A nozzle-based wet gas two-phase on-line metering device

Abstract

The present invention belongs to the technical field of natural gas multiphase flow metering, and particularly relates to a wet gas two-phase on-line metering device based on a nozzle, which includes an equipment pipeline, a pressure sensor, a temperature sensor, a differential pressure sensor group and a main circuit component; both ends of the equipment pipeline are connected in series to the pipeline to be metered for wet gas two-phase through connecting flanges, and a nozzle throttle is installed in the equipment pipeline; compared with the existing separated equipment for metering the wet gas two-phase flow, the on-line metering device provided by the present invention has the advantages of simple hardware equipment structure, convenient installation and low requirement for wellhead space; the differential pressure measurement method adopted by the metering device is technically mature and there is no safety hazard of the ray method; in addition, in the on-line metering device provided by the present invention, the nozzle throttle is different from the Venturi tube and can measure the gas production volume and liquid production volume of low gas production wells in real time.

Description

Technical Field

[0001] The invention belongs to the technical field of natural gas multiphase flow metering, and particularly relates to a wet gas two-phase on-line metering device based on a nozzle. Background Art

[0002] During the development of natural gas wells, it is necessary to master the operating status of each gas well through production metering, so as to optimize the exploitation plan and economic evaluation. In addition to natural gas, the medium produced by natural gas wells also carries a small amount of liquid. This state of gas is called wet gas, but not all gas-liquid mixed phases are called wet gas. Currently, the more recognized definition methods of wet gas include the LM parameter method, the gas volume fraction method (GVF method), and the gas mass fraction method (dryness method); among them, the LM parameter is the square root of the ratio of the liquid inertia under the condition of single-phase liquid flow in the pipeline to the gas inertia under the condition of single-phase gas flow in the pipeline. A mixed fluid composed of natural gas, hydrocarbon, and water with an LM parameter less than 0.3 is called wet gas; the GVF method means that the gas volume fraction is greater than 95% is called wet gas; the dryness method means that the gas mass fraction is greater than 0.5 is called wet gas.

[0003] The gas-liquid two-phase mixing makes the metering of wet gas different from that of traditional single-phase gas. Traditional single-phase gas flowmeters are not applicable to the metering of wet gas. Currently, large separation equipment is mostly used at the development site, and single-phase gas metering is carried out after gas-liquid separation. However, the separation equipment is large in volume and high in operating cost, and is not suitable for single wells. Regarding multiphase flow metering, some scholars began to study it in the 1970s. In recent years, energy and instrument companies at home and abroad have also started to invest, hoping to develop multiphase flow products with accurate metering. There have been many research results, but most of them can only be accurately metered under certain working conditions, and each method has certain shortcomings. For example, the radioactive method is relatively accurate in metering, but it has a high cost, a complex structure, and safety concerns. Single wells do not have the conditions in terms of cost and installation space; the Venturi throttling method is affected by the inner diameter of the hardware structure not being too small, and cannot measure low-production gas wells. Moreover, the size of the Venturi device is relatively long, and the installation has more stringent requirements for the wellhead space. Summary of the Invention

[0004] Aiming at the problems in the prior art, the purpose of the present invention is to provide a wet gas two-phase on-line metering device based on a nozzle, especially for the problem of wet gas metering of low-production gas wells, and to achieve accurate metering of the production of low-production gas wells.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions to implement:

[0006] A wet gas two-phase on-line metering device based on a nozzle, comprising:

[0007] An equipment pipeline, the two ends of which are connected in series to the pipeline to be metered for wet gas two-phase through connecting flanges, and a nozzle throttling element is installed in the equipment pipeline;

[0008] A pressure sensor, which is arranged in the equipment pipeline and is used to measure the pressure of the wet gas two-phase to be metered before entering the nozzle throttle piece;

[0009] A temperature sensor, which is arranged in the equipment pipeline and is used to measure the temperature of the wet gas two-phase to be metered before entering the nozzle throttle piece;

[0010] A differential pressure sensor group, which is arranged in the equipment pipeline and is used to measure the differential pressure before and after the wet gas to be metered enters the nozzle throttle piece;

[0011] A main circuit component, which is arranged outside the equipment pipeline and is used for data acquisition, parameter analysis, liquid crystal display and data transmission.

