Gas-gas, liquid-liquid and solid-phase mixed-phase online flow metering device and metering method

Abstract

The invention relates to the technical field of metering, and discloses a gas-gas, liquid-liquid and solid-phase mixed-phase online flow metering device and metering method. The invention discloses a gas-gas, liquid-liquid and solid-phase mixed-phase online flow metering device. A mixed-phase flow meter is used for at least measuring the flow of a gas phase in a mixed medium; the gas separation sampler is connected to the outlet end of the mixed-phase flowmeter and is used for separating and sampling a gas phase in the mixed medium; the resonance flowmeter is connected to the first outlet of the gas separation sampler; and the resonance flow meter is used for measuring the mixing density of the carbon dioxide-natural gas two phases. According to the technical scheme, gas-gas-oil-water-solid multiphase flow metering can be achieved on line without separation; the contents of carbon dioxide and natural gas are accurately analyzed and obtained. The mixed-phase flow meter can measure the flow of each phase of a mixed medium; the gas separation sampler samples and separates carbon dioxide-natural gas, the carbon dioxide-natural gas enters the resonance flowmeter, the mixing proportion of the carbon dioxide and the natural gas is measured and calculated, and the flow is calculated.

Description

Technical Field

[0001] The present invention relates to the field of metering technology, and in particular to a gas-gas, liquid-liquid and solid-phase mixed-phase online flow metering device and a metering method. Background Art

[0002] Flow measurement is an indispensable part of industrial production and is closely related to scientific research, ecological protection and the national economy. Among them, flow meters are used to accurately measure various fluids and are widely used in industrial production. In the industrial production process, flow meters are mainly used to measure production raw materials, such as medicines and chemical raw materials. In addition, in industrial production, the flow rate of the fluid is a very important parameter and is of great significance for the status monitoring of the system. The flow monitoring of the flow meter improves the accuracy of raw material control in the production process and reduces the waste and loss of raw materials.

[0003] Fluid is a general term for gas and liquid. In industrial production, pipelines are often used to transport fluids. The flow of the medium will change according to the working conditions; it is not just the flow of gas and liquid, but often contains solid particles. The mixed flow of gas, liquid, and solid is a technical problem for industrial measurement. At present, multiphase flow meters can solve the measurement of mixed media such as gas-liquid-solid, gas-liquid, and liquid-solid through their unique principles.

[0004] However, in the actual gas-liquid metering in industrial environments, liquids can be divided into oil and water according to the properties of their components. Gases can basically be divided into mixed gases and elemental gases, and the most common mixed gas is air. Air is mainly composed of nitrogen, oxygen, and rare gases; the main components of natural gas are alkanes, of which methane accounts for the vast majority, and there are also small amounts of ethane, propane and butane. In addition, there are generally hydrogen sulfide, carbon dioxide, nitrogen, water vapor, a small amount of carbon monoxide and trace amounts of rare gases; elemental gases such as nitrogen, hydrogen and carbon dioxide.

[0005] During the flow of fluid, pressure and temperature conditions will cause changes in the fluid itself due to the physical properties of the fluid itself. In industrial environments, the measurement of single gases and liquids can be measured by metering equipment; however, for complex mixed media, measurement is a technical problem.

[0006] Among them, CO2 flooding is a new technology to improve oil well recovery. CO2 flooding technology is to inject CO2 into the oil reservoir and use the physical properties of CO2 to develop the oil reservoir again; push the oil in the oil reservoir from underground to the surface. This technology will cause the natural gas, CO2, impurities and formation water contained in the oil reservoir to be discharged together. The measurement of the content of economically valuable oil, natural gas and CO2 is a key factor in evaluating whether the oil reservoir has development potential. Therefore, in the complex mixed medium formed by the above technology, the measurement of gas is difficult. Summary of the invention

[0007] The present application provides a gas-gas, liquid-liquid and solid-phase mixed online flow metering device and metering method to solve the above-mentioned technical problem that the prior art is difficult to measure for complex mixed media.

