Pipeline oil and gas leakage monitoring device and method

Abstract

The present application provides a pipeline oil and gas leakage monitoring device and method, which belongs to the field of oil and gas storage and transportation technology. The technical solution sets a sensing optical cable along the pipeline, uses two light emitting units to emit optical signals to the above-mentioned sensing optical cable respectively, and switches the above-mentioned two light emitting units through an optical switch at preset intervals, thereby realizing the transmission of two optical signals using one sensing optical cable, so that the hardware cost of the device is relatively low. After reflection from the sensing optical cable and processing by the signal processing unit, a vibration signal can be obtained based on the optical signal emitted by the first light emitting unit in the above-mentioned device, and a temperature change signal can be obtained based on the optical signal emitted by the second light emitting unit. According to the vibration signal and the temperature change signal, the leakage position of the pipeline can be further identified, so that a warning can be quickly issued after the oil and gas leak in the pipeline, so as to deal with the pipeline damage in time, thereby improving the timeliness and reliability of the monitoring results.

Description

Technical Field

[0001] The present application relates to the technical field of oil and gas storage and transportation, and in particular to a pipeline oil and gas leakage monitoring device and method. Background Art

[0002] In the process of using pipelines for oil and gas transportation, the pipeline may be damaged due to third-party hazards or its own corrosion, causing oil and gas to leak from the damaged part of the pipeline, causing environmental damage and economic losses. Therefore, it is necessary to monitor pipeline oil and gas leakage.

[0003] Since oil and gas leakage in the pipeline will cause changes in the ambient temperature of the pipeline, the currently commonly used device and method for monitoring pipeline oil and gas leakage is to deploy distributed optical fiber temperature sensors around the pipeline. The optical fiber temperature sensors detect temperature changes around the pipeline and issue warnings so that pipeline maintenance personnel can deal with pipeline damage.

[0004] However, since the temperature of the environment around the pipeline caused by oil and gas leakage changes slowly, there is a certain distance between the optical fiber temperature sensor and the pipeline. Therefore, the time when the optical fiber temperature sensor senses the temperature change lags behind the actual time of the oil and gas leakage. Therefore, when using the above-mentioned device and method to monitor pipeline oil and gas leakage, it cannot issue a warning quickly after the pipeline oil and gas leak, which may delay the time to deal with the pipeline damage and miss the best time to deal with it. Summary of the invention

[0005] The embodiment of the present application provides a pipeline oil and gas leakage monitoring device and method, which can quickly issue a warning after the pipeline oil and gas leaks, so as to deal with the pipeline damage in time. The technical solution is as follows:

[0006] In one aspect, a pipeline oil and gas leakage monitoring device is provided, the device comprising: a first light emitting unit, a second light emitting unit, an optical switch, a sensor optical cable, a pipeline, a first photodetector, a second photodetector, and a signal processing unit;

[0007] The first light emitting unit and the second light emitting unit are respectively used to emit optical signals to the sensing optical cable through the optical switch, and the optical switch is used to switch the first light emitting unit and the second light emitting unit every preset time period;

[0008] The sensing optical cable is parallel to the pipeline and has a preset distance from the outer wall of the pipeline;

[0009] The first photodetector is used to obtain a first optical signal transmitted by the sensing optical cable, convert the first optical signal into a first electrical signal, and transmit the first electrical signal to the signal processing unit, wherein the first optical signal is an optical signal affected by Rayleigh scattering phenomenon;

[0010] The second photodetector is used to obtain a second optical signal transmitted by the sensing optical cable, convert the second optical signal into a second electrical signal, and transmit the second electrical signal to the signal processing unit, wherein the second optical signal is an optical signal affected by the Raman scattering phenomenon;

[0011] The signal processing unit is used to process the first electrical signal to obtain a corresponding vibration signal, and the signal processing unit is used to process the second electrical signal to obtain a corresponding temperature change signal, and when the corresponding vibration signal at any preset position of the pipeline exceeds a first preset threshold value and the temperature change signal at the preset position exceeds a second preset threshold value, it is determined that oil and gas leakage occurs at the preset position.

[0012] In one possible design, the first light emitting unit includes: a first laser, a first electro-optical modulator, and a first optical fiber amplifier;

[0013] The first laser is used to emit a first laser to the first electro-optical modulator;

[0014] The first electro-optic modulator is used to modulate the received first laser into a first pulse light, and transmit the first pulse light to the first optical fiber amplifier;

[0015] The first optical fiber amplifier is used to amplify the received first pulse light into a second pulse light, and transmit the second pulse light to the optical switch.

