A differential pressure type metering method and system based on flow pattern discrimination

Abstract

The application provides a differential pressure type metering method and system based on flow pattern discrimination, which first discriminates and determines a list of different flow pattern working conditions, and carries out testing according to the list by using a metering test calibration system; calculates gas phase density according to dynamic test data of the testing; and determines a two-phase Lockhart-Martinelli parameter operation model based on the gas phase density and related flow data; establishes an optimal virtual height operation model under different flow patterns according to the calculated virtual height ratio and the Lockhart-Martinelli parameter fitting; determines a gas phase metering model based on flow data after calculating the optimal virtual height ratio by using the model, and establishes a gas phase metering model in combination with the best Lockhart-Martinelli parameter; and directly uses the Lockhart-Martinelli parameter operation, the optimal virtual height operation, the gas phase metering and the gas phase metering model to realize calculation according to pipeline data on site during application. The scheme overcomes the problem that the existing technology does not comprehensively consider influencing factors, considers the influence of flow patterns on virtual height, and realizes accurate metering of gas phase and liquid phase.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy metering optimization, and in particular to a differential pressure metering method and system based on flow pattern discrimination. BACKGROUND

[0002] In recent years, oil and gas field stimulation technology has been continuously improved. While the volume fracturing reconstruction well production is greatly improved, the gas well return fluid sand production is also greatly increased. Wet gas flow meters or two-phase flow meters are more commonly used in field applications. According to the structural characteristics and metering principles of the equipment, they can be roughly divided into two categories. The first type of flow meter needs to set up internal components related to metering. The internal components will be damaged after 1-2 months of field application, and accurate single well production metering cannot be achieved. The second type is a flow meter based on differential pressure metering principle. There are no internal structural components, but the metering model does not consider the influence of different flow patterns in the metering pipe section on the metering results. In the high liquid-gas ratio working condition, the accuracy of this two-phase metering method is difficult to meet the engineering metering requirements.

[0003] The information disclosed in the background section of this application is only intended to deepen the understanding of the general background of the present application, and should not be regarded as acknowledging or implying in any form that this information constitutes prior art known to those skilled in the art. SUMMARY

[0004] To solve the above problems, the present application provides a differential pressure metering method based on flow pattern discrimination. In one embodiment, the method comprises:

[0005] Flow pattern condition setting step: based on the demand, set the test flow pattern, determine the gas-liquid flow condition range of the metering pipe section corresponding to the test flow pattern according to the preset flow pattern discrimination condition data, and form a flow pattern condition list;

[0006] Gas-liquid metering test step: using the set metering test calibration system, carrying out metering test under different flow patterns according to the flow pattern condition list, and recording the dynamic test data in the test process;

[0007] Lo-Ma parameter determination step: calculating the gas phase density according to the dynamic test data of the metering test, and then determining the Lo-Ma parameter operation model based on the gas phase density and the associated flow data;

[0008] Virtual high model determination step: calculating the virtual high ratio according to the dynamic test data, and establishing the optimal virtual high operation model under different flow patterns according to the virtual high ratio and the Lo-Ma parameter fitting;

[0009] The metering model determining step: after the optimal virtual height ratio corresponding to different flow patterns is calculated by using the optimal virtual height operation model, the gas phase metering model of different flow patterns is determined based on the flow data, and the gas phase metering model of different flow patterns is further established based on the gas phase flow and the Lockhart-Martinelli parameter;

[0010] The metering application step: the initial flow pattern of the field is determined based on the field pressure difference data and the flow pattern discrimination condition data, the gas phase density of the field is calculated according to the initial flow pattern of the field and the test data, the Lockhart-Martinelli parameter of the field is calculated by using the Lockhart-Martinelli parameter operation model, and then the optimal virtual height ratio of the field is determined by using the optimal virtual height operation model, and the gas phase flow and the liquid phase flow matched with the flow pattern are determined by substituting the optimal virtual height ratio into the gas phase metering model and the liquid phase metering model.

[0011] Preferably, in one embodiment, before the flow pattern working condition setting step, the method further comprises a flow pattern discrimination condition data determining step, comprising the following operations:

[0012] Step A1. A flow operation model meeting the set requirements is established by using multiphase flow simulation software as a metering test calibration system flow model;

[0013] Step A2. Based on the gas volume parameters and the liquid volume parameters meeting the simulation requirements, the values are equally divided, for each gas volume parameter value, different liquid volume parameter values are applied to simulate and operate by using the metering test calibration system flow model, and the corresponding test pipe segment pressure difference and flow pattern are obtained;

[0014] Step A3. The gas volume parameter range of the flow pattern transition is selected according to the obtained pressure difference and flow pattern, and the values are further divided by using the bisection method, for each gas volume parameter value after the division, different liquid volume parameter values are applied to simulate and operate by using the metering test calibration system flow model, and the corresponding test pipe segment pressure difference and flow pattern are obtained;

[0015] Step A4. The liquid volume parameter range of the flow pattern transition is selected, the values are divided by using the bisection method, and the simulation operation is further performed by using the metering test calibration system flow model to obtain the corresponding test pipe segment pressure difference and flow pattern;

[0016] Step A5. It is judged whether the change value of the previous simulation pressure difference and the current simulation pressure difference in the pressure difference monitoring pipe segment and the ratio of the previous simulation pressure difference meet the set requirements, if yes, the current gas volume parameter liquid volume parameter range of each flow pattern transition, the test pipe segment pressure difference and the flow pattern are recorded as the flow pattern discrimination condition data;

[0017] If not, step A4 is re-executed until the change value of the previous simulation pressure difference and the current simulation pressure difference in the pressure difference monitoring pipe segment and the ratio of the previous simulation pressure difference meet the set requirements.

[0018] Optionally, in one embodiment, in step A1, the process of establishing the flow model of the metering test calibration system by using multiphase flow simulation software includes:

[0019] The metering test calibration system is simplified according to key flow pipe elements, the air inlet pressurizing unit is simplified as an air source inlet point, the water inlet pressurizing unit is simplified as a water source inlet point, the gas-liquid outlet separation unit is simplified as a gas-liquid outlet point, and the flow meters on the first and third test pipes are simplified as throttling elements;

[0020] The basic framework of the flow model of the simplified metering test calibration system is built by using the pipe module and throttling module of the multiphase flow simulation software.

[0021] The input structural parameters of the flow model of the metering test calibration system are determined according to the structural parameters in the actual metering test calibration system, and the flow model of the simplified metering test calibration system is constructed.

[0022] Further, in a preferred embodiment, in step A1, the process of establishing the flow model of the metering test calibration system by using multiphase flow simulation software further includes:

[0023] Step A11. According to the calculation data of the established flow model of the metering test calibration system, the working condition parameters of different flow patterns are set, experiments are carried out by using the set metering test calibration system, and the established flow model of the metering test calibration system is corrected according to the differential pressure data and temperature data obtained from the experiments, so that the error between the simulation calculation data and the experimental data is controlled within the set range.

[0024] Optionally, in one embodiment, in the gas-liquid metering test step, the metering test calibration system adopts a gas-liquid two-phase metering test calibration system, which includes an air compressor, a gas storage tank, a liquid storage tank, a test pipeline, a temperature control assembly, a gas-liquid mixer, a sensing assembly, a gas-liquid separator, a test data transmission system, and a data processing and controller; the test pipeline includes a first test pipe, a second test pipe, and a third test pipe;

[0025] The first test pipe and the second test pipe are connected with the third test pipe through the gas-liquid mixer; the third test pipe is sequentially provided with a third pressure sensor, a second temperature sensor, a second flow meter, and a fourth pressure sensor, and the second flow meter adopts a differential pressure flow meter;

[0026] A differential pressure monitoring pipe section is provided before the third pressure sensor, and the differential pressure monitoring pipe section is provided with a differential pressure sensor, and the differential pressure sensor is connected to the data processing and control system.

[0027] Further, in one embodiment, the Lockhart-Martinelli parameter determination step includes the following operations:

[0028] Gas phase density determination step: calculating gas phase density according to measured single-phase gas flow, pressure, temperature and liquid phase flow data;

[0029] Initial Lockhart-Martinelli parameter calculation step: calculating initial Lockhart-Martinelli parameter as gas phase Lockhart-Martinelli parameter based on gas flow, liquid flow and gas phase density;

[0030] Optimized Lockhart-Martinelli parameter determination step: fitting Lockhart-Martinelli parameter relationship based on pressure test data and obtained initial Lockhart-Martinelli parameter value; and then determining optimized Lockhart-Martinelli parameter calculation model under different flow patterns according to initial Lockhart-Martinelli parameter and parameter relationship to calculate liquid phase Lockhart-Martinelli parameter.

