Oil well multiphase fluid metering method and device based on throttling linear function

Abstract

The invention discloses an oil well multiphase fluid metering method and device based on a throttling linear function. The method comprises the following steps: determining the gas-phase mass content of a multiphase produced medium of an oil well by utilizing a gas-phase mass content calculation function according to a front-back throttling pressure difference standard deviation and a temperature drop amplitude of an oil nozzle device arranged in a target oil well; and obtaining the total mass flow rate of the multiphase extraction medium by utilizing the multiphase extraction medium throttling total mass flow rate linear function according to the front and back throttling pressure difference of the oil nozzle device and the determined gas phase mass content rate. The method can be used for accurately and conveniently metering the oil well multiphase produced medium, is wide in application range, and is still suitable for metering the oil well multiphase produced medium under complex working conditions such as high gas-liquid ratio; meanwhile, the ground technological process is simple, and the metering cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum geological exploration, and in particular to an oil well multiphase fluid metering method and device based on a throttling linear function. Background Art

[0002] Wellhead measurement of oil well production media is an important task in reservoir dynamic analysis and production management. Accurate and timely measurement of oil well production is of great guiding significance for understanding reservoir conditions and formulating production plans, which directly affects the rational development and economic benefits of oil fields. Most of the oil well production media exist in multiphase fluids. The measurement of multiphase production media has always been the focus and difficulty of single well measurement in oil fields at home and abroad.

[0003] In the related technology, there are many ways to achieve the metering of multiphase produced media in oil wells, such as the traditional single-well separation metering method, the non-separation metering method of multiphase flowmeters, and modern software metering technology represented by power diagram metering. Summary of the invention

[0004] The inventors found that the traditional multiphase produced medium metering method has problems such as complex ground process flow, high metering cost, and low measurement accuracy. The ground process flow of separation metering is complicated, which increases the construction investment and use cost. Although the non-separation metering of multiphase flowmeters shows superiority in terms of space occupation, the flow characteristics of the gas-liquid two-phase flow change significantly and are highly volatile, resulting in low measurement accuracy and a narrow range of applicable gas-liquid ratios; in addition, the non-separation metering device of the multiphase flowmeter generally uses microwave sensors and gamma densitometers to test the phase fraction, so the cost is relatively high. With the continuous advancement of the digital construction of oil fields, there is an urgent need for an oil well metering method that simplifies the ground gathering and transportation process, has low operating costs, and can achieve continuous, automatic, accurate, and real-time production measurement. Against this background, digital metering technology came into being, which played an important role in optimizing and simplifying the oil field gathering and transportation system, and has gradually become one of the important contents of intelligent oil field construction. In the production of single wells in conventional oil fields, software metering technology represented by power diagram metering has been widely used in pumping wells. The oil well liquid production is calculated by real-time collection and processing and analysis of oil well indicator diagram data, thereby realizing remote automatic metering of liquid production. However, the error of power diagram metering is large under high gas-liquid ratio conditions. In terms of liquid production metering of electric pump wells, considering the influence of temperature and pressure changes on the expansion coefficient of the throttling device, the conventional pressure difference method flow metering formula has been corrected based on the homogeneous flow theory to obtain higher metering accuracy. However, in the self-flowing production stage of single well production, the working conditions are complex, the gas production changes are unstable, the water content and production change rapidly and the change range is large, resulting in significant changes in flow characteristics. There is still a problem that the gas-liquid phase content after the change cannot be accurately known, resulting in large deviations in the calculation results, especially for high gas content conditions. The adaptability will be worse; and the lack of analysis of the change of the nozzle flow coefficient with the opening degree has further affected the adaptability accuracy and range of the actual single well metering.

[0005] Therefore, how to accurately and conveniently measure the multiphase produced medium of oil wells under complex working conditions such as high gas-liquid ratio is a technical problem that needs to be solved urgently.

[0006] In order to at least partially solve the technical problems existing in the prior art, the inventors have made the present invention, and through a specific implementation method, provide an oil well multiphase fluid metering method and device based on a throttling linear function, which can accurately and conveniently measure the oil well multiphase production medium.

[0007] In a first aspect, an embodiment of the present invention provides a method for measuring multiphase fluid in an oil well based on a throttling linear function, comprising:

[0008] According to the standard deviation of the throttling pressure difference before and after the choke device and the temperature drop amplitude, the gas mass content of the multiphase produced medium of the oil well is determined by using the gas mass content calculation function, wherein the gas mass content calculation function is used to characterize the relationship between the standard deviation of the throttling pressure difference before and after the choke device and the temperature drop amplitude and the gas mass content of the multiphase produced medium;

[0009] According to the throttling pressure difference before and after the choke device and the determined gas phase mass content, the total mass flow rate of the multiphase production medium is obtained by using the total mass flow linear function of the throttling of the multiphase production medium, wherein the total mass flow linear function is a linear function between the ratio of the arithmetic square root of the throttling pressure difference before and after the choke device to the total mass flow rate of the multiphase production medium and the gas phase mass content of the multiphase production medium.

[0010] In a second aspect, an embodiment of the present invention provides an oil well multiphase fluid metering device based on a throttling linear function, comprising:

[0011] A gas phase mass content determination module, used to determine the gas phase mass content of the multiphase produced medium of the oil well according to the standard deviation of the throttling pressure difference before and after the choke device and the temperature drop amplitude, using the gas phase mass content calculation function, wherein the gas phase mass content calculation function is used to characterize the relationship between the standard deviation of the throttling pressure difference before and after the choke device, the temperature drop amplitude and the gas phase mass content of the multiphase produced medium;

[0012] The mass flow metering module is used to obtain the total mass flow of the multiphase produced medium according to the throttling pressure difference before and after the nozzle device and the determined gas phase mass content, using the total mass flow linear function of the throttling of the multiphase produced medium, wherein the total mass flow linear function is a linear function between the ratio of the arithmetic square root of the throttling pressure difference before and after the nozzle device to the total mass flow of the multiphase produced medium and the gas phase mass content of the multiphase produced medium.

[0013] In a third aspect, an embodiment of the present invention provides a computer storage medium, wherein the computer storage medium stores computer executable instructions, and when the computer executable instructions are executed by a processor, the above-mentioned oil well multiphase fluid metering method based on throttling linear function is implemented.

[0014] In a fourth aspect, an embodiment of the present disclosure provides a server, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the above-mentioned oil well multiphase fluid metering method based on throttling linear function is implemented.