[0016] In one possible design, the first laser is a single longitudinal mode laser.

[0017] In one possible design, the first light emitting unit further includes a first circulator;

[0018] The first circulator is used for transmitting the second pulse light to the optical switch;

[0019] The first circulator is also used to transmit the first optical signal transmitted by the optical switch to the first photodetector.

[0020] In one possible design, the second optical transmission unit includes: a second laser, a second electro-optical modulator, and a second optical fiber amplifier;

[0021] The second laser is used to emit a second laser to the second electro-optical modulator;

[0022] The second electro-optic modulator is used to modulate the received second laser into a third pulse light, and transmit the third pulse light to the second optical fiber amplifier;

[0023] The second optical fiber amplifier is used to amplify the received third pulse light into a fourth pulse light, and transmit the fourth pulse light to the optical switch.

[0024] In one possible design, the second laser is a distributed feedback laser.

[0025] In one possible design, the second light emitting unit further includes a second circulator;

[0026] The second circulator is used for transmitting the fourth pulse light to the optical switch;

[0027] The second circulator is also used to transmit the second optical signal transmitted by the optical switch to the second photodetector.

[0028] In one possible design, the second optical transmission unit further includes: an optical fiber filter;

[0029] The optical fiber filter is used for extracting a second optical signal from the optical signal emitted by the second circulator, and transmitting the second optical signal to the second photodetector.

[0030] In one possible design, the signal processing unit includes: an analog-to-digital conversion subunit, a signal conversion subunit, and an output subunit;

[0031] The analog-to-digital conversion subunit is used to convert the received optical signal into a digital signal, and send the digital signal to the signal conversion subunit;

[0032] The signal conversion subunit is used to convert the digital signal into a vibration signal or a temperature change signal, and send the vibration signal or the temperature change signal to the output subunit.

[0033] On the one hand, a pipeline oil and gas leakage monitoring method is provided, which is applied to a pipeline oil and gas leakage monitoring device according to any one of claims 1 to 4, and the method comprises:

[0034] Step 1, the optical switch is switched to the first optical emitting unit, so that the first optical emitting unit emits an optical signal to the sensor optical cable;

[0035] Step 2: The first photodetector acquires a first optical signal transmitted by the sensing optical cable, converts the first optical signal into a first electrical signal, and transmits the first electrical signal to the signal processing unit;

[0036] Step 3: The signal processing unit processes the first electrical signal to obtain a corresponding vibration signal;

[0037] Step 4, after switching to the first light emitting unit for a preset time, the optical switch switches to the second light emitting unit, so that the second light emitting unit emits an optical signal to the sensor optical cable;

[0038] Step 5: The second photodetector obtains the second optical signal transmitted by the sensing optical cable, converts the second optical signal into a second electrical signal, and transmits the second electrical signal to the signal processing unit;

[0039] Step 6: The signal processing unit processes the second electrical signal to obtain a corresponding temperature change signal;

[0040] Step 7: After switching to the second light emitting unit for a preset time, execute steps 1 to 6. When the vibration signal corresponding to any preset position of the pipeline exceeds the first preset threshold and the temperature change signal of the preset position exceeds the second preset threshold, the signal processing unit determines that an oil and gas leak occurs at the preset position.

[0041] The technical solution provided by the embodiment of the present application is to set a sensing optical cable along the pipeline, use two optical emitting units to emit optical signals to the above-mentioned sensing optical cable respectively, and switch the above-mentioned two optical emitting units at preset intervals through an optical switch, thereby realizing the transmission of two optical signals using one sensing optical cable, so that the hardware cost of the device is relatively low. After reflection from the sensing optical cable and processing by the signal processing unit, a vibration signal can be obtained based on the optical signal emitted by the first optical emitting unit in the above-mentioned device, and a temperature change signal can be obtained based on the optical signal emitted by the second optical emitting unit. According to the vibration signal and the temperature change signal, the leakage position of the pipeline can be further identified, so that a warning can be quickly issued after the oil and gas leak in the pipeline, so as to deal with the pipeline damage in time, thereby improving the timeliness and reliability of the monitoring results. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 It is a structural schematic diagram of a pipeline oil and gas leakage monitoring device provided in an embodiment of the present application;

[0044] Figure 2 It is a flow chart of a pipeline oil and gas leakage monitoring method provided in an embodiment of the present application;

[0045] Figure 3 This is a schematic diagram of a sensor signal corresponding to an early hazard event provided in an embodiment of the present application;

[0046] Figure 4 This is a schematic diagram of a sensor signal corresponding to a natural gas leak provided in an embodiment of the present application;

[0047] Figure 5 This is a schematic diagram of a sensor signal corresponding to a crude oil leak provided in an embodiment of the present application.

