Plunger leakage experiment device and detection method

Abstract

The invention discloses a plunger leakage experimental device, and relates to the technical field of gas well plunger drainage and mining processes. A plunger leakage experiment device comprises a plunger control system used for controlling lifting of a plunger; the experimental tubular column is located in the shaft, is in butt joint with the plunger control system and is used for accommodating the plunger to perform simulation motion; the gas-liquid separation metering system is in butt joint with the plunger control system and is used for collecting and separating a gas-liquid mixture brought out by pressure in the experimental tubular column; the gas injection system is connected with the bottom of the experimental tubular column and used for providing a gas source for the experimental tubular column; and the liquid injection system is respectively communicated with the plunger control system and the gas-liquid separation metering system and is used for injecting the liquid separated by the gas-liquid separation metering system into the experimental tubular column. The problem that the running state of the real plunger in the shaft cannot be restored is solved, and a more effective experimental theoretical basis can be provided for evaluation of the discharging and mining effect of the plunger.

Description

Technical Field

[0001] This invention relates to the field of gas well plunger drainage technology, specifically to a plunger leakage test device and detection method. Background Technology

[0002] The plunger gas lift process is an economical, environmentally friendly, and easy-to-operate and maintain drainage and gas production technology. It fully utilizes the elastic energy of the gas well itself, using a plunger as the gas-liquid separation interface in the wellbore to periodically lift and remove accumulated liquid at the bottom of the well, maintaining stable gas well production. The plunger gas lift process is well-suited to the characteristics of low pressure, low production, and low water production in the later stages of gas well drainage. This technology has been widely applied in over 230 wells in the Changning block, achieving good results. With the deepening of exploration and development, more and more gas wells in the Southwest Oil and Gas Field will enter the middle and late stages of development, and the plunger gas lift process will be more widely used. Because there is a gap between the plunger and the tubing, and the motion parameters are constantly changing, water at the upper end of the plunger will slide down through the gap to the lower end during the gas lift process. Therefore, the leakage rate of the plunger is one of the most important parameters for evaluating the effectiveness of the plunger process. If the leakage rate during plunger lifting is too high, it may directly lead to unsatisfactory water lifting effect, or even ineffective plunger operation. Therefore, if we can understand the leakage of the plunger during the operation of the tubing through indoor experiments, it can provide effective support and basis for evaluating the plunger drainage effect, thereby improving the efficiency and effectiveness of process implementation.

[0003] Existing technology CN113899506A discloses a dynamic leakage testing device and method for horizontal well plungers. This method involves using a variable frequency motor to drag an experimental plunger at a constant speed upwards within an experimental tubing string, collecting leaked fluid via an upper ball valve, recording the running time, and calculating the leakage rate. The device includes an electric hoist, pulley, support frame, variable frequency motor, variable diameter through-hole connector, plexiglass tube, plunger, ball valve, water tank, water pump, and fluid flow meter. While this patent uses a variable frequency motor to drag the plunger to simulate its movement within the tubing, and its speed is controllable and more stable, it cannot accurately reproduce the actual operating state of a plunger in a wellbore.

[0004] Existing technology CN114861471B, a method for determining the application timing of plunger gas lift technology, mainly involves collecting gas well production data and plunger structure data to calculate the liquid loss under different locking device depths and different plunger upward speeds. This yields a relationship between locking device depth, plunger upward speed, and loss, converting the lost liquid volume into wellbore liquid accumulation height, and then calculating the gas well production casing pressure differential at this liquid accumulation height. However, this patent primarily calculates the plunger leakage amount through numerical simulation using gas well production data and plunger structure data. The numerical simulation involves many assumptions, resulting in a certain discrepancy with the actual plunger response.

[0005] Therefore, there is an urgent need for an experimental device and method to measure plunger leakage, to realistically simulate the plunger's motion state, and to provide a more effective experimental theoretical basis for evaluating the plunger's drainage effect. Summary of the Invention

[0006] The technical problem to be solved by this invention is that existing plunger leakage detection devices cannot reproduce the actual operating state of the plunger in the wellbore, and cannot provide an effective experimental theoretical basis for evaluating the plunger drainage effect.

