Inductance type cross-correlation flowmeter and fluid parameter calculation method

Abstract

The invention discloses an inductance type cross-correlation flowmeter and a fluid parameter calculation method, and the flowmeter comprises a multi-phase fluid flowing pipeline which is used for conveying to-be-measured fluid; the upstream inductive sensor is used for measuring a time sequence signal when the to-be-measured fluid flows through the upstream of the multi-phase fluid flowing pipeline and taking the time sequence signal as a first time sequence signal; the downstream inductive sensor is used for measuring a time sequence signal when the to-be-measured fluid flows through the downstream of the multi-phase fluid flowing pipeline and taking the time sequence signal as a second time sequence signal; and the signal processing circuit is used for processing and calculating the first time sequence signal and the second time sequence signal and outputting fluid parameters of the fluid to be measured. According to the inductance type cross-correlation flowmeter, the coil of the inductance sensor does not make direct contact with the fluid to be measured, the inductance type cross-correlation flowmeter is not affected by corrosion, scaling and oil contamination, no choked flow or movable parts exist, long-time reliable work can be achieved, the processing speed is high, precision is high, visual output can be achieved, and business personnel can rapidly understand fluid parameters of the fluid to be measured.

Description

Technical Field

[0001] This invention relates to the field of multiphase flow metering technology in oil fields and wells, and particularly to an inductive cross-correlation flowmeter and a method for calculating fluid parameters. Background Technology

[0002] Multiphase flow is widely present in various fields of production processes, including petroleum, chemical, and environmental protection. Parameter monitoring of multiphase flow is crucial for the rational development of resources, production safety, and industrial process control. Especially in crude oil extraction, oil and water are simultaneously produced from the oil layer in the well. To determine the crude oil production at each layer in the well, it is necessary to measure the flow rates of oil, gas, and water in the crude oil within the wellbore. However, due to the complexity of multiphase flow patterns, online measurement of the flow rates and water cut of each phase in oil-gas-water multiphase flow is extremely difficult.

[0003] Cross-correlation flowmeters measure flow rate based on the modulation of two sensor signals from a known distance by the disturbance of the flowing fluid. They utilize the intrinsic noise generated by the fluctuation of two-phase fluid components as a marker signal, and calculate the flow velocity through cross-correlation. Compared to other types of flowmeters, they are more suitable for measuring two-phase flows. Cross-correlation flowmeters offer a wide range of sensor options, and cross-correlation methods based on ultrasonic, capacitive, conductive, and electromagnetic sensors have been studied. Domestic oilfields generally use small-diameter wellbores, characterized by high water cut and low fluid production. Western companies' permanent intelligent wells, mostly based on fiber optic sensors, are designed for high flow rates and low water cut, but are not suitable for the fluid conditions in China. Furthermore, currently common flowmeters use an invasive structure, coming into contact with the fluid. Prolonged operation can lead to corrosion and scaling of the electrodes, and they are susceptible to contamination during operation, making them unsuitable for long-term installation inside oil wells. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in the aforementioned technologies. Therefore, the objective of this invention is to propose a non-invasive, flow-obstructing, highly reliable method for calculating the flow rate and fluid parameters of high-water-content oil-water two-phase flow operating within oil wells, thereby addressing the reliability problem of flowmeters to a certain extent.

[0005] To achieve the above objectives, the first aspect of the present invention provides an inductive cross-correlation flow meter, comprising: Multiphase fluid flow piping is used to transport the fluid to be tested; An upstream inductive sensor is used to measure the timing signal of the fluid under test flowing through the upstream of the multiphase fluid flow pipeline, and to serve as the first timing signal. A downstream inductive sensor is used to measure the timing signal of the fluid under test flowing through the downstream of the multiphase fluid flow pipeline, and to serve as a second timing signal. The signal processing circuit is used to process and calculate the first timing signal and the second timing signal, and output the fluid parameters of the fluid to be measured.

[0006] Preferably, both the upstream inductor sensor and the downstream inductor sensor are disposed on the outside of the multiphase fluid flow pipeline, and the axial distance between the upstream inductor sensor and the downstream inductor sensor is determined by the diameter of the multiphase fluid flow pipeline.

[0007] Preferably, the axial distance between the upstream inductor sensor and the downstream inductor sensor is in the range of 0.5 to 2 times the diameter of the multiphase fluid flow pipeline.

[0008] Preferably, a high-permeability magnet is provided on the outside of the multiphase fluid flow pipeline.