[0048] The reference numerals of the components in the accompanying drawings are as follows:

[0049] 1-first light emitting unit;

[0050] 11-first laser, 12-first electro-optic modulator, 13-first optical fiber amplifier, 14-first circulator;

[0051] 2-second light emitting unit;

[0052] 21-second laser, 22-second electro-optic modulator, 23-second optical fiber amplifier, 24-second circulator, 25-optical fiber filter;

[0053] 3- Optical switch;

[0054] 4-sensing optical cable;

[0055] 5-Pipeline;

[0056] 6- a first photodetector;

[0057] 7- second photodetector;

[0058] 8-Signal processing unit;

[0059] 81 - analog-to-digital conversion subunit, 82 - signal conversion subunit, 83 - output subunit. DETAILED DESCRIPTION

[0060] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0061] On the one hand, a pipeline oil and gas leakage monitoring device is provided, which includes: a first light emitting unit 1, a second light emitting unit 2, an optical switch 3, a sensor optical cable 4, a pipeline 5, a first photodetector 6, a second photodetector 7 and a signal processing unit 8;

[0062] The first light emitting unit 1 and the second light emitting unit 2 are respectively used to emit optical signals to the sensing optical cable 4 through the optical switch 3, and the optical switch 3 is used to switch the first light emitting unit 1 and the second light emitting unit 2 at preset time intervals;

[0063] The sensing optical cable 4 is parallel to the pipe 5 and has a preset distance from the outer wall of the pipe 5;

[0064] The first photodetector 6 is used to obtain the first optical signal transmitted by the sensing optical cable 4, and convert the first optical signal into a first electrical signal, and transmit the first electrical signal to the signal processing unit 8, wherein the first optical signal is an optical signal affected by the Rayleigh scattering phenomenon;

[0065] The second photodetector 7 is used to obtain the second optical signal transmitted by the sensing optical cable 4, and convert the second optical signal into a second electrical signal, and transmit the second electrical signal to the signal processing unit 8, wherein the second optical signal is an optical signal affected by the Raman scattering phenomenon;

[0066] The signal processing unit 8 is used to process the first electrical signal to obtain a corresponding vibration signal. The signal processing unit 8 is used to process the second electrical signal to obtain a corresponding temperature change signal. When the vibration signal corresponding to any preset position of the pipeline 5 exceeds a first preset threshold value and the temperature change signal of the preset position exceeds a second preset threshold value, it is determined that oil and gas leakage occurs at the preset position.

[0067] The device is used to be installed along with the pipeline 5, so as to monitor the oil and gas leakage of the pipeline 5. The working principle of the device is described in detail below:

[0068] For the distributed optical fiber vibration sensor composed of the first light emitting unit 1, the optical switch 3, the sensing optical cable 4, the first photodetector 6 and the signal processing unit 8, it is based on the φOTDR (phase-sensitive optical time-domain reflectometer) principle to collect vibration signals; for the distributed optical fiber temperature sensor composed of the second light emitting unit 2, the optical switch 3, the sensing optical cable 4, the second photodetector 7 and the signal processing unit 8, it is based on the ROTDR (raman phase-sensitive optical time-domain reflectometer) principle to collect temperature signals.

[0069] In this device, the time provided for the entire channel to transmit information is divided into several time slices through time division multiplexing, and these time slices are allocated to each signal source, so as to ensure that the same optical cable can be used to transmit two optical signals. The process includes:

[0070] Step 1, the optical switch 3 is switched to the first optical emitting unit 1, so that the first optical emitting unit 1 emits an optical signal to the sensor optical cable 4;

[0071] Step 2, the first photodetector 6 acquires the first optical signal transmitted by the sensing optical cable 4, converts the first optical signal into a first electrical signal, and transmits the first electrical signal to the signal processing unit 8;

[0072] Step 3: The signal processing unit 8 processes the first electrical signal to obtain a corresponding vibration signal;

[0073] Step 4, after switching to the first light emitting unit 1 for a preset time, the optical switch 3 switches to the second light emitting unit 2, so that the second light emitting unit 2 emits an optical signal to the sensor optical cable 4;

[0074] Step 5, the second photodetector 7 acquires the second optical signal transmitted by the sensing optical cable 4, converts the second optical signal into a second electrical signal, and transmits the second electrical signal to the signal processing unit 8;

[0075] Step 6: The signal processing unit 8 processes the second electrical signal to obtain a corresponding temperature change signal;

[0076] Step 7. After switching to the second light emitting unit 2 for a preset time, execute steps 1 to 6. When the vibration signal corresponding to any preset position of the pipeline 5 exceeds the first preset threshold and the temperature change signal of the preset position exceeds the second preset threshold, the signal processing unit 8 determines that an oil and gas leak occurs at the preset position.

