CN112944222A - Sensor suitable for long-distance submarine pipeline leakage monitoring and monitoring method thereof - Google Patents
Sensor suitable for long-distance submarine pipeline leakage monitoring and monitoring method thereof Download PDFInfo
- Publication number
- CN112944222A CN112944222A CN202110340370.XA CN202110340370A CN112944222A CN 112944222 A CN112944222 A CN 112944222A CN 202110340370 A CN202110340370 A CN 202110340370A CN 112944222 A CN112944222 A CN 112944222A
- Authority
- CN
- China
- Prior art keywords
- optical fiber
- vibration
- monitoring
- optical
- signal processing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000012544 monitoring process Methods 0.000 title claims abstract description 62
- 238000000034 method Methods 0.000 title claims abstract description 24
- 239000013307 optical fiber Substances 0.000 claims abstract description 89
- 230000003287 optical effect Effects 0.000 claims abstract description 75
- 238000012545 processing Methods 0.000 claims abstract description 23
- 230000008859 change Effects 0.000 claims abstract description 13
- 238000004458 analytical method Methods 0.000 claims abstract description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- 229910000831 Steel Inorganic materials 0.000 claims description 8
- 239000010959 steel Substances 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 claims description 6
- 238000009434 installation Methods 0.000 claims description 4
- 239000011241 protective layer Substances 0.000 claims description 3
- 238000004804 winding Methods 0.000 claims description 2
- 238000005516 engineering process Methods 0.000 description 15
- 239000000835 fiber Substances 0.000 description 15
- 239000007789 gas Substances 0.000 description 14
- 239000008399 tap water Substances 0.000 description 12
- 235000020679 tap water Nutrition 0.000 description 12
- 239000003921 oil Substances 0.000 description 11
- 239000010410 layer Substances 0.000 description 10
- 238000001228 spectrum Methods 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- 230000035945 sensitivity Effects 0.000 description 7
- 238000001514 detection method Methods 0.000 description 6
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 238000010276 construction Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 229920001971 elastomer Polymers 0.000 description 3
- 238000003032 molecular docking Methods 0.000 description 3
- 239000003345 natural gas Substances 0.000 description 3
- 239000013535 sea water Substances 0.000 description 3
- 238000013461 design Methods 0.000 description 2
- 230000001902 propagating effect Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000002390 adhesive tape Substances 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000806 elastomer Substances 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17D—PIPE-LINE SYSTEMS; PIPE-LINES
- F17D5/00—Protection or supervision of installations
- F17D5/02—Preventing, monitoring, or locating loss
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17D—PIPE-LINE SYSTEMS; PIPE-LINES
- F17D5/00—Protection or supervision of installations
- F17D5/005—Protection or supervision of installations of gas pipelines, e.g. alarm
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Examining Or Testing Airtightness (AREA)
Abstract
The invention relates to the technical field of submarine oil and gas pipeline leakage monitoring, and aims to solve the technical problem of providing a sensor suitable for long-distance marine pipe leakage monitoring and a monitoring method thereof.A vibration sensing optical fiber interferometer is arranged at each leakage monitoring point of a long-distance marine pipe, and a main end signal processing device inputs optical signals to the vibration sensing optical fiber interferometer at each monitoring point through a main optical cable; the input optical signal passes through the vibration sensing optical fiber interferometer of each monitoring point, then the interference light is output, and the interference light is output to the trunk end signal processing equipment through the trunk optical cable; the dry end signal processing equipment demodulates the change of the optical phase in the vibration sensitive coil from the change of the light intensity of the interference light output by the vibration sensing optical fiber interferometer of each monitoring point to obtain the magnitude of a vibration signal causing the change of the optical phase; through the analysis and processing of signals, the vibration sensing optical fiber interferometer with the vibration signals exceeding the early warning value is identified, and the position of the leakage point is positioned.
Description
Technical Field
The invention relates to the technical field of leakage monitoring of submarine oil and gas pipelines, in particular to a sensor suitable for long-distance submarine oil and gas pipeline leakage monitoring and a monitoring method thereof.
