A fiber-optic sensing system suitable for pipeline leak monitoring

Abstract

The application provides a kind of optical fiber sensing system suitable for pipeline leakage monitoring, comprising: pump laser, wavelength division multiplexer, at least one optical fiber hydrophone installed in pipeline, Michelson interferometer, optical fiber phase demodulator, pump laser and Michelson interferometer are connected with wavelength division multiplexer, wavelength division multiplexer is connected with optical fiber hydrophone, and optical fiber phase demodulator is connected with Michelson interferometer.Sensitive area of optical fiber hydrophone is installed in pipeline, to reduce the influence of external environment on monitoring result.Through monitoring infrasonic wave signal in pipeline by optical fiber hydrophone, real-time leakage of long distance pipeline is monitored.High sensitivity, simple installation and construction, not easy to be disturbed by external environment, to realize real-time high-precision detection of underwater sound.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas pipeline leakage monitoring, and particularly relates to a fiber-optic sensing system suitable for pipeline leakage monitoring. BACKGROUND

[0002] Oil and gas pipeline transportation has the advantages of safety, reliability, low consumption and low cost, and has become the most widely used oil and gas transportation means in the world, and is also the main means of oil and gas transportation. With the development of the pipeline oil and gas transportation industry, the safety of the pipeline has gradually become a concern of the whole people. Once a pipeline leakage accident occurs, it will cause huge economic losses and pollute the local ecological environment. If the leakage site is in a residential area, it may cause casualties.

[0003] The existing pipeline leakage monitoring technology mainly uses pressure, flow, temperature and other sensors for monitoring. The patent CN112944222A discloses a pipeline leakage monitoring sensor based on an interference fiber-optic vibration sensor. The sensing system installs an optical fiber vibration sensor on the pipeline at a certain distance, and realizes the monitoring of pipeline leakage by monitoring the vibration signal of the pipeline. The interference fiber-optic sensor is convenient to form an array, which realizes long-distance sea pipeline leakage monitoring. The patent CN115507312A discloses a pipeline leakage monitoring device using an electronic infrasound detector. The device clamps and fixes the infrasound detector on the measured pipeline through the hinge of the upper and lower clamps, and the lifting device improves the clamping effect of the connection of different specifications of oil and gas pipelines, and increases the coupling effect of the infrasound detector and the measured pipeline. The sensitivity and accuracy of the existing sensor are limited. In order to realize the comprehensive monitoring of the pipeline, a sensor needs to be installed at a certain distance. The installation and construction are relatively complex. The sensor is installed on the surface of the pipeline and is easily affected by the surrounding environment. SUMMARY

[0004] The present application solves the technical problems of the prior art, and provides a fiber-optic sensing system suitable for pipeline leakage monitoring.

[0005] The technical scheme for solving the above technical problems is as follows: a fiber-optic sensing system suitable for pipeline leakage monitoring, comprising: a pump laser, a wavelength division multiplexer, at least one optical fiber hydrophone installed in the pipeline, a Michelson interferometer, and a fiber-optic phase demodulator, wherein the pump laser and the Michelson interferometer are connected with the wavelength division multiplexer, the wavelength division multiplexer is connected with the optical fiber hydrophone, and the fiber-optic phase demodulator is connected with the Michelson interferometer.

[0006] The beneficial effects of adopting the technical solution of this invention are as follows: When a pipeline is damaged or leaks, a corresponding infrasound signal is generated near the leak point. This infrasound signal causes a change in the wavelength of the fiber optic hydrophone installed inside the pipeline. After passing through a Michelson interferometer, the wavelength change is converted into a phase change, and the amount of phase change is demodulated by a fiber optic phase demodulator. Installing the sensitive area of ​​the fiber optic hydrophone inside the pipeline reduces the influence of the external environment on the monitoring results. By monitoring the infrasound signal inside the pipeline using the fiber optic hydrophone, real-time monitoring of leaks in long-distance pipelines can be achieved. It features high sensitivity, simple installation, and is not easily affected by external environmental interference, enabling real-time, high-precision detection of underwater sounds.

[0007] Furthermore, it also includes: a station, multiple pipe root valve assemblies, a first valve chamber, an oil and gas pipeline, and a second valve chamber. The station is connected to the first valve chamber and the first valve chamber is connected to the second valve chamber via oil and gas pipelines. Multiple pipe root valve assemblies are installed on the oil and gas pipelines. Multiple fiber optic hydrophones are installed at the inlet and outlet ends of the pipelines in the station, the first valve chamber, and the second valve chamber.