[0008] According to one aspect of the present application, an embodiment provides a gas-gas, liquid-liquid and solid mixed phase online flow metering device, comprising:

[0009] A mixed phase flow meter, used to measure at least the flow rate of the gas phase in the mixed medium;

[0010] A gas separation sampler connected to the outlet end of the mixed phase flowmeter, used to separate at least a part of the gas phase from the mixed medium and obtain the gas phase; and

[0011] A resonant flow meter connected to the first outlet of the gas separation sampler; the resonant flow meter is used to measure the mixed density of the carbon dioxide-natural gas two phases;

[0012] Wherein, the gas phase contains carbon dioxide and / or natural gas.

[0013] In one embodiment, the gas separation sampler has an inner cavity, and the inner cavity is connected to a first outlet and a second outlet; the first outlet is arranged at the top of the gas separation sampler, and the second outlet is arranged at the bottom of the gas separation sampler.

[0014] In one embodiment, the inlet of the gas separation sampler is arranged in the upper middle part of the gas separation sampler.

[0015] In one embodiment, the second outlet of the gas separation sampler is connected to the liquid-solid outflow channel; and the discharge end of the resonant flowmeter is connected to the gas phase outflow channel.

[0016] In one embodiment, the liquid-solid outflow channel and the gas phase outflow channel merge into the mixed medium outflow channel.

[0017] In one embodiment, the inlet end of the mixed phase flow meter is connected to a mixed medium inflow channel.

[0018] According to another aspect of the present application, an embodiment provides a method for online flow metering of gas-gas, liquid-liquid and solid-phase mixed phases, comprising the following steps:

[0019] At least measure the flow rate of the gas phase in the mixed medium;

[0020] separating at least a portion of the gas phase from the mixed medium and sampling it;

[0021] measuring the mixed density of the sampled gas phase;

[0022] Calculate the phase fraction of carbon dioxide and natural gas;

[0023] Calculate the flow of carbon dioxide and natural gas;

[0024] Wherein, the gas phase contains carbon dioxide and / or natural gas.

[0025] In one embodiment, the calculation of the phase fraction of carbon dioxide and natural gas comprises the following steps:

[0026] Get the density ρ of the first gas g1 , the density of the second gas ρ g2 ;

[0027] According to the formula ρ g = x·ρ g1 +(1-x)·ρ g2 Calculate the mixing ratio x of the first gas; where ρ g is the density of the carbon dioxide-natural gas two-phase mixed gas, and 1-x is the mixing ratio of the second gas.

[0028] In one embodiment, the mixed density of carbon dioxide-natural gas two phases is ρ g , ρ g =n·f; wherein n is the coefficient, f is the resonant frequency, and f is obtained by measuring the vibration frequency of the resonant tube.

[0029] In one embodiment, the calculation of the flow rate of carbon dioxide and natural gas includes the following steps:

[0030] Calculate the CO2 gas flow rate Q c , Q c =Q g ·η; where Q g is the gas flow rate, Q g Measured by a mixed phase flow meter; η is the mixing ratio of carbon dioxide;

[0031] Calculate the natural gas flow rate Q n , Q n =Q g ·(1-η); where Q g is the gas flow rate, Q g Measured by a mixed phase flow meter; η is the mixing ratio of carbon dioxide, and 1-η is the mixing ratio of natural gas.

[0032] The above-mentioned embodiments of the present application realize the technical scheme of online mixed-phase flow measurement of five phases, namely, carbon dioxide-natural gas, oil-water and solid phase, through a mixed-phase flowmeter, a resonant flowmeter and a gas separation sampler. The mixed-phase flowmeter can measure the gas flow of the mixed medium (it can also measure the oil flow, water flow and solid phase flow); then the mixed medium flows through the gas separation sampler, and the gas separation sampler samples and separates the carbon dioxide-natural gas and enters the resonant flowmeter. After the measurement by the resonant flowmeter, the mixed ratio of carbon dioxide and natural gas is calculated, and the carbon dioxide gas flow and natural gas flow can be further calculated. This technical scheme can realize the online measurement of gas-gas-oil-water-solid multiphase flow without separation; accurately analyze and obtain the content of carbon dioxide and natural gas, and realize the phase measurement of natural gas and carbon dioxide.