[0031] In an optional embodiment, in the optimized Lockhart-Martinelli parameter determination step, the optimized Lockhart-Martinelli parameter calculation model under different flow patterns is as follows:

[0032]

[0033] In the formula, m 1、 m 2 is a weight coefficient; X i ’ is the calculated value of Lockhart-Martinelli parameter under required flow pattern, i =1, 2, 3, 4, respectively representing stratified flow, bubbly flow, annular flow and plug flow, X is initial Lockhart-Martinelli parameter, and A, B and C are fitting coefficients.

[0034] Preferably, in an embodiment, the optimal virtual height calculation model described in the following formula is established:

[0035]

[0036] In the formula, Q g * is the flow tested by differential pressure flowmeter Q g ’ and the virtual height ratio is calculated, Q g is the single-phase gas flow tested by rotational vortex flowmeter, Φ i is the virtual height ratio under different flow patterns, i =1, 2, 3, 4, respectively representing stratified flow, bubbly flow, annular flow and plug flow, and k1 and k2 are virtual height weight coefficients.

[0037] Based on other aspects of the method described in any one or more of the above embodiments, the application further provides a storage medium having program codes stored thereon, which can implement the method described in any one or more of the above embodiments.

[0038] Based on the application aspect of the method described in any one or more of the above embodiments, the application further provides a differential pressure type metering system based on flow pattern discrimination, which performs the method described in any one or more of the above embodiments.

[0039] Compared with the closest prior art, the application has the following beneficial effects:

[0040] The application provides a differential pressure type metering method and system based on flow pattern discrimination, which determines a list of different flow pattern working condition conditions according to horizontal pipe segment multiphase flow pattern discrimination conditions, connects a differential pressure flowmeter into a metering test calibration system, and carries out tests according to the list of working condition conditions; high-quality simulation of engineering parameters of different flow pattern working conditions is used to guarantee the authenticity of dynamic test data and provide accurate data support for the establishment of subsequent multi-level operation models;

[0041] Further, gas phase density is calculated according to the tested dynamic test data, and then a two-phase Lockhart-Martinelli parameter operation model is determined based on the gas phase density and related flow data; the optimal virtual height operation model under different flow patterns is established by combining the dynamic test data and the Lockhart-Martinelli parameter fitting; the gas phase metering model of different flow patterns is determined by using the model to calculate the optimal virtual height ratio combined with the flow data, and the gas phase metering model is established combined with the calculated Lockhart-Martinelli parameter; when applied, the gas phase density is directly calculated according to the field flow pattern and test data, and the Lockhart-Martinelli parameter operation model, the optimal virtual height operation model, the gas phase metering model and the gas phase metering model are used for calculation. The scheme constructs a two-phase metering model based on flow pattern discrimination and dynamic test data, considers the influence of flow pattern on metering virtual height, realizes accurate calculation of gas phase and liquid phase flow, is simple to operate when applied, has fast operation speed, and can improve the accuracy of operation results.

[0042] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application can be realized and attained by the structure particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0043] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application, and do not limit the application. In the drawings:

[0044] Figure 1 is a flow chart of the differential pressure type metering method based on flow pattern discrimination provided by an embodiment of the application;

[0045] Figure 2 is a simplified principle diagram of a flow model structure of a metering test calibration system of the differential pressure type metering method based on flow pattern discrimination provided by an embodiment of the application;

[0046] Figure 3 is a structural schematic diagram of a metering test calibration system used in the differential pressure metering method based on flow type discrimination provided by the embodiments of the present application;

[0047] Figure 4 is a pressure value point setting schematic diagram of a differential pressure flowmeter in the differential pressure metering method based on flow type discrimination provided by the embodiments of the present application;

[0048] Figure 5 is a structural schematic diagram of a differential pressure metering system based on flow type discrimination provided by the embodiments of the present application. DETAILED DESCRIPTION

[0049] The embodiments of the present application will be described in detail below with reference to the accompanying drawings and embodiments, so that the implementers of the present application can fully understand how the present application applies technical means to solve technical problems and achieve the implementation process of technical effects, and implement the present application according to the above implementation process. It should be noted that, as long as there is no conflict, each embodiment in the present application and each feature of each embodiment can be combined with each other, and the technical solutions formed thereby are all within the protection scope of the present application.

[0050] Although the flowchart describes each operation as a sequential process, many of the operations can be implemented in parallel, concurrently or simultaneously. The order of the operations can be rearranged. The process can be terminated when its operations are completed, but can also have additional steps not included in the accompanying figures. The process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0051] The computer device includes a user device and a network device. The user device or client includes, but is not limited to, a computer, a smart phone, a PDA, etc.; the network device includes, but is not limited to, a single network server, a server group composed of multiple network servers, or a cloud composed of a large number of computers or network servers based on cloud computing. The computer device can be independently operated to implement the present application, or can be connected to a network and interact with other computer devices in the network to implement the present application. The network in which the computer device is located includes, but is not limited to, the Internet, a wide area network, a metropolitan area network, a local area network, a VPN network, etc.

[0052] The terms "first", "second", and the like can be used to describe various elements, but these elements should not be limited by these terms. These terms are only used to distinguish one element from another. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. When a unit is referred to as "connected" or "coupled" to another unit, it can be directly connected or coupled to the other unit, or there can be an intermediate unit.

[0053] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms “a” and “an” as used herein are also intended to include the plural. It should also be understood that the terms “comprising” and / or “including” as used herein specify the presence of the stated features, integers, steps, operations, units, and / or components, without excluding the presence or addition of one or more other features, integers, steps, operations, units, components, and / or combinations thereof.

[0054] With the continuous development of oil and gas field production enhancement technologies, while the production of wells stimulated by volumetric fracturing has increased significantly, the amount of sand produced by the return fluid in gas wells has also increased substantially. In the field, wet gas flow meters or two-phase flow meters are commonly used. The former requires the installation of internal components related to metering, and these internal components will be damaged after 1-2 months of field use, making it impossible to accurately measure the production of a single well. The latter is a flow meter based on the differential pressure metering principle, which does not have internal structural components. However, its metering model does not consider the impact of different flow patterns in the metering pipe section on the metering results. Under high liquid-to-gas ratio conditions, the accuracy of this two-phase metering method is difficult to meet the engineering metering requirements.

[0055] To address the aforementioned issues, and considering the need for sand discharge protection, this study takes flow meters based on differential pressure metering principles as the research object and proposes a two-phase metering model construction method based on flow pattern discrimination. This method takes into account the influence of flow pattern on the false metering height, thereby improving the accuracy of the two-phase metering results.

[0056] The following describes the detailed flow of the method according to an embodiment of the present invention with reference to the accompanying drawings, the steps of which can be executed in a computer system containing, for example, a set of computer-executable instructions. Although the logical order of the steps is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than that shown here.

[0057] Example 1

[0058] Figure 1 This diagram illustrates a flow chart of the differential pressure metering method based on flow pattern discrimination provided in Embodiment 1 of the present invention. (Refer to...) Figure 1 As can be seen, the method includes the following steps.

[0059] Flow pattern operating condition setting steps: Set the test flow pattern based on the requirements, determine the gas-liquid flow operating condition range of the metering pipe section corresponding to the test flow pattern according to the preset flow pattern discrimination condition data, and form a flow pattern operating condition list.

[0060] Gas-liquid metering test steps: Using the metering test calibration system, conduct metering tests under different flow patterns according to the flow pattern operating condition list, and record dynamic test data during the test process;

[0061] L-M parameter determination step: calculating gas phase density according to dynamic test data of metering test, and then determining two-phase L-M parameter operation model respectively based on the gas phase density and associated flow data;

[0062] virtual height model determination step: calculating virtual height ratio according to dynamic test data, and establishing optimal virtual height operation model under different flow patterns according to virtual height ratio and L-M parameter fitting;

[0063] metering model determination step: after obtaining optimal virtual height ratio corresponding to different flow patterns by using the optimal virtual height operation model, determining gas phase metering model of different flow patterns based on the virtual height ratio and flow data, and establishing gas phase metering model of different flow patterns based on gas phase flow and the L-M parameter;

[0064] metering application step: determining initial flow pattern on site based on on-site differential pressure data and flow pattern discrimination condition data, calculating on-site gas phase density according to the initial flow pattern on site and test data, calculating two-phase L-M parameter on site by using L-M parameter operation model, and then determining optimal virtual height ratio on site by using optimal virtual height operation model, and finally substituting the optimal virtual height ratio into gas phase metering model and liquid phase metering model to determine gas phase flow and liquid phase flow matched with the flow pattern.