[0008] The advantages of adopting the above-mentioned further technical solutions are: fiber optic hydrophones have high sensitivity, and only need to be installed on the inlet and outlet pipes of the pipeline station or valve chamber, without having to install sensors on the entire pipeline. The installation is relatively simple and the construction cost is relatively low.

[0009] Furthermore, multiple fiber optic hydrophones are installed one-to-one in multiple pipe root valve assemblies.

[0010] The advantages of adopting the above-mentioned further technical solutions are: fiber optic hydrophones have high sensitivity, and only need to be installed on the inlet and outlet pipes of the pipeline station or valve chamber, without having to install sensors on the entire pipeline. The installation is relatively simple and the construction cost is relatively low.

[0011] Furthermore, the wavelength division multiplexer is connected to the fiber optic hydrophone, the pump laser is connected to the wavelength division multiplexer, and the Michelson interferometer is connected to the fiber optic phase demodulator via optical fibers.

[0012] The beneficial effects of adopting the above-mentioned further technical solutions are: facilitating signal transmission between various components and improving transmission efficiency.

[0013] Furthermore, the optical fiber is a single-mode glass optical fiber.

[0014] The beneficial effects of adopting the above-mentioned further technical solutions are: single-mode fiber can support longer transmission distances compared to multimode fiber, and single-mode fiber has lower transmission loss and dispersion. Lower transmission loss allows signals to travel further in the fiber, and lower dispersion is beneficial for high-speed, high-capacity data transmission.

[0015] Furthermore, the wavelength division multiplexer is connected to multiple fiber optic hydrophones via fiber optic couplers.

[0016] The beneficial effect of adopting the above-mentioned further technical solution is that the optical fiber coupler enables the optical energy output from the transmitting optical fiber to be coupled into the receiving optical fiber to the maximum extent.

[0017] Furthermore, the fiber optic coupler is a 1*2 coupler.

[0018] The beneficial effect of adopting the above-mentioned further technical solution is that the optical fiber coupler enables the optical energy output from the transmitting optical fiber to be coupled into the receiving optical fiber to the maximum extent.

[0019] Furthermore, the Michelson interferometer is connected to the wavelength division multiplexer via an isolator.

[0020] The beneficial effects of adopting the above-mentioned further technical solution are: the isolator converts the input signal into an output. The input, output, and operating power supply are mutually isolated, maintaining the purity of the light source spectrum.

[0021] Furthermore, the fiber optic phase demodulator is connected to a 5G terminal device.

[0022] The beneficial effect of adopting the above-mentioned further technical solution is that the data of fiber optic hydrophones in various locations can be uniformly uploaded to the server through 5G networking technology, which facilitates big data processing.

[0023] Furthermore, the fiber optic hydrophone is a distributed feedback fiber optic hydrophone.

[0024] The beneficial effects of adopting the above-mentioned further technical solution are: the distributed feedback fiber optic hydrophone converts underwater acoustic signals into electrical signals. It has high sensitivity, and the distributed feedback fiber optic hydrophone only needs to be installed at the inlet and outlet pipes of the pipeline station or valve chamber, eliminating the need to install sensors on the entire pipeline. Installation is relatively simple, and construction costs are relatively low.

[0025] The advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0026] Figure 1 This is one of the structural schematic diagrams of an optical fiber sensing system for pipeline leakage monitoring provided in an embodiment of the present invention.

[0027] Figure 2 This is the second schematic diagram of a fiber optic sensing system for pipeline leak monitoring provided in an embodiment of the present invention.

[0028] The following are the reference numerals: 1. Station; 2. Pipeline root valve group; 3. First valve chamber; 4. Oil and gas pipeline; 5. Second valve chamber; 6. Pump laser; 7. Wavelength division multiplexer; 8. Optical fiber; 9. Optical fiber coupler; 10. Optical fiber hydrophone; 11. Isolator; 12. Michelson interferometer; 13. Optical fiber phase demodulator; 14. 5G terminal equipment. Detailed Implementation

[0029] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0030] like Figure 1 and Figure 2 As shown, this embodiment of the invention provides an optical fiber sensing system suitable for pipeline leak monitoring, including: a pump laser 6, a wavelength division multiplexer 7, at least one optical fiber hydrophone 10 installed in the pipeline, a Michelson interferometer 12, and an optical fiber phase demodulator 13. The pump laser 6 and the Michelson interferometer 12 are both connected to the wavelength division multiplexer 7, the wavelength division multiplexer 7 is connected to the optical fiber hydrophone 10, and the optical fiber phase demodulator 13 is connected to the Michelson interferometer 12.

