Oil well multiphase production medium split-phase holdup determination method and determination model establishment method

Abstract

The invention discloses an oil well multiphase production medium split-phase holdup determination method and a determination model establishment method. The method for establishing the split-phase holdup determination model comprises the following steps: acquiring an experimental data set obtained in the following mode, carrying out a multiphase medium extraction simulation experiment through a gas-liquid circulation experimental system, and measuring the experimental data set when multiphase media with different gas phase mass holdups are conveyed to an experimental oil nozzle device. Obtaining an experimental data set according to front and back throttling pressure difference signals and temperature drop amplitude values of the experimental oil nozzle device; and establishing a gas phase mass content determination model based on the experimental data set, wherein the gas phase mass content determination model is used for representing the relation among the throttling pressure difference standard deviation before and after the oil nozzle device, the temperature drop amplitude and the gas phase mass content of the multiphase produced medium. The model established by the method can accurately and conveniently measure the split-phase volume fraction of the oil well multiphase extraction medium, is wide in application range, and is still suitable for the oil well multiphase extraction 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 a method for determining the phase fraction of multiphase produced medium in an oil well and a method for establishing a determination model. Background Art

[0002] Wellhead metering 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 deployment and economic benefits of oil fields. Most of the oil well production media exist in multiphase fluids. The phase content measurement of multiphase production media in oil wells usually adopts the separation metering method, which separates the multiphase production media first and then measures them, converting the multiphase metering problem into a single-phase metering problem. If non-separation metering is used, the phase content measurement of multiphase production media has always been the focus and difficulty of single-well metering in oil fields at home and abroad.

[0003] In the related art, there are many ways to achieve phase content measurement of multiphase produced media in oil wells, for example, microwave sensors and gamma densitometers used in the non-separation measurement method of multiphase flow meters. Summary of the invention

[0004] The inventors found that the traditional method of measuring the phase fraction of multiphase produced media in oil wells has problems such as complex ground process flow, high measurement cost, and low measurement accuracy. The ground process flow of separation measurement is complicated, which increases the construction investment and use cost. Although the non-separation measurement of multiphase flowmeters shows superiority in terms of space occupation, the flow characteristics of the gas-liquid two-phase flow change significantly and the volatility is strong, resulting in low phase fraction measurement accuracy and a narrow range of applicable gas-liquid ratio, which in turn affects the measurement accuracy; 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 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 measurement of production. 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 terms of single-well production in conventional oil fields, software metering technology represented by dynamometer 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 dynamometer data, thereby realizing remote automatic metering of liquid production. However, the phase fraction error of dynamometer metering under high gas-liquid ratio conditions is large. In terms of liquid production metering in 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 revised 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 fraction 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, which in turn affects the adaptability accuracy and range of actual single-well metering.

[0005] Therefore, how to accurately and conveniently measure the phase content of multiphase produced media in 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 specific implementation methods, provide a method for determining the phase content of multiphase produced media in oil wells and a method for establishing a determination model, which can accurately and conveniently measure the phase content of multiphase produced media in oil wells.

[0007] In a first aspect, an embodiment of the present invention provides a method for establishing a model for determining phase fraction of multiphase produced medium in an oil well, comprising:

[0008] The experimental data set is obtained by the following method: a multiphase medium extraction simulation 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 corresponding to the multiphase medium with different gas mass contents are transported to the experimental nozzle device are measured to obtain the experimental data set;

[0009] A gas phase mass content determination model is established based on the experimental data set 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.

[0010] In a second aspect, an embodiment of the present invention provides a method for determining phase fraction of multiphase produced medium in an oil well, comprising:

[0011] 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, the gas mass content of the multiphase produced medium of the oil well is determined using the gas mass content determination model, and the gas mass content determination model is established according to the above method.

[0012] In a third aspect, an embodiment of the present invention provides a device for establishing a model for determining phase fraction of multiphase produced medium in an oil well, comprising:

[0013] The experimental data set acquisition module is used to acquire the experimental data set obtained by the following method: a multiphase medium extraction simulation 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 corresponding to the multiphase medium with different gas mass content is transported to the experimental nozzle device are measured to obtain the experimental data set;

[0014] The gas phase mass content determination model establishment module is used to establish a gas phase mass content determination model based on the experimental data set, and 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 phase mass content of the multiphase produced medium.