[0015] The beneficial effects of the above technical solution provided by the embodiment of the present invention include at least:

[0016] The oil well multiphase fluid metering method based on throttling linear function provided by the embodiment of the present invention pre-establishes a gas phase mass content calculation function to characterize the relationship between the standard deviation of the throttling pressure difference before and after the nozzle device, the temperature drop amplitude and the gas phase mass content of the multiphase produced medium, and establishes a linear function of the total mass flow rate of the multiphase produced medium to characterize the linear relationship between the ratio of the arithmetic square root of the throttling pressure difference before and after the nozzle device and the total mass flow rate and the gas phase mass content; according to the standard deviation of the throttling pressure difference before and after the nozzle device set in the target oil well and the temperature drop amplitude, the gas phase mass content calculation function is used to determine the gas phase mass content of the multiphase produced medium of the oil well; according to the throttling pressure difference before and after the nozzle device and the determined gas phase mass content, the total mass flow rate calculation function of the multiphase produced medium is used to obtain the total mass flow rate of the multiphase produced medium. The method can accurately and conveniently meter the multiphase produced medium of the oil well; and the ground process flow is simple, the metering cost is low, the measurement accuracy is high, and it is still applicable to the multiphase produced medium of the oil well with a high gas-liquid ratio.

[0017] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 It is a structural schematic diagram of a gas-liquid circulation experimental system in an embodiment of the present invention;

[0021] Figure 2 Schematic diagram of the relationship between the ratio of the arithmetic square root of the nozzle throttling pressure difference to the total mass flow rate and the gas phase mass holdup in an embodiment of the present invention;

[0022] Figure 3 It is a schematic diagram of the pressure difference fluctuation over time in the throttling test of the multi-phase production medium with a certain gas phase content in an embodiment of the present invention;

[0023] Figure 4 It is a schematic diagram of the fluctuation characteristics of the throttling pressure difference and the temperature drop amplitude of the nozzle device according to the embodiment of the present invention as a function of the gas phase mass content;

[0024] Figure 5 It is a flow chart of a method for measuring multiphase fluid in an oil well based on a throttling linear function in an embodiment of the present invention;

[0025] Figure 6 The figure is a corresponding relationship diagram of the flow coefficient of the nozzle device according to the embodiment of the present invention as the opening changes;

[0026] Figure 7 It is a structural schematic diagram of an oil well multiphase fluid metering device based on a throttling linear function in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0028] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0029] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the invention belongs. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0030] In order to solve the problems of complex ground process flow, high metering cost and low measurement accuracy in the existing multiphase produced medium metering method, the embodiment of the present invention provides an oil well multiphase fluid metering method and device based on throttling linear function, which can accurately and conveniently meter the multiphase produced medium of the oil well.

[0031] The embodiment of the present invention firstly takes the experimental data of the multiphase medium production simulation experiment as the data basis, combines a series of mathematical derivations and corresponding relationship fitting, and pre-establishes the gas phase mass content calculation function and the total mass flow calculation function of the multiphase production medium.

[0032] Specifically, a multiphase medium production throttling experiment is carried out through a gas-liquid circulation experimental system, and the throttling pressure difference signals and temperature drop amplitudes before and after the experimental nozzle device corresponding to the multiphase medium with different gas mass contents are transported to the experimental nozzle device (the size is consistent with the nozzle device in the target oil well) are measured to obtain an experimental data set. Each set of data in the experimental data set includes the mass flow rate of the liquid medium and the mass flow rate of the gas medium in the multiphase medium, the throttling pressure difference (the throttling pressure difference signal collected in one measurement is a set of throttling pressure difference data sequences, and the average value is taken as the throttling pressure difference obtained in one measurement, and the standard value is taken as the throttling pressure difference standard value obtained in one measurement), the throttling pressure difference standard deviation and the temperature drop amplitude; based on the experimental data set, a gas mass content calculation function and a multiphase production medium total mass flow calculation function are established. Among them, the gas mass content calculation function is used to characterize the relationship between the standard deviation of the throttling pressure difference before and after the nozzle device, the temperature drop amplitude and the gas mass content of the multiphase produced medium; the multiphase produced medium total mass flow calculation function is used to characterize the relationship between the throttling pressure difference before and after the nozzle device, the gas mass content of the multiphase produced medium and the total mass flow of the multiphase produced medium.

[0033] See also Figure 1 , which is a schematic diagram of the structure of the gas-liquid circulation experimental system used in the embodiment of the present application, includes a liquid phase supply device 11, a gas phase supply device 12, a mixer 13 and an oil nozzle connecting device 14.

[0034] The nozzle connecting device 14 is used to connect the nozzle of the selected specification. The upstream first node and the downstream second node of the nozzle connecting device 14 are respectively connected to the two ends of the differential pressure transmitter 141, and the upstream third node and the downstream fourth node of the nozzle connecting device 14 are respectively connected to the two ends of the differential temperature transmitter 142.

[0035] The upstream end of the mixer 23 is connected to the downstream ends of the liquid phase supply device 11 and the gas phase supply device 12 , and the downstream end of the mixer 13 is connected to the upstream end of the nozzle connection device 14 .

[0036] A gas phase flow meter 121 , a thermometer 122 , and a pressure gauge 123 are connected to the gas phase supply device 22 , and a liquid phase flow meter 111 is connected to the liquid phase supply device 11 .

[0037] In some embodiments, the oil well multiphase medium production simulation equipment also includes a separator 15; the downstream end of the oil nozzle connecting device 14 is connected to the inlet of the separator 15; the gas phase outlet of the separator 15 is connected to the upstream end of the gas phase supply device 12, and the liquid phase outlet of the separator 15 is connected to the upstream end of the liquid phase supply device 11.

[0038] 1. Conduct experiments on hydraulic and thermal characteristics of produced media under throttling conditions.

[0039] use Figure 1The gas-liquid circulation experimental system shown is used to carry out experiments to study the hydraulic and thermal characteristics of the produced medium under throttling conditions.

[0040] Step 1.1: Open the valve of the gas phase supply device and adjust the gas phase flow rate to a fixed value Q g1 After the gas fills the entire pipeline and the flow rate stabilizes for a period of time, record the average pressure difference signal before and after the nozzle Pressure difference signal fluctuation standard deviation (σ ΔP ) g1,0 And the temperature drop ΔT g1,0 , where the standard deviation of the pressure difference signal fluctuation is calculated by obtaining the sum of the squares of the differences between all discrete pressure difference values ​​and the pressure difference mean in each experiment, then taking the average value, and finally performing square root calculation to obtain (σ ΔP ) g1,0 .

[0041] Step 1.2: Based on step 1.1, slowly open the valve of the liquid phase supply device and adjust the liquid phase flow rate to a fixed value M. l1 During the adjustment process, it is necessary to keep the gas phase flow rate at Q g1 After the flow rate stabilizes for a period of time, record the average pressure difference signal before and after the nozzle Pressure difference signal fluctuation standard deviation (σ ΔP ) g+l1,1 And the temperature drop ΔT g+l1,1 .

[0042] Step 1.3: After the collection in step 1.2 is completed, continue to slowly adjust the valve of the liquid phase supply device to increase the liquid phase flow rate to M l2 During the adjustment process, it is still necessary to keep the gas phase flow rate at Q g1 Do not change. After the flow rate stabilizes, record the average value of the pressure difference signal before and after the nozzle. Pressure difference signal fluctuation standard deviation (σ ΔP ) g+l1,2 And the temperature drop ΔT g+l1,2 .