[0012] In a further technical solution, the pressure sensor, the temperature sensor, the nozzle throttle piece and the differential pressure sensor group are arranged in sequence along the flow direction of the wet gas two-phase.

[0013] In a further technical solution, the metering device further includes a power supply circuit board for power supply.

[0014] In a further technical solution, the main circuit component includes a main circuit board and a calculation circuit board. Among them, the main circuit board is electrically connected to the pressure sensor, the temperature sensor and the differential pressure sensor group and is used for data acquisition, parameter analysis, liquid crystal display and data transmission;

[0015] The calculation circuit board is electrically connected to the main circuit board and is used for receiving the collected temperature data and pressure data, calculating the flow rate of the wet gas two-phase and then feeding it back to the main circuit board for storage, display and transmission.

[0016] In a further technical solution, a sewage discharge port is opened on the equipment pipeline, and a sewage discharge valve is arranged on the sewage discharge port for cleaning sundries in the equipment pipeline.

[0017] In a further technical solution, the metering device further includes a shield housing, which covers the outside of the equipment pipeline and is used for protecting the main circuit component.

[0018] In a further technical solution, the metering device further includes a liquid crystal display for real-time displaying the collected parameters and metering results of the wet gas to be metered.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] 1. The online metering device provided by the present invention has the advantages of simple hardware equipment structure, convenient installation and low requirement for wellhead space when metering the flow rate of wet gas two-phase compared with the existing separate equipment.

[0021] 2. The online metering device provided by the present invention adopts the technically mature differential pressure measurement method, and there is no safety hazard of the ray method.

[0022] 3. In the online metering device provided by the present invention, the nozzle throttle element is different from the Venturi tube, and it can measure the gas production rate and liquid production rate of low gas-producing wells in real time.

[0023] Other features and advantages of the present invention will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 FIG. 1 shows a schematic structural diagram of a nozzle-based wet gas two-phase flow metering device provided according to a specific embodiment of the present invention;

[0025] Figure 2 FIG. 2 shows Figure 1 a side view of the metering device in FIG. 1;

[0026] Figure 3 FIG. 3 shows Figure 1 a cross-sectional view of the K1-K1 section in FIG. 1;

[0027] Figure 4 FIG. 4 shows Figure 1 a top view of the metering device in FIG. 1;

[0028] Figure 5 FIG. 5 shows Figure 1 a cross-sectional view of the K2-K2 section in FIG. 1;

[0029] Description of reference numerals in the figures: 10, equipment pipeline; 11, connecting flange; 12, sewage outlet; 13, sewage valve; 14, shield housing; 20, pressure sensor; 30, temperature sensor; 40, differential pressure sensor group; 50, main circuit component; 60, power supply circuit board; 70, liquid crystal display. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further clarified below with reference to specific drawings.

[0031] It should be noted that in the present invention, when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0033] As described above, in combination with Figures 1-5 As shown, the present invention provides a nozzle-based wet gas two-phase on-line metering device, and the metering device includes an equipment pipeline 10, a pressure sensor 20, a temperature sensor 30, a differential pressure sensor group 40, and a main circuit assembly 50.

[0034] Wherein, both ends of the equipment pipeline 10 are connected in series to the pipeline of the wet gas two-phase to be metered through connection flanges 11, and a nozzle throttle element is installed in the equipment pipeline 10; the pressure sensor 20 is arranged in the equipment pipeline 10 and is used for measuring the pressure of the wet gas two-phase to be metered before entering the nozzle throttle element; the temperature sensor 30 is arranged in the equipment pipeline 10 and is used for measuring the temperature of the wet gas two-phase to be metered before entering the nozzle throttle element; the differential pressure sensor group 40 is arranged in the equipment pipeline 10 and is used for measuring the differential pressure of the wet gas to be metered before and after entering the nozzle throttle element; the main circuit assembly 50 is arranged outside the equipment pipeline 10 and is used for data acquisition, parameter analysis, liquid crystal display, and data transmission.