[0077] The technical solution provided by the embodiment of the present application is to set a sensing optical cable 4 along the pipeline 5, use two optical emitting units to emit optical signals to the sensing optical cable 4 respectively, and switch the two optical emitting units at preset intervals through an optical switch, thereby realizing the transmission of two optical signals using one sensing optical cable 4, so that the hardware cost of the device is relatively low. After reflection from the sensing optical cable 4 and processing by the signal processing unit 8, a vibration signal can be obtained based on the optical signal emitted by the first optical emitting unit 1 in the above device, and a temperature change signal can be obtained based on the optical signal emitted by the second optical emitting unit 2. According to the vibration signal and the temperature change signal, the leakage position of the pipeline 5 can be further identified, so that a warning can be quickly issued after the oil and gas leak in the pipeline 5, so as to promptly deal with the damage of the pipeline 5, thereby improving the timeliness and reliability of the monitoring results.

[0078] The following is a detailed description of the various structures of the device:

[0079] First light emitting unit 1:

[0080] The first light emitting unit 1 is used to transmit a light signal to the optical switch 3. The light signal enters the sensing optical cable 4 after passing through the optical switch 3 and Rayleigh scattering occurs. Rayleigh scattering means that due to the elastic collision between the incident light signal and the microscopic particles in the medium, a part of the light signal will be scattered in all directions around. Among the Rayleigh scattered light signals, some are reflected back along the sensing optical cable 4 and then enter the first photodetector 6 after passing through the optical switch 3. It should be noted that when the pipeline 5 vibrates due to third-party intrusion (such as truck movement) and other reasons, the light signal transmitted changes due to the influence of Rayleigh scattering, and the change includes changes in signal intensity, etc. Since third-party intrusion often causes damage to the pipeline 5, it can be used as an important basis for judging whether the pipeline 5 is damaged.

[0081] In one possible design, the first light emitting unit 1 includes: a first laser 11, a first electro-optical modulator 12 and a first optical fiber amplifier 13; the first laser 11 is used to emit a first laser to the first electro-optical modulator 12; the first electro-optical modulator 12 is used to modulate the received first laser into a first pulse light, and emit the first pulse light to the first optical fiber amplifier 13; the first optical fiber amplifier 13 is used to amplify the received first pulse light into a second pulse light, and emit the second pulse light to the optical switch 3.

[0082] The first laser 11 is used to emit a first laser, which may be a continuous laser with a certain intensity so as to be subsequently transmitted in an optical fiber.

[0083] In a possible design, the first laser 11 is a single longitudinal mode laser. A single longitudinal mode laser refers to a laser whose output laser mode is both a single longitudinal mode and a single transverse mode, wherein a single longitudinal mode means that there is only a single longitudinal mode in the resonant cavity, that is, a single frequency oscillates, and a single transverse mode is also called a fundamental transverse mode. The light intensity of the single transverse mode is distributed in a Gaussian distribution on the light cross section.

[0084] In a possible design, the first laser 11 is a single longitudinal mode ultra-narrow linewidth laser, so that it can output laser light with a narrow linewidth, thereby facilitating the subsequent use of the Rayleigh scattering signal generated by the first laser.

[0085] The first electro-optic modulator 12 is a switch-type SOA (Semiconductor Optical Amplifier), which is a modulator made of certain electro-optic crystals and can be used to modulate the phase, amplitude, intensity and polarization state of the optical signal. In the present embodiment, the first electro-optic modulator 12 is used to modulate the first laser into a first pulse light. The pulse light signal is a discrete signal with various shapes. The waveform is discontinuous on the Y-axis but has a certain period. For example, the pulse wave can be a rectangular wave.

[0086] The first optical fiber amplifier 13 is a new type of all-optical amplifier used to achieve signal amplification in optical fiber communication lines. Compared with traditional semiconductor laser amplifiers, optical fiber amplifiers do not need to go through complex processes such as photoelectric conversion, electro-optical conversion and signal regeneration, and can directly perform all-optical amplification on the signal, which is suitable for the device provided in this embodiment.

[0087] In a possible design, the first light emitting unit 1 also includes a first circulator 14; the first circulator 14 is used to transmit the second pulse light to the optical switch 3; the first circulator 14 is also used to transmit the first optical signal transmitted by the optical switch 3 to the first photodetector 6.

