CN110763704A - Microwave Wire mesh-based oil-water two-phase flow water content measuring system - Google Patents

Abstract

The invention provides a water content measurement system for oil-water two-phase flow based on microwave wire mesh, the system includes a wire mesh sensor, the wire mesh sensor includes two layers of electrode wires, each layer of electrode wires is arranged in parallel, and the two layers of electrodes The wires are arranged vertically to form a grid structure; one layer of electrode wires is a signal sending end, and the other layer of electrode wires is a signal receiving end; the signal sending end is connected with a microwave signal generating system, and the signal receiving end is connected with a The signal acquisition system, the microwave signal generation system and the signal acquisition system are all connected with a central control system. Based on the microwave wire mesh sensor, a non-contact measurement method is adopted. Compared with the contact measurement of the conductivity method, the contamination of the electrode will not significantly affect the measurement accuracy of the water holdup.

Description

Oil-water two-phase flow water content measurement system based on microwave wire mesh

technical field

The invention relates to the technical field of measurement, in particular to a water content measurement system for oil-water two-phase flow based on microwave wire mesh.

Background technique

The water content of crude oil is an important parameter in the oil exploration and petrochemical industries, and it is the key data in oilfield production and oil product trading. my country has successively developed a variety of different forms of crude oil water content testers. Although they have achieved certain results after being put into use in oil fields, their stability, accuracy, real-time performance, reliability and cost are limited due to technological and technical level reasons. It is difficult to adapt to the actual production requirements of high water-cut oilfields in my country. Under this premise, it is particularly important to measure the water content of pipelines in the process of oil extraction through new sensors.

SUMMARY OF THE INVENTION

In view of this, the present invention provides a water content measurement system for oil-water two-phase flow based on microwave wire mesh.

The invention provides a water content measurement system for oil-water two-phase flow based on microwave wire mesh, which is characterized in that: the system includes a wire mesh sensor, the wire mesh sensor includes two layers of electrode wires, and each layer of electrode wires is arranged in parallel, And the two layers of electrode wires are vertically arranged to form a grid structure; one layer of electrode wires is the signal sending end, and the other layer of electrode wires is the signal receiving end;

The signal receiving end is connected with a microwave signal generating system, the signal transmitting end is connected with a signal collecting system, and both the microwave signal generating system and the signal collecting system are connected with a central control system.

Preferably, the electrode wire is made of 0.2mm copper enameled wire.

Preferably, the wire mesh sensor adopts an 8×8 structure, and the layer spacing is 1.6mm, and the distance between adjacent electrode wires is 7.14mm.

Preferably, the microwave signal generation system includes a microwave signal generation module, one end of the microwave signal generation module is connected to the central control system, receives control instructions from the central control system, and generates microwave signals; the other end is connected to the central control system. The signal sending end is connected, and a microwave excitation signal is applied to the signal sending end of the wire mesh sensor.

Preferably, a microwave signal filtering module is connected between the microwave signal generating module and the signal transmitting end of the wire mesh sensor for filtering the microwave signal.

Preferably, the microwave signal generating system further comprises a microwave channel switching module, an input end of the microwave channel switching module is connected to the microwave signal generating module, and receives microwave signals of different frequencies sent by the microwave signal generating module, The filtering channel is switched according to different input frequencies; the output end is connected with the microwave signal filtering module.

Preferably, the microwave signal generating system is further provided with a power divider, the input end of the power divider is connected to the output end of the microwave signal filtering module, and the output end of the power divider is respectively connected with the Wiremesh sensor The transmitter is connected with the microwave signal comparison module in the signal acquisition system.

Preferably, the signal acquisition system includes a microwave signal comparison module, and the input end of the microwave signal comparison module is respectively connected to one of the signal receiving end of the wire mesh sensor and the power divider of the microwave signal generating system.

Preferably, the signal acquisition system further includes a microwave signal acquisition module, an input end of the microwave signal acquisition module is connected to an output end of the microwave signal comparison module, and an output end of the microwave signal acquisition module is connected to a computer device, The microwave signal acquisition module is controlled by the central control module.

Preferably, each group of signal sending ends is connected with a sending end control switch, each group of signal receiving ends is connected with a receiving end control switch, the microwave signal generation system is connected with the microwave signal sending end through the sending end control switch, and the signal The receiving end is connected with the signal acquisition system through the receiving end control switch; the sending end control switch and the receiving end control switch are both connected with the central control system.