[0065] In a preferred embodiment, since the subsequent process needs to test and metering related parameters by changing the working conditions based on the actual test system, the flow pattern working condition setting step is performed in advance, that is, the gas-liquid flow working condition ranges of the metering pipe section under four test flow patterns of stratified flow, bubbly flow, annular-mist flow and slug flow are determined according to the flow pattern discrimination conditions of the horizontal pipe section.

[0066] Optionally, in one embodiment, before the flow pattern working condition setting step, the method further includes a flow pattern discrimination condition data determination step, which includes the following operations:

[0067] Step A1. Using multiphase flow simulation software to establish a flow operation model meeting the set requirements as a metering test calibration system flow model;

[0068] In a preferred embodiment, in step A1, the process of using multiphase flow simulation software to establish the metering test calibration system flow model includes:

[0069] Further, in order to ensure the accuracy of the calculation results of the established metering test calibration system flow model, in one preferred embodiment, in step A1, the process of using multiphase flow simulation software to establish the metering test calibration system flow model further includes:

[0070] Step A11. Set the working condition parameters of different flow patterns according to the calculation data of the flow model of the built metering test calibration system, use the set metering test calibration system to conduct experiments, and correct the flow model of the built metering test calibration system according to the differential pressure data and temperature data obtained from the experiments, so as to control the error between the simulation calculation data and the experimental data within the set range.

[0071] Step A2. Based on the gas volume parameters and liquid volume parameters with simulated requirements, for each gas volume parameter value, different liquid volume parameter values are applied to simulate and calculate using the flow model of the metering test calibration system, to obtain the corresponding test pipe segment differential pressure and flow pattern;

[0072] Step A3. According to the obtained differential pressure and flow pattern, the gas volume parameter range of flow pattern transition is selected, and further divided by the bisection method, for each gas volume parameter value after the division, different liquid volume parameter values are applied to simulate and calculate using the flow model of the metering test calibration system, to obtain the corresponding test pipe segment differential pressure and flow pattern;

[0073] Step A4. Select the liquid volume parameter range of flow pattern transition, and divide the value by the bisection method, and further simulate and calculate using the flow model of the metering test calibration system to obtain the corresponding test pipe segment differential pressure and flow pattern;

[0074] Step A5. Determine whether the change value of the previous simulation differential pressure and the current simulation differential pressure in the differential pressure monitoring pipe segment and the previous simulation differential pressure satisfy the set requirement, if yes, record the current gas volume parameter and liquid volume parameter range of each flow pattern transition, test pipe segment differential pressure and flow pattern as flow pattern discrimination condition data;

[0075] If not, re-execute step A4 until the change value of the previous simulation differential pressure and the current simulation differential pressure in the differential pressure monitoring pipe segment and the previous simulation differential pressure satisfy the set requirement.

[0076] Based on this, the test flow pattern can be set based on the requirements in the flow pattern working condition setting step, and the metering pipe segment gas-liquid flow working condition range corresponding to the test flow pattern is determined according to the flow pattern discrimination condition data of the horizontal pipe segment, to form a flow pattern working condition list.

[0077] In actual application, before calculating the field gas phase density according to the field flow pattern and test data, in the optional embodiment, the initial field flow pattern can be determined according to the following operation: using the experimental test data and the multiphase flow simulation software to establish a flow calculation model meeting the set requirements as the flow model of the metering test calibration system.

[0078] The process of using experimental test data and multiphase flow simulation software to establish the flow model of the metering test calibration system includes:

[0079] Step B1, the metering test calibration system is simplified according to key flow pipe elements, in an optional embodiment, the intake pressure boosting unit is simplified as a gas source intake point, the water intake pressure boosting unit is simplified as a water source intake point, the gas-liquid outflow separation unit is simplified as a gas-liquid outflow point, and the flow meters on the first and third test pipes are simplified as throttling elements, as shown in Figure 2

[0080] Step B2, a flow model basic framework of the simplified metering test calibration system is built by using the pipe module and the throttling module of the multiphase flow simulation software.

[0081] It should be noted that the second test pipe is not simplified as a throttling element because the electromagnetic flow meter is used on the second test pipe, the pipe diameter does not change at the position of the flow meter, and there is no throttling effect, which is the same as the general pipe flow.

[0082] After simplification, the pressures of the gas source intake point and the water source intake point are the boosted pressures, and the pressure of the gas-liquid outflow point is the pressure after the flow meter on the third test pipe.

[0083] Step B3, the input structural parameters of the metering test calibration system flow model are determined according to the structural parameters of the actual metering test calibration system established by experiments, which can optionally include the pipe material, pipe diameter, wall thickness, pipe fluid heat transfer coefficient, pipe external environment heat transfer coefficient, pipe material thermal conductivity, environment temperature and throttling element diameter in the model, and the simplified metering test calibration system flow model is constructed.

[0084] In a preferred embodiment, it further includes: the model is checked and corrected according to the collected pressure and temperature data, so as to control the error between the simulation calculation data and the experimental data within 5%, and to ensure the accuracy of the operation results of the metering test calibration system flow model, and to provide a reliable basis for the subsequent operation simulation of different working condition parameters.

[0085] Further, the process of checking and correcting the model according to the collected pressure and temperature data includes:

[0086] Step C1, according to the test parameters corresponding to the four flow types, the gas source intake point flow, the water source intake point flow, the pressure and temperature of the gas-liquid outflow point are input into the software, the multiphase flow simulation software is run, and the pipe model and the throttling model are used to calculate the gas source intake point pressure, the water source intake point pressure, and the pressure after the throttling of the throttling elements on the first and third test pipes.

[0087] Step C2, after the calculation is completed, the calculation results are extracted, which include: the gas source intake point pressure, the water source intake point pressure, and the pressure after the throttling of the throttling elements on the first and third test pipes.

[0088] ​Step C3, according to the extracted calculation results, respectively compared with the pressure data collected before the flow meter on the first test pipeline, before the flow meter on the third test pipeline, after the flow meter on the first test pipeline, after the flow meter on the third test pipeline, if the error is controlled within 5%, it indicates that the calculation data of the established measurement test calibration system flow model is basically consistent with the test data;

[0089] If the error exceeds 5%, the flow model of the measurement test calibration system needs to be corrected. The correction operation mainly adjusts the roughness of the inner wall of the pipe, the heat transfer coefficient of the fluid in the pipe, the heat transfer coefficient of the environment outside the pipe, the thermal conductivity of the pipe material, the environment temperature, and the friction coefficient between gas and liquid in the model;

[0090] Step C4, after the flow model of the measurement test calibration system is corrected, the software is run again to calculate the parameters in step (2). If the error exceeds 5%, the model correction continues. If the calculation results of the four flow patterns are all controlled within 5%, the model correction is completed.

[0091] Among them, the pressure drop and temperature drop in the pipe model in the optional embodiment are calculated by the following calculation equation:

[0092]

[0093] In the formula, Q h represents the heat dissipation of unit mass of fluid to the environment, kJ / kg; k represents the heat transfer coefficient, W / (m 2 ·℃); D represents the diameter of the pipe, m; T represents the temperature of the fluid in the pipe, ℃; T 0 represents the environment temperature, ℃; M represents the mass flow rate of gas and liquid, kg / s; l represents the length of the pipe, m;

[0094] In the differential equation for calculating the pressure drop of the pipe, p represents the pressure of the pipe, MPa; p represents the density, kg / m 3 ; l represents the friction coefficient; v represents the flow rate of the fluid, m / s; g represents the acceleration of gravity, m / s 2 ; h represents the elevation of the pipe, m.

