A mobile wellhead flow calibration device and its calibration method

Abstract

The present application relates to a mobile wellhead flow calibration device and a calibration method thereof, belonging to the technical field of flowmeter calibration. It includes a gas-liquid separator for connecting and collecting a conveying pipeline, a demister and a liquid storage tank connected to the gas-liquid separator. The output end of the demister is connected with a wet gas flow metering component, and the output end of the liquid storage tank is connected with a mass flow metering component; the gas-liquid separator is used for separating the medium into a gas-phase medium mainly composed of gas and a liquid-phase medium mainly composed of liquid; the demister is used for the secondary separation of the gas-phase medium after gas-liquid separation; the liquid storage tank is located below the gas-liquid separator and is used for storing the liquid-phase medium; the wet gas flow metering component is used for measuring the wet gas mass flow mainly composed of gas medium; the mass flow metering component is used for measuring the liquid-phase mass flow mainly composed of liquid medium. The present application has the effect of improving the online metering and calibration accuracy of gas-liquid two-phase under full flow conditions.

Description

Technical Field

[0001] This application relates to the technical field of flowmeter calibration, and particularly relates to a mobile wellhead flow calibration device and its calibration method. Background Art

[0002] At present, during the exploitation of oil and gas wells, it is necessary to set up metering devices on their collection and transportation pipelines to measure the liquid and gas in the oil and gas wells in real time online. Traditional oil and gas well metering adopts two methods: station metering and wellhead metering. The station metering process first separates and then measures the gas in the natural gas. The gas metering accuracy is high, but the liquid metering error is large; while the wellhead metering belongs to online metering. With the large-scale exploitation of shale gas and the continuous optimization and improvement of the single-well gathering and transportation technology, the production metering from gathering and transporting to the metering station has been transferred to the wellhead metering. The wellhead metering has gradually changed from separated metering to a multiphase flowmeter that does not require separation. Due to the continuous progress of real-time online multiphase metering technology, the wellhead metering has begun to choose a multiphase flowmeter that does not require separation.

[0003] However, the calibration of the multiphase flowmeter still needs to calibrate the flow rate of the single-phase medium with a single-phase instrument after efficient separation. For the existing online metering and calibration device under full-flow conditions, due to the fact that gas-liquid separation cannot ensure complete separation, that is, there will be a small amount of liquid in the gas path, and there may also be a small amount of gas in the liquid path (such as foam crude oil containing dissolved gas), which causes applicability problems such as poor calibration accuracy. Summary of the Invention

[0004] In order to improve the online metering and calibration accuracy of gas-liquid two-phase under full-flow conditions, this application provides a mobile wellhead flow calibration device and its calibration method.

[0005] In the first aspect, this application provides a mobile wellhead flow calibration device, adopting the following technical solution:

[0006] A mobile wellhead flow calibration device includes a gas-liquid separator for connecting the collection and transportation pipeline, a demister connected to the gas-liquid separator, and a liquid storage tank. The output end of the demister is connected with a wet gas flow metering component, and the output end of the liquid storage tank is connected with a mass flow metering component;

[0007] The gas-liquid separator is used to separate the medium into a gas-phase medium mainly composed of gas and a liquid-phase medium mainly composed of liquid;

[0008] The demister is used for the secondary separation of the gas-phase medium after gas-liquid separation;

[0009] The liquid storage tank is located below the gas-liquid separator and is used to store the liquid-phase medium;

[0010] The wet gas flow metering component is used to measure the wet gas mass flow mainly composed of gas medium;

[0011] The mass flow measurement component is used to measure the liquid-phase mass flow mainly composed of a liquid medium.

[0012] By adopting the above technical solution, after the medium flows out of the collection and transportation pipeline, it flows into the gas-liquid separator. The gas-liquid separator separates the gas and liquid of the medium to obtain a gas-phase medium and a liquid-phase medium. The gas-phase medium flows through the demister, and the demister is connected to the wet gas flow measurement component. Through the measurement of the wet gas flow measurement component, the influence of the liquid contained in the gas-phase medium on the measurement accuracy is reduced or even eliminated; the liquid-phase medium flows through the liquid storage tank. The liquid storage tank is located below the gas-liquid separator. The liquid seal formed by maintaining the liquid level in the liquid storage tank makes the gas volume fraction / GVF in the liquid-phase medium much less than 3%. The liquid storage tank is connected with a mass flow measurement component. Since the gas content in the liquid-phase medium is less than 3%, the influence of the gas content in the liquid-phase medium on the measurement accuracy of the mass flowmeter is very low at this time. Through the position setting of the wet gas flow measurement component, the gas-liquid separator and the liquid storage tank, the measurement accuracy of the overall calibration device is greatly improved.

[0013] Preferably, the wet gas flow measurement component includes two wet gas flowmeters with different calibers and two check valves respectively arranged at the inlets of the wet gas flowmeters. The check valves are used to control the connection or cut-off of the wet gas flowmeters connected thereto and the demister.

[0014] By adopting the above technical solution, during the oil and gas well exploitation process, the user can select wet gas flowmeters with different calibers according to the different flow rates of the gas-phase medium flowing into the demister for real-time measurement, ensuring that the wet gas flow measurement component can achieve continuous and accurate measurement.

[0015] Preferably, the mass flow measurement component includes two mass flowmeters with different calibers and two valves respectively arranged at the inlets of the mass flowmeters. The valves are used to control the connection or cut-off of the mass flowmeters connected thereto and the liquid storage tank.

[0016] By adopting the above technical solution, during the oil and gas well exploitation process, mass flowmeters with different calibers can be selected according to the different flow rates of the liquid-phase medium flowing into the liquid storage tank for real-time measurement, ensuring that the mass flow measurement component can achieve continuous and accurate measurement.

[0017] Preferably, the gas-liquid separator includes a housing and a spiral deflector vertically and spirally arranged inside the housing. The axis of the spiral deflector coincides with the axis of the housing. The outer side wall of the spiral deflector is hermetically connected to the inner wall of the housing. The inlet of the gas-liquid separator is arranged above the spiral deflector.

[0018] By adopting the above technical solution, a spiral deflector is arranged in the shell. When the medium enters the gas-liquid separator through the input pipe, under the guidance of the spiral deflector, the medium flows along the inclined direction of the spiral deflector. At the same time, under the action of centrifugal force, gravity and the restriction of the spiral deflector, the medium forms an inverted conical eddy current field. The gas-phase medium with low density rises along the center of the vortex, and the liquid-phase medium with high density flows downward along the inclined surface of the spiral deflector. The spiral deflector realizes forced confinement and swirling of the medium, so as to efficiently separate gas and liquid.

[0019] Preferably, an air duct connected to the demister is provided at the center of the top of the gas-liquid separator. The center of the end of the air duct connected to the shell is located on the axis of the shell. The distance between the side wall of the spiral deflector close to the axis of the shell and the axis is less than or equal to the radius of the air duct, so that the spiral deflector forms a guide air hole aligned with the air duct.

[0020] By adopting the above technical solution, the air duct guides the gas-phase medium separated by the gas-liquid separator into the demister. By setting the guide air hole, it is convenient for the gas-phase medium to rise and enter the air duct.

[0021] Preferably, a plurality of collision separation plates for separating the gas-phase medium and the liquid-phase medium are arranged at intervals along the transmission direction of the demister. A plurality of rows of collision parts are arranged at intervals on the collision separation plates. The collision parts include a plurality of air-permeable holes horizontally distributed at intervals.