The advantages and positive effects of the present invention are as follows: First, a non-contact measurement method is adopted based on the microwave Wire mesh sensor. Compared with the conductometric contact measurement, the contamination of the electrode will not affect the water holdup measurement accuracy. Second, the multiphase flow flows through the wire mesh sensor, and the computer equipment is able to collect the data from the receiving electrode and generate an image of the cross-sectional distribution based on the relative permittivity values of the different flow phases. The spatial resolution of microwave-based wire mesh sensors is equal to the distance between two adjacent electrodes. According to specific needs, the diameter of the tube can be reduced and the number of electrodes can be increased to improve the spatial resolution. Thirdly, the microwave-based wire mesh sensor uses microwave as the excitation signal, and the excitation frequency is higher than that of the conductance and capacitance types, which provides more room for improvement in the sampling rate, and chooses better acquisition circuits and acquisition equipment. , which can increase the number of frames collected per unit time of the cross-sectional distribution image.

Description of drawings

Figure 1 is a schematic diagram of the structure of an oil-water two-phase flow water content measurement system based on microwave wire mesh;

Figure 2 is a schematic diagram of the circuit structure of the oil-water two-phase flow water content measurement system based on microwave wire mesh;

FIG. 3 is a schematic diagram of the circuit structure of another embodiment of the water content measurement system for oil-water two-phase flow based on microwave wire mesh.

Detailed ways

For a better understanding of the present invention, the present invention will be further described below with reference to specific embodiments and accompanying drawings.

As shown in FIG. 1, the present invention provides a water content measurement system for oil-water two-phase flow based on microwave wire mesh, the system includes a wire mesh sensor 10, the wire mesh sensor 10 includes two layers of electrode wires, each layer of electrodes The wires are arranged in parallel, and the two layers of electrode wires are vertically arranged to form a grid structure; one layer of electrode wires is the signal sending end 102, and the other layer of electrode wires is the signal receiving end 101;

The signal receiving end 101 is connected with a signal receiving system, the signal transmitting end is connected with a microwave signal generating system, and both the microwave signal generating system and the signal collecting system are connected with a central control system.

Wire mesh is a metal mesh sensor for measuring water content in crude oil, first proposed by Johnson ID. in 1987. By measuring the response signal of the wire mesh sensor, the conductivity distribution and permittivity distribution of the wire mesh are obtained, and then tomography is performed to obtain the oil-water volume fraction and oil bubble shape.

At present, there are two main types of wire mesh: capacitive and conductive. Traditional conductometrics have limitations in trapping, and the high diversity of the dispersed phase severely affects the measurement. Hammer et al. used the capacitance method for measurement. The capacitance method uses the average method of all mixed fluids in the pipeline to measure, which is suitable for the complex flow pattern of two-phase flow under working conditions. However, the capacitance method has a small range and poor adjustability, and is only suitable for oil fields with a water cut below 84%. And the contamination of oil and water has a great influence on the measurement accuracy.

Microwave refers to electromagnetic waves with a frequency of 300MHz to 300GHz. In recent years, microwave technology has been widely used not only in the field of communication, but also in imaging technology and measurement technology. As a non-contact measurement method, the application of microwave method in two-phase flow and binary solution has attracted attention. Because the microwave method is sensitive to changes in the dielectric constant of the fluid, it is often used to detect the type of liquid, especially various binary solutions that are not easy to detect directly.

The invention combines microwave technology with wire mesh sensing technology. Microwave method is a dielectric measurement method at high frequency. For oil-water two-phase flow, due to the difference in dielectric constant between oil-water phases, oil-water mixtures with different ratios are sensitive to microwaves. The absorption of the signal is different, according to which the phase holdup measurement of the oil-water two-phase flow can be realized. At the microwave frequency, the water holdup of the oil-water mixture can be obtained according to the phase shift and amplitude attenuation of the microwave signal after passing through the oil-water mixture.

A wire mesh sensor consists of two layers of parallel electrode wires that are perpendicular to each other and are closely spaced to form a sensor network. In the actual application process, the wire mesh sensor is installed on the section perpendicular to the flow direction of the two-phase flow in the pipeline, and the oil-water two-phase flow will pass through the mesh surface vertically.