[0015] In a fourth aspect, an embodiment of the present invention provides a computer storage medium, wherein the computer storage medium stores computer executable instructions, which, when executed by a processor, implement the above-mentioned method for establishing a model for determining the phase content of a multiphase production medium in an oil well, or implement the above-mentioned method for determining the phase content of a multiphase production medium in an oil well.

[0016] In a fifth 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 method for establishing a model for determining the phase content of multiphase production media in oil wells described above is implemented, or the method for determining the phase content of multiphase production media in oil wells described above is implemented.

[0017] The beneficial effects of the above technical solution provided by the embodiment of the present invention include at least:

[0018] The method for establishing a phase content determination model for a multiphase produced medium in an oil well provided in an embodiment of the present invention obtains an experimental data set obtained by conducting a multiphase medium production simulation experiment through a gas-liquid circulation experimental system, and establishes a gas phase mass content determination model based on the experimental data set, which 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 phase mass content of the multiphase produced medium. Based on the phase content determination model established by this method, the gas phase mass content of the multiphase produced medium of the oil well can be determined on the basis of obtaining 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, and the phase content of the multiphase produced medium of the oil well can be accurately and conveniently measured; and the ground process flow is simple, the metering cost is low, and the measurement accuracy is high, and it is still applicable to the multiphase produced medium of oil wells with a high gas-liquid ratio.

[0019] 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.

[0020] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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:

[0022] Figure 1 This is a flow chart of a method for establishing a model for determining phase fraction of multiphase produced medium in an oil well in Example 1 of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of the gas-liquid circulation experimental system in Example 1 of the present invention;

[0024] 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 the first embodiment of the present invention;

[0025] 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 gas phase mass content in the first embodiment of the present invention;

[0026] Figure 5 This is a flow chart of a method for determining phase content of multiphase produced medium in an oil well in Embodiment 2 of the present invention;

[0027] Figure 6It is a structural schematic diagram of a device for establishing a model for determining phase fraction of multiphase produced medium in an oil well in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] 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.

[0029] 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.

[0030] 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.

[0031] In order to solve the problems of complex ground process flow, high metering cost and low measurement accuracy in the existing metering methods of multiphase produced media, the embodiment of the present invention provides a method for determining the phase content of multiphase produced media in oil wells and a method for establishing a determination model, which can accurately and conveniently measure the phase content of multiphase produced media in oil wells through a non-separation method.

[0032] Embodiment 1

[0033] Embodiment 1 of the present invention provides a method for establishing a model for determining the phase fraction of multiphase produced medium in an oil well, and the process thereof is as follows Figure 1 As shown, the following steps are included:

[0034] Step S11: Acquire an experimental data set obtained in the following manner: conduct a multiphase medium extraction simulation experiment through a gas-liquid circulation experimental system, measure 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 transported to the experimental nozzle device, and obtain the experimental data set.

[0035] 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 establishes a gas phase mass content determination model for the multiphase produced medium.

[0036] Specifically, a multiphase medium production simulation experiment was carried out through a gas-liquid circulation experimental system. The throttling pressure difference signal and the temperature drop amplitude before and after the experimental nozzle device (the size of which is consistent with the nozzle device in the target oil well) were measured when the multiphase medium with different gas mass contents was transported to the experimental nozzle device (the size of which is consistent with the size of the nozzle device in the target oil well). An experimental data set was obtained. Each set of data in the experimental data set included the mass flow rate of the liquid medium and the mass flow rate of the gas medium in the multiphase medium, the mean throttling pressure difference, the standard deviation of the throttling pressure difference and the temperature drop amplitude.

[0037] See also Figure 2 , which is a schematic diagram of a gas-liquid circulation experimental system, i.e., a multiphase medium extraction simulation device for oil wells, including a liquid phase supply device 21, a gas phase supply device 22, a mixer 23 and an oil nozzle connection device 24.

[0038] The nozzle connecting device 24 is used to connect the nozzle of the selected specification. The upstream first node and the downstream second node of the nozzle connecting device 24 are respectively connected to the two ends of the differential pressure transmitter 241, and the upstream third node and the downstream fourth node of the nozzle connecting device 24 are respectively connected to the two ends of the differential temperature transmitter 242.