[0088] Among them, the circulator is a device for unidirectional annular transmission of electromagnetic waves. In modern radar and microwave multi-channel communication systems, devices with unidirectional annular characteristics are used. Since the incident light and reflected light need to be transmitted on the same sensor optical cable 4, the first circulator 14 can be used to conveniently transmit the reflected light to the signal processing unit 8, thereby simplifying the device and saving resources and expenses. The first circulator 14 has at least three terminals, wherein the first terminal is used to receive the second pulse light, and the second pulse light is transmitted to the second terminal through the first terminal, and then enters the optical switch 3; the second terminal is also used to receive the first optical signal transmitted back from the optical switch 3, and the first optical signal is transmitted to the third terminal through the second terminal, and then enters the signal processing unit 8.

[0089] Second light emitting unit 2:

[0090] In one possible design, the second light emitting unit 2 includes: a second laser 21, a second electro-optical modulator 22 and a second optical fiber amplifier 23; the second laser 21 is used to emit a second laser to the second electro-optical modulator 22; the second electro-optical modulator 22 is used to modulate the received second laser into a third pulse light, and emit the third pulse light to the second optical fiber amplifier 23; the second optical fiber amplifier 23 is used to amplify the received third pulse light into a fourth pulse light, and emit the fourth pulse light to the optical switch 3.

[0091] The second light emitting unit 2 is used to emit a second laser, which may be a continuous laser with a certain intensity so as to be subsequently transmitted in the optical fiber.

[0092] In one possible design, the second laser 21 is a distributed feedback laser (DFB laser) having a built-in Bragg grating and being a side-emitting semiconductor laser, so as to facilitate the subsequent use of the Raman scattering signal generated by the second laser.

[0093] The second electro-optic modulator 22 is a modulator made of certain electro-optic crystals, and can be used to modulate the phase, amplitude, intensity and polarization state of the optical signal. In the present embodiment, the second electro-optic modulator 22 is used to modulate the second laser into a second pulse light. The pulse light signal is a discrete signal with various shapes. The waveform is discontinuous on the Y-axis but has a certain period. For example, the pulse wave can be a rectangular wave.

[0094] The second optical fiber amplifier 23 is a new type of all-optical amplifier used to achieve signal amplification in the optical fiber communication line. Compared with the traditional semiconductor laser amplifier, the optical fiber amplifier does not need to go through complex processes such as photoelectric conversion, electro-optical conversion and signal regeneration, and can directly perform all-optical amplification on the signal, which is suitable for the device provided in this embodiment.

[0095] In a possible design, the second light emitting unit 2 further includes a second circulator 24 ; the second circulator 24 is used to transmit the fourth pulse light to the optical switch 3 ; the second circulator 24 is also used to transmit the second optical signal transmitted by the optical switch 3 to the second photodetector 7 .

[0096] Among them, the circulator is a device for unidirectional annular transmission of electromagnetic waves. In modern radar and microwave multi-channel communication systems, devices with unidirectional annular characteristics are used. Since the incident light and reflected light need to be transmitted on the same sensor optical cable 4, the second circulator 24 can be used to conveniently transmit the reflected light to the signal processing unit 8, thereby simplifying the device and saving resources and expenses. The second circulator 24 has at least three terminals, wherein the first terminal is used to receive the fourth pulse light, and the fourth pulse light is transmitted to the second terminal through the first terminal, and then enters the optical switch 3; the second terminal is also used to receive the second optical signal transmitted back from the optical switch 3, and the second optical signal is transmitted to the third terminal through the second terminal, and then enters the signal processing unit 8.

[0097] In a possible design, the second optical emission unit 2 further includes: an optical fiber filter 25 ; the optical fiber filter 25 is used to extract a second optical signal from the optical signal emitted by the second circulator 24 , and transmit the second optical signal to the second photodetector 7 .

[0098] The optical fiber filter 25 is an optical device that uses a special optical fiber structure to select or filter out a specific wavelength of light waves from light waves of different wavelengths. By using the optical fiber filter 25, the second optical signal can be easily filtered from the optical signal.

[0099] Optical switch 3:

[0100] The optical switch 3 is an optical device with one or more optional transmission ports, and its function is to physically switch or logically operate the optical signal in the optical transmission line or integrated optical circuit. The optical switch 3 may be equipped with an automatic switching program, which is used to switch the first optical emitting unit 1 and the second optical emitting unit 2 at preset time intervals, so that one sensor optical cable 4 can be used for two different signal transmission processes based on time division multiplexing technology. The preset time can be set as needed, for example, it can be 1-10ms.