In a specific embodiment of the present invention, the electrode wire is made of 0.2mm copper enameled wire, the Wiremesh sensor adopts an 8×8 structure, and the layer spacing is 1.6mm, and the distance between adjacent electrode wires is 7.14mm. The electrode wire arranged vertically is a signal sending end, and the electrode wire arranged horizontally is a signal receiving end; the signal sending end is connected to the microwave signal generating system, and a microwave excitation signal is applied to the sending end electrode. The signal receiving end is connected to the signal receiving system, and outputs a signal that can reflect the state of the two-phase flow. The wire mesh sensor is based on the instantaneous conductivity of the two-phase flow mixture. The microwave signal is sent through the signal transmitting end, and then the signal receiving end outputs the electrical signal. The signal acquisition system analyzes and judges the electrical signal, instead of the integration of the binary signal to realize the data. collection.

First, the microwave-based Wire mesh sensor uses a non-contact measurement method. Compared with the conductometric contact measurement, the contamination of the electrode will not affect the water holdup measurement accuracy.

We take the oil-water two-phase flow measurement as an example. In traditional conductometric contact measurement methods, the electrodes need to be in direct contact with the solution. When studying the flow of oil and water in the pipe, the difference between the resistivity and relative permittivity of the oil and water phases is used to distinguish the two mediums of oil and water. In the oil-water two-phase flow, the flowing oil droplets often contaminate the sensor electrodes, affecting the subsequent measurement accuracy, and the metal sensor is prone to scaling, surface corrosion, blockage or damage, which also affects the measurement accuracy. certain error.

The microwave method uses the difference in dielectric constant between oil and water phases, and the absorption of microwaves by oil and water is different. According to the changes in the amplitude and phase of the microwave signal after flowing through the oil-water mixture, the water holding capacity of the mixed solution is judged. The microwave-based wire mesh sensor uses high-quality enameled wire as the electrode material, which is in direct contact with the oil-water mixture as an insulating outer surface that is not easy to contaminate. Therefore, it can effectively reduce the impact of electrode contamination and other issues on the measurement. At the same time, the microwave transmission performance is good, and it is not easily interfered by other external factors during the transmission process, which is suitable for the analysis of aqueous solutions.

Second, the multiphase flow flows through the wire mesh sensor, and the computer equipment is able to collect the data from the receiving electrode and generate an image of the cross-sectional distribution based on the relative permittivity values of the different flow phases. The spatial resolution of microwave-based wire mesh sensors is equal to the distance between two adjacent electrodes. The diameter of the tube can be reduced and the number of electrodes can be increased to improve the spatial resolution according to specific needs.

Thirdly, the microwave-based wire mesh sensor uses microwave as the excitation signal, and the excitation frequency is higher than that of the conductance and capacitance types, which provides more room for improvement in the sampling rate, and chooses better acquisition circuits and acquisition equipment. , which can increase the number of frames collected per unit time of the cross-sectional distribution image.

Further, as shown in FIG. 2 , the microwave signal generation system includes a microwave signal generation module, and one end of the microwave signal generation module is connected to the central control system, receives control instructions from the central control system, and generates microwave signals ; The other end is connected with the signal sending end, and sends microwave signals to the signal sending end of the Wire mesh sensor.

In a preferred embodiment of the present invention, PXI-5671 is used as the microwave signal generation module; the PXI-5671 vector signal generator has the function of quadrature digital up-conversion, which reduces the time for waveform download and signal generation, and is a general-purpose Vector signal generator to generate standard modulation formats such as AM, FM, PM, ASK, FSK, MSK, GMSK, PSK, QPSK, PAM and QAM. It can generate signals of any frequency within 50MHz to 2.7GHz. Using PXI-5671 as a microwave signal generation module can ensure high-quality excitation signals.

Further, because the microwave signal output by the microwave signal generation module has a small amount of harmonics, a microwave signal filter module is connected between the microwave signal generation module and the signal receiving end of the wire mesh sensor, which is used to realize the detection of microwave signals. filter.

Further, since the filtering channel needs to be selected according to different input frequencies, a microwave channel switching module needs to be set. The input end of the microwave channel switching module is connected to the microwave signal generating module, receives microwave signals of different frequencies sent by the microwave signal generating module, and switches the filtering channel according to different input frequencies; the output end is connected to the microwave signal generating module. Signal filter module connection.

In a preferred embodiment of the present invention, the microwave channel switching module selects HMC241QS16. HMC241QS16 is a four-channel microwave channel switching chip, covering a frequency range of 0 ~ 3500MHz, and has good channel isolation performance, isolation loss is below 0.5dB; the microwave signal filtering module uses LFCN series low-pass filter bank, through Switching of different microwave channels, filtering microwave signals of different frequencies, has the excellent characteristics of low attenuation and small size.