[0022] By adopting the above technical solution, since the gas-phase medium contains a certain amount of liquid, the transmission of the gas-phase medium is blocked by setting the collision separation plates. When the gas-phase medium contacts the collision separation plates, the liquid adheres to the outer surface of the collision separation plates, so as to realize gas-liquid separation. By setting the air-permeable holes on the collision separation plates, the gas-phase medium can pass through the collision separation plates.

[0023] Preferably, the collision part further includes a guide plate arranged corresponding to one side of the air-permeable hole. The guide plate is arranged on the side of the collision separation plate away from the gas-liquid separator, and the guide plate is used to block the air-permeable hole.

[0024] By adopting the above technical solution, the guide plate is arranged on the air-permeable hole and corresponds to the air-permeable hole one by one. When the gas-phase medium passes through the air-permeable hole, it collides with the guide plate, so as to increase the contact area between the guide plate and the collision separation plate and improve the gas-liquid separation effect.

[0025] Preferably, the collision parts on adjacent two collision separation plates are arranged at intervals and staggered.

[0026] By adopting the above technical solution, the collision parts on two adjacent collision separation plates are staggered, so that the path of the gas-phase medium passing through the two collision separation plates is increased, the time for the gas-phase medium to flow through the demister is increased, and the filtration effect of the gas-phase medium in the demister is improved.

[0027] Preferably, the demister is horizontally arranged above the liquid storage tank along its transmission direction, and a connecting pipe communicating with the liquid storage tank is arranged below the demister and below the collision separation plate.

[0028] By adopting the above technical solution, the demister is arranged above the liquid storage tank, and a connecting pipe connecting the demister and the liquid storage tank is arranged. Under the action of the connecting pipe, the liquid in the demister can enter the liquid storage tank, and the gas in the liquid storage tank can also enter the demister, so as to improve the separation degree of gas and liquid and improve the calibration accuracy.

[0029] Preferably, the connecting pipe includes a connecting pipe sealingly connected to the liquid storage tank and a liquid-phase return pipe sealingly connected to the demister. The liquid-phase return pipe is inserted and communicated with the connecting pipe, and the diameter of the liquid-phase return pipe is smaller than that of the connecting pipe. The liquid-phase return pipe is sealingly connected to the end of the connecting pipe far from the liquid storage tank; a plurality of gas-liquid separation plates for separating the gas-phase medium and the liquid-phase medium are fixedly arranged inside the connecting pipe. The liquid-phase return pipe penetrates through the gas-liquid separation plates and is fixedly connected to the gas-liquid separation plates. A plurality of return air holes are arranged between the top of the connecting pipe and the gas-liquid separation plates where the liquid-phase return pipe is located.

[0030] By adopting the above technical solution, the liquid filtered out in the demister enters the liquid storage tank through the liquid-phase return pipe. During the flow of the liquid-phase medium in the liquid storage tank, the gas loaded in the liquid-phase medium is discharged and rises. Since the diameter of the connecting pipe is larger than that of the liquid-phase return pipe, in the process of rising, in addition to part of the gas directly entering the demister through the liquid-phase return pipe, most of the gas contacts the gas-liquid separation plates during the rising process and is subjected to gas-liquid separation under the action of the gas-liquid separation plates, so as to reduce the liquid content rate of the gas flowing back to the demister. At the same time, by opening return air holes on the liquid-phase return pipe, the gas in the connecting pipe can enter the demister through the liquid-phase return pipe, and at the same time, the gas-liquid separation plates are arranged to fix one end of the liquid-phase return pipe far from the demister.

[0031] Preferably, a filter mesh plate is arranged inside the demister.

[0032] By adopting the above technical solution, during the collection and development process of oil and gas wells, some particulate impurities such as sand grains will follow the medium into the collection and transportation pipeline and even the calibration device under the drive of high-pressure gas flow. The particulate impurities are filtered by the filter mesh plate to prevent the particulate impurities from damaging the wet gas flowmeter.

[0033] Preferably, the demister includes a front end tank shell and a rear end tank shell. A flange is provided between the front end tank shell and the rear end tank shell. The rear end tank shell is connected to the wet gas flow metering assembly, and the filter mesh plate is arranged at one end of the rear end tank shell away from the wet gas flow metering assembly.

[0034] By adopting the above technical solution, the front end tank shell and the rear end tank shell are connected by a flange, so that the front end tank shell and the rear end tank shell are detachably arranged, and the position of the filter mesh plate is set to facilitate the removal of particulate impurities filtered out by the filter mesh plate.

[0035] Preferably, a solenoid valve is provided between the liquid storage tank and the mass flow metering assembly. A liquid level gauge is provided on the liquid storage tank, and the liquid level gauge is electrically connected to the solenoid valve.

[0036] By adopting the above technical solution, the on-off of the solenoid valve between the liquid storage tank and the mass flow metering assembly is controlled, so that the liquid phase medium can be cached in the liquid storage tank, thereby buffering the input gas-liquid ratio and the output gas-liquid ratio to form a relatively stable flow pattern; the height of the liquid in the liquid storage tank is detected by the liquid level gauge, and the liquid level gauge is electrically connected to the liquid storage tank. When the liquid height in the liquid storage tank reaches a certain level, the opening and closing of the solenoid valve can be automatically controlled.

[0037] Preferably, a manual valve is provided between the liquid storage tank and the mass flow metering assembly, and the manual valve is arranged in parallel with the solenoid valve.

[0038] By adopting the above technical solution, the manual valve is set as a backup for the solenoid valve to ensure that it can be selected according to the usage requirements when necessary. Especially when the solenoid valve is damaged, the manual valve can ensure the normal use of the calibration device.

[0039] Preferably, an input pipe is provided between the gas-liquid separator and the collection and transportation pipeline. The output ends of the wet gas flow metering device and the mass flow metering device are jointly connected with an output pipe. The output pipe is used to connect to the collection and transportation pipeline. A first stop valve is provided on the input pipe, a second stop valve is provided on the output pipe, and the first stop valve and the second stop valve open and close synchronously.

[0040] By adopting the above technical solution, the first stop valve and the second stop valve are opened during the calibration process of the calibration device and closed during the non-calibration process of the calibration device to prevent the medium remaining in the calibration device after calibration from causing environmental pollution.

[0041] Preferably, the collection and transportation pipeline is provided with a calibration bypass connection assembly, which includes an output branch pipe for connecting the input pipe and an input branch pipe for connecting the output pipe. An output check valve is provided on the output branch pipe, an input check valve is provided on the input branch pipe, and a conduction cut-off valve is provided between the output branch pipe and the input branch pipe of the collection and transportation pipeline.

[0042] By adopting the above technical solution, the calibration device is connected to the collection and transportation pipeline by connecting with the calibration bypass connection assembly. By setting an output check valve on the output branch pipe, an input check valve on the input branch pipe, and a conduction cut-off valve, it is ensured that the normal collection of the collection and transportation pipeline is not affected when the calibration device is connected to the collection and transportation pipeline, and continuous collection and measurement are realized.

[0043] Preferably, it further includes a skid-mounted base. The gas-liquid separator, demister, liquid storage tank, wet gas flow measurement component, and mass flow measurement component are all installed on the skid-mounted base, and the skid-mounted base is used to be loaded into a mobile transport vehicle.