[0031] The beneficial effects of adopting the technical solution of this invention are as follows: When a pipeline is damaged or leaks, a corresponding infrasound signal is generated near the leak point. This infrasound signal causes a change in the wavelength of the fiber optic hydrophone installed inside the pipeline. After passing through a Michelson interferometer, the wavelength change is converted into a phase change, and the amount of phase change is demodulated by a fiber optic phase demodulator. Installing the sensitive area of ​​the fiber optic hydrophone inside the pipeline reduces the influence of the external environment on the monitoring results. By monitoring the infrasound signal inside the pipeline using the fiber optic hydrophone, real-time monitoring of leaks in long-distance pipelines can be achieved. It features high sensitivity, simple installation, and is not easily affected by external environmental interference, enabling real-time, high-precision detection of underwater sounds.

[0032] Among them, the pipeline can be an oil and gas pipeline 4.

[0033] The fiber optic sensing system for pipeline leak monitoring provided in this invention is a pipeline leak monitoring system based on a distributed feedback fiber laser (DFB-FL, fiber optic hydrophone). It uses a single-frequency, low-noise, narrow-linewidth DFB-FL (distributed feedback fiber laser, fiber optic hydrophone 10) as the sensing device, and achieves real-time, high-precision detection of underwater sound through interferometric demodulation. The high-precision, high-sensitivity fiber optic DFB hydrophone (distributed feedback fiber laser, fiber optic hydrophone 10) is installed at the inlet and outlet ends of pipelines in stations and valve chambers. By monitoring the infrasound signals within the pipeline, real-time monitoring of leaks in long-distance pipelines is achieved. Once a leak is detected, an alarm system is automatically triggered to alert relevant personnel for timely handling. A fiber optic acoustic monitoring system (a fiber optic sensing system suitable for pipeline leak monitoring) is installed at each station or valve chamber in the pipeline network. One fiber optic DFB hydrophone (fiber optic hydrophone 10) is installed on the valve group 2 at the root of the pipeline at the inlet and outlet of each station or valve chamber. When the pipeline is damaged or leaks, a corresponding infrasound signal is generated near the leak point. The infrasound signal causes a change in the wavelength of the fiber optic DFB hydrophone (fiber optic hydrophone 10) installed inside the pipeline. After passing through a Michelson interferometer 12, the wavelength change is converted into a phase change, and the amount of phase change is demodulated by a fiber optic phase demodulator 13. The demodulated phase change data is uploaded to the data service center for data processing via a 5G terminal device 14. By monitoring the infrasound changes inside the oil and gas pipeline through the fiber optic DFB hydrophone (fiber optic hydrophone 10), real-time monitoring of pipeline leaks is achieved.

[0034] like Figure 1 and Figure 2 As shown, it further includes: a station 1, multiple pipe root valve groups 2, a first valve chamber 3, an oil and gas pipeline 4, and a second valve chamber 5. The station 1 is connected to the first valve chamber 3 and the first valve chamber 3 is connected to the second valve chamber 5 via the oil and gas pipeline 4. Multiple pipe root valve groups 2 are installed on the oil and gas pipeline 4. Multiple fiber optic hydrophones 10 are installed at the inlet and outlet ends of the pipelines in the station 1, the first valve chamber 3, and the second valve chamber 5.

[0035] The advantages of adopting the above-mentioned further technical solutions are: fiber optic hydrophones have high sensitivity, and only need to be installed on the inlet and outlet pipes of the pipeline station or valve chamber, without having to install sensors on the entire pipeline. The installation is relatively simple and the construction cost is relatively low.

[0036] like Figure 1 andFigure 2 As shown, furthermore, multiple fiber optic hydrophones 10 are installed one-to-one in multiple pipe root valve groups 2.

[0037] The advantages of adopting the above-mentioned further technical solutions are: fiber optic hydrophones have high sensitivity, and only need to be installed on the inlet and outlet pipes of the pipeline station or valve chamber, without having to install sensors on the entire pipeline. The installation is relatively simple and the construction cost is relatively low.

[0038] like Figure 1 and Figure 2 As shown, further, the wavelength division multiplexer 7 is connected to the fiber optic hydrophone 10, the pump laser 6 is connected to the wavelength division multiplexer 7, and the Michelson interferometer 12 is connected to the fiber optic phase demodulator 13 via fiber optic 8.

[0039] The beneficial effects of adopting the above-mentioned further technical solutions are: facilitating signal transmission between various components and improving transmission efficiency.