Further, the present invention is also provided with a power divider, the input end of the power divider is connected with the output end of the microwave signal filtering module, and the output end of the power divider is respectively connected with the signal transmission of the wire mesh sensor. The terminal is connected to the signal acquisition system, the power divider divides the microwave signal into two paths, one is connected to the Wire mesh sensor as the measurement input signal, and the output signal of the Wire mesh sensor is connected to the signal acquisition system; and the power distribution The other channel of the device is used as a comparison signal, and is connected to the signal acquisition system, and the signal acquisition system compares the two channels of signals.

In the embodiment of the present invention, the microwave signal generating system includes: a microwave signal generating module, a microwave channel switching module, a microwave signal filtering module and a power distributor, and the input end of the microwave signal generating module is connected to the central control system. connected to receive the control instructions of the central control system to generate microwave signals; the input end of the microwave channel switching module is connected to the output end of the microwave signal generation module, receives the microwave signal of the microwave signal generation module, and outputs Microwaves with a specified frequency; the input end of the microwave signal filtering module is connected to the output end of the microwave channel switching module, receives microwave signals of different frequencies output by the microwave channel switching module, and analyzes the harmonics in the microwave signal. filter; the input end of the power divider is connected to the output end of the microwave signal filtering module, and the output end of the power divider is respectively connected to the signal transmitting end of the wire mesh sensor and the signal acquisition system.

In the embodiment of the present invention, the central control system controls the microwave signal generating module to generate microwave signals of a specified frequency, and according to different signal frequencies, the microwave channel switching module selects different microwave channels, and uses different The microwave channel transmits the microwave signal to the microwave signal filtering module. Since the microwave signal output by the microwave signal generating module has a small amount of harmonics, the microwave signal filtering module needs to filter the microwave signals of different frequencies; after filtering The microwave signal is transmitted to the power divider, and the power divider divides the microwave signal into two channels, one of which is connected to the Wire mesh sensor as a measurement input signal, and the output signal of the Wire mesh sensor is connected to the signal acquisition system; and The other channel of the power divider is used as a comparison signal and is connected to the signal acquisition system, and the signal acquisition system compares the two channels of signals.

Further, the signal acquisition system includes a microwave signal comparison module and a voltage acquisition module, and the input end of the microwave signal comparison module is respectively connected to the signal receiving end of the wire mesh sensor and the power divider of the microwave signal generating system. One of them is connected to receive a measurement signal from the wire mesh sensor and a comparison signal from the power divider of the microwave signal generation system, and compare the measurement signal with the comparison signal, and in the form of voltage, phase Two characteristic parameters of amplitude and amplitude are output; the input end of the voltage acquisition module is connected to the output end of the microwave signal comparison module, the output end of the voltage acquisition module is connected to the central control module, and the voltage acquisition module is responsible for The voltage output by the microwave signal comparison module is collected and uploaded to a computer device.

In a preferred embodiment of the present invention, AD8302 is selected as the microwave signal comparison module. AD8302 is an RF/IF amplitude and phase measurement chip. It compares and interprets two signals from two dimensions of amplitude and phase. The measurement range can reach 60dB, and the phase measurement range can reach 180°.

In order to ensure the sampling rate of raw data as high as possible, the voltage acquisition module adopts PXI multi-function I/O module—PXI-6123, which is a synchronous sampling multi-function data acquisition device. It provides analog inputs, digital I/O, two 24-bit counters and digital triggers. In the present invention, the single-channel sampling rate is 500KHz.

The central control system adopts STM32F105RBT6. STM32F105RBT6 is a 32-bit processing based on ARM platform, supports SPI, USART, I2C and other communication peripherals, and has the characteristics of low power consumption, low cost, high performance and high stability. STM32F105RBT6, as the central control of the system, controls the switching of the signal frequency of the microwave signal sent by the microwave signal generation module and the signal of the microwave channel switching module through a communication bus such as SPI, and accepts the return data from the voltage acquisition module.

Further, as shown in FIG. 3 , each group of signal transmitting ends is connected with a transmitting end control switch, and each group of signal receiving ends is connected with a receiving end control switch, and the microwave signal generation system communicates with the microwave signal through the transmitting end control switch. The sending end is connected, and the signal receiving end is connected with the signal acquisition system through the receiving end control switch; both the sending end control switch and the receiving end control switch are connected with the central control system.