[0039] The upstream end of the mixer 23 is connected to the downstream ends of the liquid phase supply device 21 and the gas phase supply device 22 , and the downstream end of the mixer 23 is connected to the upstream end of the nozzle connection device 24 .

[0040] A gas phase flow meter 221 , a thermometer 222 , and a pressure gauge 223 are connected to the gas phase supply device 22 , and a liquid phase flow meter 211 is connected to the liquid phase supply device 21 .

[0041] In some embodiments, the oil well multiphase medium production simulation equipment also includes a separator 25; the downstream end of the oil nozzle connecting device 24 is connected to the inlet of the separator 25; the gas phase outlet of the separator 25 is connected to the upstream end of the gas phase supply device 22, and the liquid phase outlet of the separator 25 is connected to the upstream end of the liquid phase supply device 21.

[0042] 1. Utilization Figure 2 The 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.

[0043] 1. Pressure difference and temperature drop signal test

[0044] Step 1.1: Open the valve of the gas phase supply device and adjust the gas phase flow rate to a fixed value Q g1After the gas fills the entire pipeline and the flow rate stabilizes for a period of time, the standard deviation of the pressure difference signal σ ΔP The characterization experiment collects the fluctuation of the pressure difference signal and records the average value of the pressure difference signal before and after the nozzle. Standard deviation of pressure difference signal (σ ΔP ) g1,0 And the temperature drop ΔT g1,0 , where the standard deviation of the pressure difference signal 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 , see formula 1 for details.

[0045]

[0046]

[0047] 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.

[0048] 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 Standard deviation of pressure difference signal (σ ΔP ) g+l1,1 And the temperature drop ΔT g+l1,1 .

[0049] 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 .

[0050] Step 1.4: 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 .

[0051] Step 1.5: 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 ΔT g2,0 . Gradually adjust the valve of the liquid supply system to increase the liquid flow rate and collect the second set of data.

[0052] Step 1.6: Gradually adjust the gas phase flow rate to the maximum value Q gm , and gradually adjust the liquid phase valve to increase the liquid phase flow 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 .

[0053] 2. Nozzle upstream pressure and temperature test

[0054] Read the temperature and pressure data of the thermometer and pressure gauge connected to the gas phase supply device for gas phase density calculation.

[0055]

[0056] In formula (3), 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.

[0057] 3. Liquid phase density test

[0058] By using the densitometer method, place the densitometer into the liquid to be tested, read the density directly, and test the liquid phase density ρ in the extracted medium. l .

[0059] 2. Optimization of sampling frequency of the measurement model establishment module: Preliminary experiments optimize the selection of the best pressure difference signal sampling frequency and sampling time

[0060] 1. Necessity of setting up sampling frequency optimization module

[0061] When throttling occurs, the phase fraction will affect the energy exchange and flow state between the gas and liquid phases, which in turn affects the stability of the differential pressure signal. The differential pressure signal will fluctuate over time. In order to obtain the most stable and reliable differential pressure signal, a preliminary experiment is first conducted to select the optimal frequency and time for collecting the differential pressure signal.

[0062] 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 collected data 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, or requiring too long an acquisition time series to supplement it. 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.

[0063] 2. Method for determining the optimal acquisition frequency and acquisition time

[0064] 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 ΔP The 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.

[0065] By establishing a module through the metering model, the signal acquisition frequency and acquisition time of the differential pressure transmitter are increased in turn, and the differential pressure signal collected at the current signal acquisition frequency and acquisition time is obtained from the differential pressure transmitter of the oil well multiphase medium production simulation equipment in real time. According to the current differential pressure signal, it is judged whether the change amplitude of the standard deviation of the throttling differential pressure fluctuation before and after the oil nozzle is less than the set amplitude, and the differential pressure fluctuation signal reaches a stable, complete and continuous state; if so, the current signal acquisition frequency and acquisition time are determined as the optimal signal acquisition frequency and acquisition time.

[0066] Preferably, the recommended acquisition time settings for the preliminary experiment are: 10s, 20s, 40s, 70s, 110s, 160s...