Background
The submarine pipeline is the most economical and reasonable choice in offshore oil and natural gas transportation modes. By the end of 2015, 336 submarine pipelines are co-constructed in China, the accumulated length is about 6307km, and the submarine pipelines are responsible for the transportation tasks of important energy sources such as marine crude oil, natural gas and the like. However, with the continuous construction and the continuous increase of service time of the submarine pipelines, the potential risks of damage to the submarine pipelines caused by seawater corrosion, third party damage and the like are accumulated continuously, and the leakage accidents of the submarine oil and gas pipelines are caused continuously. According to statistics, in recent years, 38 submarine pipeline accidents occur in China: wherein the third party is 39.5% from the point of 15% failure; the internal corrosion is 11 percent, and the proportion is 28.9 percent; the external corrosion is 3, and the proportion is 7.9%. Once the submarine pipeline leaks, if the submarine pipeline cannot be timely detected and corresponding treatment measures are taken, huge economic loss and social problems are caused.
Through years of research and practice of related research institutions at home and abroad, the current pipeline leakage monitoring method can be roughly divided into an internal monitoring method and an external monitoring method. The internal monitoring method mainly comprises a pressure gradient method, a pressure point analysis method, a negative pressure wave method, a flow balance method, an infrasonic wave method and the like; the external monitoring method mainly includes an optical fiber monitoring method, a gas imaging method, a gas monitoring method and the like. The optical fiber sensing technology has the characteristics of large detection span, good environmental adaptability, no source of underwater electricity, high sensitivity and the like, and gradually replaces some traditional monitoring technologies in recent years, so that the optical fiber sensing technology becomes one of mainstream technologies for pipeline leakage monitoring. The existing optical fiber sensing technology suitable for monitoring the leakage of a long-distance pipeline is mainly divided into a distributed temperature/vibration sensing technology and a quasi-distributed vibration sensing technology.
The distributed temperature sensing technology is characterized in that the sensing optical cable and the oil and gas pipeline are adjacently installed side by side, and the temperature distribution on the sensing optical cable is measured by adopting the distributed optical fiber temperature measurement technology. When the oil gas pipeline leaks, high-pressure liquid/gas leaks outwards due to the difference between internal pressure and external pressure, and the temperature near the leakage point changes. The occurrence of the leakage can be identified and positioned by measuring the temperature change when the leakage occurs through the sensing optical cables adjacent to the pipeline.
The distributed vibration sensing technology is characterized in that a sensing optical cable and an oil-gas pipeline are adjacently installed side by side, and vibration signals along the sensing optical cable are measured by adopting an interference principle or a back scattering principle. When the oil and gas pipeline leaks, abnormal vibration sound waves of the pipe wall can be generated. And identifying the occurrence of leakage and positioning by using a vibration signal sent when the leakage is measured by the sensing optical cable adjacent to the pipeline. The distributed sensing technology has the advantages that the sensing end structure is relatively simple, and continuous measurement in a long distance can be realized. However, the false alarm rate is high because the weak reflection signal in the optical fiber is used for detection, and the signal resolution capability is weak. Meanwhile, the longer detection distance also limits the frequency response range of detection.
Patent document CN102997063A entitled "a natural gas pipeline leakage monitoring method based on optical fiber sensing" discloses a quasi-distributed pipeline leakage monitoring system. The system is characterized in that an optical fiber vibration sensor is arranged on a pipeline at a certain distance, a frequency division/space division multiplexing mode is adopted to form a quasi-distributed sensing array, vibration signals generated by leakage on the pipeline are monitored, and the leakage occurrence is identified and positioned through analysis and processing of the signals. The optical fiber vibration sensor is composed of an elastic structure and an optical fiber interferometer. The monitoring system has higher sensitivity than a distributed sensing system. However, the mechanical structure is complicated, and the optical path structure is complicated because different sensing units need to adopt different optical path differences.
The technologies have relevant reports on onshore oil and gas pipeline monitoring, and due to the particularity of marine environment and the restriction of pipe laying technological process, the optical fiber sensing technologies suitable for onshore oil and gas pipeline leakage monitoring are not completely suitable for leakage monitoring of marine pipes.