Since the transverse electrode wires and the longitudinal electrode wires of the wire mesh sensor are intertwined to form a sensor network, each group of longitudinal electrode wires, that is, the signal receiving end, is connected with a receiving end control switch, which can be controlled by the central control system. The switch is turned on and off, so as to realize the selection of the signal input of each group of longitudinal electrode wires, that is, the signal receiving end, that is, to realize the selective input of microwave signals. The control switch can be controlled by the central control system to control the opening and closing of the control switch of the transmitting end, so as to realize the selection of the signal output of each group of transverse electrode wires, that is, the signal transmitting end; A set of signal transmitters are respectively provided with a receiver control switch and a transmitter control switch, which can realize accurate measurement of a certain point in the sensor network and make specific analysis of the oil-water two-phase flow at different points.

In this embodiment, the signal receiving end adopts switching acquisition, which effectively reduces the cost and the volume of the sensor system while ensuring the synchronization consistency of the signals, which is more beneficial to practical applications.

The embodiments of the present invention have been described in detail above, but the above contents are only preferred embodiments of the present invention, and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made according to the scope of the present invention should still fall within the scope of this patent.

Claims (10)

1. The microwave Wire mesh-based oil-water two-phase flow water content measuring system is characterized in that: the system comprises a Wire mesh sensor, wherein the Wire mesh sensor comprises two layers of Wire electrodes, each layer of Wire electrode is arranged in parallel, and the two layers of Wire electrodes are vertically arranged to form a grid structure; one layer of wire electrode is a signal sending end, and the other layer of wire electrode is a signal receiving end;

the signal transmitting end is connected with a microwave signal generating system, the signal receiving end is connected with a signal collecting system, and the microwave signal generating system and the signal collecting system are both connected with a central control system.

2. The microwave Wire mesh-based oil-water two-phase flow water content measuring system as claimed in claim 1, wherein: the electrode wire is made of a 0.2mm copper enameled wire.

3. The microwave Wire mesh-based oil-water two-phase flow water content measuring system as claimed in claim 1, wherein: the Wire mesh sensor adopts an 8 multiplied by 8 structure, and the distance between adjacent Wire electrodes with the interlayer spacing of 1.6mm is 7.14 mm.

4. The microwave Wire mesh-based oil-water two-phase flow water content measuring system as claimed in claim 1, wherein: the microwave signal generating system comprises a microwave signal generating module, one end of the microwave signal generating module is connected with the central control system, receives a control instruction of the central control system and generates a microwave signal; the other end of the microwave signal transmitting device is connected with the signal receiving end and transmits a microwave signal to the signal receiving end of the Wire mesh sensor.

5. The microwave Wire mesh-based oil-water two-phase flow water content measuring system as claimed in claim 4, wherein: and a microwave signal filtering module is connected between the microwave signal generating module and the signal receiving end of the Wire mesh sensor and is used for filtering microwave signals.

6. The microwave Wire mesh-based oil-water two-phase flow water content measuring system as claimed in claim 5, wherein: the microwave signal generation system also comprises a microwave channel switching module, wherein the input end of the microwave channel switching module is connected with the microwave signal generation module, receives microwave signals with different frequencies sent by the microwave signal generation module, and switches filtering channels according to different input frequencies; the output end is connected with the microwave signal filtering module.

7. The microwave Wire mesh-based oil-water two-phase flow water content measuring system as claimed in claim 6, wherein: the microwave signal generating system is also provided with a power divider, the input end of the power divider is connected with the output end of the microwave signal filtering module, and the output end of the power divider is respectively connected with the transmitting end of the Wire mesh sensor and the microwave signal comparing module in the signal acquisition system.

8. The microwave Wire mesh-based oil-water two-phase flow water content measuring system as claimed in claim 7, wherein: the signal acquisition system comprises a microwave signal comparison module, and the input end of the microwave signal comparison module is respectively connected with the signal receiving end of the Wire mesh sensor and one path of the power distributor of the microwave signal generation system.

9. The microwave Wire mesh-based oil-water two-phase flow water content measuring system as claimed in claim 8, wherein: the signal acquisition system further comprises a microwave signal acquisition module, wherein the input end of the microwave signal acquisition module is connected with the output end of the microwave signal comparison module, and the output end of the microwave signal acquisition module is connected with the central control module.

10. The microwave Wire mesh-based oil-water two-phase flow water content measuring system as claimed in any one of claims 1 to 9, wherein: each group of signal transmitting ends is connected with a transmitting end control switch, each group of signal receiving ends is connected with a receiving end control switch, the microwave signal generating system is connected with the microwave signal transmitting ends through the transmitting end control switches, and the signal receiving ends are connected with the signal acquisition system through the receiving end control switches; the transmitting end control switch and the receiving end control switch are both connected with the central control system.