[0033] The above technical solution is applied to carbon dioxide oil recovery technology. The natural gas, carbon dioxide, impurities and formation water contained in the oil reservoir are discharged together. The economically valuable oil, natural gas and carbon dioxide content are accurately measured, and the development potential of the oil reservoir can be accurately evaluated. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The schematic diagram of the structure of a gas-gas, liquid-liquid and solid-phase mixed-phase online flow metering device in an embodiment;

[0035] Figure 2 yes Figure 1 A half-section diagram of

[0036] Figure 3 is a schematic diagram of a mixed phase flow meter in an embodiment;

[0037] Figure 4 is a schematic diagram of a resonant flow meter in an embodiment;

[0038] Figure 5 is a schematic diagram of a gas separation sampler in one embodiment;

[0039] Reference numerals:

[0040] 1-Mixed medium outflow channel;

[0041] 2-gas phase outflow channel;

[0042] 3-Resonance flow meter;

[0043] 31- Hybrid density transmitter;

[0044] 32-Protective shell;

[0045] 33-resonance tube;

[0046] 4-Mixed phase flow meter;

[0047] 41-data acquisition module;

[0048] 42-Flow calculation module;

[0049] 43- throttling element;

[0050] 44-Photon detector;

[0051] 45-Multi-parameter sensor;

[0052] 46-Photon source;

[0053] 5-Mixed medium flows into the channel;

[0054] 6-Gas separation sampler;

[0055] 7-Liquid-solid outflow channel. DETAILED DESCRIPTION

[0056] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0057] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only embodiments of a part of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present application.

[0058] It should be noted that the terms "first", "second" etc. in the present application are used to distinguish similar objects, and need not be used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged in appropriate circumstances, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, the process, method, system, product or equipment comprising a series of steps or units need not be limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0059] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be an intermediate element. Moreover, in this application, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element through a third element.

[0060] The following embodiments of the present application may serve to supplement each other.

[0061] Embodiment 1

[0062] Please refer to Figure 1-Figure 5 The present application provides a gas-gas, liquid-liquid and solid phase mixed online flow metering device 4, comprising: a mixed phase flow meter 4, a gas separation sampler 6 and a resonant flow meter 3. Among them, the mixed phase flow meter 4 is used to measure the flow of oil, gas, water and solid (oil phase, gas phase, water phase (liquid phase) and solid phase) in the mixed medium; specifically, at least the flow of the gas phase is measured; of course, the preferred solution is to measure the flow of oil, gas, water and solid, which is convenient for comprehensive monitoring. The gas separation sampler 6 is connected to the outlet end of the mixed phase flow meter 4, and the gas separation sampler 6 is used to separate a part of the gas in the oil, gas, water and solid mixed medium and sample the gas for subsequent detection. The part of the gas separated and sampled belongs to the gas phase, and the gas phase contains carbon dioxide and / or natural gas. In general, separation refers to separating part or all of the carbon dioxide-natural gas from the oil, gas, water and solid mixed medium, preferably a part; the separated part of the carbon dioxide-natural gas is partially or completely drained to the gas separation sampler 6. The resonant flowmeter 3 is connected to the first outlet of the gas separation sampler 6; the resonant flowmeter 3 is used to measure the mixed density of the carbon dioxide-natural gas two phases.

[0063] In one embodiment, the gas separation sampler 6 has an inner cavity, and the inner cavity is connected to a first outlet and a second outlet; the first outlet is arranged at the top of the gas separation sampler 6, and the second outlet is arranged at the bottom of the gas separation sampler 6. The oil-gas-water-solid mixed medium flows into the inner cavity, and carbon dioxide-natural gas is separated in the inner cavity; the separated carbon dioxide-natural gas flows out from the first outlet to the resonant flowmeter 3 for measurement.

[0064] Preferably, the upper part of the inner cavity of the gas separation sampler 6 and / or the first outlet are provided with a demister formed by a combination of multiple layers of filter screens to ensure that the gas path outlet does not carry a liquid phase. Among them, the first outlet is the gas path outlet, or the gas sample outlet, which is used for the gas phase (the gas is a mixture of carbon dioxide and natural gas) to flow out to the resonant flowmeter 3 for measurement. It should be noted that the gas sample outlet should not carry a liquid phase, that is, the sampled mixed gas does not contain liquid. The second outlet below mainly takes all the liquid phase, solid phase, and part of the gas phase.

