] Furthermore, two groups of pressure sensors are arranged on the simulated casing, and a tubing coupling is arranged on the simulated tubing between the two pressure sensors of the first group, which is used to test the pressure difference in the annulus pipe on both sides of the tubing coupling; no tubing coupling is arranged on the simulated tubing between the two pressure sensors of the second group, which is used to test the pressure difference in the vertical section of the annulus pipe.

[0009] Furthermore, it also includes a data acquisition and processing system, which includes a data recorder. The gas flow meter, the liquid flow meter and each of the pressure sensors are connected to the data recorder. The data acquisition and processing system is used to collect data from the fluid circulation system and the pressure sensor, and perform processing and analysis to obtain quantitative results of the liquid carrying capacity of the oil casing annulus and the conditions for satisfying the liquid carrying capacity.

[0010] Furthermore, a check valve is provided between the air flow valve and the air inlet of the simulated oil pipe and between the liquid flow valve and the bottom space, and the check valve is used to prevent the backflow of gas or liquid.

[0011] The present invention also provides a visual simulation experimental test method for air-carrying liquid in an oil sleeve ring, comprising the following steps:

[0012] S1. First, inject liquid into the casing annulus body until the constant liquid level pipe flows out the excess liquid, so that the liquid level in the casing annulus body remains unchanged. Then open the gas flow valve to obtain the stable liquid carrying volume in the liquid storage tank under a certain gas flow rate within a certain period of time, as well as the pressure difference in the annulus pipes on both sides of the tubing coupling and the pressure difference in the vertical section of the annulus pipe;

[0013] S2, adjusting the gas flow valve to change the gas flow rate in step S1, and obtaining the stable liquid carrying amount under different gas flow rates, as well as the pressure difference in the annular pipe on both sides of the tubing coupling and the pressure difference in the vertical section of the annular pipe;

[0014] S3, adjust the gas flow valve to keep the gas flow constant, open the liquid supply system, adjust the liquid flow valve, determine the liquid flow, and keep the liquid level in the constant liquid level tube unchanged;

[0015] S4. Under the premise of knowing the gas flow rate, liquid flow rate and stable liquid carrying capacity, observe the gas-liquid flow pattern distribution and flow pattern characteristics in the casing annulus body, and obtain the pressure difference of the gas-liquid two-phase in the annulus pipe on both sides of the tubing coupling and the pressure difference in the vertical section of the annulus pipe through the pressure sensor;

[0016] S5. Regulate the gas flow valve to change the gas flow in step S4, adjust the liquid level in the constant liquid level pipe through the liquid flow valve, and repeat step S4 to obtain the flow state of the gas-liquid two-phase under different conditions, and draw a flow distribution diagram to study the change mode and law of the gas-liquid two-phase pressure gradient and the influence of the tubing coupling on the casing annulus pressure.

[0017] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0018] The present invention sets a constant liquid level pipe beside the casing annulus body, uses the equal liquid level principle, controls the bottom space pressure during stable liquid carrying by pressure difference, ensures that the bottom space pressure remains unchanged, and thus realizes stable liquid carrying flow test. The present invention can also measure the influence of the tubing coupling on the gas-liquid carrying in the annulus pipe, and can be used to test the flow characteristics, pressure difference characteristics, and liquid carrying characteristics of the fluid in the annulus pipe under different liquid flow rates and gas flow rates of the gas-liquid two-phase, and analyze its influencing factors, and can simultaneously measure the bottom space pressure (corresponding to the bottom hole pressure), the pressure difference on both sides of the tubing coupling, and the pressure difference in the vertical section of the annulus pipe, gas flow rate, liquid flow rate and other experimental parameters, and simulate different annulus pipe (casing annulus) sizes by changing the diameters of the simulated casing and the simulated tubing.

[0019] The test results of the gas-liquid in the annular pipe show that the present invention can make full use of the gas-liquid in the annular pipe to reduce the surface gas injection volume, effectively improve the production efficiency of liquid-producing gas wells, assist mechanical pumping production, and reduce energy consumption.