[0095] The pressure drop and temperature calculation equation in the throttling model,

[0096]

[0097] wherein, q represents gas flow, 10 4 m 3 / d; p j 、 T j 、 Z j respectively represent the pressure, temperature, compression coefficient at the inlet of the throttling element; p z 、 T z 、 v z respectively represent the pressure, temperature, flow rate at the outlet of the throttling element; k’ represents the adiabatic coefficient of natural gas; d represents the inner diameter of the pipeline, m; R represents the gas constant, 8.314 J / (mol·K); g represents the relative density of the gas.

[0098] The differential pressure flow pattern method adopted in the embodiment of the present application can quickly make a preliminary judgment on the flow pattern compared with another Taitel flow pattern judgment method, and the Taitel flow pattern judgment method can accurately judge the flow pattern, thereby reducing the repeated iterative calculation of the flow pattern judgment formula under different flow patterns by using the Taitel flow pattern judgment method to a certain extent, and reducing the calculation workload while quickly identifying the flow pattern.

[0099] Based on this, the experimental input working condition gas quantity parameter range and liquid quantity parameter range designed according to the requirements are divided and taken values, the gas quantity parameter range is divided into an even number of parts, for example, 2N parts, and the liquid quantity parameter range is M parts;

[0100] The limit values of each gas quantity parameter sub-range obtained based on the division are gas quantity parameter values, the gas quantity parameter is unchanged, the liquid quantity parameter is changed, and the flow model of the metering test calibration system is used to calculate the pressure difference in the pressure difference monitoring pipe section and the flow pattern under each gas quantity parameter;

[0101] In actual application, the gas quantity Q gn is kept unchanged, and the liquid quantity is increased from Q w1 、 Q w2 … Q wm sequentially, and the pressure difference in the pressure difference monitoring pipe section 215 and the flow pattern under different working conditions are simulated and calculated;

[0102] According to the calculated pressure difference and flow pattern, the flow pattern transition condition parameter range is selected, and the gas quantity parameter sub-range is further divided by dichotomy. Based on the limit value of each gas quantity parameter sub-range after the division, the liquid quantity parameter is changed, and the differential pressure and flow pattern in the pressure difference monitoring pipe segment under the corresponding gas quantity parameter are calculated by using the flow model of the metering test calibration system.

[0103] Alternatively, the gas quantity value can be divided by dichotomy, and the liquid quantity is sequentially increased from Q gn / 2 , Q g2n , Q g3n / 4 , Q gn / 4 , Q g5n / 4 , Q g7n / 4 …… in order, and the differential pressure and flow pattern in the pressure difference monitoring pipe segment 215 under different conditions are simulated and calculated. Q w1 , Q w2 … Q wm The differential pressure and flow pattern in the pressure difference monitoring pipe segment 215 under different conditions are simulated and calculated.

[0104] The liquid quantity is sequentially increased from Q w1 , Q w2 … Q wm The differential pressure and flow pattern in the pressure difference monitoring pipe segment 215 under different conditions are simulated and calculated.

[0105] Further, according to the calculated pressure difference and flow pattern, the flow pattern transition condition parameter is selected, the liquid quantity is divided by dichotomy, and the condition after the division is simulated. Based on the limit value of each liquid quantity parameter range after the division, the differential pressure and flow pattern in the pressure difference monitoring pipe segment under the corresponding liquid quantity parameter are calculated by using the flow model of the metering test calibration system, while keeping the gas quantity parameter unchanged.

[0106] It is judged whether the change value of the previous simulation differential pressure and the current simulation differential pressure in the pressure difference monitoring pipe segment and the ratio of the previous simulation differential pressure satisfy the set requirement. If yes, the differential pressure value obtained under the current condition parameter is determined as the flow pattern transition critical differential pressure. If not, the liquid quantity is further divided by dichotomy, and the differential pressure and flow pattern in the pressure difference monitoring pipe segment under the corresponding liquid quantity parameter are calculated by using the flow model of the metering test calibration system, while keeping the gas quantity parameter unchanged, until the change value of the previous simulation differential pressure and the current simulation differential pressure in the pressure difference monitoring pipe segment and the ratio of the previous simulation differential pressure satisfy the set requirement, and the corresponding differential pressure value is recorded as the flow pattern transition critical differential pressure.

[0107] In actual application, the working condition parameter of flow pattern transition is first selected, the liquid quantity is divided by dichotomy, the working condition after division is simulated, the working condition parameter of flow pattern transition after division is selected, the liquid quantity is further divided by dichotomy, and the working condition after division is refinedly simulated; until the change value of the simulated pressure difference in the pressure difference monitoring pipe segment and the previous simulated pressure difference is less than 0.1, the pressure difference value at the working condition point is determined as the effective flow pattern transition critical pressure difference, and is recorded.

[0108] Next, a gas-liquid metering test step is performed, the gas-liquid metering test calibration system is used, the metering test under different flow patterns is carried out according to the flow pattern working condition list, and the dynamic test data in the test process is recorded.

[0109] In an optional embodiment, in the gas-liquid metering test step, the gas-liquid two-phase metering test calibration system comprises a rotational vortex flowmeter for testing single-phase gas flow, a pressure sensor for testing pressure, a temperature sensor for testing temperature, and a current flowmeter for testing liquid phase flow.

[0110] The gas-liquid two-phase metering test calibration system comprises an air compressor 101, a gas storage tank 102, a liquid storage tank 104, a test pipeline, a gas-liquid mixer 106, a sensing assembly, a temperature control assembly 216, a gas-liquid separator 301, a test data transmission system, and a data processing and controller 404; the test pipeline comprises a first test pipeline 201, a second test pipeline 202, and a third test pipeline 203.

[0111] The first test pipeline and the second test pipeline are connected with the third test pipeline through the gas-liquid mixer.

[0112] The air compressor 101 is connected with the first test pipeline 201 through a gas phase pipeline 107, and the gas phase pipeline 107 is provided with the gas storage tank 102.

[0113] The first test pipeline 201 is sequentially provided with a first pressure sensor 211, a first temperature sensor 212, a first flowmeter 241, a second pressure sensor 213, and a test reserved section 214; the first flowmeter is a rotational vortex flowmeter.

[0114] The liquid storage tank 104 is connected with the second test pipeline 202 through a liquid phase pipeline 108, and the second test pipeline 202 is provided with an electromagnetic flowmeter 243 and a fifth pressure sensor 217.

[0115] The first test pipeline 201 and the second test pipeline 202 are connected with the third test pipeline 203 through the gas-liquid mixer 106.

[0116] The third test pipeline 203 is sequentially provided with a third pressure sensor 221, a second temperature sensor 222, a second flow meter 242, and a fourth pressure sensor 223.

[0117] A differential pressure monitoring pipe section is arranged before the third pressure sensor, and the differential pressure monitoring pipe section is provided with a differential pressure sensor connected to the data processing and control system.

[0118] The third test pipeline is connected to the gas-liquid separator through the test pipeline.

[0119] The data processing and controller 404 is connected to the sensing assembly and the temperature control assembly 216 through the first test data transmission system 401.

[0120] The system further comprises a gas phase vent pipe 302 connected to the top of the gas-liquid separator 301.

[0121] The liquid storage tank 104 is connected to the bottom of the gas-liquid separator 301 through the liquid phase return pipe 303. Figure 3

[0122] The test reserved section 214 has the same length as the third test pipeline, and the test reserved section 214 can be exchanged with the third test pipeline.

[0123] The first pressure sensor 211, the first temperature sensor 212, the first flow meter 241, and the second pressure sensor 213 are connected to the data processing and controller 404 through the first test data transmission system 401. In actual application, the first test data transmission system 401 acquires real-time monitoring pressure data of the first test pipeline 201 through the first pressure sensor 211 and the second pressure sensor 213, acquires real-time monitoring temperature of the first test pipeline 201 through the first temperature sensor 212, and acquires real-time monitoring gas phase flow of the first test pipeline 201 through the first flow meter 241.

[0124] The electromagnetic flow meter 243 is connected to the data processing and controller 404 through the second test data transmission system 402. Based on this, the second test data transmission system 402 transmits the monitoring liquid phase flow of the second test pipeline 202 through the electromagnetic flow meter 243.

[0125] ​The third pressure sensor 221, the second temperature sensor 222, the second flow meter 242 and the fourth pressure sensor 223 are connected with the data processing and controller 404 through a third test data transmission system 403. Based on this, the third test data transmission system 403 transmits the monitoring pressure of the third test pipeline 203 through the third pressure sensor 221 and the fourth pressure sensor 223, transmits the monitoring temperature of the third test pipeline 203 through the second temperature sensor 222, and transmits the monitoring gas phase flow of the third test pipeline 203 through the second flow meter 242.