[0065] In one embodiment, the inlet of the gas separation sampler 6 is arranged at the middle and upper part of the gas separation sampler 6. After the mixed medium flows through the mixed phase flowmeter 4, it flows into the inner cavity from the middle and upper part of the gas separation sampler 6. The gas phase has a low density and is discharged from the first outlet at the upper part into the resonant flowmeter 3; the liquid phase, the solid phase and a part of the gas phase mixed in the liquid phase are discharged from the second outlet at the lower part.

[0066] Preferably, in one embodiment, the second outlet of the gas separation sampler 6 is connected to the liquid-solid outflow channel 7 ; and the discharge end of the resonant flowmeter 3 is connected to the gas phase outflow channel 2 .

[0067] In one embodiment, the liquid-solid outflow channel 7 and the gas phase outflow channel 2 converge into the mixed medium outflow channel 1. After measurement and calculation, the liquid-solid phase and the gas phase are mixed in the mixed medium outflow channel 1 and then transported outward.

[0068] In one embodiment, the inlet end of the mixed phase flowmeter 4 is connected to a mixed medium inflow channel 5. The mixed medium inflow channel 5 is generally detachably connected via a flange. The liquid-solid outflow channel 7, the mixed medium outflow channel 1 and the gas phase outflow channel 2 are also generally connected via flanges and connected via elbows at the bends.

[0069] Regarding the mixed phase flowmeter 4. There is a mixed phase flowmeter 4, including a throttling element 43; the throttling element 43 has a feed end and a discharge end. The throttling element 43 is connected to a multi-parameter sensor 45, a data acquisition module 41 and a flow calculation module 42. The throttling element 43 is also provided with a photon detector 44 and a photon source 46. The photon source 46 can be fixed inside the throttling element 43, and can also be fixed outside the throttling element 43.

[0070] The mixed phase flow meter 4 is configured as a photon multiphase flow meter. Figure 1 , Figure 2 and Figure 3 The photon multiphase flowmeter consists of two parts: the first part is the Venturi mass flowmeter, which is used to measure the differential pressure formed by the medium passing through the Venturi tube in the pipeline, and the mass flow rate of the medium can be obtained; the second part is the photon phase fraction measurement part, which uses photon technology to measure the phase fraction of various fluids in the multiphase fluid and the mixed density of the multiphase fluid. The two parts of the measurement results are brought into the relevant calculation formula to accurately calculate the production of each phase of oil, gas and water. The measurement principle is as follows:

[0071] When a multiphase fluid flows through a Venturi tube, a differential pressure ΔP is generated because the flow interface is reduced in the Venturi.

[0072] Select three different energy rays emitted by the photon generator, with initial intensities of N 10 、N 20 and N 30 After gas-liquid-solid absorption, the residual intensities detected at the photon receiving end are N1, N2 and N3 respectively. According to the absorption characteristics of the photon rays, the relevant parameters are calculated respectively:

[0073]

[0074] m g+m l +m s =m.

[0075] Let GMF = m g / m,LMF=m l / m,SMF=m s / m;

[0076] Taking the logarithms of the above three equations, we can list the following set of equations:

[0077]

[0078]

[0079]

[0080] GMF+LMF+SMF=1.

[0081] According to the oil-gas-water phase fraction calculated by the photon phase fraction, the density of the mixed fluid is calculated using the following formula:

[0082] ρ mix =GMF·ρ g +LMF·ρ l +SMF·ρ s .

[0083] Substituting the mixed density into the following formula, the total mass of the mixed fluid can be calculated:

[0084]

[0085] Based on the total mass flow calculation results, the mass flow rate Q of each phase is calculated separately in combination with the phase fraction. mg , Q ml and Q ms Finally, according to the density, temperature, pressure and other parameters of oil, gas and water, the mass flow rate of oil, gas and water is converted into the volume flow rate under standard conditions, thus completing the measurement of multiphase fluid.