The heat capacity of the seawater is large, and the temperature change of the seawater caused by pipeline leakage is small. The sea pipe is usually a double-layer pipe structure, the inner layer is a steel pipe for conveying oil gas, and the outer layer is a cement counterweight protective layer. Due to the existence of the counterweight protection layer, the sensitivity and the signal-to-noise ratio of the temperature/vibration measurement outside the pipe are greatly reduced. In addition, the sea pipe is processed into a section of tens of meters to tens of meters in a factory for convenient transportation. Before pipe laying on a ship, the segmented sea pipes need to be welded, wrapped by counterweights and the like to form a continuous long-distance pipeline and put into the sea. If the sensing trunk optical cable is directly buried in the counterweight protection layer in order to improve the monitoring sensitivity, the optical path connection between each section of the marine pipe can be realized only by field welding or watertight connectors. Under the long-distance condition, the huge number of connection points on the sensing trunk optical cable can cause the trunk optical path loss to be accumulated point by point, and the effective transmission of sensing signals cannot be realized. Assuming a total length of 100km for a single marine pipe of 12m, there will be 8000 connection points on the sensing cable. Assuming that the optical loss at the connection point is 0.05dB, the optical loss for a 100km round trip would exceed 800 dB.
The above reasons make the existing distributed optical fiber temperature/vibration sensing technology unsuitable for leakage monitoring of long-distance marine pipelines. The quasi-distributed pipeline leakage monitoring system proposed in the above patent CN102997063A is not suitable for being buried in a counterweight protection layer of a marine pipe due to the large volume of the sensor; and the leaked vibration signal can be applied to the sensing optical fiber only through the coupling between the pipeline and the elastic structure of the sensor, so that certain energy loss exists, and the further improvement of the detection sensitivity is limited.
Therefore, research and development of sensors and monitoring methods thereof suitable for long-distance marine vessel leakage monitoring are urgently needed.
Disclosure of Invention
The invention aims to solve the technical problem of the prior art and provides a sensor suitable for long-distance marine vessel leakage monitoring and a monitoring method thereof.
In order to solve the technical problems, the invention adopts the following technical scheme:
the utility model provides a sensor suitable for monitoring is revealed to long distance sea pipe which characterized in that: arranging a vibration sensing optical fiber interferometer on each leakage monitoring point of the long-distance marine pipe, wherein the vibration sensing optical fiber interferometer comprises a first vibration sensitive coil 23, a first Faraday reflector 24, a first optical fiber coupler 33 and a second optical fiber watertight connector 37; the first vibration sensitive coil 23 is formed by directly winding a sensing optical fiber of which one end is connected with a first Faraday reflector 24 on the steel pipe 21 in the single submarine pipe of the monitoring point, the counterweight protection layer 22 is led out from the other end of the first vibration sensitive coil 23, and a first optical fiber watertight connector 25 is installed; a junction box 32 is arranged corresponding to the installation position of the first vibration sensitive coil 23, and the first optical fiber coupler 33 and the first faraday reflector 24 are installed in the junction box 32; the first vibration sensitive coil 23 is connected with the first optical fiber coupler 33 in the junction box 32 through the first optical fiber watertight connector 25, each junction box 32 is arranged on the trunk optical cable 31 on the sea pipe, and the optical fiber 38 in the trunk optical cable 31 is used for connecting the optical signal input end and the optical signal output end of the first optical fiber coupler 33 in the junction box 32; one end of the trunk cable 31 is led over the water to be connected with the dry-end signal processing device.
Further, the dry-end signal processing device includes a light source 45, a first photoelectric conversion device 46, and a signal processing terminal 47.
Further, the shape of the connection box 32 is designed to be consistent with the shape of the main optical cable 31, and the main optical cable 31 provided with the connection box 32 adopts an external armor structure.
Further, the main optical cable 31 is fast fixed with the submarine through the mother-son pipe clamp 53 and is laid out in the sea along with the submarine.
A monitoring method suitable for long-distance submarine pipeline leakage monitoring is characterized by comprising the following steps: the method comprises the following steps:
step one, the main end signal processing equipment inputs optical signals to a vibration sensing optical fiber interferometer of each monitoring point through a main optical cable;
step two, after the input optical signal passes through the vibration sensing optical fiber interferometer of each monitoring point, the interference light is output and is output to the trunk end signal processing equipment through the trunk optical cable;
thirdly, the dry end signal processing equipment demodulates the change of the optical phase in the first vibration sensitive coil 23 from the change of the light intensity of the interference light output by the vibration sensing optical fiber interferometer of each monitoring point through a phase demodulation algorithm to obtain the magnitude of the vibration signal causing the change of the optical phase; through the analysis and processing of signals, the vibration sensing optical fiber interferometer with the vibration signals exceeding the early warning value is identified, and the position of the leakage point is positioned through the one-to-one correspondence relation of the installation positions of the vibration sensing optical fiber interferometer.