[0043] Repeat the above acquisition process, and each subsequent adjustment will increase the liquid phase flow rate by a certain amount until the liquid phase flow rate is adjusted to the maximum value M. ln , record the average value of the pressure difference signal before and after the nozzle Pressure difference signal fluctuation standard deviation (σ ΔP ) g+l1,n And the temperature drop ΔT g+l1,n .

[0044] Step 1.4: Adjust the gas phase flow rate to Q g2 , record the average value of the pressure difference signal before and after the nozzle Pressure difference signal fluctuation standard deviation (σ ΔP ) g2,0 And the temperature drop ΔTg2,0 The valve of the liquid supply device was gradually adjusted to increase the liquid flow rate, and the second set of data was collected.

[0045] Step 1.5: Gradually adjust the gas phase flow rate to the maximum value Q gm , and gradually adjust the valve of the liquid phase supply device to increase the liquid phase flow rate until M ln Repeat the above acquisition process and record the average pressure difference signal before and after the nozzle device Pressure difference signal fluctuation standard deviation (σ ΔP ) g+lm,n And the temperature drop ΔT g+lm,n .

[0046] 1. Experimental setup The gas-liquid flow matrix is ​​as follows:

[0047]

[0048] 2. Experimental setup The gas phase mass fraction matrix is ​​as follows, where the gas phase mass fraction x g The calculation method is to take the ratio of the mass flow rate of the gas phase to the sum of the mass flow rates of the gas and liquid phases:

[0049]

[0050] 3. Experimental test records of hydraulics (differential pressure mean value B1 and fluctuation value data set matrix B2) and thermals (temperature drop value data set matrix B3) are as follows:

[0051]

[0052]

[0053] Based on the experimental data set, the Lockhart-Martinelli parameter (Lockhart parameter X LM ) The expression of the phase flow pressure drop model is transformed and solved to obtain the expression of the full liquid phase medium conversion coefficient. The gas and liquid are considered as full liquid phases with the same mass flow rate. The total mass flow rate of the multiphase produced medium is calculated according to the full liquid phase medium conversion coefficient. The calculation function of the total mass flow rate of the multiphase produced medium is established through the following steps 2-4.

[0054] 2. Determine the conversion factor λ used to characterize the gas phase according to the experimental data set g With Loma parameter X LM The split-phase flow pressure drop model based on the relationship between them.

[0055] The split-phase flow pressure drop model is based on the theory that the gas and liquid phases pass through the nozzle device separately. It is assumed that the gas-liquid mixture flows through the nozzle device completely separately and the flow coefficient is the same in the same nozzle device.

[0056] Step 2.1: Determine the Lockhart-Martinelli parameter X LM .

[0057] X LM It is a dimensionless number and is often used to summarize and organize data. LM It is determined by the following formula (1).

[0058]

[0059] In formula (1), X LM is the Loma parameter, dimensionless; ΔP l The mass flow rate is M l When the liquid medium passes through the nozzle alone, the throttling pressure difference before and after the nozzle device, Pa; ΔP g The mass flow rate is M g When the gas phase medium passes through the nozzle alone, the throttling pressure difference before and after the nozzle is Pa; Δl is the pipeline length, m; M l is the mass flow rate of liquid medium passing through the nozzle, kg / s; M g is the mass flow rate of gas phase medium passing through the nozzle, kg / s; ρ l is the liquid density, kg / m 3 ρ g is the gas phase density, kg / m 3 .

[0060] Furthermore, the liquid mass flow rate and gas mass flow rate (M g or Q g (represented) is obtained by the above matrix A1; the density of the liquid phase in the produced medium can be tested by placing the density meter into the liquid to be tested and directly reading the density; the gas phase density can be calculated according to the gas pressure and temperature upstream of the nozzle by the following formula (2):

[0061]

[0062] In formula (2), P is the gas pressure upstream of the nozzle, Pa; M mol is the gas phase molar mass, g / mol; n is the molar number of the gas substance, mol; R is the gas state constant, J / (mol·K); T is the absolute temperature of the gas phase, K.

[0063] Step 2.2: Determine the gas phase conversion factor λ g .

[0064] Let the mass flow rate be M g+l The pressure drop of the gas-liquid two-phase medium flowing through the Δl pipe section is related to the mass flow rate M gThe square root of the pressure drop ratio of the gas phase medium passing through the Δl long pipe section is calculated, and the result is defined as the gas phase conversion coefficient, which is expressed by the dimensionless number λ g express.

[0065] M g+l =M g +M l (3)

[0066]

[0067]

[0068] Where M g+l is the mass flow rate of gas-liquid two-phase medium passing through the nozzle, kg / s; λ g is the gas phase conversion coefficient, dimensionless; ΔP g+l The mass flow rate is M g+l The throttling pressure difference value generated when the gas-liquid two-phase medium passes through the oil nozzle, Pa.

[0069] Step 2.3: Determine the applicability of the phase separation flow pressure drop model expression.

[0070] The gas phase conversion coefficient λ obtained by converting the experimental pressure difference g With Loma parameter X LM The changing relationship is plotted, and based on the trend of the graph, an applicable pressure drop model is selected from the existing phase flow pressure drop models.

[0071] Four commonly used expressions for the split-phase flow pressure drop model are listed below.

[0072] Murdock Model:

[0073] λ g =1+1.26X L-M (6)

[0074] Bizon Model:

[0075] λ g =a+bX L-M (7)

[0076] Chisholm Model:

[0077]

[0078] Steven Model:

[0079]

[0080] In the formula, Fr gis the gas phase Froude number, dimensionless; a, b, A, B, C0, C1 and D are different constants to be fitted.

[0081] The model parameters are determined by data regression. Generally, the applicability of the phase separation flow pressure drop model expression is shown in the following functional relationship:

[0082] λ g =f(X LM ) (10)

[0083]

[0084]

[0085] 3. Based on the phase-separated flow pressure drop model, the conversion coefficient expression of the full liquid phase medium is established, that is, the ternary function expression of gas phase mass content, liquid phase density and gas phase density.

[0086] Step 3.1: Assume the mass flow rate is M g+l The pressure difference generated when the liquid phase passes through the nozzle is ΔP l-Full According to the single-phase fluid flow metering formula, ΔP l-Full With M g+l , ΔP l With M l , ΔP g With M g The relationships between them are shown in formulas (13) to (15):

[0087]

[0088]

[0089]

[0090] In the formula, ΔP l-Full The mass flow rate is M g+l The throttling pressure difference value generated when the liquid medium passes through the nozzle, Pa; ξ is the throttling ratio, that is, the ratio of the cross-sectional diameter of the nozzle throat to the cross-sectional diameter of the pipe, dimensionless; C v is the flow coefficient, dimensionless; A is the cross-sectional area of ​​the nozzle throat, m 2 ; ε is the dimensionless expansion coefficient of the measured medium, ε<1 for compressible fluids, and ε=1 for incompressible fluids. g 、M l and M g+l The relationship between them is expressed in terms of gas phase mass fraction x g Establish:

[0091] M g =M g+l x g(16)

[0092] M l =M g+l (1-x g ) (17)

[0093] Step 3.2: Set the mass flow rate to M g+l The pressure drop (throttling pressure difference) caused by the gas-liquid two-phase medium flowing through the Δl pipe section is the same as the pressure drop (throttling pressure difference) of the same mass flow rate M g+l The square root of the pressure drop ratio of the liquid phase passing through the Δl long pipe section is calculated, and the result is defined as the full liquid phase medium conversion coefficient, expressed as the dimensionless number λ l-Full express.