[0086] In the above formula:

[0087] : Attenuation coefficient per unit mass of the medium, which is a calibrable quantity, kg -1 ;

[0088] N0: initial photon count value, which is a calibrable quantity;

[0089] N x : The actual count value after the light quantum passes through the multiphase fluid medium, which is the measured value;

[0090] M: mass, kg;

[0091] m=Q m t, when t = 1s, m and Q m The values ​​are the same;

[0092] ΔP: pressure difference, Pa, real-time measurement value;

[0093] Q m : mass flow rate, kg / s;

[0094] Q mg : Gas phase mass flow rate, kg / s;

[0095] Q ml : Liquid mass flow rate, kg / s;

[0096] Q ms : solid phase mass flow rate, kg / s;

[0097] GMF: gas mass fraction, the ratio of the gas mass to the total mass in a multiphase mixed fluid, dimensionless;

[0098] LMF: Liquid mass fraction, the ratio of the liquid mass to the total mass in a multiphase mixed fluid, dimensionless;

[0099] SMF: solid mass fraction, the ratio of the solid mass to the total mass in a multiphase mixed fluid is dimensionless;

[0100] ρ mix : Multiphase mixed density, kg / m 3 ;

[0101] Subscripts: g is gas phase; l is water phase; s is solid phase.

[0102] About the resonance flowmeter 3. There is a resonance flowmeter 3, such as Figure 1 , Figure 4 , including a protective shell 32 and a resonance tube 33 disposed in the protective shell 32; the resonance flowmeter 3 has a feed port and a discharge port. A mixed density transmitter 31 is fixedly connected to the protective shell 32. A multi-parameter sensor element can be arranged on the resonance flowmeter 3. Among them, the (resonance) mixed density sensor calculates the phase fraction of the gas-gas two phases according to the measured mixed density of the gas-gas two phases: the phase fraction of carbon dioxide-natural gas, that is, the carbon dioxide content and the natural gas content. The above-mentioned photon multiphase flowmeter is provided with the phase fraction of carbon dioxide-natural gas in the gas phase: carbon dioxide content / natural gas content. The flow rate of each phase is given by the photon multiphase flowmeter.

[0103] Embodiment 2

[0104] Please refer to Figure 1-Figure 5, one embodiment provides a gas-gas, liquid-liquid and solid phase mixed online flow metering device 4, including: a mixed phase flow meter 4, a gas separation sampler 6 and a resonant flow meter 3. Among them, the mixed phase flow meter 4 is used to measure the flow of oil, gas, water and solid in the mixed medium. The gas separation sampler 6 is connected to the outlet end of the mixed phase flow meter 4, and the gas separation sampler 6 is used to separate the gas from the mixed medium and sample; the gas contains carbon dioxide and / or natural gas, generally a mixed gas containing carbon dioxide and / or natural gas, a part of the mixed gas is separated from the mixed medium for sampling, and then drained to the resonant flow meter 3 for further measurement. The resonant flow meter 3 is connected to the first outlet of the gas separation sampler 6, for receiving the sampled and separated gas; the resonant flow meter 3 is used to measure the mixed density of the sampled carbon dioxide-natural gas two-phase.

[0105] The above technical solution realizes an online mixed phase flow meter 4 measuring device of five phases including carbon dioxide-natural gas, oil-water and solid phase through the combination of the mixed phase flow meter 4, the resonant flow meter 3 and the gas separation sampler 6.

[0106] Among them, for the gas in the mixed medium, only the absorption coefficient of the mixed gas can be obtained through the absorption of gamma rays. For this type of mixed gas composed of natural gas and carbon dioxide, the density of natural gas is generally 0.75kg / m 3 ~0.8kg / m 3 The relative density is generally 0.58-0.62 (assuming the density of air is 1, the density of natural gas relative to air is 0.5548), and the density of carbon dioxide gas is 1.977 kg / m 3 , relative density 1.56; the density difference is about 3 times.

[0107] A single gamma ray cannot distinguish the specific ratio of natural gas and carbon dioxide in a mixed gas. In the actual production process, the content of natural gas and carbon dioxide changes at any time, and this change is crucial for evaluating carbon dioxide recovery technology. Therefore, a high-efficiency cyclone separator (which can be understood as a gas separation sampler 6) is used to separate the medium, allowing the gas to flow out through the gas path at the upper end of the separator, and the remaining liquids and solids to flow out through the liquid path at the lower end. Figure 5 The separator (i.e., the gas separation sampler 6) can sample and separate the gas, so that the gas flows upward and the liquid flows downward, thereby achieving a gas-liquid separation effect.