[0020] The present invention tests the flow law of gas-liquid carrying in the annulus pipe, obtains the quantitative result of the gas-liquid carrying capacity in the annulus pipe and the conditions satisfying the gas-liquid carrying capacity, and provides a basis for the design of the integrated process string for gas well drainage and gas production.

[0021] The present invention conducts visual measurement of the gas-liquid carrying capacity in the annulus pipe, conducts visual simulation test of the air-liquid carrying capacity in the oil-casing annulus and determines the air-liquid carrying conditions in the oil-casing annulus. It is of great significance for studying the flow law of the air-liquid carrying capacity in the oil-casing annulus, the air-liquid two-phase flow pattern and the pressure difference in the oil-casing annulus, and realizing the integration of gas well drainage and gas production, and has a good application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be described in detail below with reference to the accompanying drawings and in combination with examples, and the advantages and implementation methods of the present invention will become more obvious. The contents shown in the accompanying drawings are only used to explain the present invention and do not constitute any limitation to the present invention in any sense. In the accompanying drawings:

[0023] Figure 1 It is a structural schematic diagram of the present invention.

[0024] In the figure:

[0025] 1. Air compressor; 2. High-pressure gas storage tank; 3. Gas flow meter; 4. Gas flow valve; 5. Check valve; 6. Gas pipeline; 7. Water pump; 8. Water tank; 9. Liquid flow meter; 10. Liquid flow valve; 11. Liquid pipeline; 12. Data recorder; 13. Pressure sensor; 15. Simulated casing; 16. Simulated oil pipeline; 17. Control ball valve; 18. Liquid storage tank; 19. Oil pipe coupling; 20. Constant liquid level pipe; 21. Annular pipe; 22. Bottom space; 23. Fluid outlet. DETAILED DESCRIPTION

[0026] like Figure 1 As shown, the present invention provides a visual simulation experimental test device for oil casing annulus air carrying liquid, comprising an oil casing annulus body, a fluid circulation system and a data acquisition and processing system.

[0027] The casing annulus body is vertically arranged, and the casing annulus body includes a simulated casing 15 and a simulated oil pipe 16. The simulated oil pipe 16 is installed in the simulated casing 15. The simulated oil pipe 16 and the simulated casing 15 are coaxially arranged, and an annulus pipe 21 is formed between the side wall of the simulated oil pipe 16 and the side wall of the simulated casing 15; the top of the simulated casing 15 is closed; the top of the simulated oil pipe 16 is an air inlet, and the air inlet is arranged to extend out of the simulated casing 15, the bottom of the simulated oil pipe 16 is connected with the simulated casing 15, and a bottom space 22 is formed between the bottom of the simulated oil pipe 16 and the bottom of the simulated casing 15, and the annulus pipe 21 is connected with the bottom space 22; a fluid outlet 23 is arranged on the side wall of the simulated casing 15 near the top, and the fluid outlet 23 is connected to the liquid storage tank 18, which is used to collect the discharged liquid and perform liquid carrying analysis, so as to test the stable liquid carrying amount.

[0028] The casing annulus body is made of transparent material to facilitate observation of the fluid flow in the annulus pipe 21. The simulated casing 15 and simulated oil pipe 16 of the casing annulus body have adjustable diameters and lengths to meet different testing requirements.

[0029] The simulated oil pipe 16 is provided with an oil pipe coupling 19 , and the oil pipe coupling 19 can be provided at different positions of the simulated oil pipe 16 .

[0030] Among them, two groups of pressure sensors 13 are arranged on the simulated casing 15, and a tubing coupling 19 is arranged on the simulated oil pipe 16 between the two pressure sensors 13 of the first group, so as to test the pressure difference in the annulus pipe 21 on both sides of the tubing coupling 19; no tubing coupling 19 is arranged on the simulated oil pipe 16 between the two pressure sensors 13 of the second group, so as to test the pressure difference in the vertical section of the annulus pipe 21; each pressure sensor 13 is connected to a data recorder 12 (a computer can be used) through a data line, and the influence of the tubing coupling 19 on the flow field, pressure difference and liquid carrying can be determined through test comparison.