[0094] Multiply both sides of formula (11) by The total liquid phase medium conversion coefficient λ can be obtained l-Full for and The binary function of As shown in formula (18).

[0095]

[0096] In the formula, λ l-Full is the conversion factor of the full liquid medium, dimensionless.

[0097] Step 3.3: Substitute equations (13) to (17) into the full liquid phase medium conversion factor λ l-Full The function formula (18) is further transformed and simplified to analyze the final full liquid phase medium conversion coefficient expression, which is a three-variable function of gas mass fraction, liquid density, and gas density. Let the function form be F(x g ,ρ l ,ρ g ), see formula (19) for details.

[0098]

[0099] 4. Based on the conversion coefficient expression of the full liquid phase medium, a calculation function for the total mass flow rate of multiphase produced medium is established.

[0100] Step 4.1: Assume that the gas-liquid two-phase flow is uniformly mixed, there is no slip between the phases and the two phases have the same velocity, and the mixture density is ρ m , the flow parameters of the two-phase flow are taken as pseudo-single-phase fluid. The actual pressure difference ΔP is tested when the pressure difference uses a two-phase nozzle to throttle g+l Calculate the total mass flow rate:

[0101]

[0102] In the formula, ρ mis the density of the mixed fluid upstream of the nozzle before throttling under working conditions, kg / m 3 .

[0103] Now consider the fluid as a full liquid phase and assume that the total mass flow rate is M g+l When the full liquid medium flows through the nozzle, the throttling pressure difference is ΔP l-Full , the total mass flow rate of the entire liquid phase can be expressed as follows:

[0104]

[0105] Step 4.2: Equalize the gas and liquid to the same mass flow rate M g+l The density of the liquid phase is ρ l , the pressure difference is tested when two-phase flow flows through the nozzle throttling. g+l Calculate the mass flow rate M g+l , the full liquid medium conversion factor λ l-Full After conversion calculation, the total mass flow rate of multiphase produced medium is:

[0106]

[0107] ε is the dimensionless expansion coefficient of the measured medium, ε<1 for compressible fluid and ε=1 for incompressible fluid.

[0108] Just as an example: Now take the split-phase flow pressure drop model λ g =f(X LM ) conforms to the Bizon model: λ g =a+bX L-M Formal example derivation M g+l Calculation relationship:

[0109] Now make the following assumptions: gas phase conversion coefficient λ g With Loma parameter X LM Relationship λ g =f(X LM ) conforms to the Bizon model linear relationship (9), then:

[0110]

[0111] Multiply both sides of the equation by We can get:

[0112]

[0113] Substitute formula (15) to formula (19) to further transform and simplify, and analyze the final λ l-Full It is a function of gas phase mass fraction, liquid phase density, and gas phase density in the form of:

[0114]

[0115] The total liquid phase medium reduction factor λ l-Full Substituting into formula (22), the total mass flow rate of multiphase produced medium is calculated as:

[0116]

[0117] A total mass flow calculation function is established through the above steps 2 to 4. Optionally, another total mass flow calculation function can be established through the following step 5, which is a total mass flow linear function:

[0118] 5. Establish a linear function of the total mass flow rate of oil well produced medium based on the linear relationship of multiphase fluid throttling.

[0119] Step 5.1: Derive and establish the linear function relationship of total mass flow rate.

[0120] Assume that the mass flow rate is M g+l The average pressure difference generated when the liquid phase passes through the nozzle is but and The square root of the ratio of the gas mass fraction x g The following relationship is met:

[0121]

[0122] In the formula, The mass flow rate is M g+l The average pressure drop caused by the gas-liquid two-phase medium flowing through the nozzle throttling, Pa; The mass flow rate is M g+l The average pressure difference generated when the single-phase liquid passes through the nozzle, Pa; ρ l Liquid density. The density value is read by placing the densitometer into the liquid to be tested, kg / m 3 ; ψ is the correction coefficient, which is related to the gas-liquid density ratio and is dimensionless.

[0123] According to the single-phase fluid flow metering formula, With M g+l The relationship between them conforms to the following formula:

[0124]

[0125] Where ξ is the throttling ratio, which is the ratio of the cross-sectional diameter of the nozzle throat to the cross-sectional diameter of the pipe, dimensionless; C v is the flow coefficient, dimensionless; A is the cross-sectional area of ​​the nozzle throat, m 2 ; ε is the dimensionless expansion coefficient of the measured medium, ε<1 for compressible fluid and ε=1 for incompressible fluid.

[0126] Calculate formula (28) Substituting into formula (27), we can get:

[0127]

[0128] It can be seen that the ratio of the mean square root of the throttling pressure difference to the total mass flow rate is and gas phase mass fraction x g There is the above linear relationship between them.

[0129] Step 5.2: Based on the experimental data set, linear fitting is used to establish the total mass flow measurement function.

[0130] Specifically establish the total mass flow rate M g+l In the process of metering function, based on the differential pressure mean matrix B1, gas-liquid total mass flow matrix A3 and gas phase mass content matrix A2 of the experimental data set obtained in step 1, a third data set including multiple throttling pressure differences, gas phase mass content and total mass flow data sets is obtained; the data fitting method is adopted and the least squares method is used to obtain and x g The linear relationship between them.

[0131]

[0132] Where M and N are dimensionless parameters obtained by fitting the experimental data set.

[0133] According to experiments, the recommended M value range is generally between 0.76 and 1.99; the recommended N value range is between 6.11 and 10.73. Figure 2 As shown, it is a schematic diagram of the relationship between the ratio of the arithmetic square root of the nozzle throttling pressure difference to the total mass flow rate and the gas phase mass content. It can be seen that the two are in a good linear relationship.

[0134] The total mass flow rate M g+l The measurement function is:

[0135]

[0136] Furthermore, the flow coefficient of the nozzle device can be determined according to the opening value of the nozzle device by using the corresponding relationship between the nozzle flow coefficient and the opening; and the linear function of the total mass flow can be corrected according to the flow coefficient of the nozzle device:

[0137]

[0138] 6. Establish a calculation function for gas phase mass content.

[0139] Solve the above expressions (22), (26) and (31) for the total mass flow rate of produced fluid, and the unknown gas phase mass fraction xg To solve the phase mass flow rate, it is also necessary to know the phase mass content. The embodiment of the present invention innovatively integrates the standard deviation of the nozzle throttling pressure difference fluctuation and the temperature drop characteristics to invert and calculate the phase mass content.