[0108] Regarding the resonant flowmeter 3, it can be a flowmeter based on resonance and differential pressure measurement, which obtains the mixed density of the medium by measuring the resonant frequency of the vibrating tube (resonance tube 33). It is necessary to first obtain the density ρ under the calibration state. g1 , and then the gas density ρ is calculated by temperature and pressure values g2, and then through algebraic operations, the standard phase fraction can be obtained. Specifically, the measurement principle is: if x represents the volume liquid content, the liquid is incompressible, and its liquid density is ρ L ; There is a formula ρ mix =(1-x)·ρ g2 +x·ρ L .

[0109] The prior art resonant flowmeter 3 (mixed medium contains water) needs to first obtain the density ρ under the calibration state. g1 , the mixed density ρ of the medium is obtained by the resonant frequency mix , and thus calculate the phase fraction of the medium. Because the current mixed gas is natural gas and carbon dioxide (without water), and the component content is constantly changing, it is impossible to accurately obtain the density ρ under the calibration state g1 Through the cooperation with the mixed phase flowmeter 4 and the separator, the medium flowing into the resonant flowmeter 3 does not contain liquid, and the mixed density of the gas has been measured by the mixed phase flowmeter 4, ρ mix is a known quantity, and x = 0 (because it contains no water), then the formula ρ mix =(1-x)·ρ g2 +x·ρ L .

[0110] ρ g2 =ρ mix (1);

[0111] The formula for the original gas density and the frequency of the resonance measurement is:

[0112] ρ g =n·f (2);

[0113] Among them, ρ g is the density of the carbon dioxide-natural gas two-phase mixture, n is the coefficient, and f is the resonant frequency.

[0114] In combination with the technical solution, further, the relationship formula of the density of the carbon dioxide-natural gas two-phase mixed gas is:

[0115] ρ g = x·ρ g1 +(1-x)·ρ g2 (3);

[0116] Among them, ρ g is the density of the carbon dioxide-natural gas two-phase mixture, ρ g1 is the density of the first gas, ρ g2 is the density of the second gas, and x is the mixing ratio of the first gas. Depending on the situation, x can be set to the mixing ratio of carbon dioxide or the mixing ratio of natural gas.

[0117] Afterwards, by combining equations (1), (2) and (3), the respective proportions of the mixed gas can be calculated, that is, the respective flow rates of natural gas and carbon dioxide can be further measured through the resonant flowmeter 3.

[0118] Further, based on the above analysis of the measurement principle, it can be understood that:

[0119] Assuming the carbon dioxide content is η, the natural gas content is 1-η.

[0120] have:

[0121] ρ mix =η·ρ g1 +(1-η)·ρ g2 ;

[0122] ρ mix It is calculated based on the coefficient n and by measuring the vibration frequency f of the resonance tube 33; that is,

[0123] ρ g =n·f;

[0124] ρ g1 and ρ g2 It is the operating density of the two gases (calculated based on their respective standard density and PVT equation).

[0125] Therefore, by measuring the vibration frequency f of the resonance tube 33, the mixed density ρ of carbon dioxide and natural gas is obtained. mix , knowing the working density ρ of carbon dioxide and natural gas g1 and ρ g2 , their phase fraction η can be calculated; that is, the carbon dioxide content is η, and the natural gas content is 1-η. According to η and 1-η, the flow rates of carbon dioxide and natural gas can be further calculated; the specific calculation method is described in the following embodiments.

[0126] This technical solution can realize gas-gas-oil-water-solid multiphase flow measurement without separation online; it can accurately analyze the content of carbon dioxide and natural gas and realize phase-by-phase measurement of natural gas and carbon dioxide.

[0127] Embodiment 3

[0128] An embodiment provides a method for measuring the online flow of gas-gas, liquid-liquid and solid phase mixed phases, wherein the mixed medium is not separated, and carbon dioxide, natural gas, oil, water and solid multiphases are measured; specifically, the method for measuring the online flow of gas-gas, liquid-liquid and solid phase mixed phases comprises the following steps:

[0129] S102, at least measure the flow rate of the gas phase in the mixed medium; preferably, measure the flow rate of oil, gas, water and solid in the mixed medium. Further, measure the flow rate of the oil phase, gas phase, water phase and solid phase in the mixed medium by a mixed phase flowmeter; preferably, the mixed phase flowmeter is a photon multiphase flowmeter.