[0067] Recommended acquisition frequency settings: 50Hz, 80Hz, 120Hz, 170Hz, 230Hz...

[0068] Recommended acquisition time range: 10 to 160 seconds; acquisition frequency range: 50 to 230 Hz.

[0069] 3. Optimization of sampling frequency and sampling time based on field instruments

[0070] If it meets the needs of the site, query the upper limit of the frequency f of the differential pressure transmitter instrument signal data that can be allowed by the on-site communication system. max After that, according to the upper frequency limit, the experiment can be carried out according to The frequency is used as the optimal frequency to conduct experiments and select the appropriate sampling time. During the experiment, the sampling time is gradually increased (it is recommended to increase from 10s upwards), and the extracted pressure difference fluctuation signal will become more and more complete and effective. Until the fluctuation signal is stable and the fluctuation standard deviation value meets the minimum time t required for analysis min sequence as the optimal sampling time.

[0071] If the minimum time series exceeds 160s, increase the sampling frequency to Restart the experiment until the lowest time series is tested to be within 160s.

[0072] The laboratory tests the pressure difference signal fluctuation standard deviation σ according to the above standards ( ΔP , until σ ΔP The value remains stable and no longer changes with the increase of pressure difference signal acquisition frequency and the extension of acquisition time). Experiments are carried out to select the best sampling time for field testing.

[0073] The specific plan is as follows:

[0074] Table 1 Optimal signal acquisition frequency and acquisition time determination experiment recommended signal acquisition frequency and acquisition time setting table

[0075]

[0076]

[0077] According to the optimized optimal pressure difference signal sampling frequency and sampling time, the experimental data set is obtained through the above experimental process.

[0078] 3. Obtain the experimental dataset.

[0079] Step 3.1: Statistical experimental data set. Specifically, as an example only, the experimental gas-liquid flow matrix is ​​as follows:

[0080]

[0081] Then, the corresponding experimental setting gas mass fraction matrix is ​​as follows:

[0082]

[0083] 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:

[0084]

[0085] M g+l =M g +M l =ρ g Q g +M l (7)

[0086] In the formula, x g is the gas phase mass fraction of the gas-liquid two-phase medium in the experiment, dimensionless; ρ g is the gas phase density, kg / m 3 .

[0087] In formula (6), ρ g The calculation is performed using formula (3) based on the temperature and pressure data of the thermometer and pressure gauge connected to the gas phase supply device in the gas-liquid circulation system.

[0088] Step 3.2: Experimental test records hydraulic (differential pressure fluctuation value data set matrix B 1 ), thermal (temperature drop value data set matrix B 2 ) is as follows:

[0089]

[0090]

[0091] Step S12: A gas phase mass content determination model is established based on the experimental data set 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.

[0092] The embodiment of the present invention innovatively integrates the nozzle throttling pressure difference fluctuation standard deviation and temperature drop characteristics to invert and calculate the phase mass content.

[0093] Step 12.1: Establish a first functional relationship for characterizing the relationship between gas phase mass holdup and the standard deviation of throttling pressure difference.

[0094] 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.

[0095] The gas phase mass fraction is determined by the characteristic value of the pressure difference fluctuation:

[0096] 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.

[0097] Typically, a pressure difference signal fluctuation standard deviation σ ΔP and gas phase mass fraction x g For the corresponding relationship, see Figure 4 shown.

[0098] Therefore, based on the matrix A in the throttling experiment results in step 1, 2 and B 2 , establish the standard deviation of pressure difference signal fluctuation σ when reaching a stable state ΔP and gas phase mass fraction x g The functional relationship of .

[0099] σ ΔP =H(x g ) (10)

[0100] 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:

[0101] x g =H -1 (σ ΔP ) (11)

[0102] Through experiments, it is commonly used that a typical pressure difference signal fluctuation standard deviation σ ΔP and gas phase mass fraction x g The expression is formula (12), which is used as an example to illustrate the inversion calculation of gas phase mass content x g Method:

[0103]

[0104] 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.

[0105] By σ ΔP Inverse calculation x g :

[0106]

[0107] 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. The specific values ​​of the fitting parameters α, β and γ are obtained by fitting, and the first functional relationship for characterizing the relationship between the gas phase mass content and the throttling pressure difference standard deviation is obtained, namely, formula (13).