Compared with the prior art, the invention has the following beneficial effects:
1. the sensitivity is high: the sensitive optical fiber/optical cable is directly wound on the measured submarine pipe to directly sense the vibration information on the submarine pipe, so that the energy transmission of an intermediate link does not exist, and the energy loss is effectively avoided; meanwhile, the length of a single submarine pipe reaches dozens of meters, and the length of the windable sensitive optical fiber/optical cable reaches hundreds of meters or even thousands of meters, so that high sensing sensitivity can be realized.
2. The transmission loss is low: in the scheme, the position of using the watertight connector is only the connection between the vibration sensitive coil and the connection box on the main optical cable, and the connection loss of each watertight connector cannot be accumulated; the optical paths of the main optical cable are connected in an optical fiber welding mode, and the connection loss of each point can be reduced to 0.01 dB. When the main optical cable is manufactured, the splitting ratio of the optical fiber coupler on the time division light path and the optical signal amplification range on each space division light path are configured, so that the signal light intensity of each sensor is approximately equivalent, and the accurate demodulation of the array signal is facilitated.
3. The construction is convenient: due to the adoption of the design of the watertight connector, the optical path quick connection between the vibration sensitive coil and the main optical cable can be realized during offshore construction; the design of the primary and secondary pipe clamps can be adopted to realize the fast and reliable binding of the main optical cable and the submarine pipe.
4. Multiple leak event differentiation: a plurality of optical fiber vibration sensing units are arranged along the submarine pipeline, and each sensing unit has a certain detection range. Even if there are a plurality of leakage events on the pipeline, the sensing units at different positions can respectively sense and effectively distinguish.
Drawings
FIG. 1 is a basic principle structure diagram of an optical fiber vibration sensor
FIG. 2 is a schematic view of a first vibration-sensitive coil wound around a marine vessel
FIG. 3 is a schematic view of the internal optical path structure of the main optical cable and the junction box
FIG. 4 is a schematic diagram of a fiber sensor array system
FIG. 5 is a schematic view showing the structure of the main optical cable and the submarine pipeline connected by the mother-son pipe clamp
FIG. 6 is a photograph of a tap water pipe leakage monitoring sensor for a simulation test
FIG. 7 is a schematic view of a tap water pipe leakage monitoring and sensing system for a simulation test
FIG. 8 is a signal frequency spectrum diagram measured by the sensing system under the condition that the tap water pipe is not filled with water
FIG. 9 is a signal spectrum diagram measured by the sensing system under the condition of low water flow speed, wherein a gray curve is a test result curve, and a white curve is a curve measured by the sensing system under the condition that the tap water pipe is not filled with water
FIG. 10 is a signal spectrum diagram measured by the sensing system under the condition of larger water flow speed, wherein a gray curve is a test result curve, and a white curve is a curve measured by the sensing system under the condition that the tap water pipe is not filled with water
FIG. 11 is a signal spectrum diagram of a sensing system in the case of a water pipe leak, in which the gray curve is a test result curve and the white curve is a curve measured by the sensing system in the case of no water flowing through the water pipe
Description of reference numerals:
11: a vibration sensitive coil; 12: an elastomer; 13: a reference optical fiber; 14: a Faraday mirror; 15: an input optical fiber; 16: an output optical fiber; 17: a fiber coupler; 21: a steel pipe; 22: a counterweight protective layer; 23: a first vibration sensitive coil; 24: a first Faraday mirror; 25: a first fiber watertight connector; 31: a trunk optical cable; 32: a docking box; 33: a first fiber coupler; 35: a second fiber coupler; 37: a second fiber watertight connector; 38: an optical fiber; 39: a sensor unit; 45: a light source; 46: a first photoelectric conversion device; 47: a signal processing terminal; 53: a master-slave pipe clamp; 71: a tap water pipe; 72: a second vibration sensitive coil; 73: a second Faraday mirror; 74: a third fiber coupler; 75: a narrow line width light source; 76: a second photoelectric conversion device; 77: a phase signal demodulator; 78: and (4) a hole.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples.