[0007] One of the objectives is to provide a plunger leakage test device, which solves the problem of not being able to reproduce the actual operating state of the plunger in the wellbore, and can provide a more effective experimental theoretical basis for evaluating the plunger drainage effect.

[0008] The second objective is to provide a method for experimentally detecting plunger leakage, which, together with the experimental apparatus, provides an effective way to reconstruct the actual operating state of the plunger in the wellbore.

[0009] This invention is achieved through the following technical solution:

[0010] A plunger leakage test apparatus, comprising

[0011] A plunger control system is used to control the raising and lowering of the plunger.

[0012] The experimental tubing, located inside the wellbore, is connected to the plunger control system and is used to accommodate the plunger for simulated movement.

[0013] The gas-liquid separation metering system, which interfaces with the plunger control system, is used to collect and separate the gas-liquid mixture carried out by the pressure inside the experimental column.

[0014] The gas injection system is connected to the bottom of the experimental column and is used to provide a gas source for the experimental column.

[0015] The liquid injection system is connected to both the plunger control system and the gas-liquid separation and metering system, and is used to inject the liquid separated by the gas-liquid separation and metering system into the experimental column.

[0016] As one possible design, the aforementioned plunger control system includes a blowout preventer and a plunger catcher.

[0017] The blowout preventer is connected to the experimental column to accommodate the simulated movement of the plunger and to contain the gas-liquid mixture carried out by the pressure inside the experimental column.

[0018] The plunger catcher is mounted on the blowout preventer to catch the plunger when it moves to the plunger catcher and to release the plunger for testing at the start of the experiment.

[0019] As one possible design, the aforementioned plunger control system also includes a flow guide and a diaphragm valve.

[0020] The guide tube is connected to the blowout preventer and is used to input the gas-liquid mixture carried out by the pressure inside the experimental column into the gas-liquid separation and metering system.

[0021] The diaphragm valve is installed on the flow guide tube and is used to control the switch of the detection.

[0022] As one possible design, the aforementioned experimental string includes tubing and a check valve.

[0023] The tubing is located inside the wellbore and is connected to the plunger control system;

[0024] A check valve is installed at the bottom of the oil pipe and connected to the air injection system to input compressed gas into the oil pipe.

[0025] As one possible design, the aforementioned gas-liquid separation metering system includes a gas-liquid separator, a water tank, a first vent pipe, and a compressed air inlet pipe.

[0026] The gas-liquid separator is connected to the plunger control system and is used to separate the incoming gas-liquid mixture into gas and liquid components.

[0027] The water tank is connected to both the gas-liquid separator and the liquid injection system, and is used to receive the separated liquid and to input the separated liquid into the liquid injection system.

[0028] The first vent line is connected to the gas-liquid separator and is used to discharge gas.

[0029] The compressed air inlet pipe is connected to the gas-liquid separator and is used to input compressed gas so that the liquid in the gas-liquid separator is discharged into the water tank.

[0030] As one possible design, the aforementioned gas-liquid separation metering system also includes a regulating valve, which is installed on the connecting pipe between the water tank and the gas-liquid separator, and is used to adjust the pressure between the water tank and the gas-liquid separator.

[0031] As one possible design, the gas-liquid separation metering system described above also includes a second venting line connected to a water tank for discharging gas from the water tank.

[0032] As one possible design, the aforementioned air injection system includes an air compressor connected to a check valve pipeline.

[0033] As one possible design, the aforementioned injection system includes a plunger pump, an injection line, and a flow meter.

[0034] The plunger pump is connected to the gas-liquid separation metering system to receive the liquid to be separated;

[0035] The injection tube is connected to the plunger pump and the plunger control system respectively, and is used to input the pumped liquid into the experimental tubing through the plunger control system.

[0036] The flow meter is installed on the injection pipe to record the amount of liquid injected.

[0037] Preferably, this experimental apparatus further includes a pressure relief system, which comprises a back pressure valve, a pressure sensor, and a pressure relief pipe.

[0038] The pressure relief pipe is connected to the plunger control system and is used to reduce the gas pressure in the plunger control system and the experimental column.