[0130] S104. Separate and sample the gas in the mixed medium; the gas is a mixture of carbon dioxide and natural gas; preferably, a portion of the carbon dioxide-natural gas mixture is separated. A gas separation sampler is generally used for the separation and sampling of carbon dioxide-natural gas. One embodiment provides a gas separation sampler, which has an inner cavity, and a first outlet of the inner cavity is provided with a demister formed by a combination of multiple layers of filter screens to ensure that the first outlet is used as a gas path outlet and does not bring out the liquid phase when the gas flows out. The outflowing gas phase (a mixture of carbon dioxide and natural gas) flows out to the resonant flowmeter for measurement. It should be noted that the gas sample outlet should not carry the liquid phase, that is, the sampled mixed gas does not contain liquid. The second outlet below mainly takes out all the liquid phase, the solid phase, and a portion of the gas phase.

[0131] S106. Measure the mixed density of the sampled carbon dioxide-natural gas two-phase; generally, the mixed density is obtained by measuring with a resonant flowmeter.

[0132] S108, calculating the phase fraction and flow rate of carbon dioxide and natural gas; calculating the phase fraction of carbon dioxide and natural gas based on the mixed density of carbon dioxide-natural gas two phases, the operating density of carbon dioxide gas and the operating density of natural gas gas.

[0133] In one embodiment, the calculation of the phase fraction of carbon dioxide and natural gas comprises the following steps:

[0134] S1082. Obtain the density ρ of the first gas g1 , the density of the second gas ρ g2 ρ g1 , g2 It can be obtained through measurement or calculation; for example, it can be calculated based on the standard density of carbon dioxide and natural gas and the PVT equation (i.e., the ideal gas state equation, also known as the ideal gas law, universal gas law).

[0135] S1084, according to the formula ρ g = x·ρ g1 +(1-x)·ρ g2 Calculate the mixing ratio x of the first gas; where ρ g is the density of the carbon dioxide-natural gas two-phase mixed gas, and 1-x is the mixing ratio of the second gas.

[0136] The mixed density of carbon dioxide and natural gas is ρg , ρ g =n·f; n is the coefficient, f is the resonant frequency, and f is obtained by measuring the vibration frequency of the resonant tube through the resonant flowmeter.

[0137] In one embodiment, S110 is further included, a step of calculating the flow rates of carbon dioxide and natural gas; for ease of understanding, the mixing ratio of carbon dioxide is set to η, and 1-η is the mixing ratio of natural gas; specifically, S110 includes the following sub-steps:

[0138] S1102. Calculate the carbon dioxide gas flow rate Q c , Q c =Q g ·η; where Q g is the gas flow rate, Q g Measured by mixed phase flow meter;

[0139] S1104. Calculate the natural gas flow rate Q n , Q n =Q g ·(1-η); where Q g is the gas flow rate, Q g Measured by a mixed phase flow meter.

[0140] When the mixed phase flowmeter is set as a photon multiphase flowmeter, the metering principle is described in Example 1. The metering principle of the resonant flowmeter is described in Example 2.

[0141] The above technical solution can be directly measured by the photon multiphase flowmeter to obtain: gas flow Q g , Oil flow Q o , water flow Q w and solid phase flow rate Q s ; According to the carbon dioxide content η provided by the resonant flowmeter, the carbon dioxide gas flow rate Q can be calculated c , Q c =Q g ·η; at this time, the natural gas flow rate Q n , Q n =Q g ·(1-η); where Q g is the gas flow rate, Q g Measured by a mixed phase flow meter; η is the mixing ratio of carbon dioxide (i.e. η is the carbon dioxide content), and 1-η is the mixing ratio of natural gas.

[0142] In this way, the entire metering system completes the mixed phase metering of carbon dioxide-natural gas, oil-water and solid / sand, and obtains the flow rates of the five phases:

[0143] 1. Carbon dioxide gas flow Q c ;

[0144] 2. Natural gas flow Q n ;

[0145] 3. Oil flow Q o ;

[0146] 4. Water flow Q w ;

[0147] 5. Solid phase flow / sand flow Q s .