[0101] Sensing optical cable 4:

[0102] Optical fiber is the abbreviation of optical fiber, which is a fiber made of glass or plastic and can be used as a light transmission tool. Its transmission principle is "total reflection of light". The sensing optical cable 4 has an optical fiber, which is used to convert the physical quantity of non-optical signal into optical signal, which is sensed and transmitted through the optical fiber and finally converted into the measured physical quantity to measure physical quantities such as temperature, pressure, displacement, speed, voltage, current and concentration of melt.

[0103] Pipeline 5:

[0104] The pipeline 5 in the present technical solution is a pipeline for transporting oil and gas, which is usually buried underground. Once a leak occurs, it is relatively complicated to find and deal with it, including long-distance pipelines, plant and station pipelines, and urban gas pipeline networks.

[0105] The first photodetector 6, the second photodetector 7:

[0106] The first photodetector 6 can be a bipolar cooled, wide bandwidth, high sensitivity APD (Avalanche Photodiode Detectors) for converting optical signals into electrical signals. The working principle of the second photodetector 7 is similar and will not be described in detail here.

[0107] Signal processing unit 8:

[0108] The signal processing unit 8 is used to receive the first optical signal and the second optical signal. It can obtain a vibration signal by processing the above-mentioned first optical signal, and can obtain a temperature change signal by processing the above-mentioned second optical signal, and further identify the leakage position of the pipeline 5, so as to quickly issue a warning after the oil and gas leak in the pipeline 5, so as to deal with the damage of the pipeline 5 in time.

[0109] In one possible design, the signal processing unit 8 includes: an analog-to-digital conversion subunit 81, a signal conversion subunit 82 and an output subunit 83; the analog-to-digital conversion subunit 81 is used to convert the received optical signal into a digital signal, and send the digital signal to the signal conversion subunit 82; the signal conversion subunit 82 is used to convert the digital signal into a vibration signal or a temperature change signal, and send the vibration signal or the temperature change signal to the output subunit 83.

[0110] The analog-to-digital conversion subunit 81 is used to perform high-speed A / D conversion (analog to digital converter). Analog-to-digital conversion is to convert the received analog signal into a digital signal for subsequent processing.

[0111] The signal conversion subunit 82 is used for performing DSP signal processing (digital signal processing), that is, processing the received digital signal to obtain the corresponding vibration signal or temperature change signal.

[0112] The output subunit 83 is used to output at least one of a vibration signal and a temperature change signal, and the output method can be various. For example, the waveform diagram of the above signal can be output through a display screen so that the operator can observe it intuitively; or it can be based on the above signal to output the monitoring results of the pipeline 5, including whether the pipeline 5 is damaged, the location of the damage, etc.

[0113] All the above optional technical solutions can be arbitrarily combined to form optional embodiments of the present application, which will not be described one by one here.

[0114] Figure 2 : is a flow chart of a pipeline oil and gas leakage monitoring method provided in an embodiment of the present application, which is applied to a pipeline oil and gas leakage monitoring device provided in any of the possible designs described above, and the method includes:

[0115] Step 1: The optical switch 3 is switched to the first optical emitting unit 1 , so that the first optical emitting unit 1 emits an optical signal to the sensor optical cable 4 .

[0116] The optical switch 3 may have a built-in automatic switching program for switching the first optical emitting unit 1 and the second optical emitting unit 2 at preset time intervals, so that one sensor optical cable 4 can be used for two different signal transmission processes based on time division multiplexing technology.

[0117] Step 2: The first photodetector 6 acquires the first optical signal transmitted by the sensing optical cable 4 , converts the first optical signal into a first electrical signal, and transmits the first electrical signal to the signal processing unit 8 .

[0118] Step 3: The signal processing unit 8 processes the first electrical signal to obtain a corresponding vibration signal.

[0119] Step 4: After switching to the first light emitting unit 1 for a preset time, the optical switch 3 switches to the second light emitting unit 2 , so that the second light emitting unit 2 emits an optical signal to the sensor optical cable 4 .

[0120] Step 5: The second photodetector 7 acquires the second optical signal transmitted by the sensing optical cable 4 , converts the second optical signal into a second electrical signal, and transmits the second electrical signal to the signal processing unit 8 .

[0121] Step 6: The signal processing unit 8 processes the second electrical signal to obtain a corresponding temperature change signal.

[0122] Step 7. After switching to the second light emitting unit 2 for a preset time, execute steps 1 to 6. When the vibration signal corresponding to any preset position of the pipeline 5 exceeds the first preset threshold and the temperature change signal of the preset position exceeds the second preset threshold, the signal processing unit 8 determines that an oil and gas leak occurs at the preset position.