[0039] The back pressure valve is installed on the pressure relief pipe and is used to control the opening and closing of the pressure relief pipe;

[0040] A pressure sensor is installed on the pressure relief pipe to record the air pressure in the pipe.

[0041] The present invention also provides a method for detecting plunger leakage, comprising the following steps:

[0042] Insert the plunger into the plunger control system, release the plunger through the plunger system, and the plunger falls to the bottom of the experimental column;

[0043] Start the liquid injection system to inject liquid into the experimental column through the plunger control system; start the gas injection system to inject compressed gas from the bottom of the experimental column; and the liquid is input into the gas-liquid separation metering system through the plunger control system under the action of pressure difference.

[0044] The gas and liquid are separated and the liquid is collected by a gas-liquid separation metering system, and the leakage amount is calculated.

[0045] Preferably, the above leakage amount is calculated using the following formula:

[0046] S = L1 - L2

[0047] S: Leakage amount;

[0048] L1: Liquid injected by the injection system;

[0049] L2: Liquid collected by the gas-liquid separation metering system.

[0050] Preferably, the above detection method can be repeated multiple times to conduct multi-cycle experiments and improve detection accuracy.

[0051] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0052] This invention simulates real plunger movement by using both air pressure and liquid to compress the plunger. By leveraging the pressure difference to compress the plunger, it effectively provides a reference for understanding the impact of changes in plunger operating parameters on its liquid-carrying capacity. Simultaneously, it offers indoor experimental comparison data for numerical simulations and theoretical calculations, providing data support for optimizing plunger production processes, selecting tools, and improving plunger structures. Furthermore, the device of this invention can measure leakage during process implementation for plungers of different types and sizes, making it widely applicable. Attached Figure Description

[0053] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0054] Figure 1 This is a schematic diagram of the connection structure of a plunger leakage test device according to the present invention;

[0055] Figure 2 This is an experimental flowchart of a plunger leakage test device according to the present invention.

[0056] The attached diagram shows the markings and corresponding component names:

[0057] 1-Blowout preventer; 2-Plunger catcher; 3-Guide pipe; 4-Diaphragm valve; 5-Oil pipe; 6-Check valve; 7-Gas-liquid separator; 8-Water tank; 9-First vent line; 10-Compressor intake pipe; 11-Regulating valve; 12-Second vent line; 13-Air compressor; 14-Plunger pump; 15-Injection pipe; 16-Flow meter; 17-Pressure sensor; 18-Back pressure valve; 19-Pressure relief pipe. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0059] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0061] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0062] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0063] Because existing plunger leakage detection devices cannot reproduce the actual operating state of the plunger in the wellbore, they cannot provide effective experimental theoretical basis for evaluating the plunger drainage effect.

[0064] Example

[0065] On one hand, the present invention provides a plunger leakage test apparatus, referring to Figure 1 The system includes a plunger control system, experimental tubing, a gas-liquid separation and metering system, a gas injection system, and a liquid injection system. The plunger control system interfaces with the experimental tubing and can engage or disengage the plunger during operation, thereby controlling the entire experimental setup. The experimental tubing is vertically installed into the wellbore and is suitable for test wells of various depths, including 900m, 1200m, and other depths. 3 / 8、2 7 / 8、3 1The tubing, in various sizes such as / 8, is used to accommodate plungers for simulated motion tests of various specifications. The gas-liquid separation and metering system is connected to the plunger control system. When the plunger moves upward with the liquid under pressure difference, the plunger is engaged by the plunger control system. The liquid flows through the plunger control system into the gas-liquid separation and metering system, where it is collected and separated into gas and liquid. The gas injection system, connected to the bottom of the experimental column, provides compressed gas to the column. During use, the liquid injected by the liquid injection system falls onto the plunger, while the compressed gas injected by the gas injection system is located at the bottom of the plunger. The higher pressure of the compressed gas creates an upward pressure difference ΔP, which pulls the plunger and liquid upward together. The liquid injection system, connected to both the plunger control system and the gas-liquid separation and metering system, extracts the liquid separated by the gas-liquid separation and metering system and inputs it into the experimental column through the plunger control system.