[0044] By adopting the above technical solution, the gas-liquid separator, demister, liquid storage tank, wet gas flow measurement component, and mass flow measurement component are integrated on the skid-mounted base, thus integrating a calibration device with a small volume, light weight, and convenient movement; by transferring the skid-mounted base and the equipment thereon to a mobile transport vehicle, the mobility of the calibration device is realized, and it is convenient to transport it to various different oil and gas well sites for on-site calibration.

[0045] In the second aspect, the present application provides a calibration method for a mobile wellhead flow calibration device, adopting the following technical solution:

[0046] A calibration method for a mobile wellhead flow calibration device includes the following steps:

[0047] Step 1: When calibration measurement is required,

[0048] Connect the input pipe and the output pipe to the collection and transportation pipeline in a butted and connected manner respectively;

[0049] Open the first cut-off valve, the second cut-off valve, the output cut-off valve, and the input cut-off valve simultaneously, and close the conduction cut-off valve synchronously;

[0050] The medium enters the gas-liquid separator through the input pipe, and gas-liquid separation is carried out to obtain a gas-phase medium mainly composed of gas and a liquid-phase medium mainly composed of liquid;

[0051] The gas-phase medium enters the demister and is transmitted along the demister to the output pipe. The gas-phase medium collides and contacts with the collision separation plate in the demister, and the liquid in the gas-phase medium contacts the collision separation plate and flows into the liquid storage tank through the connecting pipe;

[0052] The liquid-phase medium enters the liquid storage tank and is conveyed towards the output pipe. When the liquid-phase medium flows in the liquid storage tank, the gas in the liquid-phase medium rises and enters the demister through the connecting pipe;

[0053] The gas-phase medium enters the wet gas flow metering assembly, and the wet gas flow metering assembly measures the mass flow rates of the gas and liquid two-phase media flowing through it;

[0054] The liquid-phase medium enters the mass flow metering assembly, and the mass flow metering assembly measures the mass flow rates of the gas and liquid two-phase media flowing through it;

[0055] The liquid-phase medium and the gas-phase medium converge in the output pipe and then flow back into the collection and transportation pipeline;

[0056] Step 2: After the calibration measurement is completed,

[0057] Simultaneously close the first shut-off valve, the second shut-off valve, the output shut-off valve, and the input shut-off valve, and synchronously open the conduction shut-off valve;

[0058] Remove the input pipe and the output pipe from the collection and transportation pipeline.

[0059] By adopting the above technical solution, when it is necessary to calibrate the inlet metering device, the input pipe and the output pipe are connected to the collection and transportation pipeline, and the first shut-off valve, the second shut-off valve, the output shut-off valve, and the input shut-off valve are opened simultaneously, and the conduction shut-off valve is closed synchronously, so that the medium in the collection and transportation pipeline can flow into the calibration device, and the medium is separated into gas and liquid by the gas-liquid separator; after the medium is separated by the gas-liquid separator, the gas-phase medium enters the demister for further filtration and demisting, the liquid-phase medium enters the liquid storage tank, the liquid-phase medium flows into the liquid storage tank to discharge the entrained gas, under the connection and guidance of the connecting pipe, the gas in the liquid storage tank rises and enters the demister, and the liquid filtered out in the demister flows back into the liquid storage tank through the connecting pipe to further improve the gas-liquid separation effect; by adopting the wet gas flow metering assembly, from the equipment usage characteristics, the influence of the liquid content in the gas-phase medium on the metering accuracy is reduced; after the calibration is completed, by closing the first shut-off valve, the second shut-off valve, the output shut-off valve, and the input shut-off valve, and synchronously opening the conduction shut-off valve, the access and removal of the calibration device will not affect the exploitation of the oil and gas well, and continuous metering is achieved.

[0060] In summary, the present application includes at least one of the following beneficial technical effects:

[0061] 1. By setting up a gas-liquid separator to separate the medium, the gas-liquid separation effect is improved. At the same time, the wet gas flow metering assembly is connected to the calibration device, and by using the metering characteristics of the wet gas flow metering assembly, the metering accuracy is improved. Through the positional relationship between the liquid storage tank and the gas-liquid separator, the gas content in the liquid-phase medium is reduced to achieve the high-precision metering effect of using this device;

[0062] 2. By setting collision separation plates inside the demister, the transmission of the gas-phase medium is blocked by the collision separation plates. When the gas-phase medium passes through the demister, the gas-phase medium comes into full contact and collision with the collision separation plates. When the liquid-phase medium mixed in the gas-phase medium contacts the collision separation plates, the liquid-phase medium adheres to the collision separation plates, thereby further realizing gas-liquid separation and improving the metering accuracy of the wet gas flow measurement component;

[0063] 3. By setting a connecting pipe connecting the demister and the liquid storage tank, the liquid-phase medium in the demister flows back into the liquid storage tank through the connecting pipe under the action of gravity. The gas-phase medium in the liquid storage tank rises into the demister through the connecting pipe during the rising process, further improving the metering accuracy of the medium;

[0064] 4. By setting a skid-mounted base, the instruments and equipment required for calibration are integrally installed on the skid-mounted base, which facilitates the transfer of the calibration device at the on-site of each oil and gas well field and reduces the calibration cost of the multiphase flowmeter used at the on-site of multiple oil and gas well fields. Description of the Drawings

[0065] Figure 1 is the structural schematic diagram when the calibration device of the embodiment of the present application is connected to the collection and transportation pipeline of the oil and gas well field;

[0066] Figure 2 is the overall structural schematic diagram of the calibration device of the embodiment of the present application;

[0067] Figure 3 is the partial structural schematic diagram of the embodiment of the present application;

[0068] Figure 4 is the partial structural cross-sectional view of the embodiment of the present application, mainly showing the structure of the gas-liquid separator;

[0069] Figure 5 is the partial structural cross-sectional view of the embodiment of the present application, mainly showing the internal structure of the demister;

[0070] Figure 6 is Figure 5 the enlarged view of part A in;

[0071] Figure 7 is the partial structural cross-sectional view of the embodiment of the present application, mainly showing the structure and positional relationship of multiple collision separation plates;

[0072] Figure 8 is the partial structural cross-sectional view of the embodiment of the present application, mainly showing the structure of the connecting pipe;

[0073] Figure 9 is Figure 8 the enlarged view of part B in;

[0074] Figure 10It is a partial structural sectional view of an embodiment of the present application, mainly showing the structure and positional relationship of multiple gas-liquid separation plates;

[0075] Figure 11 It is a schematic diagram of the overall structure of the calibration device of an embodiment of the present application;

[0076] Figure 12 It is a connection schematic diagram of the calibration device and the calibration bypass connection assembly of an embodiment of the present application;

[0077] Figure 13 It is a flow chart of the calibration method of the calibration device of an embodiment of the present application.