[0108] Step 12.2: Establish a second functional relationship for characterizing the relationship between gas phase mass content and temperature drop amplitude.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] Therefore, based on the matrix A in the throttling experiment results in step 1, 2 and B 2 , establish the functional relationship model between temperature drop characteristics and gas mass fraction:

[0113] ΔT=h(x g ) (14)

[0114] Where ΔT is the nozzle throttling temperature drop value collected during a certain set of experiments, ℃.

[0115] 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:

[0116] x g =h -1 (ΔT) (15)

[0117] 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 (16), which is used as an example to illustrate the inversion calculation of gas phase mass content x g Method:

[0118]

[0119] 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.

[0120] By σ ΔP Inverse calculation x g :

[0121]

[0122] Based on the experimental data set, a second data set containing multiple pairs of temperature drop amplitudes and gas mass content data is obtained. The specific values ​​of the fitting parameters p and q are obtained by fitting, and the second functional relationship for characterizing the relationship between the gas mass content and the temperature drop amplitude is obtained, namely, formula (17).

[0123] Step 12.3: Based on the first functional relationship and the second functional relationship, establish a gas phase mass content calculation function.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] x g =aH -1 (σ ΔP )+bh -1 (ΔT) (18)

[0128] When the gas mass holdup is low, H -1 (σ ΔP ) has a higher weight a than h -1 The weight b value of (ΔT) is lower than the weight b value when the gas mass content is high. The recommended values ​​of a and b are shown in Table 2:

[0129] Table 2 Recommended weights a and b for the inverse function relationship of the inverse calculation of gas mass holdup by comprehensively considering the hydraulic and thermal characteristics of the nozzle throttling

[0130] Gas phase mass holdup range Recommended a weight value Recommended b 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

[0131] Step 12.4: Establish other phase mass fraction calculation models.

[0132] Accordingly, the liquid mass content is;

[0133] x l =1-aH -1 (σ ΔP )-bh -1 (ΔT) (19)

[0134] According to the sampling of the liquid phase of the produced fluid, the water content analyzer tests the mass water content result m w , the mass fraction of water in the liquid phase x can be established w and oil phase mass fraction x o :

[0135] x w =m w [1-aH -1 (σ ΔP )-bh -1 (ΔT)] (20)

[0136] x o =(1-m w )[1-aH -1 (σ ΔP )-bh -1 (ΔT)] (21)

[0137] 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 (13) and equation (17): g :

[0138]

[0139] That is, based on the first functional relationship (Formula 13) and the second functional relationship (Formula 17), a gas phase mass content calculation function (Formula 22) is established.

[0140] The established liquid mass holdup determination model is:

[0141]

[0142] Water phase mass content x w Determine the model and oil phase mass fraction x o The determined models are:

[0143]

[0144]

[0145] The method for establishing a model for determining the phase content of a multiphase produced medium in an oil well provided in the first embodiment of the present invention obtains an experimental data set obtained by conducting a multiphase medium production simulation experiment through a gas-liquid circulation experimental system, and establishes a gas phase mass content determination model based on the experimental data set, which 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 phase mass content of the multiphase produced medium. The phase content determination model established based on this method can determine the gas phase mass content of the multiphase produced medium in the oil well on the basis of obtaining 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, and can accurately and conveniently measure the phase content of the multiphase produced medium in the oil well; and the ground process flow is simple, the metering cost is low, and the measurement accuracy is high, and it is still applicable to the multiphase produced medium of oil wells with a high gas-liquid ratio.

[0146] In some embodiments, the method may further include obtaining a new experimental data set through the above experimental steps, and using the new experimental data set to further correct the currently established gas phase mass content determination model to obtain higher prediction accuracy.

[0147] In some embodiments, the method may further include calculating the gas phase density in combination with the above formula (3), and establishing a gas phase volume fraction determination model based on the gas phase mass fraction determination model.