[0066] This experimental setup utilizes the volume difference between the injected liquid and the pumped liquid to obtain the plunger leakage rate. Furthermore, this setup simulates the actual movement of a plunger, providing a more effective experimental theoretical basis for evaluating the plunger drainage effect.

[0067] In some embodiments of the present invention, reference is made to... Figure 1 The aforementioned plunger control system includes a blowout preventer (BOP) 1 and a plunger catcher 2. The BOP 1 is connected to the experimental tubing. The BOP 1 is cylindrical and sealed at the top, with a larger inner diameter at the top than at the bottom, which improves liquid collection capacity and resistance to impact. It also provides a holding space for the plunger after it is impacted by a pressure differential and reaches the wellhead, where it is captured by the plunger catcher 2. Its side is connected to a gas-liquid separation and metering system to input the gas-liquid mixture into the system. The plunger catcher 2 is mounted on the BOP 1 and features a buffer spring and locking function. It captures the plunger when it reaches the wellhead and releases it when needed for the experiment. The plunger catcher 2 can be existing equipment, such as the PCS Ferguson LBS-238.

[0068] In some embodiments of the present invention, reference is made to... Figure 1 The aforementioned plunger control system also includes a guide tube 3 and a diaphragm valve 4. One end of the guide tube 3 is connected to the blowout preventer 1 and is used to input the gas-liquid mixture carried out by the pressure inside the experimental column into the gas-liquid separation and metering system. The other end of the guide tube 3 is connected to the gas-liquid separator 7 of the gas-liquid separation and metering system. The diaphragm valve 4 is installed on the guide tube 3 and is used to control the detection switch. When the gas injection system injects gas into the experimental column, the diaphragm valve 4 is closed to ensure sufficient gas pressure to squeeze the upper end, thereby carrying out the gas-liquid mixture. Then, the diaphragm valve 4 is opened to discharge it.

[0069] In some embodiments of the present invention, reference is made to... Figure 1The experimental string includes tubing 5 and a check valve 6. Tubing 5 is installed vertically inside the wellbore, with its top connected to the plunger control system, specifically to the blowout preventer 1. When the pressure differential squeezes the plunger, the liquid on the plunger mixes with the gas and fills the blowout preventer 1. Check valve 6 is installed at the bottom of tubing 5 to prevent liquid leakage, and it is connected to the gas injection system via a pipeline, allowing compressed gas from the gas injection system to be delivered into tubing 5.

[0070] In some embodiments of the present invention, reference is made to... Figure 1 The aforementioned gas-liquid separation and metering system includes a gas-liquid separator 7, a water tank 8, a first vent pipe 9, and a compressed air inlet pipe 10. The gas-liquid separator 7 is connected to the plunger control system, specifically to the body of the blowout preventer 1, preferably to the middle section of the blowout preventer 1, for separating the incoming gas-liquid mixture into gas and liquid components. The water tank 8 is connected to both the gas-liquid separator 7 and the liquid injection system. Specifically, the water tank 8 is connected to the plunger pump 14, allowing the liquid in the water tank 8 to be transferred to the blowout preventer 1 by the plunger pump 14. Preferably, the water tank 8 is made of transparent material and has metering scales on it; preferably, it has a level gauge inside to facilitate the measurement of the amount of liquid carried out. The first vent pipe 9 is connected to the gas-liquid separator 7. After the gas-liquid mixture is separated by the gas-liquid separator 7, the gas is discharged through the first vent pipe 9. Preferably, the first vent pipe 9 is equipped with a valve. The compressed air inlet pipe 10 is connected to the gas-liquid separator 7 and is connected to the top of the gas-liquid separator 7. It is used to input compressed gas to squeeze the liquid in the gas-liquid separator 7 so that the liquid is discharged into the water tank 8. Preferably, the compressed air inlet pipe 10 is connected to the gas injection system to introduce compressed gas so that all the liquid in the gas-liquid separator 7 is discharged into the water tank 8 to ensure the accuracy of the liquid volume measurement in the water tank 8.