[0035] Furthermore, according to the metering device provided by the present invention, the pressure sensor 20, the temperature sensor 30, the nozzle throttle element, and the differential pressure sensor group 40 are arranged in sequence along the flow direction of the wet gas two-phase.

[0036] That is to say, the pressure sensor 20 is arranged at the most upstream, the temperature sensor 30 is arranged downstream of the pressure sensor 20 and upstream of the nozzle throttle element; the differential pressure sensor group 40 is arranged downstream, thus avoiding the influence of the temperature sensor 30 on the measurement of the pressure sensor 20.

[0037] Preferably, the pressure sensor 20 is horizontally installed on the equipment pipeline 10, the temperature sensor 30 is vertically installed on the equipment pipeline 10, and the differential pressure sensor group 40 is installed at 45° on the equipment pipeline 10, thus ensuring that the entire metering device has a compact structure and meets the installation requirements of most on-site wellheads.

[0038] Furthermore, the metering device provided by the present invention further includes a power supply circuit board 60 for power supply.

[0039] The main circuit component 50 includes a main circuit board and a calculation circuit board. Among them, the main circuit board is electrically connected to the pressure sensor 20, the temperature sensor 30, and the differential pressure sensor group 40, and is used for data acquisition, parameter analysis, liquid crystal display, and data transmission; the calculation circuit board is electrically connected to the main circuit board, and is used for receiving the collected temperature data and pressure data, calculating the wet gas two-phase flow rate, and then feeding it back to the main circuit board for storage, display, and transmission.

[0040] Furthermore, according to the metering device provided by the present invention, a sewage discharge port 12 is provided on the equipment pipeline 10, and a sewage discharge valve 13 is provided on the sewage discharge port 12 for cleaning debris in the equipment pipeline 10. Preferably, the sewage discharge port 12 and the sewage discharge valve 13 are arranged vertically below the equipment pipeline 10, which is convenient for subsequent maintenance.

[0041] In the present invention, the metering device further includes a shield housing 14, and the shield housing 14 covers the outside of the equipment pipeline 10 for protecting the main circuit component 50.

[0042] In the present invention, the metering device further includes a liquid crystal display 70, and the liquid crystal display 70 is used for real-time displaying the acquisition parameters and metering results of the wet gas to be metered. Preferably, the liquid crystal display 70 is embedded in the shield housing 14, eliminating the instrument head, which is beautiful and protects the display module.

[0043] In the present invention, the temperature sensor 30 can be selected as commonly used by those skilled in the art, specifically such as a platinum resistance temperature sensor.

[0044] When the metering device provided by the present invention is specifically used, the working pipeline at the wellhead of the gas well is cut, mating flanges are welded, and connection can be achieved through the matching bolts, which is simple and convenient; and the overall structure of the metering device is compact and highly integrated. In a specific embodiment of the present invention, the total length of the DN50 metering device is only 360 mm, and thus the requirement for the wellhead space is relatively low, which can meet the installation requirements of most on-site wellheads.

[0045] Connect the equipment by leading a 24V wire from the well site power supply. The line is encapsulated according to explosion-proof requirements. After the equipment is powered on, configure the parameters, check the equipment, open the well for operation, collect real-time data of temperature, pressure, and differential pressure, calculate the flow rate, and display it on the liquid crystal display; and, the metering device provided by the present invention can also transmit the data remotely by using wired or wireless technology according to on-site requirements.