[0126] Preferably, in one embodiment, the gas phase pipeline 107 is further sequentially provided with a flow regulating valve 103, a first pressure regulating valve 206 and a first stop valve 204; the flow regulating valve 103 is connected with the output gas path of the gas storage tank 102.

[0127] In actual application, the gas pressure entering the first test pipeline 201 is controlled by adjusting the first pressure regulating valve 206, and the gas flow entering the first test pipeline 201 is controlled by adjusting the flow regulating valve 103.

[0128] The liquid phase pipeline 108 is sequentially provided with a booster pump 105, a second pressure regulating valve 207 and a second stop valve 205.

[0129] The water pressure entering the second test pipeline 202 is controlled by adjusting the second pressure regulating valve 207.

[0130] The third test pipeline is provided with a differential pressure monitoring pipe section 215 before the third pressure sensor, and the length of the pipe section is more than 0.5 m.

[0131] The differential pressure monitoring pipe section is provided with a differential pressure sensor 218 connected with the data processing and control system, and the starting point and the ending point of the differential pressure monitoring pipe section are the pressure taking points of the differential pressure sensor, as shown in the figure. Figure 4 The pressure taking points are arranged at four directions (0°, 90°, 180° and 270°) of the same cross section of the test pipeline (one, two, three or four directions can be selected as the pressure taking points).

[0132] The test reserved section of the embodiment of the application can be used for calibrating the natural gas single-phase flow meter and the gas-liquid two-phase flow meter.

[0133] (1) The test reserved section 214 and the third test pipeline are exchanged, which can be used for calibrating the natural gas single-phase flow meter, and the following formula is used for fitting calculation of the actual flow of the single-phase flow meter to be calibrated after correction Q gs The flow meters on the first test pipeline and the third test pipeline can be different, and can be orifice flow meters, rotational vortex flow meters, V-cone flow meters or conical orifice flow meters.

[0134]

[0135] (2) Do not exchange test reserved section 214 and the third test pipe position, can be used for calibration gas-liquid two-phase flowmeter, the first test pipe and the third test pipe on the flowmeter can use different models, different types of flowmeter, in practical application, can use orifice plate flowmeter, vortex flowmeter, V internal cone flowmeter, conical orifice plate flowmeter.

[0136] In an optional embodiment, the temperature control assembly comprises a heating element and a heat preservation sleeve;

[0137] The heating element is spirally wound on the pipeline along the pipeline wall surface and is packaged on the pipeline by the heat preservation sleeve;

[0138] The heating element adopts a controllable temperature electric heat tracing winding belt, and the heat preservation sleeve can adopt a heat preservation sleeve type including a polyurethane foam heat preservation sleeve, a rubber plastic heat preservation sleeve and a glass wool heat preservation sleeve.

[0139] Further, in a preferred embodiment, the third pressure sensor 221 is provided with one or more pressure taking points at different positions of the same section of the test pipeline, and the second temperature sensor 222 and the fourth pressure sensor 223 are provided in the same manner as the third pressure sensor 221.

[0140] In an optional embodiment, the third pressure sensor (221) is provided with pressure taking points at 0°, 90°, 180° and 270° of the same section of the test pipeline (one, two, three or four positions can be selected as pressure taking points).

[0141] The first pressure sensor 211, the first temperature sensor 212, the first flowmeter 241 and the second pressure sensor 213 are connected with the data processing and controller 404 through the first test data transmission system 401. In actual application, the first test data transmission system 401 acquires real-time monitoring pressure data of the first test pipeline 201 through the first pressure sensor 211 and the second pressure sensor 213, collects real-time monitoring temperature of the first test pipeline 201 through the first temperature sensor 212, and acquires real-time monitoring gas phase flow of the first test pipeline 201 through the first flowmeter 241.

[0142] The data processing and controller is connected with the second pressure regulating valve through the test data transmission system, compares the pressures tested and transmitted by the first pressure sensor and the fifth pressure sensor, controls the opening size of the second pressure regulating valve, and finally makes the test pressures of the first pressure sensor and the fifth pressure sensor equal.

[0143] The test reserved section in the gas-liquid metering test calibration system can realize flexible calibration of natural gas single-phase flow meter and gas-liquid two-phase flow meter, and through real-time monitoring of temperature control data and pressure state in the pipeline by the data processing and controller, precise temperature and pressure control can be realized automatically.

[0144] In actual application, the gas-liquid metering test calibration system is used to perform experiments and obtain test data, and the specific experimental process includes the following operations:

[0145] S11, start the air compressor 101, fully open the first pressure regulating valve 206, and then open the flow regulating valve 103 and the first stop valve 204 in sequence. After the gas is pressurized by the first pressure regulating valve, the gas enters the third test pipeline 203 through the first test pipeline 201.

[0146] S12, open the second stop valve 205, fully open the second pressure regulating valve 207, and start the booster pump 105. The water in the liquid storage tank 104 is pressurized by the booster pump and then enters the third test pipeline 203 through the second test pipeline 202.

[0147] S13, the gas in the first test pipeline 201 and the water in the second test pipeline 202 are mixed by the gas-liquid mixer 106 and then enter the third test pipeline 203 for metering test, and after the test, the gas is separated by the gas-liquid separator 301; during the experiment, the gas separated by the gas-liquid separator 301 is vented through the gas phase venting pipe 302, and the water is recycled by entering the liquid phase return pipe 303 into the liquid storage tank 104.

[0148] S14, the first flow meter 241 measures the single-phase gas flow entering the first test pipeline 201, the electromagnetic flow meter 243 measures the liquid phase flow entering the second test pipeline 202, and the second flow meter 242 measures the wet gas flow entering the third test pipeline 203; during the experiment, the flow and pressure are adjusted to complete the metering test experiment under different working conditions.

[0149] S15, the first test data transmission system 401, the second test data transmission system 402, and the third test data transmission system 403 respectively transmit the collected flow, pressure, and temperature data to the data processing and controller 404.

[0150] In actual application, based on the above-mentioned two-phase metering test calibration system, metering tests under four flow patterns are carried out, and the test data is transmitted to the preset data processing system.

[0151] Next, the gas phase density is calculated according to the dynamic test data of the metering test by the Lockhart-Martinelli parameter determination step, and then the Lockhart-Martinelli parameter operation model is determined based on the gas phase density and the associated flow data.

[0152] Further, in the preferred embodiment, the Lockhart-Martinelli parameter determination step includes the following operations:

[0153] Gas phase density determination step: calculating gas phase density according to measured single-phase gas flow rate, pressure, temperature and liquid phase flow rate data;

[0154] Initial L-M parameter calculation step: calculating initial L-M parameter based on gas flow rate, liquid flow rate and gas phase density as gas phase L-M parameter;

[0155] Optimized L-M parameter determination step: fitting L-M parameter relation according to pressure test data and obtained initial L-M parameter value; and then determining optimized L-M parameter operation model under different flow patterns according to initial L-M parameter and parameter relation to calculate liquid phase L-M parameter.

[0156] In the gas phase density determination step, the process of calculating initial L-M parameter based on gas flow rate, liquid flow rate and gas phase density includes: calculating single-phase gas flow rate Q g according to the progressing vortex flowmeter, testing pressure by the first pressure sensor, testing temperature by the first temperature sensor and testing liquid flow rate Q l calculating gas phase density p g ; and then calculating L-M parameter X according to the following formula:

[0157] (1)

[0158] In the formula, Q Q g is single-phase gas flow rate tested by the progressing vortex flowmeter, Q l is liquid flow rate tested by the electromagnetic flowmeter, p l , p g are liquid phase density and gas phase density respectively.

[0159] Further, in the optimized L-M parameter determination step, L-M parameter X relation fitting is performed according to the following formula in the optional embodiment:

[0160] (2)

[0161] (3)

[0162] In the formula, △ p 1 is the difference between pressure at point a and pressure at point b of the test pipe segment, △ p 2 is the difference between pressure at point b and pressure at point c of the test pipe segment, and A, B and C are fitting coefficients.