The scheme adopts the scheme that the sensing trunk optical cable and the submarine pipe are independently manufactured, and optical path connection and binding are carried out when the submarine is laid on the sea.
The basic principle structure of the optical fiber vibration sensor is shown in fig. 1, and an optical fiber is wound on an elastic body 12 to form a vibration sensitive coil 11. When the elastic body 12 vibrates under the action of the external environment, the vibration sensitive coil 11 wound on the elastic body 12 will be slightly strained, thereby modulating the phase of the light wave propagating in the vibration sensitive coil 11. Finally, the magnitude of the vibration signal can be obtained by measuring the phase change of the light wave. The measurement of the phase of the light wave is achieved by laser interference. The vibration sensitive coil 11, the optical fiber coupler 17 and the Faraday mirror 14 form a set of optical fiber interferometer. The signal light is input into the optical fiber coupler 17 through the input optical fiber 15, is divided into two beams, respectively enters the vibration sensitive coil 11 and the reference optical fiber 13, is reflected by the Faraday mirror 14, returns to the optical fiber coupler 17 to generate interference, and the interference light is output through the interferometer output optical fiber 16. The phase of the signal light transmitted in the vibration-sensitive coil 11 is changed correspondingly by the influence of the vibration signal, while the signal light transmitted in the reference optical fiber 13 is not influenced by the vibration signal, so that the light intensity of the interference light is changed correspondingly with the change of the optical phase in the vibration-sensitive coil 11. The variation of the optical phase in the vibration sensitive coil 11 is demodulated from the variation of the output light intensity through a phase demodulation algorithm, so that the magnitude of the vibration signal causing the variation of the optical phase can be obtained.
In the present invention, a sensing fiber connected to a first faraday mirror 24 is directly wound on a steel pipe 21 inside a single submarine pipe to form a first vibration sensing coil 23, as shown in fig. 2. In order to enhance the mechanical strength of the sensing optical fiber, the sensing optical fiber can be made into a sensing optical cable, and then wound on the steel tube 21, and embedded in the counterweight protection layer 22 together with the steel tube 21. The other end of the first vibration sensitive coil 23 leads out of the counterweight protection layer 22 and is provided with a first optical fiber watertight connector 25. When the sea pipe leaks, the high-pressure oil gas can cause the sea pipe near the leakage hole to generate corresponding vibration through the leakage hole. The vibration of the sea-pipe causes a slight strain to the optical fiber wound around the sea-pipe, thereby modulating the phase of the light wave propagating in the optical fiber.
As shown in fig. 3, the remaining components constituting the vibration sensing fiber interferometer, including the first fiber coupler 33 and the first faraday mirror 24, are mounted in a junction box 32 on the trunk cable 31. The signal arm of the vibration sensing fiber optic interferometer is provided with a second fiber watertight connector 37 for connection with the first fiber watertight connector 25 on the marine vessel. To facilitate storage and deployment of long-haul submarine cables, the docking box 32 may be contoured to conform to the trunk cable 31. In order to ensure the mechanical strength of the main optical cable 31, an external armored structure may be adopted. The position of each docking box 32 on the trunk cable 31 corresponds to the position of each first vibration-sensitive coil 23 on the sea pipe. The optical fiber 38 in the trunk optical cable 31 is used for connecting each vibration sensing optical fiber interferometer in the junction box, and hundreds or even thousands of sensor units 39 with the same structure can be flexibly integrated on one trunk optical cable 31 in a wavelength division/time division/space division multiplexing mode. The second optical fiber couplers 35 with different splitting ratios are used for forming the time division array light path.
Fig. 4 is a schematic structural diagram of the entire optical fiber sensor system. Each first vibration sensitive coil 23 wound on the steel pipe 21 is quickly connected with the connection box 32 on the trunk optical cable 31 through the first optical fiber watertight connector 25, and one end of the trunk optical cable 31 is led to an onshore machine station or a drilling platform and connected with a dry end signal processing device: the light source 45, the first photoelectric conversion device 46, and the signal processing terminal 47 are connected.