[0046] The present invention also proposes a method for metering wet gas two-phase flow based on the above metering device, and the method includes the following steps:

[0047] S1: Collect the temperature T and pressure P of the wet gas to be metered in the pipeline, and calculate the gas phase density ρ of the wet gas to be metered by using an empirical formula gand viscosity μ g ;

[0048] ρ g = f(T, P)

[0049] μ g = f(T, P)

[0050] S2: Take a certain time as an interval. Within this certain time, collect 1 temperature value T of the wet gas to be metered, 30 pressure values P

[30] , and 3000 differential pressure values ΔP

[3000] ; perform filtering on the above data to eliminate abnormally high and low values, and then calculate the average value to obtain the pressure P tp , differential pressure ΔP tp ;

[0051] P tp = average(P

[30] )

[0052] ΔP tp = average(ΔP

[3000] );

[0053] According to the metering method provided by the present invention, in the present invention, the said certain time can be selected within a certain range. Preferably, the said certain time is 10 - 30 s, and more preferably 15 s.

[0054] S3: Use the differential pressure ΔP tp to calculate the gas production rate q g :

[0055]

[0056] where q g is the gas production rate; C is the nozzle discharge coefficient; β = d / D, where d is the nozzle inner diameter and D is the pipe inner diameter; ε is the expansion coefficient; ρ g is the gas phase density in the wet gas to be metered;

[0057] S4: Calculate the standard deviation ΔP of ΔP

[3000] st :

[0058] ΔP st = stdev(ΔP

[3000] )

[0059] S5: Assume that the differential pressure when the gas phase flows through the throttling element alone is ΔP g ; establish the relationship between ΔP g and ΔP tp , ΔP st :

[0060]

[0061]

[0062] ΔP g = ΔP tp -θΔP st

[0063] ΔP g = ΔP tp -(az 2 +bz + c)ΔP st

[0064] where a, b, and c are all experimentally fitted coefficients;

[0065] ρ g is the gas-phase density in the wet gas to be metered, ρ l is the liquid-phase density in the wet gas to be metered; z is a set intermediate parameter, a dimensionless variable;

[0066] S6: The corrected gas-phase flow rate is:

[0067]

[0068] where q gx is the corrected gas-phase flow rate; C is the nozzle discharge coefficient; β = d / D, where d is the nozzle inner diameter and D is the pipe inner diameter; ε is the expansion coefficient;

[0069] S7: The gas-phase Froude number represents the degree of influence of gravity on the flow, is related to the superficial velocity and density, i.e., is affected by the flow rate and pressure. The gas-phase Froude function is defined as the root mean square of the ratio of the gas-phase apparent inertial force to the liquid-phase gravity;

[0070]

[0071]

[0072] where v sg is the gas-phase superficial velocity; g is the acceleration due to gravity; D is the pipe inner diameter; S is the cross-sectional area of the equipment pipe; q gx is the corrected gas-phase flow rate; Fr g is the gas-phase Froude number;

[0073] S8: Let the differential pressure when the liquid phase flows through the throttling element alone be △P l ; establish the model of △P l and △P tp :

[0074] ΔP l = (d*Frg 2 + f*Frg + g)ΔP tp

[0075]

[0076] Among them, d, f, and g are experimental fitting coefficients;

[0077] q l is the liquid-phase flow rate, C is the nozzle discharge coefficient, β = d / D, where d is the inner diameter of the nozzle and D is the inner diameter of the pipeline; ε is the expansion coefficient;

[0078] S9: Calculate the mass gas content as:

[0079]

[0080] Among them, x hg is the mass gas content, q gx is the corrected gas-phase flow rate, q l is the liquid-phase flow rate;

[0081] S10: Calculate the wet gas two-phase volume flow rates respectively as:

[0082]

[0083]

[0084] Among them, q 气 is the standard-condition gas-phase volume flow rate, q 液 is the liquid-phase volume flow rate, q gx is the corrected gas-phase flow rate, q l is the liquid-phase flow rate, ρ l is the liquid-phase density in the wet gas to be metered, ρ gb is the natural gas density under standard conditions.