[0009] Preferably, the upstream inductor sensor is nested outside the high permeability magnet disposed at the upstream end of the multiphase fluid flow pipeline, and the downstream inductor sensor is nested outside the high permeability magnet disposed at the downstream end of the multiphase fluid flow pipeline.

[0010] Preferably, the upstream inductor sensor and the downstream inductor sensor have the same structure.

[0011] Preferably, the upstream inductive sensor consists of an excitation circuit and a coil.

[0012] Preferably, the signal processing circuit includes: Signal conditioning circuitry, cross-correlation processor, and function parser, among which, The input terminal of the signal conditioning circuit is connected to the output terminal of the upstream inductor sensor and the output terminal of the downstream inductor sensor, respectively, and the output terminal of the signal conditioning circuit is connected to the input terminal of the cross-correlation processor. The input of the function parser is connected to the output of the cross-correlation processor; The signal conditioning circuit is used to perform signal preprocessing on the first timing signal and the second timing signal, including signal amplification and signal filtering. The cross-correlation processor is used to perform cross-correlation operations on the preprocessed first time-series signal and the preprocessed second time-series signal to obtain a cross-correlation function; The function parser is used to parse the cross-correlation function and output the fluid parameters of the fluid to be measured based on the parsing result; the fluid parameters include the actual flow rate of the fluid to be measured and the content of a specific fluid in the fluid to be measured.

[0013] Preferably, when the function parser outputs the fluid parameters of the fluid to be measured based on the parsing result, the method further includes: visualizing the fluid parameters.

[0014] A second aspect of the present invention provides a method for calculating fluid parameters, comprising: The fluid to be tested is transported using a multiphase fluid flow pipeline; The timing signal of the fluid under test flowing through the upstream of the multiphase fluid flow pipeline is measured using an upstream inductive sensor and used as the first timing signal; The timing signal of the fluid under test flowing downstream of the multiphase fluid flow pipeline is measured using a downstream inductive sensor and used as a second timing signal. The first timing signal and the second timing signal are processed and calculated using a signal processing circuit, and the fluid parameters of the fluid to be tested are output; the fluid parameters include the actual flow rate of the fluid to be tested and the content of a specific fluid in the fluid to be tested.

[0015] Preferably, the signal processing circuit processes and calculates the first timing signal and the second timing signal, and outputs the flow rate of the fluid to be measured, including: The first timing signal and the second timing signal are respectively subjected to signal preprocessing, including signal amplification and signal filtering; A cross-correlation operation is performed on the preprocessed first time-series signal and the preprocessed second time-series signal to obtain the cross-correlation function; Obtain the peak value of the dependent variable of the cross-correlation function and the value of the independent variable corresponding to the peak value of the dependent variable, and use the value of the independent variable as the transit time; The axial distance between the upstream inductor sensor measuring the first timing signal and the downstream inductor sensor measuring the second timing signal in the multiphase fluid flow pipeline is obtained. The ratio of the axial distance to the transit time is used as the cross-correlation velocity; The product of the cross-sectional area of ​​the multiphase fluid flow pipeline and the cross-correlation velocity is taken as the correlation flow rate of the fluid to be measured. The actual flow rate of the fluid to be measured is calculated based on the relevant flow rate and the preset relevant flow rate-actual flow rate relationship.

[0016] Preferably, the first timing signal and the second timing signal are processed and calculated using a signal processing circuit to determine the content of a specific fluid in the fluid to be measured, including: The preprocessed first timing signal is added to the preprocessed second timing signal to obtain the third timing signal; Obtain the signal amplitude of the third timing signal; The content of the specific fluid is calculated based on the signal amplitude and the preset relationship between signal amplitude and specific fluid content.

[0017] Preferably, the preset relevant flow rate-actual flow rate relationship and the preset signal amplitude-specific fluid content relationship are determined by the calibration results of the flow meter.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. The inductive sensor coil of the inductive cross-correlation flowmeter provided by this invention does not directly contact the fluid being measured, is unaffected by corrosion, scaling and oil, has no flow obstruction or moving parts, and can work reliably for a long time.

[0019] 2. The inductive cross-correlation flowmeter provided in this invention can effectively measure the fluid parameters of multiphase flow, and the measurement results are accurate and reliable.

[0020] 3. The flow meter and fluid parameter calculation method provided in this invention can process the signal of the flow meter inductive sensor with fast processing speed, high accuracy, and visualization, allowing business personnel to quickly understand the fluid parameters of the fluid to be measured.