[0078] Explanation of reference numerals: 1, skid-mounted base; 2, gas-liquid separator; 21, housing; 22, spiral flow guide; 221, air guide hole; 23, gas pipeline; 24, liquid pipeline; 3, demister; 31, front end tank shell; 32, rear end tank shell; 33, flange; 34, collision separation plate; 341, collision part; 3411, ventilation hole; 3412, guide plate; 35, filter mesh plate; 4, liquid storage tank; 41, solenoid valve; 42, manual valve; 43, liquid level gauge; 5, input pipe; 51, first stop valve; 6, output pipe; 61, second stop valve; 62, return air pipe; 63, return liquid pipe; 7, wet gas flow measurement assembly; 71, wet gas flowmeter; 711, resonant tube wet gas flowmeter; 712, gas phase flow measurement module; 72, check valve; 8, mass flow measurement assembly; 81, mass flowmeter; 82, valve; 9, connecting pipe; 91, connecting tube; 92, liquid phase return pipe; 921, return air hole; 93, gas-liquid separation plate; 931, filtering part; 9311, through hole; 9312, collision plate; 100, calibration bypass connection assembly; 1001, output branch pipe; 1002, input branch pipe; 1003, input stop valve; 1004, output stop valve; 1005, conduction stop valve. Detailed implementation manners

[0079] The following will Figure 1-13 further describe the present application in detail with reference to the attached

[0080] A metering device is installed on the collection and transportation pipeline of an oil and gas well to measure the production of liquid and gas in the oil and gas well, which is used as the basis for oil and gas well development. The metering device operates at the wellhead all year round, and its metering instrument may produce systematic deviations, resulting in large errors in its metering data. Therefore, a calibration device is needed to verify the metering data of the metering device. Currently, for the device that calibrates the flow rate of a multiphase flowmeter, according to the classification of oil, gas and water media used in the device, generally, multiphase flow test calibration devices are divided into two categories; one is the device that uses simulated media, which is mainly used for multiphase flow simulation tests and indoor standard loop tests of the prototype of the multiphase flowmeter principle. This type of device is generally built indoors and has a small scale, and it is difficult to meet the needs of on-site actual applications in terms of flow conditions; the other is the device that uses real liquid media and actual working conditions. The test and calibration results of this device are more in line with production reality. Therefore, for wellhead calibration metering, it is more recommended to use the device with real liquid media and actual working conditions.

[0081] An embodiment of the present application discloses a mobile wellhead flow calibration device. Referring to Figure 1 and Figure 2 , the calibration device includes a skid-mounted base 1, a gas-liquid separator 2 vertically arranged on the skid-mounted base 1, a demister 3 connected to the gas-liquid separator 2, and a liquid storage tank 4. Among them, the demister 3 is horizontally arranged above the liquid storage tank 4 along its transmission direction, the liquid storage tank 4 is located below the gas-liquid separator 2, and to ensure that the gas-phase medium is more smooth during transmission, the demister 3 is located above the gas-liquid separator 2. An input pipe 5 is connected to the inlet of the gas-liquid separator 2, and the output ends of the demister 3 and the liquid storage tank 4 are jointly connected to an output pipe 6. The input pipe 5 and the output pipe 6 are used to connect the original collection and transportation pipeline of the oil and gas well. At the same time, the ports of the input pipe 5 and the output pipe 6 connected to the collection and transportation pipeline are located on the same horizontal plane to prevent the pressure difference between the input pipe 5 and the output pipe 6 from affecting the calibration accuracy. The medium flows into the calibration device through the input pipe 5 for gas-liquid separation and calibration measurement. After the measurement is completed, the gas and liquid converge in the output pipe 6 and then flow back into the collection and transportation pipeline.

[0082] Referring to Figure 1 and Figure 2 , for the convenience of mobile detection of the calibration device, all calibration equipment and instruments of the calibration device are installed on the skid-mounted base 1 to be integrated into a skid-mounted calibration device with a small volume, light weight and high metering accuracy. The skid-mounted base 1 and the calibration equipment and instruments installed on it can be installed on a mobile transport vehicle, and the transferability of the calibration device is realized through the mobile transport vehicle, which is convenient to transport the calibration device to each oil and gas well site for on-line calibration test use.

[0083] Referring to Figure 1 and Figure 2, To ensure that the access of the calibration device does not affect the metering of the original acquisition, transportation, and metering devices of the oil and gas well, a calibration bypass connection assembly 100 is provided on the acquisition and transportation pipeline. The calibration bypass connection assembly 100 is used to connect the acquisition and transportation pipeline with the output branch pipe 1001 of the input pipe 5 and to connect the acquisition and transportation pipeline with the input branch pipe 1002 of the output pipe 6. An output shut-off valve 1004 is provided on the output branch pipe 1001, an input shut-off valve 1003 is provided on the input branch pipe 1002, and a conduction shut-off valve 1005 is provided on the acquisition and transportation pipeline between the input branch pipe 1002 and the output branch pipe 1001. When the calibration device needs to be accessed, connect the input pipe 5 to the output branch pipe 1001, connect the output pipe 6 to the input branch pipe 1002, then open the output shut-off valve 1004 and the output shut-off valve 1004, and at the same time close the conduction shut-off valve 1005.

[0084] Refer to Figure 2 and Figure 3 , The gas-liquid separator 2 is used to separate the medium into a gas-phase medium mainly composed of gas and a liquid-phase medium mainly composed of liquid. To improve the measurement accuracy of the calibration device, the gas-liquid separator 2 adopts a vertical cyclone separator. An air duct 23 communicating with the demister 3 is provided at the top of the gas-liquid separator 2, and a liquid duct 24 communicating with the liquid storage tank 4 is provided at the lower end of the gas-liquid separator 2. The gas-liquid separator 2 includes a housing 21 and a spiral deflector 22 vertically and spirally arranged inside the housing 21. The axis of the spiral deflector 22 coincides with the axis of the housing 21, and the outer side wall of the spiral deflector 22 is hermetically connected to the inner wall of the housing 21. One end of the air duct 23 is vertically arranged at the center of the top of the housing 21, so that the axis of the end of the air duct 23 coincides with the axis of the housing 21. The distance between the side wall of the spiral deflector 22 close to the axis and the axis is less than or equal to the radius of the air duct 23, so that the spiral deflector 22 forms a guide air hole 221 aligned with the air duct 23. The diameter of the guide air hole 221 is much smaller than the diameter of the housing 21, reducing the amount of the medium flowing along the spiral deflector 22 directly falling from the guide air hole 221 to the bottom of the housing 21.

[0085] Refer to Figure 4 and Figure 5 , The inlet of the gas-liquid separator 2 is arranged at the upper end of the spiral deflector 22. When the medium enters the gas-liquid separator 2 through the input pipe 5, under the guidance of the spiral deflector 22, the medium flows along the inclined direction of the spiral deflector 22. At the same time, under the action of centrifugal force, gravity, and the restriction of the spiral deflector 22, the medium forms an inverted conical eddy field. The gas-phase medium with a small density rises along the center of the vortex, that is, rises from the guide air hole 221 and enters the air duct 23. The liquid-phase medium with a large density flows downward along the inclined surface of the spiral deflector 22 until it flows out from the bottom of the gas-liquid separator 2 and enters the liquid duct 24. The spiral deflector 22 realizes forced confinement and swirling of the medium, enabling efficient gas-liquid separation.

[0086] Reference Figure 3 and Figure 5 Figure 5 , one end of the demister 3 is connected to the gas pipeline 23, and a wet gas flow measurement component 7 is connected to the end of the demister 3 away from the gas pipeline 23. The wet gas flow measurement component is used to measure the mass flow rate of wet gas mainly composed of gas medium. The wet gas flow measurement component 7 includes two wet gas flow meters 71 with different calibers and two check valves 72 respectively arranged at the inlets of the wet gas flow meters 71. The check valve 72 is used to control the connection or cut-off between the wet gas flow meter 71 connected thereto and the demister 3. As the oil and gas well is continuously exploited, the exploitation volume of the oil and gas well will change. When the flow rate entering the gas pipeline 23 is relatively large, the wet gas flow meter 71 with a large caliber is adopted to meet the large flow rate measurement; when the flow rate entering the gas pipeline 23 is relatively small, the wet gas flow meter 71 with a small caliber is adopted to meet the small flow rate measurement. During the calibration process, when the medium flow rate in the gas pipeline 23 changes, only the check valve 72 connected to the wet gas flow meter 71 with the required caliber needs to be opened, and the check valve 72 of the wet gas flow meter 71 that was originally conducting measurement is closed, ensuring that the wet gas flow measurement component 7 can achieve continuous and accurate measurement.