[0123] The first preset threshold and the second preset threshold may be obtained and set by personnel based on experience or calculation; or may be identified and set by the signal processing unit 8 based on the normal operation of the pipeline, which is not limited in this embodiment.

[0124] In this step, the signal processing unit 8 is used to process and analyze the vibration signal and the temperature change signal. Since there are many possible reasons for the damage of the pipeline 5, the corresponding vibration signal and temperature change signal are also different. Several cases are described below as examples.

[0125] The first one: Figure 3 This is a schematic diagram of a sensor signal corresponding to an early hazard event provided in an embodiment of the present application. Figure 3 The horizontal direction represents the mileage information, and the vertical direction represents the size and direction of the signal. Early hazard events refer to events that may cause damage to pipeline 5, including third-party hazards. For example, construction and excavation activities within 5m around pipeline 5 often increase the risk of damage to pipeline 5, so it is worthy of attention.

[0126] Second type: Figure 4 This is a schematic diagram of a sensor signal corresponding to a natural gas leak provided in an embodiment of the present application. Figure 4 The horizontal direction represents the mileage information, and the vertical direction represents the size and direction of the signal. When natural gas leaks, it will cause the vibration signal to oscillate and the temperature signal to decrease. The operator can identify the signal changes and take corresponding measures.

[0127] The third type: Figure 5 This is a schematic diagram of a sensor signal corresponding to a crude oil leak provided in an embodiment of the present application. Figure 5 The horizontal direction represents the mileage information, and the vertical direction represents the size and direction of the signal. When crude oil leaks, it will cause the vibration signal to oscillate and the temperature signal to increase. The operator can identify the changes in the signal and take corresponding measures.

[0128] The technical solution provided by the embodiment of the present application is to set a sensing optical cable 4 along the pipeline 5, use two optical emitting units to emit optical signals to the sensing optical cable 4 respectively, and switch the two optical emitting units at preset intervals through an optical switch, thereby realizing the transmission of two optical signals using one sensing optical cable 4, so that the hardware cost of the device is relatively low. After reflection from the sensing optical cable 4 and processing by the signal processing unit 8, a vibration signal can be obtained based on the optical signal emitted by the first optical emitting unit 1 in the above device, and a temperature change signal can be obtained based on the optical signal emitted by the second optical emitting unit 2. According to the vibration signal and the temperature change signal, the leakage position of the pipeline 5 can be further identified, so that a warning can be quickly issued after the oil and gas leak in the pipeline 5, so as to promptly deal with the damage of the pipeline 5, thereby improving the timeliness and reliability of the monitoring results.