[0148] Based on the inventive concept of the present invention, an embodiment of the present invention further provides a method for determining phase fraction of multiphase produced medium in an oil well, comprising:

[0149] 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, the gas mass content of the multiphase production medium of the oil well is determined using the gas mass content determination model. The gas mass content determination model is established according to the above-mentioned method for establishing the phase content determination model of the multiphase production medium of the oil well.

[0150] Embodiment 2

[0151] Embodiment 2 of the present invention provides a method for determining the phase fraction of multiphase produced medium in an oil well, and the process thereof is as follows Figure 5 As shown, the following steps are included:

[0152] Step S51: According to the current values ​​of the first weight a and the second weight b, and 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 mass content of the multiphase produced medium of the oil well is determined by using the gas mass content determination model.

[0153] According to the estimated range of the gas phase mass content, the specific weight values ​​of a and b are determined by the above Table 2, and then the specific value of the gas phase mass content is determined by the gas phase mass content determination model, that is, the above formula (22).

[0154] Furthermore, the estimated range of the gas phase mass content can be estimated based on the specific value of the gas phase mass content determined last time; when the gas phase mass content is determined for the first time, it can be estimated by other field parameters.

[0155] Step S52: Obtain the liquid phase mass content of the multiphase produced medium according to the gas phase mass content of the multiphase produced medium.

[0156] Through the liquid phase mass content calculation model, the above formula (23), the liquid phase mass content of the multiphase produced medium is determined on the basis of the gas phase mass content.

[0157] Step S53: According to the water content and liquid mass content of the multiphase produced medium, the water mass content and the oil mass content in the multiphase produced medium are obtained.

[0158] The water content of the multiphase produced medium is measured using a water content analyzer. Based on the water content and liquid mass content of the multiphase produced medium, the water mass content in the multiphase produced medium is obtained by formula (24) (model for determining the water mass content), and the oil mass content in the multiphase produced medium is obtained by formula (25) (model for determining the oil mass content).

[0159] Step S54: According to the determined gas mass content, the values ​​of a and b are determined by the pre-established correspondence between the gas mass content and a and b, which is used to determine the gas mass content of the multiphase production medium of the target oil well at the next moment.

[0160] The corresponding relationship between the gas phase mass content and a and b is shown in Table 2 above.

[0161] The above steps may be executed cyclically at set intervals, or may be executed once each time new data (standard deviation of throttling pressure difference before and after the nozzle device in the target oil well) is acquired.

[0162] For example, as described in the above example, after experiment:

[0163] (1) Establish a model for determining gas phase mass holdup:

[0164] ① Determine the first functional relationship through the characteristic value of the pressure difference fluctuation:

[0165]

[0166] ② Through the nozzle throttling temperature drop value, establish the second functional relationship for calculating the gas mass fraction based on the temperature drop characteristics:

[0167]

[0168] ③Integrating the nozzle throttling pressure difference fluctuation and temperature drop characteristics, a gas phase mass holdup determination model is established for gas phase mass holdup calculation:

[0169]

[0170] Liquid mass holdup determination model:

[0171]

[0172] Take samples of the produced liquid phase every week and test the mass water content with a water analyzer. w , the water phase mass holdup determination model and the oil phase mass holdup determination model are established as follows:

[0173]

[0174]

[0175] In summary, the standard deviation of the nozzle throttling pressure difference fluctuation σ is known ΔP , and throttling temperature drop ΔT, test moisture content m w , substituting into the above formulas (28) to (31), the oil, gas and water three-phase fraction can be measured.

[0176] Measuring accuracy effect

[0177] Using formulas (28)-(31), the mass phase contents of oil, gas and water in the well were measured and compared with the actual data of field separation measurement. The average daily production of the single well was calculated, as shown in Table 3. It can be seen that the average deviation is within 2%, and the measurement effect meets the requirements.

[0178] Table 3 Comparison of metering effects

[0179] Measuring method Oil phase mass content Water phase mass content Gas mass holdup On-site separation metering 9.51％ 87.34％ 3.15％ Metrology Model System Metrology 9.68％ 87.11％ 3.21％ Relative error rate 1.75％ -0.26％ 1.87％

[0180] Based on the inventive concept of the present invention, an embodiment of the present invention further provides a device for establishing a model for determining the phase fraction of a multiphase produced medium in an oil well. The structure of the device is as follows: Figure 6 As shown, including:

[0181] The experimental data set acquisition module 61 is used to acquire the experimental data set obtained by the following method: a multiphase medium extraction simulation 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 corresponding to the multiphase medium with different gas phase mass content is transported to the experimental nozzle device are measured to obtain the experimental data set;

[0182] The gas phase mass content determination model establishment module 62 is used to establish a gas phase mass content determination model based on the experimental data set, which 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 phase mass content of the multiphase produced medium.