[0087] Reference Figure 5 Figure 5 , in the present application, the wet gas flow meter 71 preferably adopts a wet gas flow meter 71 based on a resonant tube, which includes a resonant tube wet gas flow meter 711, pipelines respectively arranged at the inlet and outlet of the resonant tube wet gas flow meter 711, a gas phase flow measurement module 712, and a sensor group. Among them, the resonant tube wet gas flow meter 711 is used to measure the total mass flow rate Qm, the mixed density ρmix, and the medium temperature T; the sensor group is installed on the pipeline and is used to measure the differential pressure ΔP at the inlet and outlet of the resonant tube wet gas flow meter 711; the gas phase flow measurement module 712 performs multi-physical field coupling calculations, calculates the pressure at the corresponding position according to the resonant tube wet gas flow meter 711 for measuring different positions in the pipeline, and generates a function curve of position and pressure. The gas phase flow measurement module 712 calculates the average pressure P in the measurement tube of the resonant tube wet gas flow meter 711 through the function curve, calculates the average gas density ρg through the average pressure P combined with the PVT equation, and then calculates the mass liquid content ηm of the mixed medium according to the mixed density ρmix, the average gas density ρg, and the liquid density ρl (constant); the total mass flow rate Qm is corrected by the mass liquid content ηm of the mixed medium, the average pressure P in the measurement pipeline, and the medium temperature T to obtain the total mass flow rate Qm'; finally, the gas mass flow rate Qg and the liquid mass flow rate Ql are calculated according to the mass liquid content ηm and the total mass flow rate Qm'. The gas-liquid two-phase flow is calculated through the wet gas flow meter 71 and the measurement method, reducing or even eliminating the influence of a small amount of liquid phase medium mixed in the gas phase medium on the gas phase flow measurement accuracy, thereby improving the calibration accuracy.

[0088] Reference Figure 5 andFigure 6 In order to reduce the liquid content of the gas phase medium entering the wet gas flow meter 71, the demister 3 is used for secondary separation of the gas phase medium mainly composed of gas after gas-liquid separation. In order to ensure the separation effect of the demister 3, the demister 3 is provided with a plurality of collision separation plates 34 (shown as 3 pieces in the figure) for separating the gas phase medium and the liquid phase medium at intervals along its transmission direction. In the present application, it is preferred that the demister 3 is placed horizontally, that is, the axis of the demister 3 is arranged horizontally.

[0089] Reference Figure 6 and Figure 7 The collision separation plate 34 is provided with a plurality of rows of collision parts 341 at intervals along its height direction, and the collision part 341 includes a plurality of air holes 3411 distributed at horizontal intervals; after the gas phase medium enters the demister 3, the gas phase medium flows along the length direction of the demister 3 and contacts and collides with the three collision separation plates 34 in turn during its flow process, and the gas phase medium enters the transmission rear end of the collision separation plate 34 from the transmission front end of the collision separation plate 34 through the air holes 3411 corresponding to the collision separation plate 34, and at the same time, when the gas phase medium collides with the collision separation plate 34, the liquid phase medium mixed in the gas phase medium will adhere to the collision separation plate 34 to achieve gas-liquid separation, and the liquid phase medium adhered to the collision separation plate 34 will drip downward under the action of gravity.

[0090] Reference Figure 6 and Figure 7 In order to improve the collision effect between the medium flowing through the demister 3 and the collision separation plate 34, the collision part 341 also includes a guide plate 3412 arranged one by one at the upper end of the air hole 3411, and the guide plate 3412 is used to block the air hole 3411. The guide plate 3412 is arranged on the side of the collision separation plate 34 away from the gas pipe 23, and the end of the guide plate 3412 away from the air hole 3411 is tilted downward. When the gas phase medium passes through the air hole 3411, the gas phase medium collides and contacts with the guide plate 3412 to increase the contact area between the medium and the collision separation plate 34, thereby improving the gas-liquid separation effect. At the same time, in order to increase the collision time of the gas phase medium in the demister 3, the collision parts 341 on the two adjacent collision separation plates 34 are arranged alternately at intervals up and down, thereby extending the flow distance of the gas phase medium through the two collision separation plates 34. The demister 3 is located below the collision separation plate 34 and is provided with a connecting pipe 9 connected to the liquid storage tank 4. The liquid medium separated by the collision separation plate 34 flows back into the liquid storage tank 4 through the connecting pipe 9 to ensure the calibration accuracy of the calibration device.

[0091] Reference Figure 5 and Figure 6, during the acquisition and development process of oil and gas wells, some particulate impurities such as sand grains will follow the medium under the drive of high-pressure gas flow into the acquisition and transportation pipeline and even the calibration device. To prevent the particulate impurities from damaging the wet gas flowmeter 71 when passing through the wet gas flow measurement component 7, the demister 3 is provided with a filter mesh plate 35 at one end of the collision separation plate 34 away from the wet gas flow measurement component 7. The filter mesh plate 35 is in a grid shape, filtering the particulate impurities, preventing the particulate impurities from damaging the wet gas flowmeter 71, and reducing the impact of the particulate impurities on the collision separation plate 34.

[0092] Refer to Figure 3 and Figure 5 , to facilitate the removal of the particulate impurities filtered by the filter mesh plate 35, the demister 3 includes a front end tank shell 31 connected to the gas connection pipe 23 and a rear end tank shell 32 connected to the wet gas flow measurement component 7, and the rear end tank shell 32 and the front end tank shell 31 are provided with flanges 33, and the front end tank shell 31 and the rear end tank shell 32 are detachably and sealedly connected through the flanges 33. The collision separation plate 34 and the filter mesh plate 35 are both fixedly installed in the rear end tank shell 32, and the filter mesh plate 35 is installed at one end of the rear end tank shell 32 away from the wet gas flow measurement component 7. When it is necessary to clean the particulate impurities, the particulate impurities in the demister 3 can be taken out by removing the flanges 33 on the front end tank shell 31 and the rear end tank shell 32.

[0093] Refer to Figure 5 , one end of the liquid storage tank 4 is communicated with the liquid pipeline 24, and a mass flow measurement component 8 is connected to the end of the liquid storage tank 4 away from the liquid pipeline 24. The mass flow measurement component 8 includes two mass flowmeters 81 with different calibers and two valves 82 respectively arranged at the inlets of the mass flowmeters 81. The valves 82 are used to control the connection or cut-off of the mass flowmeters 81 connected thereto and the liquid storage tank 4. In this application, the mass flowmeter 81 adopts a Coriolis mass flowmeter. When the flow rate entering the liquid pipeline 24 is large, the mass flowmeter 81 with a large caliber is used to meet the large flow rate measurement; when the flow rate entering the liquid pipeline 24 is small, the mass flowmeter 81 with a small caliber is used to meet the small flow rate measurement. During the calibration process, when the medium flow rate in the liquid pipeline 24 changes, only the valve 82 connected to the mass flowmeter 81 with the required caliber needs to be opened, and the valve 82 of the mass flowmeter 81 that was originally conducting measurement is closed, ensuring that the mass flow measurement component 8 can achieve continuous and accurate measurement.