[0140] The throttling pressure difference fluctuation standard deviation here refers to the standard deviation of multiple throttling pressure differences measured each time. Correspondingly, each throttling pressure difference value in the above matrix B1 refers to the average value of a group of throttling pressure difference data measured.

[0141] Step 6.1: Establish a first functional relationship for characterizing the relationship between gas phase mass holdup and the standard deviation of throttling pressure difference.

[0142] When throttling occurs, the phase mass content will affect the energy exchange and flow state between the gas and liquid phases, and then affect the stability of the pressure difference signal. The pressure difference signal will fluctuate with time. Therefore, the characteristic value and fluctuation law of the pressure difference signal contain information about the gas-liquid two-phase flow parameters. By analyzing the characteristic value and fluctuation law of the pressure difference signal and establishing a correlation model, online measurement of the gas mass content can be achieved. Specifically, based on the experimental data set obtained from the hydraulic and thermal characteristics experiment of the produced medium throttling condition in the above steps, a first data set containing multiple pairs of throttling pressure difference standard deviations and gas mass content data is obtained, and the first functional relationship used to characterize the relationship between the gas mass content and the throttling pressure difference standard deviation is obtained by fitting.

[0143] (1) The optimal pressure difference signal sampling frequency and sampling time are optimized through preliminary experiments.

[0144] In order to obtain the most stable and reliable differential pressure signal, a preliminary experiment is first carried out to select the optimal frequency and time for collecting the differential pressure signal.

[0145] See also Figure 3 As shown in the figure, it is a schematic diagram of the pressure difference fluctuation over time in the nozzle throttling test. If the acquisition frequency is too high and the acquisition time is too long, the amount of data collected will be too large and the processor will be overloaded. If the acquisition frequency is too low, the most comprehensive pressure difference signal cannot be obtained, and even the fluctuation of the pressure difference signal over time cannot be sensitively captured, resulting in the failure of the collected pressure difference data. If the acquisition time is too short, the pressure difference signal fluctuation may not even reach a stable state and cannot be used for phase content prediction. Therefore, before the metering experiment begins, it is necessary to compare and select the optimal acquisition frequency and time of the nozzle throttling device through preliminary experiments to find the minimum frequency and time that meet the experimental requirements.

[0146] During the preliminary experiment, adjust the valve and select a set of liquid flow M li and gas phase flow rate Q gi Keep it constant. Gradually increase the frequency and time of pressure difference signal acquisition, and test the standard deviation of pressure difference signal fluctuation σ ΔP , until σ ΔPThe value remains stable and no longer changes with the increase of the pressure difference signal acquisition frequency and the extension of the acquisition time. The acquisition frequency and acquisition time corresponding to this point are the optimal acquisition frequency and acquisition time.

[0147] Preferably, the recommended acquisition time settings for the preliminary experiment are: 10s, 20s, 40s, 70s, 110s, 160s...

[0148] Recommended acquisition frequency settings: 50Hz, 80Hz, 120Hz, 170Hz, 230Hz...

[0149] (2) Determine the gas phase mass fraction through the characteristic value of the pressure difference fluctuation.

[0150] Gas mass fraction x g When it is smaller, the liquid phase flow content is larger and belongs to the continuous phase in the two-phase flow, while the gas phase belongs to the dispersed phase. When the bubbles in the liquid flow pass through the nozzle, the bubbles break into small bubbles, causing pressure difference fluctuations. g The gas phase content gradually increases and becomes the continuous phase of the two-phase flow. The liquid phase will be blown by the airflow and transformed into tiny droplets, which are distributed more evenly in the gas phase. At this time, the pressure difference fluctuation through the nozzle becomes gentle.

[0151] The standard deviation of pressure difference signal fluctuation σ ΔP Characterization experiment collects the fluctuation size of the pressure difference signal:

[0152]

[0153]

[0154] In the formula, σ ΔP is the standard deviation of the pressure difference signal fluctuation collected during a certain set of experiments, Pa; n is the number of points of the pressure difference signal collected during a certain set of experiments, ΔP i is the pressure difference value at the i-th point collected during a certain set of experiments, Pa; The average value of the pressure difference signal collected during a group of experiments, Pa.

[0155] Typically, a pressure difference signal fluctuation standard deviation σ ΔP and gas mass fraction x g For the corresponding relationship, see Figure 4 shown.

[0156] Therefore, based on the matrices A2 and B2 in the throttling experiment results in step 1, the standard deviation σ of the pressure difference signal fluctuation when reaching a stable state can be established. ΔP and gas mass fraction x g The functional relationship of .

[0157] σ ΔP=H(x g ) (35)

[0158] The standard deviation of pressure difference fluctuation σ ΔP Inverse calculation of gas phase mass fraction x g , the functional relationship is established as above g ) is the inverse function of:

[0159] x g =H -1 (σ ΔP ) (36)

[0160] Through experiments, it is commonly used that a typical pressure difference signal fluctuation standard deviation σ ΔP and gas mass fraction x g The expression is formula (25), which is used as an example to illustrate the inversion calculation of gas phase mass fraction x g Method:

[0161] σ ΔP =αln(βx g +γ)

[0162]

[0163] In the above, α<0, β>0, which means that the higher the gas mass content, the higher the standard deviation of the pressure difference signal fluctuation σ ΔP The smaller it is, the more stable the pressure difference signal is.

[0164] By σ ΔP Inverse calculation x g :

[0165]

[0166] Through the above steps, based on the experimental data set, a first data set containing multiple pairs of throttling pressure difference standard deviations and gas phase mass content data is obtained, and a first functional relationship for characterizing the relationship between the gas phase mass content and the throttling pressure difference standard deviation is obtained by fitting, namely, Formula 38.

[0167] Step 6.2: Establish a second functional relationship for characterizing the relationship between gas phase mass content and temperature drop amplitude.

[0168] The relationship between the temperature drop characteristics and the phase separation fraction of the gas and liquid phases when throttling occurs is very complex. After the gas phase component in the produced liquid passes through the nozzle, the Joule-Thomson effect will cause a temperature drop. The higher the gas mass fraction, the more significant the Joule-Thomson effect, and the greater the temperature drop after the nozzle throttling.

[0169] Based on the above experimental data set, a second data set including multiple pairs of temperature drop amplitude and gas mass content is obtained, and a second functional relationship for characterizing the relationship between gas mass content and temperature drop amplitude is obtained by fitting.

[0170] Typically, the temperature drop amplitude ΔT of a nozzle throttling is related to the gas mass fraction x g For the corresponding relationship, see Figure 4 shown.

[0171] Therefore, based on the matrices A2 and B3 in the throttling experiment results in step 1, a functional relationship model between the temperature drop characteristics and the gas phase mass fraction can be established:

[0172] ΔT=h(x g ) (39)

[0173] Where ΔT is the nozzle throttling temperature drop value collected during a certain set of experiments, ℃.