[0183] In some embodiments, the gas phase mass content determination model building module 62 is used to:

[0184] 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 determination model is established.

[0185] 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.

[0186] 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 method for establishing a model for determining the phase content of multiphase production media in oil wells or the above-mentioned method for determining the phase content of multiphase production media in oil wells can be implemented.

[0187] 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 method for establishing a model for determining the phase content of multiphase production media in oil wells mentioned above is implemented, or the method for determining the phase content of multiphase production media in oil wells mentioned above is implemented.

[0188] 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.

[0189] 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.

[0190] 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.

[0191] 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.

[0192] 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.

[0193] 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.

[0194] 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 establishing a model for determining phase fraction of multiphase produced medium in oil wells, characterized in that: include: The experimental data set is obtained by the following method: a multiphase medium extraction simulation 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 corresponding to the multiphase medium with different gas mass contents are transported to the experimental nozzle device are measured to obtain the experimental data set; A gas phase mass content determination model is established based on the experimental data set 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.

2. The method according to claim 1, characterized in that The step of establishing a gas phase mass content determination model based on the experimental data set includes: 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 determination model is established.

3. The method according to claim 2, characterized in that The first functional relationship is: In formula (1), x g is the gas phase mass fraction, σ ΔP is the standard deviation of the throttling pressure difference, α, β and γ are fitting parameters obtained through fitting.

4. The method according to claim 2, characterized in that: The second functional relationship is: In formula (2), x g is the gas mass fraction, ΔT is the temperature drop amplitude, p and q are fitting parameters obtained by fitting.

5. The method according to claim 2, characterized in that: The gas phase mass holdup determination model is: In formula (3), 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, a is the first weight, b is the second weight, and a+b=1.

6. A method for determining phase fraction of multiphase produced medium in an oil well, characterized in that: include: 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, the gas mass content of the multiphase produced medium of the oil well is determined using the gas mass content determination model, and the gas mass content determination model is established according to any one of the methods described in claims 1 to 5.

7. The method according to claim 6, characterized in that Also includes: The liquid phase mass content of the multiphase produced medium is obtained according to the gas phase mass content of the multiphase produced medium.

8. The method according to claim 7, characterized in that Also includes: The water phase mass content and / or the oil phase mass content in the multiphase production medium are obtained according to the water content of the multiphase production medium and the liquid phase mass content.

9. The method according to claim 6, characterized in that After determining the gas phase mass content of the multiphase produced medium of the oil well, the method further comprises: According to the determined gas mass content, the values ​​of a and b are determined through the pre-established correspondence between the gas mass content and a and b, which are used to determine the gas mass content of the multiphase production medium of the target oil well at the next moment.

10. A device for establishing a model for determining phase fraction of multiphase produced medium in oil wells, characterized in that: The device comprises: The experimental data set acquisition module is used to acquire the experimental data set obtained by the following method: a multiphase medium extraction simulation 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 corresponding to the multiphase medium with different gas mass content is transported to the experimental nozzle device are measured to obtain the experimental data set; The gas phase mass content determination model establishment module is used to establish a gas phase mass content determination model based on the experimental data set, and 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 phase mass content of the multiphase produced medium.

11. A computer storage medium, characterized in that: The computer storage medium stores computer executable instructions, which, when executed by a processor, implement the method for establishing a model for determining the phase content of multiphase produced media in oil wells as described in any one of claims 1 to 5, or implement the method for determining the phase content of multiphase produced media in oil wells as described in any one of claims 6 to 9.

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 method for establishing a model for determining the phase fraction of a multiphase produced medium in an oil well as described in any one of claims 1 to 5 is implemented, or the method for determining the phase fraction of a multiphase produced medium in an oil well as described in any one of claims 6 to 9 is implemented.

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