[0094] Refer to Figure 5, the mass flowmeter 81 is connected to the corresponding liquid phase flow metering module, and the gas phase flow metering module 712 and the liquid phase flow metering module are jointly connected to a multiphase flow computer or MFC system (not shown in the figure). In this application, a multiphase flow computer is used, and the multiphase flow computer is also connected to the multiphase flow meter system or MPFM of the original metering device at the wellhead. When the gas phase medium and the liquid phase medium pass through the wet gas flowmeter 71 and the mass flowmeter 81 respectively, the wet gas flowmeter 71 and the mass flowmeter 81 perform real-time gas phase and liquid phase metering on the media flowing through them, and obtain the liquid phase mass flow rate and the gas phase mass flow rate respectively, and compare and calibrate the data in real time through the multiphase flow computer.

[0095] Reference Figure 5 A solenoid valve 41 is provided between the liquid storage tank 4 and the mass flow metering component 8. By opening and closing the solenoid valve 41, the liquid phase medium can be cached in the liquid storage tank 4, so that the input gas-liquid ratio and the output gas-liquid ratio are buffered to form a relatively stable flow pattern. The liquid storage tank 4 is provided with a liquid level meter 43, which is electrically connected to the multiphase flow computer. The differential pressure formed by the liquid in the liquid storage tank 4 is measured by the liquid level meter 43; the liquid level meter 43 transmits the measurement signal to the multiphase flow computer, and the multiphase flow computer controls the opening and closing of the solenoid valve 41 by measuring the data of the wet gas flow meter 71. In order to prevent the calibration device from being unable to be used normally due to the failure of the solenoid valve 41, a manual valve 42 parallel to the solenoid valve 41 is provided between the liquid storage tank 4 and the mass flow metering component 8. The manual valve 42 or the solenoid valve 41 is selected for control according to the actual use situation to ensure that the mass flow metering component 8 can achieve continuous and normal metering work.

[0096] Reference Figure 5 and Figure 8 The connecting pipe 9 connects the demister 3 and the liquid storage tank 4, and introduces the liquid medium filtered out by collision in the demister 3 into the liquid storage tank 4. At the same time, during the flow of the liquid medium in the liquid storage tank 4, the gaseous medium mixed with the liquid medium rises to the upper end of the liquid storage tank 4 along with the flow of the liquid medium, and enters the demister 3 through the connecting pipe 9, thereby improving the metering accuracy of the gaseous medium and the liquid medium.

[0097] Reference Figure 8 and Figure 9, the connecting pipe 9 includes a connecting pipe 91 that is hermetically connected to the liquid storage tank and a liquid-phase return pipe 92 that is hermetically connected to the demister. The connecting pipe 91 and the liquid-phase return pipe 92 are inserted and communicated with each other, and the axis of the connecting pipe 91 coincides with the axis of the liquid-phase return pipe 92. The diameter of the liquid-phase return pipe 92 is smaller than that of the connecting pipe 91. A plurality of gas-liquid separation plates 93 (shown as 3 in the figure) for separating gas-phase medium and liquid-phase medium are fixedly provided inside the connecting pipe 91. The liquid-phase return pipe 92 penetrates through the gas-liquid separation plates 93 and is fixedly connected to the gas-liquid separation plates 93, thereby ensuring the stability of the installation of the liquid-phase return pipe 92.

[0098] Refer to Figure 9 and Figure 10 , the gas-liquid separation plates 93 have the same structure as the collision separation plates 34. The diameter of the gas-liquid separation plates 93 is perpendicular to the axis of the liquid-phase return pipe 92. A plurality of rows of filtering parts 931 are provided at intervals along any diameter direction of the gas-liquid separation plates 93. The filtering parts 931 include a plurality of through holes 9311 distributed at intervals and collision plates 9312 correspondingly arranged above the through holes 9311. When the gas-phase medium collides with the gas-liquid separation plates 93, the liquid-phase medium mixed in the gas-phase medium contacts the gas-liquid separation plates 93 and adheres to the gas-liquid separation plates 93. At the same time, to increase the collision time of the medium with the gas-liquid separation plates 93, the filtering parts 931 on adjacent two gas-liquid separation plates 93 are arranged at intervals and staggered along the arrangement direction of the filtering parts 931, thereby extending the flow distance of the gas-phase medium through the two gas-liquid separation plates 93 and filtering and dehumidifying the gas-phase medium recovered into the demister 3.

[0099] Refer to Figure 9 and Figure 11 , to ensure that the gas-phase medium in the liquid storage tank 4 can be introduced into the demister 3, the length of the connecting pipe 91 is smaller than that of the liquid-phase return pipe 92. When the connecting pipe 91 does not reach the demister 3, the top of the connecting pipe 91 is in a sealed state and is hermetically fixed to the liquid-phase return pipe 92. A plurality of return air holes 921 are provided between the top of the connecting pipe 91 and the gas-liquid separation plates 93 in the liquid-phase return pipe 92. The gas-phase medium in the connecting pipe 91 enters the liquid-phase return pipe 92 through the return air holes 921 and enters the demister 3 along the liquid-phase return pipe 92.

[0100] Refer to Figure 11 , the output pipe 6 is provided with a return air pipe 62 and a return liquid pipe 63. One end of the return air pipe 62 far from the output pipe 6 is communicated with one end of the wet gas flow metering assembly 7 away from the demister 3, and one end of the return liquid pipe 63 far from the output pipe 6 is communicated with one end of the mass flow metering assembly 8 away from the liquid storage tank 4, so that the separated gas-phase medium and liquid-phase medium are mixed again in the output pipe 6 and then flow into the collection and conveying pipeline again through the output pipe 6.

[0101] Refer to Figure 11 and Figure 12, after the calibration device completes the calibration, to prevent the medium remaining in the calibration device from causing air pollution, a first shut-off valve 51 is provided on the input pipe 5, and a second shut-off valve 61 is provided on the output pipe 6. The first shut-off valve 51 and the second shut-off valve 61 are opened and closed synchronously with the input shut-off valve 1003 and the output shut-off valve 1004. When calibration detection is required, after the input pipe 5 and the output pipe 6 are respectively connected to the output branch pipe 1001 and the input branch pipe 1002, the first shut-off valve 51, the second shut-off valve 61, the input shut-off valve 1003, and the output shut-off valve 1004 are opened, and the conduction shut-off valve 1005 is synchronously closed; when the calibration detection is over, the first shut-off valve 51, the second shut-off valve 61, the input shut-off valve 1003, and the output shut-off valve 1004 are simultaneously closed, and the conduction shut-off valve 1005 is synchronously opened, so as to achieve non-interference between calibration and collection. At the same time, the first shut-off valve 51 and the second shut-off valve 61 are provided to ensure that when the calibration device is used again, the calibration device does not need to be emptied.