[0021] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of an inductive cross-correlation flowmeter provided in an embodiment of the present invention; Figure 2 This is a partial enlarged view of the inductive cross-correlation flowmeter provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the flow parameter calculation method given in an embodiment of the present invention; Figure 4 The following is a waveform diagram of the upstream and downstream timing signals given in an embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the linear relationship between the moisture content measured by the inductive sensor and the standard moisture content, as given in an embodiment of the present invention.

[0024] Reference numerals: 1. Multiphase fluid flow pipeline; 2. High permeability magnet; 3. Upstream inductive sensor coil; 4. Downstream inductive sensor coil. Detailed Implementation

[0025] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0026] like Figure 1 As shown, the present invention provides an inductive cross-correlation flow meter, comprising: Multiphase fluid flow piping is used to transport the fluid to be tested; An upstream inductive sensor is used to measure the timing signal of the fluid under test flowing through the upstream of the multiphase fluid flow pipeline, and to serve as the first timing signal. A downstream inductive sensor is used to measure the timing signal of the fluid under test flowing through the downstream of the multiphase fluid flow pipeline, and to serve as a second timing signal. The signal processing circuit is used to process and calculate the first timing signal and the second timing signal, and output the fluid parameters of the fluid to be measured.

[0027] In some embodiments of the present invention, the signal processing circuit includes a signal conditioning circuit, a cross-correlation processor, and a function resolver. The signal conditioning circuit includes an excitation circuit, an amplification circuit, a filtering circuit, and an A / D conversion circuit. The excitation circuit applies an excitation signal to the coil, and the sensor output signal generates eddy currents due to the electromagnetic induction effect of the fluid, thus being sensitive to the fluid water content. By superimposing the signals from the two sensors, water content information can be obtained; by performing cross-correlation processing on the two signals, a cross-correlation function can be obtained, and the function resolver is used to process the cross-correlation function to obtain the flow rate parameter. In some embodiments of the present invention, the function resolver is composed of a deep learning model that has been extensively trained.

[0028] Figure 2 This is a partially enlarged view of the cross-correlation flowmeter and pipeline in some embodiments of the present invention, including: a multiphase fluid flow pipeline 1, a high-permeability magnet 2, an upstream inductive sensor coil 3, and a downstream inductive sensor coil 4. The multiphase fluid flow pipeline 1 is externally wrapped with the high-permeability magnet 2. The upstream inductive sensor coil 3 and the downstream inductive sensor coil 4 are externally mounted on the high-permeability magnet 2. The distance between the upstream inductive sensor coil 3 and the downstream inductive sensor coil 4 is L. The fluid to be measured is a high-water-content oil-water two-phase flow. The cross-correlation flowmeter for measuring the flow rate parameter of this fluid includes installing the upstream and downstream inductive sensors along the flow direction on an insulating pipeline carrying the high-water-content oil-water two-phase flow. The axial distance between the two inductive sensors is L. The range of L is selected from 0.5 to 2 times the pipe diameter. Within this range, the distance L can ensure good correlation between the two signals, thus accurately obtaining the flow velocity of the oil-water two-phase flow.

[0029] In other embodiments of the present invention, the signal conditioning circuit includes an excitation circuit, an amplification circuit, a bandpass filter circuit, and an A / D conversion circuit. The excitation circuit applies a high-frequency excitation signal with a certain amplitude of 1MHz current to the coil, and the amplification circuit amplifies the voltage signal output by the inductor sensor. The two random fluctuation signals output by the upstream and downstream inductor sensors are processed by the signal conditioning circuit to extract the flow noise signals x(t) and y(t) of the measured fluid. Because the signal directly output from the coil is relatively weak and contains high-frequency interference signals, it is necessary to filter this signal to remove irrelevant interference signals. A bandpass filter circuit is used to filter the amplified signal, with a frequency range of 10Hz to 500Hz. The filtered signal is then digitized by the A / D conversion circuit. The sensor output signal generates eddy currents due to the electromagnetic induction effect within the fluid, and the sensor output signal is sensitive to the fluid conductivity, and therefore sensitive to the water content. After calibration on a multiphase flow device, the water content Kw can be measured based on the signal output amplitude. The cross-correlation processor performs cross-correlation processing on the fluctuating noise signals of the two inductive sensors to calculate the transit time τ of the fluid passing through the upstream and downstream sensors, thereby obtaining the average flow velocity V. In this way, an integrated sensor can be used to simultaneously measure the flow rate and water content of two-phase flow.