[0163] In the operation process, the formula of the Lockhart-Martinelli parameter X in formula (2) and formula (3) is the same, but different coefficients A1 and A2 are used because the values of the variables considered in the formula fitting are different. Formula (2) is the ratio of the two pressure differences, i.e., the pressure difference Δ x 1 between the internal throttling element of the flowmeter before throttling and the throat of the throttling element and the pressure difference Δ p 2 between the throat of the throttling element and the throttling element after throttling, and formula (3) is the relationship between the difference of the two pressure differences and the ratio of the pressure difference between the throat of the throttling element and the throttling element after throttling and the Lockhart-Martinelli parameter. p

[0164] Some scholars have proposed the following formula (a) that the ratio of the two pressure differences is linearly related to the Lockhart-Martinelli parameter, and formula (b) that the difference of the two pressure differences is linearly related to the ratio of the pressure difference between the throat of the throttling element and the throttling element after throttling and the Lockhart-Martinelli parameter. However, under the flow conditions of slug flow and bubbly flow, the ratio of the pressure difference is no longer linearly related to the Lockhart-Martinelli parameter, resulting in inaccurate calculation of the Lockhart-Martinelli parameter X, which makes it impossible to accurately calculate the liquid phase flow rate in the two-phase flow, and leads to large errors in the gas phase and liquid phase flow rates measured by the flowmeter.

[0165] (a)

[0166] (b)

[0167] Therefore, considering the complexity of the flow conditions, a polynomial relationship between the pressure difference ratio and the Lockhart-Martinelli parameter is proposed based on existing research, and the working conditions suitable for the two relationship formulas are different, which reduces the problem of large errors and poor working condition adaptability caused by using one formula to calculate the Lockhart-Martinelli parameter X i ' model is used to calculate the Lockhart-Martinelli parameter, and the calculation results can adapt to any flow pattern under different working conditions.

[0168] In the preferred embodiment, the distance from the test pipe section a point to the throat is D (1 times the pipe diameter) or more, the test pipe section b point is in the middle of the throat pipe, and the distance from the test pipe section c point to the throat is 2D or more.

[0169] According to the initial Lockhart-Martinelli parameter X calculated by the test data and formula (1), the Lockhart-Martinelli parameter X relationship formula is fitted according to formula (2) and formula (3), respectively.

[0170] Further, in one embodiment, in the step of determining the optimized Lockhart-Martinelli parameter, the Lockhart-Martinelli parameter X calculated according to formula (1) is used to determine the optimized Lockhart-Martinelli parameter operation model under different flow patterns as follows:

[0171] (4)

[0172] In the formula,​m 1、 m 2 is the weight coefficient; X i ’ is the calculation value of the Lockhart-Martinelli parameter under the demand flow type, i =1, 2, 3, 4, respectively representing stratified flow, bubble flow, annular flow, plug flow, X is the initial Lockhart-Martinelli parameter, A, B, C are fitting coefficients.

[0173] Further, by the virtual height model determination step: according to the dynamic test data to calculate the virtual height ratio, according to the virtual height ratio and the Lockhart-Martinelli parameter fitting to establish the optimal virtual height operation model under different flow types.

[0174] In the preferred embodiment, in the virtual height ratio determination step, the virtual height ratio is calculated according to the single-phase gas flow and the gas flow test data; in actual application, the single-phase gas flow is tested according to the progressing vortex flowmeter Q g , the gas flow is tested by the differential pressure flowmeter Q g ’ The virtual height ratio Φ is calculated according to the following formula:

[0175] (5)

[0176] Further, according to the virtual height ratio Φ, the Lockhart-Martinelli parameter X calculated by formula (1), the virtual height ratio Φ and the Lockhart-Martinelli parameter X relationship formula fitting is carried out according to formula (6), formula (7) respectively, in actual application, the virtual height ratio and the Lockhart-Martinelli parameter relationship formula fitting is carried out according to the following formula:

[0177] (6)

[0178] (7)

[0179] In the formula, Φ is the virtual height ratio, X is the Lockhart-Martinelli parameter, D 1、 E 1、 E 2、 n 1、 n 2 is the fitting coefficient, p l 、 p g are the liquid phase and gas phase density respectively. Among them, Φ1, Φ2 are the intermediate operation vectors of the virtual height ratio, the formula of Φ1, Φ2 is different, the variable X here is the calculation value of the optimized Lockhart-Martinelli parameter operation model.

[0180] Further, in the optional embodiment, the following formula (8) is used to fit the optimal virtual height model according to the test parameters under different flow types:

[0181] (8)

[0182] wherein, Q g * is the single-phase gas flow tested by the vortex precession flowmeter, Q g is the virtual height ratio calculated by the differential pressure flowmeter, Q g is the single-phase gas flow tested by the vortex precession flowmeter, Φ i is the virtual height ratio under different flow patterns, i =1, 2, 3, 4 respectively represent stratified flow, bubbly flow, annular flow, plug flow, k1, k2 are virtual height weight coefficients.

[0183] Next, the metering model determining step is performed, the optimal virtual height ratio corresponding to different flow patterns is calculated by using the optimal virtual height operation model, and the gas phase metering model of different flow patterns is determined based on the flow data, and the gas phase metering model of different flow patterns is further established based on the gas phase flow and the Lockhart-Martinelli parameter; which are respectively used for calculating the gas phase flow data and the liquid phase flow data.

[0184] In the embodiment of the application, the gas phase flow is calculated according to the optimal virtual height ratio under different flow patterns, and specifically, in the optional embodiment, the gas phase metering model is established as follows in the metering model determining step:

[0185]

[0186] wherein, ;

[0187] wherein, Q g * is the gas phase flow value, Q g is the gas flow tested by the differential pressure flowmeter, Φ i is the optimal virtual height ratio under the flow pattern corresponding to the number i, C u is the discharge coefficient of the flowmeter, β is the throttling ratio of the flowmeter, D is the diameter of the pipe section before throttling of the flowmeter, p g is the gas phase density, e is the dimensionless expansion coefficient of the gas phase.

[0188] Further, the liquid flow is calculated based on the gas phase flow data and the optimal Lockhart-Martinelli parameter under different flow patterns. In the optional embodiment, the liquid phase metering model described in the following formula is established based on the gas phase flow and the optimal Lockhart-Martinelli parameter in the metering model determining step:

[0189]

[0190] wherein, Q l is the liquid phase flow rate value, X i is the calculated optimal Lockhart-Martinelli parameter under the flow pattern corresponding to the number i, Q g * is the gas phase flow rate corresponding to the flow pattern, p l is the liquid phase density, p g is the gas phase density.

[0191] Further, when the engineering site has gas phase or liquid phase metering requirements, the following metering application steps can be performed: after calculating the site gas phase density according to the site flow pattern and test data, the two-phase Lockhart-Martinelli parameter of the site is calculated using the Lockhart-Martinelli parameter operation model, and then the optimal virtual height ratio of the site is determined using the optimal virtual height operation model, and the gas phase flow rate and the liquid phase flow rate matched with the flow pattern are determined by substituting into the gas phase metering model and the liquid phase metering model.

[0192] The differential pressure metering method based on flow pattern discrimination of the embodiment of the present application constructs a two-phase metering model based on flow pattern discrimination and dynamic test data, realizes accurate calculation of the gas phase and liquid phase flow rates, and has simple operation, fast operation speed, and can improve the accuracy of the operation result when applied.

[0193] For each of the method embodiments described above, in order to simply describe, they are all expressed as a series of action combinations, but those skilled in the art should know that the present application is not limited by the action sequence described, because according to the present application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification all belong to preferred embodiments, and the actions and modules involved are not necessarily necessary for the present application.

[0194] It should be noted that in other embodiments of the present application, the method can also be obtained by combining one or several of the above embodiments to obtain a new differential pressure metering method based on flow pattern discrimination, so as to realize accurate optimization of engineering gas phase and liquid phase metering technology.

[0195] It should be noted that based on the method in any one or more of the above embodiments of the present application, the present application further provides a storage medium having a program code for realizing the method in any one or more of the above embodiments stored thereon, and the code can realize the differential pressure metering method based on flow pattern discrimination when executed by an operating system.

[0196] Example Two

[0197] The method is described in detail in the above disclosed embodiments of the present application, and the method of the present application can be implemented in various forms of devices or systems, and therefore, based on other aspects of the method described in any one or more of the above embodiments, the present application also provides a differential pressure metering system based on flow pattern discrimination, which is used to perform the differential pressure metering method based on flow pattern discrimination described in any one or more of the above embodiments. The following specific embodiments are given to explain in detail.