[0040] like Figure 1 and Figure 2 As shown, the optical fiber 8 is further described as a single-mode glass optical fiber.

[0041] The beneficial effects of adopting the above-mentioned further technical solutions are: single-mode fiber can support longer transmission distances compared to multimode fiber, and single-mode fiber has lower transmission loss and dispersion. Lower transmission loss allows signals to travel further in the fiber, and lower dispersion is beneficial for high-speed, high-capacity data transmission.

[0042] like Figure 1 and Figure 2 As shown, the wavelength division multiplexer 7 is further connected to a plurality of fiber optic hydrophones 10 via fiber optic couplers 9.

[0043] The beneficial effect of adopting the above-mentioned further technical solution is that the optical fiber coupler enables the optical energy output from the transmitting optical fiber to be coupled into the receiving optical fiber to the maximum extent.

[0044] like Figure 1 and Figure 2 As shown, the fiber optic coupler 9 is further described as a 1*2 coupler.

[0045] The beneficial effect of adopting the above-mentioned further technical solution is that the optical fiber coupler enables the optical energy output from the transmitting optical fiber to be coupled into the receiving optical fiber to the maximum extent.

[0046] like Figure 1 and Figure 2 As shown, the Michelson interferometer 12 is further connected to the wavelength division multiplexer 7 via an isolator 11.

[0047] The beneficial effects of adopting the above-mentioned further technical solution are: the isolator converts the input signal into an output. The input, output, and operating power supply are mutually isolated, maintaining the purity of the light source spectrum.

[0048] like Figure 1 and Figure 2 As shown, the fiber optic phase demodulator 13 is further connected to a 5G terminal device 14.

[0049] The beneficial effect of adopting the above-mentioned further technical solution is that the data of fiber optic hydrophones in various locations can be uniformly uploaded to the server through 5G networking technology, which facilitates big data processing.

[0050] Furthermore, the fiber optic hydrophone 10 is a distributed feedback fiber optic hydrophone.

[0051] The beneficial effects of adopting the above-mentioned further technical solution are: the distributed feedback fiber optic hydrophone converts underwater acoustic signals into electrical signals. It has high sensitivity, and the distributed feedback fiber optic hydrophone only needs to be installed at the inlet and outlet pipes of the pipeline station or valve chamber, eliminating the need to install sensors on the entire pipeline. Installation is relatively simple, and construction costs are relatively low.

[0052] A wavelength division multiplexer is used to combine a series of optical signals carrying information but with different wavelengths into a single beam, which is then transmitted along a single optical fiber. At the receiving end, the optical signals of different wavelengths are separated using some method.

[0053] Compared to multimode fiber, single-mode fiber supports longer transmission distances. In 100Mbps Ethernet and even 1Gbps Gigabit Ethernet, single-mode fiber can support transmission distances exceeding 5000m. Single-mode fiber also has lower transmission loss and dispersion. Lower transmission loss allows signals to travel further within the fiber, while lower dispersion is beneficial for high-speed, high-capacity data transmission.

[0054] A fiber optic coupler, also known as a splitter, connector, adapter, or fiber optic flange, is used to split / combine optical signals or to extend fiber optic links. It maximizes the coupling of optical energy from the transmitting fiber to the receiving fiber.

[0055] A hydrophone (fiber optic hydrophone 10), also known as an underwater microphone, converts underwater sound signals into electrical signals.

[0056] The isolator uses the principle of linear optocoupler isolation to convert the input signal into an output. The input, output, and power supply are isolated from each other to maintain the purity of the light source spectrum.

[0057] The Michelson interferometer uses amplitude division to generate two beams to achieve interference. By adjusting the interferometer, it is possible to produce interference fringes of equal thickness or equal inclination.

[0058] A phase modulator is used to change the phase of light according to a certain pattern.

[0059] 1. Using fiber optic DFB hydrophones (fiber optic hydrophone 10) as sensors, changes in infrasound inside the pipeline are monitored to detect pipeline leaks. The sensitive area of ​​the fiber optic hydrophone is installed inside the pipeline to reduce the influence of the external environment on the monitoring results and achieve real-time monitoring over a longer distance.

[0060] 2. The fiber optic DFB hydrophone (fiber optic hydrophone 10) has high sensitivity. The sensor (fiber optic hydrophone 10) only needs to be installed on the inlet and outlet pipelines of the pipeline station or valve chamber. There is no need to install the sensor on the entire pipeline. The installation is relatively simple and the construction cost is relatively low.