[0031] The fluid circulation system comprises an air supply system and a liquid supply system. The fluid circulation system is used to inject fluid into the oil casing annulus body and monitor the flow rate and pressure of the fluid in real time.

[0032] The gas supply system includes an air compressor 1, a high-pressure gas storage tank 2, a gas flow meter 3 and an air flow valve 4. The air compressor 1, the high-pressure gas storage tank 2, the gas flow meter 3, the air flow valve 4 and the air inlet of the simulated oil pipe 16 are connected in sequence through a gas pipeline 6. The air compressor 1 pressurizes the air and enters the high-pressure gas storage tank 2. After being measured by the gas flow meter 3, the air is injected through the air inlet of the simulated oil pipe 16, and after mixing with the liquid in the bottom space 22, it enters the annulus pipe 21 upward to observe the flow law of the annular air and liquid. The gas and liquid flow out through the fluid outlet 23, the liquid enters the liquid storage tank 18, and the gas is directly discharged.

[0033] The liquid supply system includes a water tank 8, a liquid flow meter 9, a liquid flow valve 10 and a constant liquid level tube 20. The constant liquid level tube 20 is vertically arranged on one side of the casing annulus body. The water pump 7 of the water tank 8, the liquid flow meter 9, the connecting point at the bottom of the constant liquid level tube 20 and the bottom space 22 are connected in sequence through the liquid infusion line 11. The water tank 8 is also connected to the control ball valve 17 (corresponding to the actual wellhead position) at the top of the constant liquid level tube 20 through the liquid infusion line 11. The constant liquid level tube 20 can ensure that the pressure of the bottom space 22 (corresponding to the actual well bottom position) is constant in a certain state, avoiding the increase of the pressure in the bottom space 22 causing the liquid to flow out, thereby failing to accurately test the liquid carrying capacity in a certain state, and ensuring that the liquid carrying flow in a certain state is not affected by the change of the bottom hole pressure.

[0034] Among them, a check valve 5 is arranged between the air flow valve 4 and the air inlet of the simulated oil pipe 16, and between the liquid flow valve 10 and the bottom space 22. The check valve 5 is used to prevent the backflow of gas or liquid.

[0035] The data acquisition and processing system includes a data recorder 12, which is used to collect data of the fluid circulation system, and perform processing and analysis to obtain quantitative results of the oil casing annulus liquid carrying capacity and the conditions for satisfying liquid carrying.

[0036] The data acquisition and processing system inputs the pressure difference measured by the two groups of pressure sensors 13 and the data collected by each flow meter into the computer for data processing in combination with the discharge volume in the liquid storage tank 18 (and also in combination with the video captured by the camera of the fluid).

[0037] In this embodiment, a plurality of pressure test points can be set, and the data recorder 12 can store one data point per second, and can record the instantaneous pressure values ​​under various flow states.

[0038] Working process of the present invention:

[0039] After the air compressor 1 is turned on, the compressed gas is stored in the high-pressure gas storage tank 2 for standby use; the high-pressure gas storage tank 2 is connected to the air inlet of the simulated oil pipe 16, and a gas flow meter 3, an air flow valve 4, and a one-way valve 5 for preventing gas backflow are arranged in sequence in the middle; the water tank 8 is a liquid storage device, and a water pump 7 transports the liquid in the water tank 8 to the bottom space 22 of the oil casing annulus body, and a liquid flow meter 9, a liquid flow valve 10, and a one-way valve 5 for preventing liquid backflow are arranged in sequence in the middle; a control ball valve 17 is arranged on the top of the constant liquid level tube 20, and is directly connected to the water tank 8, and a pressure sensor 13 for monitoring pressure is arranged on the simulated casing 15 of the oil casing annulus body, and the data recorder 12 can store the pressure difference data transmitted by multiple pressure sensors 13. In the experiment, the liquid flow valve 10 is fully opened; the liquid level is controlled by adjusting the control ball valve 17; the pressure of the bottom space 22 is controlled by the liquid height in the constant liquid level tube 20; and the annular space liquid volume over a period of time is recorded by the water tank 8 and the liquid flow meter 9.