As shown in fig. 5, during offshore construction, the main optical cable 31 is quickly fixed to the weight protection layer 22 of the marine pipe by the mother-son pipe clamp 53 and laid down to the sea together with the marine pipe.
When leakage occurs at a certain position of the submarine pipeline, vibration signals with specific frequency can appear on the submarine pipeline around the leakage point, and interference signals of nearby optical fiber vibration sensing units can be correspondingly changed. Through analysis and processing of signals, the two sensing units with the most obvious signals can be identified, and the positions of the leakage points are positioned through the one-to-one correspondence relationship between the units and the installation positions. If a section of the marine pipe is seriously leaked, and the first vibration sensitive coil wound on the section is broken, the sensing system can automatically identify the position of the damaged sensing unit.
Examples
As the leakage monitoring and verification of the marine pipe is carried out at sea, the engineering is large and the time is long, so that the tap water pipe is adopted to simulate and verify the monitoring effect of the leakage.
As shown in FIG. 7, a small mode field optical fiber with a cladding diameter of 80 μm, which is a 10m long tightly-packed optical fiber, is uniformly wound around a 3 m long metal tap water pipe 71 with a diameter of 20mm with a certain prestress to form a second vibration sensitive coil 72. The periphery is wrapped and fixed by an adhesive tape. A second faraday mirror 73 is attached to one end of the tight-buffered fiber. The second vibration sensitive coil 72 forms a pair of vibration sensing optical fiber interferometers together with a third optical fiber coupler 74 and a second Faraday mirror 73 on the periphery through optical fiber connectors, wherein the optical fiber length of the reference arm is 40 mm. The vibration sensing fiber interferometer is connected with a C-band narrow linewidth light source 75, a second photoelectric conversion device 76 and a phase signal demodulator 77 to constitute a sensing system. The phase signal demodulator 77 has a phase resolution of 10 μ rad; the frequency response range is 20 Hz-50 kHz. To simulate the leakage situation, a hole 78 with a diameter of 2mm was drilled in the tap water pipe 71 and sealed with a rubber stopper.
The signal spectrum of the sensing system measured when the tap water pipe is not filled with water and the surrounding is quiet is shown in fig. 8. It can be seen from the figure that the self-noise level of the system is around 110 dB.
The signal frequency spectrum measured by the sensing system in the state of water flowing through the tap water pipe is shown as the grey line in fig. 9 and 10. As can be seen from the figure, the spectrum signal is significantly changed and the spectrum component is abundant compared to the white curve in the state of no water supply. There is a distinct signal peak at 770 Hz. As the water flow gradually increases, the frequency band of the sample widens toward a high frequency band.
The water flow was maintained at a moderate flow rate through the sample. The rubber plug on the tap water pipe is pulled out. The spectrogram of the water leakage measurement result is shown as a grey line in fig. 11, and two obvious signal peaks of 470Hz and 770Hz exist. Comparing the signals when no water was leaked, it was found that the peak at 470Hz was due to a water pipe leak.
The test results show that the characteristic vibration signals generated by leakage can be measured in a high-sensitivity manner by adopting a mode that the optical fibers are directly wound on the submarine pipe to be detected and combining the corresponding interference sensing technology, so that the monitoring of pipeline leakage is realized.
In addition, if an optical path multiplexing method of 8 wavelength division × 8 time division × 4 space division is adopted, 256 sensing units can be integrated by using 8 optical fibers in the same trunk optical cable. And setting the distance between the sensing units to be 500m, so that the leakage monitoring of the submarine pipeline of 128km can be realized by adopting the scheme of the invention.
Claims (5)
1. The utility model provides a sensor suitable for monitoring is revealed to long distance sea pipe which characterized in that: arranging a vibration sensing optical fiber interferometer on each leakage monitoring point of the long-distance submarine pipeline, wherein the vibration sensing optical fiber interferometer comprises a first vibration sensitive coil (23), a first Faraday reflector (24), a first optical fiber coupler (33) and a second optical fiber watertight connector (37); the first vibration sensitive coil (23) is formed by directly winding a sensing optical fiber of which one end is connected with a first Faraday reflector (24) on a steel pipe (21) in a single submarine pipe of a monitoring point, the other end of the first vibration sensitive coil (23) is led out of a counterweight protective layer (22), and a first optical fiber watertight connector (25) is installed; a connection box (32) is arranged at the mounting position corresponding to the first vibration sensitive coil (23), and the first optical fiber coupler (33) and the first Faraday reflector (24) are mounted in the connection box (32); the first vibration sensitive coil (23) is connected with a first optical fiber coupler (33) in each junction box (32) through a first optical fiber watertight connector (25), each junction box (32) is arranged on a main optical cable (31) on the sea pipe, and an optical fiber (38) in the main optical cable (31) is used for connecting an optical signal input end and an optical signal output end of the first optical fiber coupler (33) in each junction box (32); one end of the trunk optical cable (31) is led to the water to be connected with the signal processing equipment at the dry end.