[0085] Taking actual applications as examples, the inner diameter of the instrument pipeline is DN50, the throttling inner diameter of the nozzle is DN12, and the actual data of a gas well are collected and calculated and analyzed as follows:

[0086] (1) Collect the temperature T of the wet gas to be metered in the pipeline, 30 pressure values P

[30] , and 3000 differential pressure values ΔP

[3000] with a 15-second cycle, and organize the data to obtain:

[0087] Temperature: T = 12.85 °C

[0088] Average pressure: P tp = average(P

[30] ) = 1.33 MPa

[0089] Average differential pressure: ΔP tp = average(ΔP

[3000] ) = 19.81 KPa

[0090] Differential pressure standard deviation: ΔP st=stdev(△P

[3000] ) = 3.46

[0091] (2) Calculate the gas-phase density ρ and viscosity μ of the wet gas to be metered using the empirical formula g and viscosity μ g ;

[0092] ρ g = f(T, P) = 11.06 kg / m 3

[0093] μ g = f(T, P) = 0.22 mPa·s

[0094] (3) Use the differential pressure △P to calculate the gas production rate q tp Calculate the gas production rate q g :

[0095]

[0096] where q g is the gas-phase flow rate; C is the nozzle discharge coefficient = 0.98; β = d / D = 0.24, where d is the nozzle inner diameter = 12 mm and D is the pipe inner diameter = 50 mm; ε is the expansion coefficient = 0.99; ρ g is the gas-phase density of the wet gas to be metered = 11.06 kg / m 3 ;

[0097] (4) Find the differential pressure when the gas phase flows through the throttling element alone as △P g ;

[0098]

[0099] θ = f(z) = az 2 + bz + c = 0.86

[0100] ΔP g = ΔP tp - θΔP st = 19.81 - 0.86 * 3.46 = 16.83 KPa

[0101] (5) Find the corrected gas-phase flow rate as:

[0102]

[0103] where q gx is the corrected gas-phase flow rate; C is the nozzle discharge coefficient = 0.98; β = d / D = 0.24, where d is the nozzle inner diameter = 12 mm and D is the pipe inner diameter = 50 mm; ε is the expansion coefficient = 0.99;

[0104] (6) The gas-phase Froude number represents the degree of influence of gravity on the flow, which is related to the superficial velocity and density, i.e., affected by the flow rate and pressure. The gas-phase Froude function is defined as the root mean square of the ratio of the gas-phase apparent inertial force to the liquid-phase gravity;

[0105]

[0106]

[0107] Among them, v sg is the gas-phase superficial velocity; g is the acceleration due to gravity; D is the inner diameter of the pipeline;

[0108] S is the cross-sectional area of the equipment pipeline. q gx is the corrected gas-phase flow rate; Fr g is the gas-phase Froude number;

[0109] (7) Calculate the differential pressure of the liquid phase flowing through the throttling element alone as △P l ;

[0110] ΔP l =(d*Frg 2 +f*Frg+g)ΔP tp =0.0056*19.81 = 0.11 KPa

[0111]

[0112] q l is the liquid-phase flow rate, C is the nozzle discharge coefficient = 0.98; β = d / D = 0.24, where d is the inner diameter of the nozzle = 12 mm, D is the inner diameter of the pipeline = 50 mm; ε is the expansibility coefficient = 0.99;

[0113] (8) Calculate the mass gas holdup as:

[0114]

[0115] (9) Calculate the wet gas two-phase volume flow rates respectively as:

[0116]

[0117]

[0118] Among them, ρ gb is the natural gas density under standard conditions = 0.75 kg / m 3 .

[0119] (10) The oilfield on-site separation equipment measures the gas production of this gas well as 8012.7 Nm 3 / d, and the liquid production as 4.28 m 3 / d. Compare and analyze with the metering equipment:

[0120] Gas-phase error = (7689.6 - 8012.7) / 8012.7 = -4.03%

[0121] Liquid-phase error = (4.5 - 4.28) / 4.28 = 5.14%

[0122] For the measurement at the wellhead of gas wells, it is acceptable to control the measurement deviation of the gas phase and the liquid phase within 10%.