[0040] The present invention also provides a visual simulation experimental test method for air-carrying liquid in an oil sleeve ring, comprising the following steps:

[0041] S1, firstly, inject liquid into the oil casing annulus body until the constant liquid level pipe 20 flows out the excess liquid, so that the liquid level in the oil casing annulus body remains unchanged, and then open the gas flow valve 4 to obtain the stable liquid carrying amount in the liquid storage tank 18 under a certain gas flow rate within a certain time, as well as the pressure difference in the annulus pipe 21 on both sides of the oil pipe coupling 19 and the pressure difference in the vertical section of the annulus pipe 21;

[0042] S2, adjusting the gas flow valve 4 to change the gas flow rate in step S1, obtaining the stable liquid carrying amount under different gas flow rates, as well as the pressure difference in the annular pipe 21 on both sides of the tubing coupling 19 and the pressure difference in the vertical section of the annular pipe 21; and drawing them into a table;

[0043] S3, adjust the gas flow valve 4 to stabilize the gas flow at a certain fixed value, open the liquid supply system, adjust the liquid flow valve 10, determine the liquid flow, and keep the liquid level in the constant liquid level tube 20 unchanged;

[0044] S4. Under the premise of knowing the gas flow rate, liquid flow rate (bottom space pressure), and stable liquid carrying capacity, observe the gas-liquid flow pattern distribution and flow pattern characteristics in the casing annulus body, and obtain the pressure difference of the gas-liquid two-phase in the annulus pipe 21 on both sides of the tubing coupling 19 and the pressure difference of the vertical section in the annulus pipe 21 through the pressure sensor 13;

[0045] S5. Regulate the gas flow valve 4 to change the gas flow in step S4, adjust the liquid level in the constant liquid level tube 20 through the liquid flow valve 10, and repeat step S4 to obtain the flow state of the gas-liquid two-phase under different conditions, and draw a flow distribution diagram to study the change law of the gas-liquid two-phase pressure gradient and the influence of the oil pipe coupling 19 on the casing annulus pressure.

[0046] Example:

[0047] The minimum gas velocity and gas flow rate required for gas-liquid carrying in the annulus pipe 21 under certain bottom hole and wellhead (bottom space 22 and control ball valve 17) pressure conditions are tested, and the liquid-carrying flow state and the corresponding pressure difference gradient are observed. The pressure difference and flow state of the gas-liquid two-phase flow in the annulus pipe 21 can also be tested.

[0048] The configuration of the oil casing annulus is as follows: the outer diameter of the simulated oil pipe 16 is 73.0 mm, the inner diameter of the simulated casing 15 is 99.6 mm, the liquid level in the constant liquid level pipe 20 is 2 m, and when the wellhead pressure is atmospheric pressure, the minimum gas-liquid flow rate in the annulus pipe is 65 m 3 / h, the minimum gas flow rate is 4.02m / s, and the flow state is observed to be annular flow. By changing the liquid level and the configuration of the casing annulus, the gas-liquid carrying conditions and the string configuration in the annulus pipe 21 can be determined. When testing the gas-liquid two-phase flow in the annulus pipe 21, the gas flow rate is 40m 3 / h, liquid flow rate is 0.2m 3 / h, the flow state is tested to be slug flow, and the pressure gradient is 0.687kPa / m. By changing the gas-liquid flow rate and the casing annulus configuration, the annular gas-liquid two-phase flow state and pressure difference law can be determined.