[0174] The gas phase fraction x can be calculated by the nozzle throttling temperature drop ΔT g , the functional relationship is established as above g ) is the inverse function of:

[0175] x g =h -1 (ΔT) (40)

[0176] Through experiments, it is commonly found that a typical nozzle throttling temperature drop value ΔT is related to the gas mass fraction x g The expression is formula (40), which is used as an example to illustrate the inversion calculation of gas phase mass content x g Method:

[0177]

[0178] In the above, p>0 means that the higher the gas mass fraction, the greater the temperature drop after the nozzle is throttled; q>1 means that the higher the gas mass fraction, the greater the throttling temperature drop ΔT g The more significant the change.

[0179] By σ ΔP Inverse calculation x g :

[0180]

[0181] Based on the experimental data set, a second data set containing multiple pairs of temperature drop amplitudes and gas mass content data is obtained. By fitting, a second functional relationship for characterizing the relationship between gas mass content and temperature drop amplitude is obtained, namely, equation (42).

[0182] Step 6.3: Based on the first functional relationship and the second functional relationship, establish a gas phase mass content calculation function.

[0183] Typically, when the gas mass holdup is low, the fluctuation characteristics of the throttling pressure difference are more obvious, and the standard deviation of the fluctuation σ ΔP The value is large and σ ΔP Value for gas mass fraction x g The change of x is more sensitive. g The changes are significant.

[0184] When the gas mass fraction is high, the throttling temperature drop characteristics are more obvious, and the throttling temperature drop ΔT value is larger, and the ΔT value has a significant effect on the gas mass fraction x. g The change of x is more sensitive. g The changes are significant.

[0185] Therefore, it is recommended to comprehensively consider the hydraulic and thermal characteristics of the nozzle throttling, assign different weights to the inverse function relationship of the nozzle throttling pressure difference fluctuation and temperature drop characteristics to calculate the gas mass holdup according to the gas mass holdup, and inversely calculate the phase holdup.

[0186] x g =mH -1 (σ ΔP )+nh -1 (ΔT) (43)

[0187] When the gas mass holdup is low, H -1 (σ ΔP ) has a higher weight m than h -1 The weight n value of (ΔT) is lower than the weight n value when the gas mass content is high. The recommended values ​​of m and n are shown in Table 1:

[0188] Table 1 Recommended weights m and n for inverse function relationship of inverse calculation of gas mass holdup by comprehensively considering the hydraulic and thermal characteristics of nozzle throttling

[0189] Gas phase mass content range Recommended m weight value Recommended n weight value [0，25％) 0.8 0.2 [25％，50％) 0.6 0.4 [50％，75％) 0.4 0.6 [75％，100％] 0.2 0.8

[0190] Through experiments, a typical method for calculating the phase fraction by inverting the throttling pressure difference fluctuation and temperature drop characteristics of the nozzle is to calculate the gas phase mass fraction x by integrating equation (38) and equation (42): g :

[0191]

[0192] That is, based on the first functional relationship (Equation 38) and the second functional relationship (Equation 42), a gas phase mass content calculation function (Equation 44) is established.

[0193] 7. Establish a phase-separated mass flow measurement model.

[0194] Substituting the mass gas phase holdup function of formula (43) into formula (32), the total mass flow rate of the multiphase medium can be calculated:

[0195]

[0196] Step 7.1: Based on the total mass flow linear metering function and the gas phase mass fraction calculation model, the gas phase mass flow rate M can be established. g and liquid mass flow rate M l Computational model:

[0197]

[0198]

[0199] Step 7.2: Test the moisture content according to the moisture analyzer result x w , the mass flow rate M of the water phase in the liquid phase can be established w and oil phase mass flow rate M o :

[0200]

[0201]

[0202] Where M w is the mass flow rate of water phase, kg / s; M o is the oil phase mass flow rate, kg / s; x w is the mass moisture content.

[0203] Example

[0204] The embodiment of the present invention provides a method for measuring multiphase fluid in oil wells based on a throttling linear function, and the process thereof is as follows: Figure 5 As shown, the following steps are included:

[0205] Step S51: according to the standard deviation of the throttling pressure difference before and after the choke device installed in the target oil well and the temperature drop amplitude, the gas mass content calculation function is used to determine the gas mass content of the multiphase produced medium of the oil well.

[0206] According to the estimated range of the gas phase mass content, the specific weight values ​​of m and n are determined through Table 1, and then the specific value of the gas phase mass content is determined through the gas phase mass content calculation function, that is, the above formula (44).

[0207] Step S52: According to the throttling pressure difference before and after the nozzle device and the determined gas phase mass content, the total mass flow rate of the multiphase produced medium is obtained by using the total mass flow rate linear function of the throttling of the multiphase produced medium.

[0208] According to the throttling pressure difference before and after the nozzle device and the determined gas mass content, the total mass flow rate of the multiphase produced medium is calculated using formula (31).

[0209] In some embodiments, the flow coefficient of the nozzle device can also be determined based on the opening value of the nozzle device and the corresponding relationship between the nozzle flow coefficient and the opening, and the total mass flow of the multiphase produced medium can be calculated using formula (32).

[0210] Among them, the corresponding relationship between the nozzle flow coefficient and the opening can be established by changing the opening D value of the nozzle throttling device, restarting the above experimental test process, and analyzing the corresponding relationship between the nozzle flow coefficient and the opening C v (D).

[0211] Recommended opening D selection: 20%, 40%, 60%, 80% and 100% for research, regression analysis C v (D) Curve. Typical C v (D) Curvilinear relationship see Figure 6 shown.

[0212] A commonly used recommended adjustment coefficient corresponding to the change in opening C v (D) The expression is:

[0213] C v (D)=ke iD+j +t (50)

[0214] The above parameters such as k, i, j and t are determined through throttling experiments.

[0215] Optionally, the total mass flow rate of the multiphase produced medium can be obtained using formula (26) based on the throttling pressure difference before and after the nozzle device and the determined gas phase mass content.

[0216] Specifically, according to the opening value of the nozzle device, the flow coefficient of the nozzle device is determined by utilizing the corresponding relationship between the nozzle flow coefficient and the opening; according to the throttling pressure difference before and after the nozzle device and the determined gas phase mass content and flow coefficient, the total mass flow calculation function of the multiphase produced medium is utilized to obtain the total mass flow of the multiphase produced medium.

[0217] The calculation function of the total mass flow rate of multiphase produced medium is the above formula (22), wherein the liquid phase density is obtained by measurement, and usually does not need to be measured in real time, for example, once a week or two weeks; the gas phase density is calculated by formula (2), which can be calculated once in a period of time or in real time.