[0198] Specifically, Figure 5 The structure diagram of the differential pressure metering system based on flow pattern discrimination provided in the embodiments of the present application is shown in FIG. 1, and as shown in FIG. 1, the system comprises: Figure 5

[0199] A flow pattern working condition setting module configured to set a test flow pattern based on a requirement, determine a range of gas-liquid flow working condition of the metering pipe section corresponding to the test flow pattern according to preset flow pattern discrimination condition data, and form a flow pattern working condition list;

[0200] A gas-liquid metering test module configured to use a set metering test calibration system to carry out metering tests under different flow patterns according to the flow pattern working condition list, and record dynamic test data in the test process;

[0201] A Lockhart-Martinelli parameter determination module configured to calculate gas phase density according to the dynamic test data of the metering test, and then determine a Lockhart-Martinelli parameter operation model based on the gas phase density and associated flow data;

[0202] A virtual height model determination module configured to calculate a virtual height ratio according to the dynamic test data, and establish an optimal virtual height operation model under different flow patterns according to the virtual height ratio and the Lockhart-Martinelli parameter fitting;

[0203] A metering model determination module configured to, after calculating the optimal virtual height ratio corresponding to different flow patterns by using the optimal virtual height operation model, determine a gas phase metering model of different flow patterns based on the optimal virtual height ratio and flow data, and further establish a gas phase metering model of different flow patterns based on the gas phase flow and the Lockhart-Martinelli parameter;

[0204] A metering application module configured to determine an initial flow pattern on site based on on-site differential pressure data and flow pattern discrimination condition data, calculate on-site gas phase density according to the initial flow pattern on site and test data, calculate on-site Lockhart-Martinelli parameter by using the Lockhart-Martinelli parameter operation model, and then determine the optimal virtual height ratio on site by using the optimal virtual height operation model, and finally determine the gas phase flow and the liquid phase flow matched with the flow pattern by substituting the optimal virtual height ratio into the gas phase metering model and the liquid phase metering model.

[0205] Preferably, in one embodiment, the system further comprises a flow pattern discrimination condition data determination module configured to determine the flow pattern discrimination condition data by performing the following operations: ​

[0206] Step A1. A flow calculation model meeting the set requirements is established by using multiphase flow simulation software as a flow model of the metering test calibration system;

[0207] Step A2. Based on the gas volume parameters and liquid volume parameters meeting the simulation requirements, for each gas volume parameter value, different liquid volume parameter values are applied to perform simulation calculation by using the flow model of the metering test calibration system, to obtain the corresponding test pipe section pressure difference and flow pattern;

[0208] Step A3. According to the obtained pressure difference and flow pattern, the gas volume parameter range of flow pattern transition is selected, and further divided by using the bisection method, for each gas volume parameter value after the division, different liquid volume parameter values are applied to perform simulation calculation by using the flow model of the metering test calibration system, to obtain the corresponding test pipe section pressure difference and flow pattern;

[0209] Step A4. The liquid volume parameter range of flow pattern transition is selected, and the bisection method is used to divide the value, and further simulation calculation is performed by using the flow model of the metering test calibration system to obtain the corresponding test pipe section pressure difference and flow pattern;

[0210] Step A5. It is judged whether the change value of the previous simulation pressure difference and the current simulation pressure difference in the pressure difference monitoring pipe section and the previous simulation pressure difference meet the set requirements, if yes, the current gas volume parameter and liquid volume parameter range of each flow pattern transition, the test pipe section pressure difference and the flow pattern are recorded as flow pattern discrimination condition data;

[0211] If not, step A4 is re-executed until the change value of the previous simulation pressure difference and the current simulation pressure difference in the pressure difference monitoring pipe section and the previous simulation pressure difference meet the set requirements.

[0212] Further, the flow pattern discrimination condition data determination module is configured to establish the flow model of the metering test calibration system by using the multiphase flow simulation software according to the following operations:

[0213] The metering test calibration system is simplified according to the key flow pipe elements, the gas inlet pressurizing unit is simplified as a gas source inlet point, the water inlet pressurizing unit is simplified as a water source inlet point, the gas-liquid outflow separation unit is simplified as a gas-liquid outflow point, and the flow meters on the first and third test pipes are simplified as throttling elements;

[0214] The flow model basic framework of the simplified metering test calibration system is built by using the pipe module and the throttling module of the multiphase flow simulation software;

[0215] According to the structure parameters in the actual metering test calibration system, the input structure parameters of the flow model of the metering test calibration system are determined, and the simplified flow model of the metering test calibration system is constructed.

[0216] Further, in order to guarantee the accuracy of the calculation result of the flow model of the built metering test calibration system, the flow pattern discrimination condition data determination module is further configured to perform the following operations:

[0217] Step A11. Setting the working condition parameters of different flow patterns according to the calculation data of the built metering test calibration system flow model, performing experiments by using the set metering test calibration system, and correcting the built metering test calibration system flow model according to the differential pressure data and temperature data obtained from the experiments, so as to control the error between the simulation calculation data and the experimental data within the set range.

[0218] Preferably, in one embodiment, the metering test calibration system applied by the gas-liquid metering test module adopts a gas-liquid two-phase metering test calibration system, which includes an air compressor, an air storage tank, a liquid storage tank, a test pipeline, a temperature control assembly, a gas-liquid mixer, a sensing assembly, a gas-liquid separator, a test data transmission system, and a data processing and controller; the test pipeline includes a first test pipeline, a second test pipeline, and a third test pipeline;

[0219] The first test pipeline and the second test pipeline are connected with the third test pipeline through the gas-liquid mixer; the third test pipeline is sequentially provided with a third pressure sensor, a second temperature sensor, a second flow meter, and a fourth pressure sensor, and the second flow meter adopts a differential pressure flow meter;

[0220] A differential pressure monitoring pipe section is provided before the third pressure sensor, and the differential pressure monitoring pipe section is provided with a differential pressure sensor, and the differential pressure sensor is connected to the data processing and control system.

[0221] Further, in an optional embodiment, the Lockhart-Martinelli parameter determination module determines the Lockhart-Martinelli parameters according to the following steps:

[0222] Gas phase density determination step: calculating the gas phase density according to the measured single-phase gas flow, pressure, temperature, and liquid phase flow data;

[0223] Initial Lockhart-Martinelli parameter calculation step: calculating the initial Lockhart-Martinelli parameters based on the gas flow, liquid flow, and gas phase density as the gas phase Lockhart-Martinelli parameters;

[0224] Optimized Lockhart-Martinelli parameter determination step: fitting the Lockhart-Martinelli parameter relationship based on the pressure test data and the obtained initial Lockhart-Martinelli parameter value; and then determining the optimized Lockhart-Martinelli parameter calculation model under different flow patterns according to the initial Lockhart-Martinelli parameters and the parameter relationship to calculate the liquid phase Lockhart-Martinelli parameters.

[0225] Further, the Lockhart-Martinelli parameter determination module is configured to determine the optimized Lockhart-Martinelli parameter calculation model under different flow patterns as follows:

[0226]

[0227] In the formula, m 1、 m 2 is a weight coefficient; X i ’ is the calculation value of the Lockhart-Martinelli parameter under the demand flow type, i =1, 2, 3, 4, respectively representing stratified flow, bubble flow, annular flow, and plug flow, X is an initial Lockhart-Martinelli parameter, A, B, and C are fitting coefficients.

[0228] Preferably, in an embodiment, the virtual height model determination module is configured to establish an optimal virtual height operation model according to the following formula:

[0229]

[0230] In the formula, Q g * is the test flow rate of the differential pressure flowmeter Q g ’ and the virtual height ratio is calculated, Q g is the test single-phase gas flow rate of the rotational vortex flowmeter, Φ i is the virtual height ratio under different flow types, i =1, 2, 3, 4, respectively representing stratified flow, bubble flow, annular flow, and plug flow, k1 and k2 are virtual height weight coefficients.

[0231] In the differential pressure metering system based on flow type discrimination provided by the embodiments of the present application, each module or unit structure can be independently operated or combined to operate according to actual flow type setting requirements and data operation requirements, so as to realize corresponding technical effects.