[0071] In some embodiments of the present invention, reference is made to... Figure 1 The above-mentioned gas-liquid separation metering system also includes a regulating valve 11, which is installed on the connecting pipe between the water tank 8 and the gas-liquid separator 7 and is used to adjust the pressure between the water tank 8 and the gas-liquid separator 7.

[0072] In some embodiments of the present invention, reference is made to... Figure 1 The gas-liquid separation metering system also includes a second vent pipe 12, which is connected to the water tank 8 and is used to discharge the gas in the water tank 8. Preferably, a valve is installed on the second vent pipe 12.

[0073] In some embodiments of the present invention, reference is made to... Figure 1 The aforementioned gas injection system includes an air compressor 13, which is connected to a check valve 6 and a compressed air inlet pipe 10 for pumping compressed gas into the check valve 6.

[0074] In some embodiments of the present invention, reference is made to... Figure 1 The aforementioned liquid injection system includes a plunger pump 14, an injection pipe 15, and a flow meter 16. The plunger pump 14 is connected to the gas-liquid separation metering system, specifically through a pipe connected to the water tank 8, to receive the separated liquid; the injection pipe 15 is connected to both the plunger pump 14 and the plunger control system, specifically through a link to the middle section of the blowout preventer 1, for pumping the liquid into the experimental tubing via the blowout preventer 1; the flow meter 16 is installed on the injection pipe 15 to record the amount of liquid injected.

[0075] In some embodiments of the present invention, reference is made to... Figure 1 The experimental setup also includes a pressure relief system to ensure pressure balance in the experimental tubing. The pressure relief system includes a back pressure valve 18, a pressure sensor 17, and a pressure relief pipe 19. The pressure relief pipe 19 is connected to the plunger control system, specifically to the blowout preventer 1. When the pressure in the oil pipe 5 is too high, gas is discharged through the pressure relief pipe 19 to ensure pressure balance. The back pressure valve 18 is installed on the pressure relief pipe 19 to control its opening and closing. The pressure sensor 17 is installed on the pressure relief pipe 19 to record the gas pressure in the pressure relief pipe 19.

[0076] Preferably, the pressure relief pipe 19 is connected to the first venting pipe 9 for discharging gas.

[0077] On the other hand, the present invention provides a method for experimental detection of plunger leakage. This embodiment is based on a simulated test well with a depth of 900 meters, with reference to... Figure 2 It includes the following steps:

[0078] Insert the plunger into the plunger catcher 2, release the plunger through the plunger catcher 2, and under the action of gravity, the plunger falls into the position of the check valve 6 at the bottom of the oil pipe 2;

[0079] Start the plunger pump 14 to inject liquid L1 into the oil pipe 2 via the blowout preventer 1. Due to the action of the check valve 15, a fixed amount of liquid will be retained in the oil pipe 2. At the same time, due to the liquid injection, the pressure in the experimental column rises to ΔP. Open the back pressure valve 18, and release excess gas through the pipeline to the pressure relief pipe 19 and the first vent pipe 9 to ensure the pressure balance of the experimental column. Start the air compressor 13 and open the diaphragm valve 4 to inject compressed gas into the experimental column through the check valve 6 at the bottom of the experimental column.

[0080] The plunger and the liquid in the upper part will rise under the action of pressure difference. When the plunger reaches the wellhead, it will be captured by the plunger catcher 2. Under the action of pressure difference, the liquid will enter the guide pipe 3 through the blowout preventer 1 and then enter the gas-liquid separator 7.

[0081] Gas and liquid are separated by gas-liquid separator 7. Gas is discharged through the first vent pipe 9 and liquid is squeezed by the compression inlet pipe 10, so that liquid L2 enters water tank 8. Calculate the leakage S, S = L1 - L2.

[0082] Preferably, the air pressure in the oil pipe 2 is detected by the pressure sensor 17 before the test. If the pressure is too high, it is adjusted by the pressure relief pipe 19. Alternatively, gas can be injected into the blowout preventer 1 to adjust the gas in the blowout preventer 1 to 3-4 MPa. This can eliminate interference factors and make the pressure in the experimental tubing balanced, so that the plunger can move upward when the bottom gas is squeezed later.