[0218] The oil well multiphase fluid metering method based on throttling linear function provided by the embodiment of the present invention pre-establishes a gas phase mass content calculation function to characterize the relationship between the standard deviation of the throttling pressure difference before and after the nozzle device, the temperature drop amplitude and the gas phase mass content of the multiphase produced medium, and establishes a linear function of the total mass flow rate of the multiphase produced medium to characterize the linear relationship between the ratio of the square root of the throttling pressure difference before and after the nozzle device to the total mass flow rate and the gas phase mass content; according to the standard deviation of the throttling pressure difference before and after the nozzle device set in the target oil well and the temperature drop amplitude, the gas phase mass content calculation function is used to determine the gas phase mass content of the multiphase produced medium of the oil well; according to the throttling pressure difference before and after the nozzle device and the determined gas phase mass content, the total mass flow rate calculation function of the multiphase produced medium is used to obtain the total mass flow rate of the multiphase produced medium. The method can accurately and conveniently meter the multiphase produced medium of the oil well; and the ground process flow is simple, the metering cost is low, the measurement accuracy is high, and it is still applicable to the multiphase produced medium of the oil well with a high gas-liquid ratio.

[0219] In some embodiments, after determining the total mass flow rate of the multiphase produced medium, the mass flow rate of the liquid phase medium and / or the mass flow rate of the gas phase medium in the multiphase produced medium can also be obtained based on the total mass flow rate of the multiphase produced medium and the gas phase mass content.

[0220] Furthermore, the mass flow rate of the liquid medium is obtained by the above formula (17), and the mass flow rate of the gas medium is obtained by the above formula (16).

[0221] It is also possible to obtain the mass flow rate of water phase produced liquid and / or the mass flow rate of oil phase produced liquid in the multiphase produced medium according to the water content of the multiphase produced medium and the mass flow rate of the liquid phase medium. The water content of the multiphase produced medium is measured by a water content analyzer.

[0222] For example, as described in the above example, the multiphase throttling model conforms to the linear relationship: The method of inverting the phase fraction by integrating the nozzle throttling pressure difference fluctuation and temperature drop characteristics is as follows: Calculation, C v (D) The expression conforms to C v (D)=ke iD+j +t, the total mass flow rate and phase flow rate measurement formula are as follows:

[0223]

[0224]

[0225]

[0226]

[0227]

[0228] In summary, the nozzle throttling pressure difference ΔP is known g+l , standard deviation of throttling pressure difference fluctuation σ ΔP , and throttling temperature drop ΔT, test moisture content x w , substituting into the above formulas (51)~(55), the three-phase metering of oil, gas and water can be realized.

[0229] For example, using formulas 51-55, the three-phase flow rates of oil, gas and water in the well are measured, compared with the field separation measurement data, and the daily average value of the single well is calculated to verify the measurement accuracy. As shown in Table 2, the average deviation is within 4%, and the measurement effect meets the requirements.

[0230] Table 2 Comparison of metering effects

[0231]

[0232] Based on the inventive concept of the present invention, the embodiment of the present invention also provides a device for measuring oil well produced medium based on the total mass flow linear function, the structure of the device is as follows Figure 7 As shown, including:

[0233] The gas phase mass content determination module 71 is used to determine the gas phase mass content of the multiphase produced medium of the oil well according to the standard deviation of the throttling pressure difference before and after the oil nozzle device set in the target oil well and the temperature drop amplitude, using the gas phase mass content calculation function;

[0234] The mass flow metering module 72 is used to obtain the total mass flow of the multiphase produced medium according to the throttling pressure difference before and after the nozzle device and the determined gas phase mass content, using the total mass flow linear function of the throttling of the multiphase produced medium, wherein the total mass flow linear function is a linear function between the ratio of the arithmetic square root of the throttling pressure difference before and after the nozzle device to the total mass flow of the multiphase produced medium and the gas phase mass content of the multiphase produced medium.

[0235] In some embodiments, the mass flow metering module 72 is further used to obtain the mass flow rate of the liquid phase medium and / or the mass flow rate of the gas phase medium in the multiphase produced medium according to the total mass flow rate of the multiphase produced medium and the gas phase mass content.

[0236] In some embodiments, the mass flow metering module 72 is also used to obtain the mass flow rate of the water phase produced fluid and / or the mass flow rate of the oil phase produced fluid in the multiphase produced medium according to the water content of the multiphase produced medium and the mass flow rate of the liquid phase medium.

[0237] In some embodiments, the above apparatus further includes a function establishment module 73, which is used to:

[0238] A multiphase medium production throttling experiment was carried out through a gas-liquid circulation experimental system. The throttling pressure difference signal and temperature drop amplitude before and after the experimental nozzle device corresponding to the multiphase medium with different gas mass contents were measured when the multiphase medium was transported to the experimental nozzle device, and an experimental data set was obtained. Based on the experimental data set, the gas mass content calculation function and the multiphase production medium total mass flow calculation function were established.

[0239] In some embodiments, the function establishment module 73 is specifically used to:

[0240] Based on the experimental data set, a first data set including a plurality of data pairs of throttling pressure difference standard deviation and gas phase mass content is obtained, and a first functional relationship for characterizing the relationship between the gas phase mass content and the throttling pressure difference standard deviation is obtained by fitting; based on the experimental data set, a second data set including a plurality of data pairs of temperature drop amplitude and gas phase mass content is obtained, and a second functional relationship for characterizing the relationship between the gas phase mass content and the temperature drop amplitude is obtained by fitting; based on the first functional relationship and the second functional relationship, a gas phase mass content calculation function is established.

[0241] In some embodiments, the function establishment module 73 is specifically used to:

[0242] Based on the experimental data set, a third data set including multiple throttling pressure difference, gas phase mass content and total mass flow data groups is obtained; a linear function between the ratio of the square root of the throttling pressure difference before and after the choke device to the total mass flow of the multiphase produced medium and the gas phase mass content of the multiphase produced medium is obtained by fitting, and a total mass flow linear function is established:

[0243]

[0244] Where M g+l is the total mass flow rate of multiphase produced medium, ΔP g+l The mass flow rate is M g+l When the gas-liquid two-phase medium flows through the nozzle device, the average throttling pressure difference before and after the nozzle device, x g is the gas mass content of the multiphase produced medium, M and N are fitting parameters obtained by fitting.

[0245] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0246] Based on the inventive concept of the present invention, an embodiment of the present invention further provides a computer storage medium, in which computer executable instructions are stored. When the computer executable instructions are executed by a processor, the above-mentioned oil well multiphase fluid metering method based on throttling linear function is implemented.

[0247] Based on the inventive concept of the present invention, an embodiment of the present invention also provides a server, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the above-mentioned oil well multiphase fluid metering method based on throttling linear function is implemented.

[0248] Unless otherwise specifically stated, terms such as processing, computing, calculating, determining, displaying, etc. may refer to the actions and / or processes of one or more processing or computing systems, or similar devices, which operate and convert data represented as physical (e.g., electronic) quantities within registers or memories of a processing system into other data similarly represented as physical quantities within memories, registers, or other such information storage, transmission, or display devices of the processing system. Information and signals may be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0249] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of protection of the present disclosure. The attached method claims present the elements of the various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy described.