[0049] The embodiments of the present invention are described in detail above, but the contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A visual simulation test device for oil sleeve ring air carrying liquid, characterized by: It includes an oil casing annulus body and a fluid circulation system, wherein the oil casing annulus body is vertically arranged, and the oil casing annulus body includes a simulated casing and a simulated oil pipe, wherein the simulated oil pipe is installed in the simulated casing, and the simulated oil pipe and the simulated casing are coaxially arranged, and an annulus pipe is formed between the side wall of the simulated oil pipe and the side wall of the simulated casing; the top of the simulated casing is closed; the top of the simulated oil pipe is an air inlet, and the air inlet extends out of the simulated casing, the bottom of the simulated oil pipe is connected with the simulated casing, a bottom space is formed between the bottom of the simulated oil pipe and the bottom of the simulated casing, and the annulus pipe is connected with the bottom space; a fluid outlet is arranged near the top of the side wall of the simulated casing, The fluid outlet is connected with the liquid storage tank; the fluid circulation system includes an air supply system and a liquid supply system, the air supply system includes an air compressor, a high-pressure gas storage tank, a gas flow meter and an air flow valve, and the air compressor, high-pressure gas storage tank, gas flow meter, air flow valve and the air inlet of the simulated oil pipe are connected in sequence through an air supply pipeline; the liquid supply system includes a water tank, a liquid flow meter, a liquid flow valve and a constant liquid level pipe, and the constant liquid level pipe is vertically arranged on one side of the oil casing annulus body, and the water pump, liquid flow meter, bottom connecting point of the constant liquid level pipe and the bottom space of the water tank are connected in sequence through a liquid supply pipeline, and the water tank is also connected to the control ball valve at the top of the constant liquid level pipe through the liquid supply pipeline.

2. The oil sleeve ring air-carrying liquid visualization simulation experiment test device according to claim 1 is characterized by: The oil casing annulus body is made of transparent material.

3. The oil sleeve ring air-carrying liquid visualization simulation experiment test device according to claim 1 is characterized by: The simulated oil pipe is provided with an oil pipe coupling.

4. The oil sleeve ring air-carrying liquid visualization simulation experiment test device according to claim 3 is characterized by: Two groups of pressure sensors are arranged on the simulated casing. A tubing coupling is arranged on the simulated tubing between the two pressure sensors of the first group, which is used to test the pressure difference in the annulus pipe on both sides of the tubing coupling. No tubing coupling is arranged on the simulated tubing between the two pressure sensors of the second group, which is used to test the pressure difference in the vertical section of the annulus pipe.

5. The oil sleeve ring air-carrying liquid visualization simulation experiment test device according to claim 4 is characterized in that: It also includes a data acquisition and processing system, which includes a data recorder. A gas flow meter, a liquid flow meter and a pressure sensor are connected to the data recorder.

6. The oil sleeve ring air-carrying liquid visualization simulation experiment test device according to claim 1 is characterized by: Check valves are arranged between the air flow valve and the air inlet of the simulated oil pipe, and between the liquid flow valve and the bottom space.

7. A visual simulation test method for air-carrying liquid in an oil sleeve ring, which is implemented by using the visual simulation test device for air-carrying liquid in an oil sleeve ring according to any one of claims 1 to 6, and is characterized in that: The following steps are involved: S1, inject liquid into the casing annulus body until the constant liquid level pipe flows out the excess liquid, so that the liquid level in the casing annulus body remains unchanged, and then open the gas flow valve to obtain the stable liquid carrying volume in the liquid storage tank under a certain gas flow rate within a certain period of time, as well as the pressure difference in the annulus pipes on both sides of the tubing coupling and the pressure difference in the vertical section of the annulus pipe; S2, adjusting the gas flow valve to change the gas flow rate in step S1, and obtaining the stable liquid carrying amount under different gas flow rates, as well as the pressure difference in the annular pipe on both sides of the tubing coupling and the pressure difference in the vertical section of the annular pipe; S3, adjust the gas flow valve to keep the gas flow constant, open the liquid supply system, adjust the liquid flow valve, determine the liquid flow, and keep the liquid level in the constant liquid level tube unchanged; S4. Under the premise of knowing the gas flow rate, liquid flow rate and stable liquid carrying capacity, observe the gas-liquid flow pattern distribution and flow pattern characteristics in the casing annulus body, and obtain the pressure difference of the gas-liquid two-phase in the annulus pipe on both sides of the tubing coupling and the pressure difference in the vertical section of the annulus pipe through the pressure sensor; S5, adjusting the gas flow valve to change the gas flow in step S4, adjusting the liquid level in the constant liquid level tube through the liquid flow valve, repeating step S4, and obtaining the flow state of the gas-liquid two phases under different conditions.

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