[0102] The implementation principle of the mobile wellhead flow calibration device in the embodiment of the present application is as follows: The calibration device is transported to the corresponding oil and gas well site by a mobile transport vehicle, and the input pipe 5 is hermetically connected to the output branch pipe 1001, and the output pipe 6 is hermetically connected to the input branch pipe 1002. Then, the first shut-off valve 51, the second shut-off valve 61, the input shut-off valve 1003, and the output shut-off valve 1004 are simultaneously opened, and the conduction shut-off valve 1005 is synchronously closed. The medium enters the gas-liquid separator 2 through the input pipe 5, and under the action of centrifugal force and gravity, an inverted conical eddy field is formed. The gas-phase medium rises along the center of the vortex to the top of the gas-liquid separator 2, and enters the demister 3 through the gas pipeline 23. The liquid-phase medium flows into the liquid pipeline 24 at the lower end of the gas-liquid separator 2 along the spiral guide body 22 and is discharged into the liquid storage tank 4. The gas-phase medium in the demister 3 collides with the collision separation plate 34 and filters the carried liquid-phase medium. The liquid-phase medium flows into the liquid storage tank 4 along the connecting pipe 9. The gas-phase medium separated from the liquid-phase medium in the liquid storage tank 4 during the flow process enters the demister 3 through the connecting pipe 9. The separated gas-phase medium and liquid-phase medium respectively enter the wet gas flowmeter 71 and the mass flowmeter 81 for measurement, and then converge and enter the production pipeline through the output pipe 6. At the same time, the measurement data is compared with the multiphase flowmeter by the multiphase flow computer, so as to perform online real-time measurement calibration on the multiphase flowmeter.

[0103] The embodiment of the present application also discloses a calibration method for a mobile wellhead flow device. Refer to Figure 13 , the calibration method includes the following steps:

[0104] Step 1: When calibration measurement is required,

[0105] Step a: Connect the input pipe 5 and the output pipe 6 to the collection and transportation pipeline respectively for connection and communication.

[0106] Step b: Then, simultaneously open the first shut-off valve 51, the second shut-off valve 61, the output shut-off valve 1004, and the input shut-off valve 1003, and synchronously close the conduction shut-off valve 1005, so that the original collection and conveying pipeline is interrupted under the action of the conduction shut-off valve 1005. The medium flows into the calibration device from the output branch pipe 1001, and after being calibrated by the calibration device, it flows back into the collection and conveying pipeline through the input branch pipe 1002 again.

[0107] Step c: The medium enters the gas-liquid separator 2 through the input pipe 5 and undergoes gas-liquid separation to obtain a gas-phase medium mainly composed of gas and a liquid-phase medium mainly composed of liquid.

[0108] Specifically, when the medium enters the gas-liquid separator 2, the medium forms an inverted conical eddy field under the guidance of the spiral guide plate and under the action of centrifugal force and gravity. The gas-phase medium rises along the center of the vortex to the top of the gas-liquid separator 2 and enters the demister 3 through the gas pipeline 23. The liquid-phase medium flows along the spiral guide 22 into the liquid pipeline 24 at the lower end of the gas-liquid separator 2 and is discharged into the liquid storage tank 4.

[0109] Step d: The gas-phase medium enters the demister 3 and is conveyed along the demister 3 towards the output pipe 6. The gas-phase medium collides with the collision separation plate 34 in the demister 3. The liquid in the gas-phase medium comes into contact with the collision separation plate 34 and flows into the liquid storage tank 4 through the connecting pipe 9.

[0110] Specifically, when the gas-phase medium comes into contact with the collision separation plate 34, the liquid in the gas-phase medium adheres to the surface of the collision separation plate 34 and slides downward along the surface of the collision separation plate 34 under the action of gravity, converges at the bottom of the demister 3, and flows into the liquid storage tank 4 under the conduction of the connecting pipe 9.

[0111] Step e: The liquid-phase medium enters the liquid storage tank 4 and is conveyed towards the output pipe 6. When the liquid-phase medium flows in the liquid storage tank 4, the gas in the liquid-phase medium rises and enters the demister 3 through the connecting pipe 9.

[0112] Specifically, during the flow of the liquid-phase medium, the gas mixed in it is discharged. Since the gas of liquefied petroleum gas is lighter than air, the gas rises. During the rising process of the gas, it is filtered again by the gas-liquid separation plate 93 to remove the moisture in the gas. The gas separated by the gas-liquid separation plate 93 continues to rise through the return air hole 921 and enters the demister 3.

[0113] Step d and step e are not in sequence and are carried out synchronously.

[0114] Step f: The gas-phase medium enters the wet gas flow metering component 7, and the wet gas flow metering component 7 performs mass flow metering on the gas-liquid two-phase medium flowing through it.

[0115] Specifically, after the gas-phase medium enters the wet gas flow measurement assembly 7, when the liquid content rate in the gas-phase medium is less than 3%, the influence of the liquid content rate on the measurement accuracy of the wet gas flowmeter 71 can be ignored, and high-precision measurement is achieved at one time by measuring the flow rates of both the gas phase and the liquid phase in the medium to ensure the measurement accuracy.

[0116] Step g: The liquid-phase medium enters the mass flow measurement assembly 8, and the mass flow measurement assembly 8 measures the mass flow rates of the gas and liquid phases flowing through it.

[0117] Specifically, after the liquid-phase medium enters the mass flow measurement assembly 8, when the gas content rate in the liquid-phase medium is less than 3%, the influence of the gas content rate on the measurement accuracy of the mass flowmeter 81 can be ignored, thereby achieving high-precision measurement.

[0118] Step f and step g are not in a specific order and are carried out simultaneously.

[0119] Step h: The liquid-phase medium and the gas-phase medium converge in the output pipe 6 and then flow back into the collection and transportation pipeline.

[0120] Step two: After the calibration measurement is completed,

[0121] Step A: Close the first cut-off valve 51, the second cut-off valve 61, the output cut-off valve 1004, and the input cut-off valve 1003 simultaneously, and open the conduction cut-off valve 1005 synchronously. At this time, the original collection and transportation pipeline is conducted again, and the passage between the collection and transportation pipeline and the calibration device is closed, and the medium is transmitted along the collection and transportation pipeline.

[0122] Step B: Remove the input pipe 5 and the output pipe 6 from the collection and transportation pipeline.

[0123] The above are all the preferred embodiments of the present application, and the protection scope of the present application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A mobile wellhead flow calibration device, characterized in that: It includes a gas-liquid separator (2) for connecting the collection and transportation pipeline, a demister (3) connected to the gas-liquid separator (2), and a liquid storage tank (4). The output end of the demister (3) is connected with a wet gas flow metering component (7), and the output end of the liquid storage tank (4) is connected with a mass flow metering component (8); The gas-liquid separator (2) is used to separate the medium into a gas-phase medium mainly composed of gas and a liquid-phase medium mainly composed of liquid; The demister (3) is used for the secondary separation of the gas-phase medium after gas-liquid separation; The liquid storage tank (4) is located below the gas-liquid separator (2) and is used to store the liquid-phase medium; The wet gas flow metering component (7) is used to measure the mass flow of wet gas mainly composed of gas medium; The mass flow metering component (8) is used to measure the mass flow of the liquid-phase mainly composed of liquid medium; A number of collision separation plates (34) for separating the gas-phase medium and the liquid-phase medium are arranged at intervals along the transmission direction of the demister (3). A number of rows of collision parts (341) are arranged at intervals on the collision separation plates (34). The collision parts (341) include a number of ventilation holes (3411) horizontally distributed at intervals. The collision parts (341) also include guide plates (3412) arranged corresponding to one side of the ventilation holes (3411). The guide plates (3412) are arranged on the side of the collision separation plates (34) away from the gas-liquid separator (2), and the guide plates (3412) are used to block the ventilation holes (3411). The collision parts (341) on adjacent two collision separation plates (34) are arranged at intervals and staggered; The demister (3) is horizontally arranged above the liquid storage tank (4) along its transmission direction. A connecting pipe (9) communicating with the liquid storage tank (4) is arranged below the collision separation plates (34) of the demister (3). The connecting pipe (9) includes a connecting pipe (91) hermetically connected to the liquid storage tank (4) and a liquid-phase return pipe (92) hermetically connected to the demister (3). The liquid-phase return pipe (92) is inserted and communicated with the connecting pipe (91), and the diameter of the liquid-phase return pipe (92) is smaller than that of the connecting pipe (91). The end of the connecting pipe (91) away from the liquid storage tank (4) is hermetically connected to the liquid-phase return pipe (92); A number of gas-liquid separation plates (93) for separating the gas-phase medium and the liquid-phase medium are fixedly arranged inside the connecting pipe (91). The liquid-phase return pipe (92) penetrates through the gas-liquid separation plates (93) and is fixedly connected to the gas-liquid separation plates (93). A number of return air holes (921) are arranged between the top of the connecting pipe (91) and the gas-liquid separation plates (93) where the liquid-phase return pipe (92) is located.