2. A sensor adapted for long distance marine pipeline leak monitoring according to claim 1, wherein: the dry-end signal processing device comprises a light source (45), a first photoelectric conversion device (46) and a signal processing terminal (47).
3. A sensor adapted for long distance marine pipeline leak monitoring according to claim 2, wherein: the shape of the connection box (32) is designed to be consistent with the shape of the main optical cable (31), and the main optical cable (31) provided with the connection box (32) adopts an external armor structure.
4. A sensor adapted for long distance marine pipeline leak monitoring according to claim 3, wherein: the main optical cable (31) is quickly fixed with the submarine pipeline through the mother-son pipeline clamp (53) and is laid in the sea along with the submarine pipeline.
5. A monitoring method suitable for long distance marine pipeline leakage monitoring using the sensor of claims 1 to 4, characterized by: the method comprises the following steps:
step one, the main end signal processing equipment inputs optical signals to a vibration sensing optical fiber interferometer of each monitoring point through a main optical cable;
step two, after the input optical signal passes through the vibration sensing optical fiber interferometer of each monitoring point, the interference light is output and is output to the trunk end signal processing equipment through the trunk optical cable;
thirdly, the dry end signal processing equipment demodulates the change of the optical phase in the first vibration sensitive coil (23) from the change of the light intensity of the interference light output by the vibration sensing optical fiber interferometer of each monitoring point through a phase demodulation algorithm to obtain the magnitude of the vibration signal causing the change of the optical phase; through the analysis and processing of signals, the vibration sensing optical fiber interferometer with the vibration signals exceeding the early warning value is identified, and the position of the leakage point is positioned through the one-to-one correspondence relation of the installation positions of the vibration sensing optical fiber interferometer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110340370.XA CN112944222A (en) | 2021-03-30 | 2021-03-30 | Sensor suitable for long-distance submarine pipeline leakage monitoring and monitoring method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110340370.XA CN112944222A (en) | 2021-03-30 | 2021-03-30 | Sensor suitable for long-distance submarine pipeline leakage monitoring and monitoring method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112944222A true CN112944222A (en) | 2021-06-11 |
Family
ID=76230534
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110340370.XA Pending CN112944222A (en) | 2021-03-30 | 2021-03-30 | Sensor suitable for long-distance submarine pipeline leakage monitoring and monitoring method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112944222A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024027542A1 (en) * | 2022-08-01 | 2024-02-08 | 中广核研究院有限公司 | Mutual-induction type liquid metal leakage monitoring apparatus and use thereof |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5475216A (en) * | 1990-05-22 | 1995-12-12 | Danver; Bruce A. | Fiber optic sensor having mandrel wound reference and sensing arms |
| CN1307678A (en) * | 1998-06-26 | 2001-08-08 | 塞德拉公司 | Non-intrusion fiber optic pressure-sensor for measuring unsteady pressures within pipe |
| US20030174924A1 (en) * | 2002-03-14 | 2003-09-18 | Tennyson Roderick C. | Monitoring of large structures using brillouin spectrum analysis |
| RU2011125945A (en) * | 2011-06-24 | 2012-12-27 | Общество с ограниченной ответственностью "Инновационное предприятие "НЦВО-ФОТОНИКА" (ООО ИП "НЦВО-Фотоника") | DISTRIBUTION FIBER OPTICAL SYSTEM OF VIBROACOUSTIC SIGNALS RECORDING |
| CN102997062A (en) * | 2011-09-14 | 2013-03-27 | 中国石油天然气集团公司 | Optical fiber sensor-based natural gas pipeline leakage monitoring method and system and installation method for system |