[0030] like Figure 3 As shown, this invention provides a method for calculating multiphase flow parameters, including: The fluid to be tested is transported using a multiphase fluid flow pipeline; The timing signal of the fluid under test flowing through the upstream of the multiphase fluid flow pipeline is measured using an upstream inductive sensor and used as the first timing signal; The timing signal of the fluid under test flowing downstream of the multiphase fluid flow pipeline is measured using a downstream inductive sensor and used as a second timing signal. The first timing signal and the second timing signal are processed and calculated using a signal processing circuit, and the fluid parameters of the fluid to be tested are output; the fluid parameters include the actual flow rate of the fluid to be tested and the content of a specific fluid in the fluid to be tested.

[0031] In some embodiments of the present invention, the method for calculating multiphase fluid flow parameters includes: The fluid passes through an upstream inductive sensor and then through a downstream inductive sensor with the same structure. A time-series signal reflecting the flow of the measured fluid is extracted from the upstream inductive sensor as x(t), and a time-series signal reflecting the flow of the measured fluid is extracted from the downstream sensor as y(t). These two signals are correlated. A signal processor is used to perform cross-correlation on two time series signals x(t) and y(t). The formula for calculating the cross-correlation function is as follows:

[0032] Where Rxy(τ) represents the cross-correlation function of the measured signals x(t) and y(t), x(t) represents the random signal of the upstream measured signal with respect to time, y(t) represents the random signal of the downstream measured signal with respect to time, and τ is the integration variable; Perform a cross-correlation operation on the measured signals x(t) and y(t) to obtain the cross-correlation function Rxy(τ). Read the position of the peak value of the Rxy(τ) function on the τ axis, which is the transit time τ0. The physical meaning of the transit time is the time it takes for the fluid under test to flow from the upstream inductive sensor to the downstream inductive sensor. Then, the cross-correlated velocity V is obtained using the transit time τ0, as shown in the formula:

[0033] After obtaining the cross-correlation velocity, the total flow rate Q of the oil-water two-phase flow is calculated using the cross-correlation velocity V. The specific calculation formula is as follows:

[0034] Equation A represents the cross-sectional area of ​​the fluid pipe. After calibration on the oil-water two-phase flow experimental setup, the relationship between the relevant flow rate Q and the standard flow rate is established, allowing the actual measured flow rate to be estimated based on the measured signal. The amplitude of the summed signal (x(t) and y(t)) is related to the measured water content. After calibration on the oil-water two-phase flow experimental device, the relationship between the summed signal amplitude and the standard water content is established, and the actual water content can be estimated based on the measured signal.

[0035] In other embodiments of the invention, the flow pipe diameter is 20 mm, the sensor length is 15 mm, the distance between the two inductive sensors is 30 mm, the excitation frequency is 1 MHz, and the length of the acquired signal sample is 2048. In the multiphase flow experimental setup, the total oil-water flow rate is 60 m³ / s. 3 / d, under conditions of 80% moisture content, the obtained two signal waveforms and the cross-correlation moisture content waveform are as follows: Figure 4 As shown. The calculated transit time is 10ms, and the calculated flow rate is 59.6m³. 3 / d. The sum of the output data from the two inductive sensors was collected, and the water content was read as 82.2% using a moisture content chart. The relationship between the measured water fraction (vertical axis in the figure) and the standard water fraction (horizontal axis in the figure) obtained on the multiphase flow experimental setup is as follows: Figure 5 As shown, the two have a good linear relationship.

[0036] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An inductance-based cross-correlation flow meter characterized by, The application relates to a multi-phase fluid flow pipeline for conveying a fluid to be measured, an upstream inductive sensor for measuring a time sequence signal of the fluid to be measured flowing upstream of the multi-phase fluid flow pipeline as a first time sequence signal, a downstream inductive sensor for measuring a time sequence signal of the fluid to be measured flowing downstream of the multi-phase fluid flow pipeline as a second time sequence signal, and a signal processing circuit for processing and calculating the first time sequence signal and the second time sequence signal and outputting a fluid parameter of the fluid to be measured. The upstream inductive sensor and the downstream inductive sensor are arranged outside the multi-phase fluid flow pipeline, and the axial spacing of the upstream inductive sensor and the downstream inductive sensor is determined by the pipe diameter of the multi-phase fluid flow pipeline. The axial spacing of the upstream inductive sensor and the downstream inductive sensor ranges from 0.5 times to 2 times the pipe diameter of the multi-phase fluid flow pipeline. The outside of the multi-phase fluid flow pipeline is provided with high magnetic permeability magnetic steel. The upstream inductive sensor is nested outside the high magnetic permeability magnetic steel arranged at the upstream end of the multi-phase fluid flow pipeline, and the downstream inductive sensor is nested outside the high magnetic permeability magnetic steel arranged at the downstream end of the multi-phase fluid flow pipeline.