2. The mobile wellhead flow calibration device according to claim 1, characterized in that: The wet gas flow metering component (7) includes two wet gas flow meters (71) with different diameters and two check valves (72) respectively arranged at the inlets of the wet gas flow meters (71). The check valves (72) are used to control the connection or cut-off between the wet gas flow meters (71) connected thereto and the demister (3).

3. The mobile wellhead flow calibration device according to claim 1, characterized in that: The mass flow measurement assembly (8) includes two mass flow meters (81) with different calibers and two valves (82) respectively arranged at the inlets of the mass flow meters (81). The valves (82) are used to control the connection or cut-off between the mass flow meters (81) connected thereto and the liquid storage tank (4).

4. A mobile wellhead flow calibration device according to claim 1, characterized in that: The gas-liquid separator (2) includes a housing (21) and a spiral deflector (22) vertically spirally arranged inside the housing (21). The axis of the spiral deflector (22) coincides with the axis of the housing (21). The outer side wall of the spiral deflector (22) is hermetically connected to the inner wall of the housing (21). The inlet of the gas-liquid separator (2) is arranged above the spiral deflector (22).

5. The mobile wellhead flow calibration device according to claim 4, wherein: A gas pipeline (23) connecting to a demister is provided at the center of the top of the gas-liquid separator (2). The center of the end of the gas pipeline (23) connected to the housing (21) is located on the axis of the housing (21). The distance between the side wall of the spiral deflector (22) close to the axis of the housing (21) and the axis is less than or equal to the radius of the gas pipeline (23), so that the spiral deflector (22) forms a guide air hole (221) aligned with the gas pipeline (23).

6. The mobile wellhead flow calibration device according to claim 1, characterized in that: A filter mesh plate (35) is arranged inside the demister (3).

7. A mobile wellhead flow calibration device according to claim 6, characterized in that: The demister (3) includes a front tank shell (31) and a rear tank shell (32). A flange (33) is provided between the front tank shell (31) and the rear tank shell (32). The rear tank shell (32) is connected to the wet gas flow measurement assembly (7). The filter mesh plate (35) is arranged at one end of the rear tank shell (32) away from the wet gas flow measurement assembly (7).

8. The mobile wellhead flow calibration device according to claim 1, characterized in that: An electromagnetic valve (41) is provided between the liquid storage tank (4) and the mass flow measurement assembly (8). A liquid level gauge (43) is provided on the liquid storage tank (4). The liquid level gauge (43) is electrically connected to the electromagnetic valve (41).

9. The mobile wellhead flow calibration device according to claim 8, wherein: A manual valve (42) is provided between the liquid storage tank (4) and the mass flow measurement assembly (8). The manual valve (42) is arranged in parallel with the electromagnetic valve (41).

10. A mobile wellhead flow calibration device according to claim 1, characterized in that: An input pipe (5) is provided between the gas-liquid separator (2) and the collection and transportation pipeline. The output ends of the wet gas flow meter (71) device and the mass flow meter (81) device are jointly connected with an output pipe (6). The output pipe (6) is used to connect to the collection and transportation pipeline. A first stop valve (51) is provided on the input pipe (5). A second stop valve (61) is provided on the output pipe (6). The first stop valve (51) and the second stop valve (61) are opened and closed synchronously.

11. A mobile wellhead flow calibration device according to claim 10, characterized in that: A calibration bypass connection assembly (100) is provided on the collection and transportation pipeline. The calibration bypass connection assembly (100) includes an output branch pipe (1001) for connecting to the input pipe (5) and an input branch pipe (1002) for connecting to the output pipe (6). An output check valve (72) is provided on the output branch pipe (1001). An input check valve (72) is provided on the input branch pipe (1002). A conduction stop valve (1005) is provided on the collection and transportation pipeline between the output branch pipe (1001) and the input branch pipe (1002).

12. A mobile wellhead flow calibration device according to claim 1, characterized in that: It further includes a skid-mounted base (1), and the gas-liquid separator (2), the demister (3), the liquid storage tank (4), the wet gas flow metering assembly (7) and the mass flow metering assembly (8) are all installed on the skid-mounted base (1), and the skid-mounted base (1) is used to be loaded into a mobile transport vehicle.

13. A calibration method for the mobile wellhead flow calibration device according to any one of claims 1-12, characterized in that: It includes the following steps: Step 1: When calibration measurement is required, Connect the input pipe (5) and the output pipe (6) to the collection and transportation pipeline in butt joint and communicate them respectively; Open the first stop valve (51), the second stop valve (61), the output stop valve (1004) and the input stop valve (1003) simultaneously, and close the conduction stop valve (1005) synchronously; The medium enters the gas-liquid separator (2) through the input pipe (5), and gas-liquid separation is carried out to obtain a gas-phase medium mainly composed of gas and a liquid-phase medium mainly composed of liquid; The gas-phase medium enters the demister (3) and is conveyed along the demister (3) towards the output pipe (6). The gas-phase medium collides and contacts with the collision separation plate (34) in the demister (3), and the liquid in the gas-phase medium contacts the collision separation plate (34) and flows into the liquid storage tank (4) through the connecting pipe (9); The liquid-phase medium enters the liquid storage tank (4) and is conveyed towards the output pipe (6). When the liquid-phase medium flows in the liquid storage tank (4), the gas in the liquid-phase medium rises and enters the demister (3) through the connecting pipe (9); The gas-phase medium enters the wet gas flow metering assembly (7), and the wet gas flow metering assembly (7) performs various mass flow metering on the gas-liquid two-phase medium flowing through it; The liquid-phase medium enters the mass flow metering assembly (8), and the mass flow metering assembly (8) performs various mass flow metering on the gas-liquid two-phase medium flowing through it; The liquid-phase medium and the gas-phase medium converge in the output pipe (6) and then flow back into the collection and transportation pipeline; Step 2: When the calibration measurement is completed, Close the first stop valve (51), the second stop valve (61), the output stop valve (1004) and the input stop valve (1003) simultaneously, and open the conduction stop valve (1005) synchronously; Remove the input pipe (5) and the output pipe (6) from the collection and transportation pipeline.

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