[0148] In one embodiment, after metering, the carbon dioxide-natural gas two phases separated for sampling are mixed with the oil-water and solid phases and then output. Preferably, the carbon dioxide-natural gas two phases and the oil-water and solid phases are output after converging in the mixed medium outflow channel.

[0149] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. Gas-gas, liquid-liquid and solid-phase mixed online flow metering device, It is characterized in that include: A mixed phase flow meter, used to measure at least the flow rate of the gas phase in the mixed medium; A gas separation sampler connected to the outlet end of the mixed phase flowmeter, used to separate at least a part of the gas phase from the mixed medium and obtain the gas phase; and A resonant flow meter connected to the first outlet of the gas separation sampler; the resonant flow meter is used to measure the mixed density of the carbon dioxide-natural gas two phases; Wherein, the gas phase contains carbon dioxide and / or natural gas.

2. The gas-gas, liquid-liquid and solid-phase mixed-phase online flow metering device according to claim 1, It is characterized in that The gas separation sampler has an inner cavity, and the inner cavity is connected to a first outlet and a second outlet; the first outlet is arranged at the top of the gas separation sampler, and the second outlet is arranged at the bottom of the gas separation sampler.

3. The gas-gas, liquid-liquid and solid-phase mixed-phase online flow metering device according to claim 1 or 2, It is characterized in that The inlet of the gas separation sampler is arranged in the upper middle part of the gas separation sampler.

4. The gas-gas, liquid-liquid and solid-phase mixed-phase online flow metering device according to claim 2, It is characterized in that The second outlet of the gas separation sampler is connected to the liquid-solid outflow channel; the discharge end of the resonant flowmeter is connected to the gas phase outflow channel.

5. The gas-gas, liquid-liquid and solid-phase mixed-phase online flow metering device according to claim 4, It is characterized in that The liquid-solid outflow channel and the gas phase outflow channel converge into the mixed medium outflow channel.

6. The gas-gas, liquid-liquid and solid-phase mixed-phase online flow metering device according to claim 1, It is characterized in that The inlet end of the mixed phase flow meter is connected with a mixed medium inflow channel.

7. Gas-gas, liquid-liquid and solid-phase mixed online flow measurement method, It is characterized in that The following steps are involved: At least measure the flow rate of the gas phase in the mixed medium; separating at least a portion of the gas phase from the mixed medium and sampling it; measuring the mixed density of the sampled gas phase; Calculate the phase fraction of carbon dioxide and natural gas; Calculate the flow of carbon dioxide and natural gas; Wherein, the gas phase contains carbon dioxide and / or natural gas.

8. The method for measuring gas-gas, liquid-liquid and solid-phase mixed-phase online flow according to claim 7, It is characterized in that The calculation of the phase fraction of carbon dioxide and natural gas comprises the following steps: Get the density ρ of the first gas g1 , the density of the second gas ρ g2 ; According to the formula ρ g = x·ρ g1 +(1-x)·ρ g2 Calculate the mixing ratio x of the first gas; where ρ g is the density of the carbon dioxide-natural gas two-phase mixed gas, and 1-x is the mixing ratio of the second gas.

9. The method for measuring gas-gas, liquid-liquid and solid-phase mixed-phase online flow according to claim 8, It is characterized in that The mixed density of carbon dioxide and natural gas is ρ g , ρ g =n·f; wherein n is the coefficient, f is the resonant frequency, and f is obtained by measuring the vibration frequency of the resonant tube.

10. The method for measuring gas-gas, liquid-liquid and solid-phase mixed-phase online flow rate according to any one of claims 7 to 9, It is characterized in that The calculation of the flow rate of carbon dioxide and natural gas comprises the following steps: Calculate the CO2 gas flow rate Q c , Q c =Q g ·η; where Q g is the gas flow rate, Q g Measured by a mixed phase flow meter; η is the mixing ratio of carbon dioxide; Calculate the natural gas flow rate Q n , Q n =Q g ·(1-η); where Q g is the gas flow rate, Q g Measured by a mixed phase flow meter; η is the mixing ratio of carbon dioxide, and 1-η is the mixing ratio of natural gas.

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