[0129] The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A pipeline oil and gas leakage monitoring method, characterized in that: Applicable to a pipeline oil and gas leakage monitoring device, the device comprising: a first light emitting unit (1), a second light emitting unit (2), an optical switch (3), a sensor optical cable (4), a pipeline (5), a first photoelectric detector (6), a second photoelectric detector (7) and a signal processing unit (8); The first light emitting unit (1) and the second light emitting unit (2) are respectively used to emit optical signals to the sensor optical cable (4) through the optical switch (3); the optical switch (3) has a built-in automatic switching program; the optical switch (3) is used to switch the first light emitting unit (1) and the second light emitting unit (2) at preset time intervals, so that one sensor optical cable (4) is used for two different signal transmission processes based on time division multiplexing technology; the preset time is 1-10 ms; The sensing optical cable (4) is parallel to the pipeline (5) and has a preset distance from the outer wall of the pipeline (5); the pipeline (5) is a pipeline for transporting oil and gas and is buried underground; The first photodetector (6) is used to obtain a first optical signal transmitted by the sensing optical cable (4), convert the first optical signal into a first electrical signal, and transmit the first electrical signal to the signal processing unit (8), wherein the first optical signal is an optical signal affected by Rayleigh scattering phenomenon; The second photodetector (7) is used to obtain a second optical signal transmitted by the sensing optical cable (4), convert the second optical signal into a second electrical signal, and transmit the second electrical signal to the signal processing unit (8), wherein the second optical signal is an optical signal affected by Raman scattering; The signal processing unit (8) is used to process the first electrical signal to obtain a corresponding vibration signal, and the signal processing unit (8) is used to process the second electrical signal to obtain a corresponding temperature change signal, and when the vibration signal corresponding to any preset position of the pipeline (5) exceeds a first preset threshold value, and the temperature change signal of the preset position exceeds a second preset threshold value, it is determined that oil and gas leakage occurs at the preset position; The first light emitting unit (1) comprises: a first laser (11), a first electro-optical modulator (12), a first optical fiber amplifier (13) and a first circulator (14); The first laser (11) is used to emit a first laser to the first electro-optical modulator (12), the first laser is a continuous laser, and the first laser (11) is a single longitudinal mode laser; The first electro-optic modulator (12) is used to modulate the received first laser into a first pulse light, and transmit the first pulse light to the first optical fiber amplifier (13), and the first electro-optic modulator is a switch-type semiconductor optical amplifier; The first optical fiber amplifier (13) is used to amplify the received first pulse light into a second pulse light, and transmit the second pulse light to the optical switch (3); The first circulator (14) is used to transmit the second pulse light to the optical switch (3); The first circulator (14) is also used to transmit the first optical signal transmitted by the optical switch (3) to the first photodetector (6); wherein the first circulator (14) has at least three terminals, wherein the first terminal is used to receive the second pulse light, the second pulse light is transmitted to the second terminal through the first terminal, and then enters the optical switch (3); the second terminal is also used to receive the first optical signal transmitted back from the optical switch (3), the first optical signal is transmitted to the third terminal through the second terminal, and then enters the signal processing unit (8); The second light emitting unit (2) comprises: a second laser (21), a second electro-optical modulator (22), a second optical fiber amplifier (23), an optical fiber filter (25) and a second circulator (24); The second laser (21) is used to emit a second laser to the second electro-optical modulator (22), the second laser is a continuous laser, the second laser (21) is a distributed feedback laser, the distributed feedback laser has a built-in Bragg grating, and is a side-emitting semiconductor laser, so as to utilize the Raman scattering signal generated by the second laser; The second electro-optical modulator (22) is used to modulate the received second laser into a third pulse light, and emit the third pulse light to the second optical fiber amplifier (23); The second optical fiber amplifier (23) is used to amplify the received third pulse light into a fourth pulse light, and transmit the fourth pulse light to the optical switch (3); The second circulator (24) is used to transmit the fourth pulse light to the optical switch (3); The second circulator (24) is also used to transmit the second optical signal transmitted by the optical switch (3) to the second photodetector (7); the second circulator (24) has at least three terminals, wherein the first terminal is used to receive a fourth pulse of light, the fourth pulse of light is transmitted to the second terminal through the first terminal, and then enters the optical switch (3); the second terminal is also used to receive a second optical signal transmitted back from the optical switch (3), the second optical signal is transmitted to the third terminal through the second terminal, and then enters the signal processing unit (8); The optical fiber filter (25) is used to extract a second optical signal from the optical signal emitted by the second circulator (24), and transmit the second optical signal to the second photodetector (7); The signal processing unit (8) comprises: an analog-to-digital conversion subunit (81), a signal conversion subunit (82) and an output subunit (83); The analog-to-digital conversion subunit (81) is used to convert the received optical signal into a digital signal, and send the digital signal to the signal conversion subunit (82); The signal conversion subunit (82) is used to convert the digital signal into a vibration signal or a temperature change signal, and send the vibration signal or the temperature change signal to the output subunit (83); The output subunit (83) is used to output a waveform of at least one of the vibration signal and the temperature change signal through a display screen, causing the vibration signal to oscillate and the temperature signal to decrease when natural gas leaks, and causing the vibration signal to oscillate and the temperature signal to increase when crude oil leaks. The method comprises: Step 1, the optical switch (3) is switched to the first light emitting unit (1), so that the first light emitting unit (1) emits an optical signal to the sensor optical cable (4); Step 2, the first photodetector (6) acquires the first optical signal transmitted by the sensing optical cable (4), converts the first optical signal into a first electrical signal, and transmits the first electrical signal to the signal processing unit (8); Step 3, the signal processing unit (8) processes the first electrical signal to obtain a corresponding vibration signal; Step 4: After switching to the first light emitting unit (1) for a preset time, the optical switch (3) switches to the second light emitting unit (2), so that the second light emitting unit (2) emits an optical signal to the sensor optical cable (4); Step 5: the second photodetector (7) acquires the second optical signal transmitted by the sensing optical cable (4), converts the second optical signal into a second electrical signal, and transmits the second electrical signal to the signal processing unit (8); Step 6: the signal processing unit (8) processes the second electrical signal to obtain a corresponding temperature change signal; Step 7, after switching to the second light emitting unit (2) for a preset time, execute steps 1 to 6, and when the vibration signal corresponding to any preset position of the pipeline (5) exceeds the first preset threshold, and the temperature change signal of the preset position exceeds the second preset threshold, the signal processing unit (8) determines that an oil and gas leak occurs at the preset position.

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