[0083] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A plunger leakage test apparatus, characterized in that, include A plunger control system is used to control the raising and lowering of the plunger. The experimental tubing, located inside the wellbore, is connected to the plunger control system and is used to accommodate the plunger for simulated movement. A gas-liquid separation metering system, which interfaces with the plunger control system, is used to collect and separate the gas-liquid mixture carried out by the pressure inside the experimental column. The gas injection system is connected to the bottom of the experimental column and is used to provide a gas source for the experimental column. The liquid injection system is connected to both the plunger control system and the gas-liquid separation and metering system, and is used to inject the liquid separated by the gas-liquid separation and metering system into the experimental column.

2. The plunger leakage test apparatus according to claim 1, characterized in that, The plunger control system includes a blowout preventer and a plunger catcher. The blowout preventer is connected to the experimental column to accommodate the simulated movement of the plunger and to accommodate the gas-liquid mixture carried out by the pressure inside the experimental column. The plunger catcher is mounted on the blowout preventer and is used to catch the plunger when it moves to the plunger catcher, and to release the plunger for testing at the start of the experiment.

3. The plunger leakage test apparatus according to claim 2, characterized in that, The plunger control system also includes a flow guide tube and a diaphragm valve. The guide tube is connected to the blowout preventer and is used to input the gas-liquid mixture carried out by the pressure in the experimental column into the gas-liquid separation and metering system. The diaphragm valve is installed on the flow guide tube and is used to control the detection switch.

4. The plunger leakage test apparatus according to claim 1, characterized in that, The experimental tubing string includes tubing and a check valve. The tubing is located inside the wellbore and is connected to the plunger control system. The one-way valve is installed at the bottom of the oil pipe and connected to the air injection system to input compressed gas into the oil pipe.

5. The plunger leakage test apparatus according to claim 1, characterized in that, The gas-liquid separation and metering system includes a gas-liquid separator, a water tank, a first vent pipe, and a compressed air inlet pipe. The gas-liquid separator is connected to the plunger control system and is used to separate the incoming gas-liquid mixture into gas and liquid. The water tank is connected to the gas-liquid separator and the liquid injection system respectively, and is used to receive the separated liquid and to input the separated liquid into the liquid injection system; The first vent pipe is connected to the gas-liquid separator and is used to discharge gas. The compressed air inlet pipe is connected to the gas-liquid separator and is used to input compressed gas so that the liquid in the gas-liquid separator is discharged into the water tank.

6. The plunger leakage test apparatus according to claim 5, characterized in that, The gas-liquid separation metering system also includes a regulating valve, which is installed on the connecting pipe between the water tank and the gas-liquid separator and is used to adjust the pressure between the water tank and the gas-liquid separator.

7. The plunger leakage test apparatus according to claim 5, characterized in that, The gas-liquid separation metering system also includes a second venting pipeline, which is connected to a water tank and is used to discharge the gas in the water tank.

8. The plunger leakage test apparatus according to claim 4, characterized in that, The air injection system includes an air compressor connected to a check valve pipe.

9. The plunger leakage test apparatus according to claim 4, characterized in that, The injection system includes a plunger pump, an injection pipe, and a flow meter. The plunger pump is connected to the gas-liquid separation metering system and is used to receive the separated liquid; The injection tube is connected to the plunger pump and the plunger control system respectively, and is used to input the pumped liquid into the experimental tubing through the plunger control system. The flow meter is installed on the injection pipe and is used to record the amount of liquid injected.

10. A method for detecting plunger leakage, characterized in that, The experimental apparatus applied to any one of claims 1-9 comprises the following steps: Insert the plunger into the plunger control system, release the plunger through the plunger system, and the plunger falls to the bottom of the experimental column; Start the liquid injection system to inject liquid into the experimental column through the plunger control system; start the gas injection system to inject compressed gas from the bottom of the experimental column; and the liquid is input into the gas-liquid separation metering system through the plunger control system under the action of pressure difference. The gas and liquid are separated and the liquid is collected by a gas-liquid separation metering system, and the leakage is calculated.

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