2. The inductance mutual correlation flow meter of claim 1 wherein, The upstream inductive sensor and the downstream inductive sensor have the same structure.

3. The inductance mutual correlation flow meter of claim 2 wherein, The upstream inductive sensor is composed of an excitation circuit and a coil.

4. The inductance mutual correlation flow meter of claim 1 wherein, The signal processing circuit comprises a signal conditioning circuit, a cross-correlation processor and a function resolver.

5. The inductance mutual correlation flow meter of claim 4 wherein, The input ends of the signal conditioning circuit are connected with the output ends of the upstream inductive sensor and the downstream inductive sensor respectively, and the output end of the signal conditioning circuit is connected with the input end of the cross-correlation processor.

6. The inductance mutual correlation flow meter of claim 1 wherein, The input end of the function resolver is connected with the output end of the cross-correlation processor.

7. The inductance mutual correlation flow meter of claim 6 wherein, The signal conditioning circuit is used for pre-processing the first time sequence signal and the second time sequence signal, including signal amplification and signal filtering.

8. The inductively coupled mutual correlation flow meter of any one of claims 1-7, wherein, The cross-correlation processor is used for cross-correlation calculation of the pre-processed first time sequence signal and the pre-processed second time sequence signal to obtain a cross-correlation function. The function resolver is used for analyzing the cross-correlation function and outputting the fluid parameter of the fluid to be measured according to the analysis result; the fluid parameter includes the actual flow of the fluid to be measured and the content of a specific fluid in the fluid to be measured. When the function resolver outputs the fluid parameter of the fluid to be measured according to the analysis result, the fluid parameter is further subjected to visual processing. The application relates to a multi-phase fluid flow pipeline for conveying a fluid to be measured, an upstream inductive sensor for measuring a time sequence signal of the fluid to be measured flowing upstream of the multi-phase fluid flow pipeline as a first time sequence signal, a downstream inductive sensor for measuring a time sequence signal of the fluid to be measured flowing downstream of the multi-phase fluid flow pipeline as a second time sequence signal, and a signal processing circuit for processing and calculating the first time sequence signal and the second time sequence signal and outputting a fluid parameter of the fluid to be measured. ​ ​ ​ 9. The inductance mutual correlation flow meter of claim 8 wherein, ​ 10. A method of fluid parameter calculation, characterized by, ​ ​ ​ ​ ​ 11. The fluid parameter calculation method of claim 10 wherein, The first time sequence signal and the second time sequence signal are processed and operated by a signal processing circuit, and a flow rate of the fluid to be measured is output, comprising: respectively, the first time sequence signal and the second time sequence signal are preprocessed including signal amplification and signal filtering; the first time sequence signal and the second time sequence signal after preprocessing are cross-correlation operated to obtain a cross-correlation function; obtain the dependent variable peak value of the cross-correlation function and the independent variable value corresponding to the dependent variable peak value, and take the independent variable value as the transit time; obtain the axial distance of the upstream inductance sensor for measuring the first time sequence signal and the downstream inductance sensor for measuring the second time sequence signal in the multiphase fluid flow pipeline; the ratio of the axial distance and the transit time is taken as the cross-correlation flow rate; the product of the pipeline cross-sectional area of the multiphase fluid flow pipeline and the cross-correlation flow rate is taken as the correlation flow rate of the fluid to be measured; according to the correlation flow rate and the preset correlation flow rate-actual flow rate relationship, the actual flow rate of the fluid to be measured is calculated.

12. The fluid parameter calculation method of claim 11, wherein, The first time sequence signal and the second time sequence signal are processed and operated by a signal processing circuit, and the content of a specific fluid in the fluid to be measured is output, comprising: the first time sequence signal and the second time sequence signal after preprocessing are added to obtain a third time sequence signal; obtain the signal amplitude of the third time sequence signal; according to the signal amplitude and the preset signal amplitude-specific fluid content relationship, the content of the specific fluid is calculated.

13. The fluid parameter calculation method of claim 12, wherein, The preset correlation flow rate-actual flow rate relationship and the preset signal amplitude-specific fluid content relationship are determined by the calibration result of the flowmeter.

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