[0232] It should be understood that the disclosed embodiments of the present application are not limited to the specific structure, processing steps or materials disclosed herein, but should extend to equivalent alternatives of these features understood by those skilled in the relevant art. It should also be understood that the terms used herein are only for the purpose of describing specific embodiments and do not mean limitation.

[0233] The phrase "one embodiment" mentioned in the specification means that the specific features, structures or characteristics described in connection with the embodiment are included in at least one embodiment of the present application. Therefore, the phrase "one embodiment" appearing throughout the specification does not necessarily mean the same embodiment.

[0234] Although the embodiments of the present application have been disclosed with reference to the above embodiments, the above description is merely used to understand the present application and is not used to limit the present application. Any person skilled in the art, without departing from the spirit and scope of the present application, can make any modification and change in the form and details of the embodiments, but the patent protection scope of the present application should be subject to the scope defined by the appended claims.

Claims

1. A differential pressure type metering method based on flow pattern discrimination, characterized by, The method comprises: Flow pattern working condition setting step: setting a test flow pattern based on requirements, determining a gas-liquid flow working condition range corresponding to the test flow pattern according to preset flow pattern discrimination condition data, and forming a flow pattern working condition list; Gas-liquid metering test step: using a set metering test calibration system, carrying out metering tests under different flow patterns according to the flow pattern working condition list, and recording dynamic test data in the test process; Lockhart-Martinelli parameter determination step: calculating gas phase density according to the dynamic test data of the metering test, and then determining a Lockhart-Martinelli parameter operation model based on the gas phase density and associated flow data; Virtual height model determination step: calculating a virtual height ratio according to the dynamic test data, and fitting an optimal virtual height operation model under different flow patterns according to the virtual height ratio and the Lockhart-Martinelli parameter; Metering model determination step: after the optimal virtual height operation model is used to calculate optimal virtual height ratios corresponding to different flow patterns, gas phase metering models of different flow patterns are determined based on the virtual height ratios and flow data, and liquid phase metering models of different flow patterns are further determined based on gas phase flow and the Lockhart-Martinelli parameter; Metering application step: determining a field initial flow pattern based on field pressure difference data and flow pattern discrimination condition data, calculating a field gas phase density according to the field initial flow pattern and test data, calculating a field Lockhart-Martinelli parameter by using the Lockhart-Martinelli parameter operation model, and then determining a field optimal virtual height ratio by using the optimal virtual height operation model, and finally determining gas phase flow and liquid phase flow matched with the flow pattern by substituting the gas phase metering model and the liquid phase metering model with the field optimal virtual height ratio; The Lockhart-Martinelli parameter determination step comprises the following operations: Gas phase density determination step: calculating gas phase density according to measured single-phase gas flow, pressure, temperature and liquid phase flow data; Initial Lockhart-Martinelli parameter calculation step: calculating an initial Lockhart-Martinelli parameter based on gas flow, liquid flow and gas phase density as a gas phase Lockhart-Martinelli parameter; Optimized Lockhart-Martinelli parameter determination step: fitting a Lockhart-Martinelli parameter relationship based on pressure test data and the obtained initial Lockhart-Martinelli parameter value; and then determining an optimized Lockhart-Martinelli parameter operation model under different flow patterns according to the initial Lockhart-Martinelli parameter and the parameter relationship, so as to calculate a liquid phase Lockhart-Martinelli parameter.

2. The method of claim 1, wherein, Before the flow pattern working condition setting step, the method further comprises a flow pattern discrimination condition data determination step comprising the following operations: Step A1. Using multiphase flow simulation software to establish a flow operation model meeting the set requirements as a metering test calibration system flow model; Step A2. Based on gas volume parameters and liquid volume parameters meeting simulation requirements, performing simulation operation by using the metering test calibration system flow model for each gas volume parameter value respectively by applying different liquid volume parameter values, to obtain corresponding test pipe section pressure difference and flow pattern; Step A3. Selecting a gas volume parameter range of flow pattern transition according to the obtained pressure difference and flow pattern, and further performing bisectional value splitting respectively, and performing simulation operation by using the metering test calibration system flow model for each gas volume parameter value after the splitting respectively by applying different liquid volume parameter values, to obtain corresponding test pipe section pressure difference and flow pattern; Step A4. Selecting the liquid volume parameter range of the flow pattern transition, using the bisection method to split the value, and further using the metering test calibration system flow model to obtain the corresponding test pipe segment pressure difference and flow pattern through simulation operation; Step A5. Judging whether the change value of the previous simulation pressure difference and the current simulation pressure difference in the pressure difference monitoring pipe segment and the previous simulation pressure difference meet the set requirements, if yes, recording the current gas volume parameter liquid volume parameter range, test pipe segment pressure difference and flow pattern of each flow pattern transition as the flow pattern discrimination condition data; If not, re-executing step A4 until the change value of the previous simulation pressure difference and the current simulation pressure difference in the pressure difference monitoring pipe segment and the previous simulation pressure difference meet the set requirements.

3. The method of claim 2, wherein, In step A1, the process of establishing the flow model of the metering test calibration system by using the multiphase flow simulation software includes: Simplifying the metering test calibration system according to key flow pipe elements, simplifying the air inlet booster unit into an air source inlet point, simplifying the water inlet booster unit into a water source inlet point, simplifying the gas-liquid outflow separation unit into a gas-liquid outflow point, and simplifying the flow meters on the first and third test pipelines into throttle elements; Using the pipeline module and throttle module of the multiphase flow simulation software to build the basic framework of the simplified flow model of the metering test calibration system; According to the structure parameters in the actual metering test calibration system, determining the input structure parameters of the flow model of the metering test calibration system, and completing the construction of the simplified flow model of the metering test calibration system.

4. The method of claim 3, wherein, In step A1, the process of establishing the flow model of the metering test calibration system by using the multiphase flow simulation software also includes: Step A11. Setting the operating parameters of different flow patterns according to the calculation data of the established flow model of the metering test calibration system, using the set metering test calibration system to conduct experiments, and correcting the established flow model of the metering test calibration system according to the pressure difference data and temperature data obtained from the experiments, so as to control the error between the simulation calculation data and the experimental data within the set range.

5. The method of claim 1, wherein, In the gas-liquid metering test step, the metering test calibration system adopts a gas-liquid two-phase metering test calibration system, which includes an air compressor, a gas storage tank, a liquid storage tank, a test pipeline, a temperature control assembly, a gas-liquid mixer, a sensing assembly, a gas-liquid separator, a test data transmission system, and a data processing and controller; The first test pipeline and the second test pipeline are connected with the third test pipeline through the gas-liquid mixer; the third test pipeline is sequentially provided with a third pressure sensor, a second temperature sensor, a second flow meter, and a fourth pressure sensor, and the second flow meter is a differential pressure flow meter; A pressure difference monitoring pipe segment is arranged before the third pressure sensor, and the pressure difference monitoring pipe segment is provided with a pressure difference sensor, which is connected to the data processing and control system.

6. The method of claim 1, wherein, In the optimization of the Lockhart-Martinelli parameter determination step, the operation model of the optimized Lockhart-Martinelli parameter under different flow patterns is as follows: In the formula, m 1、 m 2 is a weight coefficient; X i ’ is the calculation value of the Lockhart-Martinelli parameter under the demand flow type, i = 1, 2, 3, 4, respectively representing stratified flow, bubble flow, annular mist flow, plug flow, X is the initial Lockhart-Martinelli parameter, A, B, C are fitting coefficients, x is a fitting variable.

7. The method of claim 1, wherein, An optimal virtual height operation model is established as follows: In the formula, Q g * is the test flow rate of the differential pressure flowmeter Q g ’ and the virtual height ratio calculation, Q g is the test flow rate of the single-phase gas of the spin-vortex flowmeter, Φ i is the virtual height ratio under different flow patterns, i =1, 2, 3, 4, respectively representing stratified flow, bubbly flow, annular mist flow, and plug flow, k1, k2 are virtual height weight coefficients, X is the Lockhart-Martinelli parameter value calculated based on the Lockhart-Martinelli parameter operation model; D1, D2, E1, E2 are fitting coefficients.

8. A storage medium, characterized by The storage medium stores program codes capable of realizing the method of any one of claims 1-7.

9. A differential pressure based metering system based on flow regime discrimination, characterized in that, The system executes the method of any one of claims 1-7. The system executes the method of any one of claims 1-7.

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