[0123] In the prior art, the wet gas two-phase flow is still measured by separated devices at the oil and gas development site. However, the separated devices are large in volume and high in cost, and are more suitable for the measurement at the station yard. For the measurement of single gas wells, there are mainly two methods: the Venturi throttling method and the ray plus throttling method. Among them, the throttling size of the Venturi cannot be too small, and it is almost impossible to measure gas wells with a daily output of less than 15,000. Moreover, the length of the Venturi throttling device is relatively long, and the on-site requirements are high. The ray method has radioactivity, does not conform to the on-site safety specifications, and the cost of the ray method is relatively high, and the cost-benefit for low-production gas wells is low.

[0124] In the measurement method provided by the present invention, by adopting the high-frequency differential pressure acquisition method, the differential pressure data is quickly acquired, and the flow and fluctuation of the wet gas in the pipeline can be better captured, so that the data can better reflect the real fluid change, and the flow calculation is more accurate.

[0125] Based on the acquired differential pressure data and the calculated differential pressure standard deviation, a correction model for the gas-phase differential pressure and the liquid-phase differential pressure is established, and then the gas-liquid two-phase flow is calculated. The method is novel and unique, and has been proved to have high stability, reliability and accuracy in practice.

[0126] In the present invention, by using a nozzle as the throttling element, the nozzle size can be made smaller in terms of technology, that is, the ratio range of the throttling element to the inner diameter of the pipeline is wider, and it is possible to measure gas wells with a daily output of less than 150,000 cubic meters. That is to say, the present invention is particularly suitable for the measurement of the wet gas two-phase flow of low-production gas wells.

[0127] In addition, the nozzle throttling element can be disassembled flexibly, and the straight pipe sections before and after are shorter, making the overall structure of the measurement device compact and having low requirements for the installation space of the on-site wellhead. The measurement device provided by the present invention belongs to the throttling method, and compared with the ray method device, the cost is controllable, and it more meets the on-site cost-benefit requirements of low gas wells.