[0250] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that an embodiment of the claimed subject matter requires more features than those set forth in each claim. On the contrary, as reflected in the appended claims, the invention is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0251] Those skilled in the art will also appreciate that the various illustrative logic blocks, modules, circuits, and algorithmic steps described in conjunction with the embodiments herein can all be implemented as electronic hardware, computer software, or a combination thereof. In order to clearly illustrate the interchangeability between hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above around their functions. Whether such functions are implemented as hardware or software depends on specific applications and the design constraints imposed on the entire system. A skilled person can implement the described functions in an alternative manner for each specific application, but such implementation decisions should not be interpreted as departing from the scope of protection of the present disclosure.

[0252] The steps of the method or algorithm described in conjunction with the embodiments herein may be directly embodied as hardware, a software module executed by a processor, or a combination thereof. The software module may be located in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a mobile disk, a CD-ROM, or any other form of storage medium well known in the art. An exemplary storage medium is connected to the processor so that the processor can read information from the storage medium and can write information to the storage medium. Of course, the storage medium may also be an integral part of the processor. The processor and the storage medium may be located in an ASIC. The ASIC may be located in a user terminal. Of course, the processor and the storage medium may also be present in a user terminal as discrete components.

[0253] For software implementation, the techniques described in this application can be implemented with modules (e.g., procedures, functions, etc.) that perform the functions described in this application. These software codes can be stored in a memory unit and executed by a processor. The memory unit can be implemented within the processor or outside the processor. In the latter case, it is coupled to the processor in a communication manner via various means, which are well known in the art.

[0254] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments can be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", just as "including," explained as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to represent "non-exclusive or". The terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

Claims

1. A method for measuring multiphase fluid in oil wells based on throttling linear function, characterized in that: include: According to the standard deviation of the throttling pressure difference before and after the choke device and the temperature drop amplitude, the gas mass content of the multiphase produced medium of the oil well is determined by using the gas mass content calculation function, wherein the gas mass content calculation function is used to characterize the relationship between the standard deviation of the throttling pressure difference before and after the choke device and the temperature drop amplitude and the gas mass content of the multiphase produced medium; According to the throttling pressure difference before and after the choke device and the determined gas phase mass content, the total mass flow rate of the multiphase production medium is obtained by using the total mass flow linear function of the throttling of the multiphase production medium, wherein the total mass flow linear function is a linear function between the ratio of the arithmetic square root of the throttling pressure difference before and after the choke device to the total mass flow rate of the multiphase production medium and the gas phase mass content of the multiphase production medium.

2. The method according to claim 1, characterized in that Also includes: The mass flow rate of the liquid phase medium and / or the mass flow rate of the gas phase medium in the multiphase produced medium is obtained according to the total mass flow rate of the multiphase produced medium and the gas phase mass content.

3. The method according to claim 2, characterized in that Also includes: According to the water content of the multiphase produced medium and the mass flow rate of the liquid phase medium, the mass flow rate of the water phase produced liquid and / or the mass flow rate of the oil phase produced liquid in the multiphase produced medium is obtained.

4. The method according to claim 1, characterized in that: Also includes: A multiphase medium production throttling experiment is carried out through a gas-liquid circulation experimental system, and the throttling pressure difference signal and temperature drop amplitude before and after the experimental nozzle device are measured when the multiphase medium with different gas mass content is transported to the experimental nozzle device, and an experimental data set is obtained. The size of the experimental nozzle device is consistent with that of the nozzle device in the target oil well; The gas phase mass content calculation function and the multiphase produced medium total mass flow calculation function are established based on the experimental data set.

5. The method according to claim 4, characterized in that The gas phase mass content calculation function is pre-established in the following manner: Based on the experimental data set, a first data set including a plurality of data pairs of throttling pressure difference standard deviation and gas phase mass holdup is obtained, and a first functional relationship for characterizing the relationship between the gas phase mass holdup and the throttling pressure difference standard deviation is obtained by fitting; Based on the experimental data set, a second data set including a plurality of temperature drop amplitude and gas phase mass content data pairs is obtained, and a second functional relationship for characterizing the relationship between the gas phase mass content and the temperature drop amplitude is obtained by fitting; Based on the first functional relationship and the second functional relationship, a gas phase mass content calculation function is established.

6. The method according to claim 5, characterized in that The first functional relationship is: The second functional relationship is: In formula (1) and formula (2), x g is the gas phase mass fraction; σ ΔP is the standard deviation of the throttling pressure difference, ΔT is the temperature drop amplitude, α, β, γ, p and q are all fitting parameters obtained by fitting, where α<0, β>0, p>0, q>1.

7. The method according to claim 6, characterized in that The gas phase mass holdup calculation function is: In formula (3), m is the first weight, n is the second weight, and m+n=1.

8. The method according to claim 4, characterized in that The linear function of the total mass flow rate of the multiphase produced medium is pre-established in the following manner: Based on the experimental data set, a third data set including a plurality of throttling pressure difference, gas phase mass fraction and total mass flow rate data sets is obtained; The linear function between the ratio of the arithmetic square root of the throttling pressure difference before and after the nozzle device and the total mass flow rate of the multiphase produced medium and the gas mass content of the multiphase produced medium is obtained by fitting, and the total mass flow rate linear function is established: In formula (4), M g+l is the total mass flow rate of multiphase produced medium, ΔP g+l The mass flow rate is M g+l When the gas-liquid two-phase medium flows through the nozzle device, the average throttling pressure difference before and after the nozzle device, x g is the gas mass content of the multiphase produced medium, M and N are fitting parameters obtained by fitting.

9. The method according to claim 8, characterized in that Also includes: According to the opening value of the nozzle device, the flow coefficient of the nozzle device is determined by using the corresponding relationship between the nozzle flow coefficient and the opening; According to the flow coefficient of the nozzle device, the total mass flow linear function is corrected: In formula (5), C v is the flow coefficient of the nozzle device.

10. An oil well multiphase fluid metering device based on throttling linear function, characterized in that: The device comprises: A gas phase mass content determination module, used to determine the gas phase mass content of the multiphase produced medium of the oil well according to the standard deviation of the throttling pressure difference before and after the choke device and the temperature drop amplitude, using the gas phase mass content calculation function, wherein the gas phase mass content calculation function is used to characterize the relationship between the standard deviation of the throttling pressure difference before and after the choke device, the temperature drop amplitude and the gas phase mass content of the multiphase produced medium; The mass flow metering module is used to obtain the total mass flow of the multiphase produced medium according to the throttling pressure difference before and after the nozzle device and the determined gas phase mass content, using the total mass flow linear function of the throttling of the multiphase produced medium, wherein the total mass flow linear function is a linear function between the ratio of the arithmetic square root of the throttling pressure difference before and after the nozzle device to the total mass flow of the multiphase produced medium and the gas phase mass content of the multiphase produced medium.

11. A computer storage medium, characterized in that: The computer storage medium stores computer executable instructions, and when the computer executable instructions are executed by a processor, the oil well multiphase fluid metering method based on a throttling linear function as claimed in any one of claims 1 to 9 is implemented.

12. A server, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the oil well multiphase fluid metering method based on a throttling linear function as claimed in any one of claims 1 to 9 is implemented.

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