[0061] 3. Data from sensors (fiber optic hydrophones 10) at various locations are uploaded to the server via 5G networking technology to facilitate big data processing.

[0062] A fiber optic DFB hydrophone (fiber optic hydrophone 10) is installed on the valve group 2 at the root of the pipeline at the inlet or outlet of the station or valve chamber. A pump laser 6 is connected to a wavelength division multiplexer 7 via optical fiber. The other two ends of the wavelength division multiplexer 7 are connected to an optical fiber coupler 9 and an isolator 11 via optical fibers, respectively. The other two ends of the optical fiber coupler 9 are connected to the fiber optic DFB hydrophone (fiber optic hydrophone 10) via optical fibers. The other end of the isolator 11 is connected to a Michelson interferometer 12 via optical fiber. The Michelson interferometer 12 is connected to an optical fiber phase demodulator 13 via optical fiber. The optical fiber phase demodulator 13 transmits the demodulated data to a 5G terminal device 14 via a wire.

[0063] The pump light emitted by pump laser 6 is transmitted through wavelength division multiplexing (WDM) 7 and optical fiber to fiber coupler 9, where it is split into two beams that reach fiber optic DFB hydrophones (fiber optic hydrophone 10). Fiber optic DFB hydrophones (fiber optic hydrophone 10) reflect light of a specific wavelength. When a leak occurs in the pipe, infrasound signals are generated, causing a change in the DFB wavelength within the fiber optic DFB hydrophone (fiber optic hydrophone 10). The reflected light passes through fiber coupler 9 (which can be a 1x2 coupler), optical fiber 8 (which can be a single-mode glass fiber), WDM 7, and isolator 11 before entering Michelson interferometer 12. Michelson interferometer 12 converts the wavelength change of the fiber optic DFB hydrophone (fiber optic hydrophone 10) into a phase change. The light exiting Michelson interferometer 12 enters fiber optic phase demodulator 13 for phase demodulation. The demodulated result is then sent to the server for data processing via 5G terminal equipment 14.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fiber optic sensing system suitable for pipeline leak monitoring, characterized in that, include: The system includes a pump laser (6), a wavelength division multiplexer (7), at least one fiber optic hydrophone (10) installed in a pipe, a Michelson interferometer (12), and a fiber optic phase demodulator (13). The pump laser (6) and the Michelson interferometer (12) are both connected to the wavelength division multiplexer (7), the wavelength division multiplexer (7) is connected to the fiber optic hydrophone (10), and the fiber optic phase demodulator (13) is connected to the Michelson interferometer (12). It also includes a field station (1) and multiple pipe roots. The station (1) is connected to the first valve chamber (3) and the first valve chamber (3) and the second valve chamber (5) respectively through the oil and gas pipeline (4). Multiple valve groups (2) at the root of the pipeline are installed on the oil and gas pipeline (4). Multiple fiber optic hydrophones (10) are installed at the inlet and outlet ends of the pipelines of the station (1), the first valve chamber (3) and the second valve chamber (5).

2. The fiber optic sensing system for pipeline leak monitoring according to claim 1, characterized in that, Multiple fiber optic hydrophones (10) are installed one-to-one in multiple pipe root valve groups (2).

3. The fiber optic sensing system for pipeline leak monitoring according to claim 1, characterized in that, The wavelength division multiplexer (7) is connected to the fiber optic hydrophone (10), the pump laser (6) is connected to the wavelength division multiplexer (7), and the Michelson interferometer (12) is connected to the fiber optic phase demodulator (13) via optical fiber (8).

4. The fiber optic sensing system for pipeline leak monitoring according to claim 3, characterized in that, The optical fiber (8) is a single-mode glass optical fiber.

5. The fiber optic sensing system for pipeline leak monitoring according to claim 1, characterized in that, The wavelength division multiplexer (7) is connected to a plurality of optical fiber hydrophones (10) via an optical fiber coupler (9).

6. The fiber optic sensing system for pipeline leak monitoring according to claim 5, characterized in that, The fiber optic coupler (9) is a 1*2 coupler.

7. The fiber optic sensing system for pipeline leak monitoring according to claim 1, characterized in that, The Michelson interferometer (12) is connected to the wavelength division multiplexer (7) via an isolator (11).

8. The fiber optic sensing system for pipeline leak monitoring according to claim 1, characterized in that, The fiber optic phase demodulator (13) is connected to a 5G terminal device (14).

9. A fiber optic sensing system for pipeline leak monitoring according to claim 1, characterized in that, The fiber optic hydrophone is a distributed feedback fiber optic hydrophone.

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