[0128] The above has shown and described the basic principles, main features and characteristics of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. An online metering device for wet gas two-phase based on a nozzle, characterized in that, Comprising: An equipment pipeline (10), the two ends of which are connected in series to the pipeline of the wet gas two-phase to be metered through connecting flanges (11), and a nozzle throttle is installed in the equipment pipeline (10); A pressure sensor (20), arranged in the equipment pipeline (10), for measuring the pressure of the wet gas two-phase to be metered before entering the nozzle throttle; A temperature sensor (30), arranged in the equipment pipeline (10), for measuring the temperature of the wet gas two-phase to be metered before entering the nozzle throttle; A differential pressure sensor group (40), arranged in the equipment pipeline (10), for measuring the differential pressure of the wet gas to be metered before and after entering the nozzle throttle; A main circuit component (50), arranged outside the equipment pipeline (10), for data acquisition, parameter analysis, liquid crystal display and data transmission; A method for metering the flow rate of wet gas two-phase based on the above metering device, the method comprising the following steps: S1: Collect the temperature T and pressure P of the wet gas to be metered in the pipeline, and calculate the gas-phase density ρ and viscosity μ of the wet gas to be metered using empirical formulas; g g ​​ ρ g = f(T, P) μ g = f(T, P) S2: Taking a certain period of time as an interval, within this certain period of time, collect the temperature value T of the wet gas to be metered, 30 pressure values P[30], and 3000 differential pressure values △P[3000]; perform filtering processing on the above data to eliminate abnormally high and low values, and then calculate the mean value to obtain the pressure P tp , differential pressure △P tp ; P tp = average(P[30]) △P tp = average(△P[3000]); S3: Use the differential pressure △P tp Calculate the gas production rate q g : where q g is the gas production rate; C is the nozzle discharge coefficient; β = d / D, where d is the inner diameter of the nozzle and D is the inner diameter of the pipeline; ε is the expansion coefficient; ρ g is the gas-phase density in the wet gas to be metered; S4: Calculate the standard deviation △P of △P[3000] st : △P st = stdev(△P[3000]) S5: Let the differential pressure of the gas phase flowing through the throttling element alone be ΔP g ; Establish ΔP g and ΔP tp , ΔP st relation: ΔP g = ΔP tp - θΔP st ΔP g = ΔP tp -(az 2 + bz + c)ΔP st Wherein, a, b, and c are all experimental fitting coefficients; ρ g is the gas-phase density of the wet gas to be metered, ρ l is the liquid-phase density of the wet gas to be metered; z is a set intermediate parameter, a dimensionless variable; S6: The corrected gas-phase flow rate is: where q gx is the corrected gas flow rate; C is the nozzle discharge coefficient; β = d / D, where d is the nozzle inner diameter and D is the pipe inner diameter; ε is the expansion coefficient; S7: The gas-phase Froude number represents the degree of influence of gravity on the flow, is related to the superficial velocity and density, that is, affected by the flow rate and pressure. The gas-phase Froude function is defined as the root mean square of the ratio of the gas-phase apparent inertial force to the liquid-phase gravity; Among them, v sg is the superficial gas velocity; g is the acceleration due to gravity; D is the inner diameter of the pipe; S is the cross-sectional area of the equipment pipeline; q gx is the corrected gas flow rate; Fr g is the gas-phase Froude number; S8: Let the differential pressure of the liquid phase flowing through the throttling element alone be △P l ; Establish △P l and the model of △P tp : ΔP l =(d*Frg 2 +f*Frg+g)ΔP tp Wherein, d, f, and g are experimental fitting coefficients; q l is the liquid phase flow rate, C is the nozzle discharge coefficient, β = d / D, where d is the inner diameter of the nozzle and D is the inner diameter of the pipe; ε is the expansion coefficient; S9: Calculate the mass gas content as: where x hg is the mass void fraction, q gx is the corrected gas phase flow rate, and q l is the liquid phase flow rate; S10: Calculate the volume flow rates of the wet gas two-phase respectively as: Among them, q 气 is the volumetric flow rate of the gas phase under standard conditions, q 液 is the volumetric flow rate of the liquid phase, q gx is the corrected gas-phase flow rate, q l is the liquid-phase flow rate, ρ l is the liquid-phase density in the wet gas to be metered, ρ gb is the density of natural gas under standard conditions.

2. The nozzle-based wet gas two-phase on-line metering device according to claim 1, wherein The pressure sensor (20), temperature sensor (30), nozzle throttle and differential pressure sensor group (40) are arranged in sequence along the flow direction of the wet gas two-phase.

3. The nozzle-based wet gas two-phase on-line metering device according to claim 1, characterized in that, It further includes a power supply circuit board (60) for power supply.

4. The nozzle-based wet gas two-phase on-line metering device according to claim 1, wherein The main circuit component (50) includes a main circuit board and a calculation circuit board. Among them, the main circuit board is electrically connected to the pressure sensor (20), temperature sensor (30) and differential pressure sensor group (40), and is used for data acquisition, parameter analysis, liquid crystal display and data transmission; The calculation circuit board is electrically connected to the main circuit board, and is used for receiving the collected temperature data and pressure data, calculating the flow rate of the wet gas two-phase and then feeding it back to the main circuit board for storage, display and transmission.

5. The nozzle-based wet gas two-phase on-line metering device according to claim 1, characterized in that A drain port (12) is opened on the equipment pipeline (10), and a drain valve (13) is provided on the drain port (12) for cleaning debris in the equipment pipeline (10).

6. The nozzle-based wet gas two-phase on-line metering device according to claim 1, characterized in that, It further includes a shield housing (14), which covers the outside of the equipment pipeline (10) for protecting the main circuit component (50).

7. The nozzle-based wet gas two-phase on-line metering device according to claim 1, characterized in that, It further includes a liquid crystal display (70) for real-time displaying the acquisition parameters and metering results of the wet gas to be metered.

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