| CN215908883U (en) * | 2021-03-30 | 2022-02-25 | 上海传输线研究所（中国电子科技集团公司第二十三研究所） | Sensor suitable for long distance sea pipe leakage monitoring |
-
2021
- 2021-03-30 CN CN202110340370.XA patent/CN112944222A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5475216A (en) * | 1990-05-22 | 1995-12-12 | Danver; Bruce A. | Fiber optic sensor having mandrel wound reference and sensing arms |
| CN1307678A (en) * | 1998-06-26 | 2001-08-08 | 塞德拉公司 | Non-intrusion fiber optic pressure-sensor for measuring unsteady pressures within pipe |
| US20030174924A1 (en) * | 2002-03-14 | 2003-09-18 | Tennyson Roderick C. | Monitoring of large structures using brillouin spectrum analysis |
| RU2011125945A (en) * | 2011-06-24 | 2012-12-27 | Общество с ограниченной ответственностью "Инновационное предприятие "НЦВО-ФОТОНИКА" (ООО ИП "НЦВО-Фотоника") | DISTRIBUTION FIBER OPTICAL SYSTEM OF VIBROACOUSTIC SIGNALS RECORDING |
| CN102997062A (en) * | 2011-09-14 | 2013-03-27 | 中国石油天然气集团公司 | Optical fiber sensor-based natural gas pipeline leakage monitoring method and system and installation method for system |
| CN215908883U (en) * | 2021-03-30 | 2022-02-25 | 上海传输线研究所（中国电子科技集团公司第二十三研究所） | Sensor suitable for long distance sea pipe leakage monitoring |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024027542A1 (en) * | 2022-08-01 | 2024-02-08 | 中广核研究院有限公司 | Mutual-induction type liquid metal leakage monitoring apparatus and use thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102011940B (en) | Distributed optical fiber and flow pressure value-based pipeline leakage joint detection method | |
| CN1303411C (en) | Interference distributed fibre-optical pipe leakage real-time monitoring method and device | |
| CN102735996B (en) | Exact locating method for fault points of submarine cable | |
| CN215908883U (en) | Sensor suitable for long distance sea pipe leakage monitoring | |
| CN102997045B (en) | Optical fiber sensing natural gas pipeline leakage event identification method and device | |
| KR100945290B1 (en) | Pipe and system detecting breakdown and leakage of pipe by fiber-optic calbe | |
| KR101098528B1 (en) | System and method for watching pipeline | |
| CN203868702U (en) | Underground pipeline leakage early-warning system based on fiber bragg grating sensors | |
| CN205919126U (en) | Novel oil pipe leaks pressure detecting system | |
| CN102944613A (en) | Detecting and positioning system for optical fiber acoustic emission | |
| CN101858488A (en) | Oil gas pipeline monitoring method and system | |
| CN202100946U (en) | Monitoring device for pipeline leakage based on double-Sagnac optical fiber interferometers | |
| CN106931896A (en) | The optical fiber sensing technology and system of geomembrane anti-seepage earth and rockfill dam deformation monitoring | |
| CN102997055B (en) | Leakage point locating method and system of optical fiber sensing natural gas pipeline leakage monitoring system | |
| CN105509979A (en) | Fiber optic negative pressure wave-based oil and gas pipeline leakage monitoring positioning system and method | |
| CN104596576A (en) | Optical fiber temperature sensing and vibration sensing collineation fusion system and monitoring method | |
| CN111122068A (en) | Water pipeline leakage position positioning method based on optical fiber hydrophone | |
| CN116972343A (en) | Optical fiber sensing system suitable for pipeline leakage monitoring | |
| CN103047541A (en) | Optical fiber sensing natural gas pipeline leakage accident recognition device | |
| CN112944222A (en) | Sensor suitable for long-distance submarine pipeline leakage monitoring and monitoring method thereof | |
| CN209638791U (en) | A kind of submarine pipeline leakage monitoring system | |
| WO2008003224A1 (en) | An optical fiber control system for safety early-warning | |
| US20180136017A1 (en) | Integration of fiber optic sensors into sleeve | |
| CN100487509C (en) | Optical fiber safety early warning polarization control system | |
| CN202338780U (en) | Optical fiber sensing natural gas pipeline leakage incident recognition device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |