WO2017183455A1 - Optical fiber sensing system and riser pipe - Google Patents

Optical fiber sensing system and riser pipe Download PDF

Info

Publication number
WO2017183455A1
WO2017183455A1 PCT/JP2017/014226 JP2017014226W WO2017183455A1 WO 2017183455 A1 WO2017183455 A1 WO 2017183455A1 JP 2017014226 W JP2017014226 W JP 2017014226W WO 2017183455 A1 WO2017183455 A1 WO 2017183455A1
Authority
WO
WIPO (PCT)
Prior art keywords
optical
optical fiber
sensing system
amplifying
signal
Prior art date
Application number
PCT/JP2017/014226
Other languages
French (fr)
Japanese (ja)
Inventor
石岡　昌人
Original Assignee
三菱重工業株式会社
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by 三菱重工業株式会社 filed Critical 三菱重工業株式会社
Publication of WO2017183455A1 publication Critical patent/WO2017183455A1/en

Links

Images

Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
    • E21B17/01—Risers
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B47/00—Survey of boreholes or wells
    • E21B47/12—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
    • E21B47/13—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling by electromagnetic energy, e.g. radio frequency
    • E21B47/135—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling by electromagnetic energy, e.g. radio frequency using light waves, e.g. infrared or ultraviolet waves
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
    • G02B6/4401—Optical cables
    • G02B6/4415—Cables for special applications
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/46—Processes or apparatus adapted for installing or repairing optical fibres or optical cables
    • G02B6/50—Underground or underwater installation; Installation through tubing, conduits or ducts
    • G02B6/502—Installation methods in fluid conducts, e.g. pipelines
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/46—Processes or apparatus adapted for installing or repairing optical fibres or optical cables
    • G02B6/50—Underground or underwater installation; Installation through tubing, conduits or ducts
    • G02B6/506—Underwater installation
    • G—PHYSICS
    • G08—SIGNALLING
    • G08C—TRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS
    • G08C23/00—Non-electrical signal transmission systems, e.g. optical systems
    • G08C23/06—Non-electrical signal transmission systems, e.g. optical systems through light guides, e.g. optical fibres
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
    • H01S3/067—Fibre lasers
    • H01S3/06754—Fibre amplifiers
    • H01S3/06758—Tandem amplifiers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/23—Arrangements of two or more lasers not provided for in groups H01S3/02 - H01S3/22, e.g. tandem arrangements of separate active media
    • H01S3/2383—Parallel arrangements
    • H01S3/2391—Parallel arrangements emitting at different wavelengths

Definitions

  • the present invention relates to an optical fiber sensing system and a riser tube.
  • production fluid mixed with crude oil, natural gas, etc. is pumped from a production well drilled to a depth of several thousand meters from the seabed.
  • the pumped production fluid is separated into a gas such as natural gas and a liquid such as crude oil by a separator such as a scrubber.
  • the production fluid is then sent to a ship at sea via a riser tube that extends under the sea.
  • the riser pipe has a very long structure that reaches from the sea to the sea floor. Therefore, when the riser tube breaks, local buckling becomes the main failure mode. Further, the riser pipe is disposed under a high tide, so that not only local buckling but also fatigue failure due to vibration becomes a problem.
  • Patent Document 1 describes a structure in which a measurement technique using an optical fiber is applied in order to precisely measure the response of the riser pipe to the flow of seawater.
  • the riser pipe described in Patent Document 1 is configured by connecting a plurality of riser pipe main bodies.
  • An optical fiber capable of transmitting an optical signal in both directions is disposed on the surface of the riser tube main body so that the end portion protrudes.
  • the optical fibers are connected by connecting the riser tube bodies together. Thereby, an optical fiber sensing system extending over a long distance along the surface of the riser tube is constructed.
  • optical loss in the optical fiber becomes a problem. Therefore, a repeater type optical amplifier that amplifies the optical signal is used to compensate for the optical loss.
  • the optical amplifier can basically amplify only the optical signal transmitted in one direction among the optical signals transmitted through the optical fiber. Therefore, even if only the incident light signal is amplified at the point where the amplifier is disposed, the reflected light signal may not be sufficiently amplified. Specifically, if the position where the reflected light signal is generated becomes far because the measurement location is away from the measurement unit, the light intensity necessary for receiving the light by the measuring instrument is maintained even if the incident light signal is amplified. It is difficult to give. Therefore, it is required to amplify both the incident optical signal and the reflected optical signal even when the bidirectional optical signal is propagated through a single optical fiber.
  • the present invention provides an optical fiber sensing system and a riser tube capable of amplifying both an incident optical signal and a reflected optical signal even when a bidirectional optical signal propagates through a single optical fiber section. provide.
  • the optical fiber sensing system is capable of propagating a bidirectional optical signal so as to guide an incident optical signal input from a light source and a reflected optical signal generated by a sensor unit, and is serially connected.
  • a second optical waveguide that amplifies only the reflected light signal.
  • the optical loss of both the incident light signal and the reflected light signal can be compensated by amplifying not only the incident light signal but also the reflected light signal.
  • the amplification unit receives the incident optical signals of the first optical waveguide and the second optical waveguide arranged in parallel.
  • a first optical path converter connecting the first side, a second optical path converter connecting the second side to which the reflected light signal of the first optical waveguide and the second optical waveguide arranged in parallel is input, and
  • the first optical path converter may guide the incident optical signal to the first optical waveguide, and the second optical path converter may guide the reflected optical signal to the second optical waveguide.
  • the incident light signal and the reflected light signal can be amplified individually and stably.
  • the optical fiber sensing system in the first or second aspect, includes a plurality of the amplifying units, and the plurality of amplifying units amplify optical signals in different wavelength ranges. May be.
  • the measurement distance can be extended without being limited by optical loss while adopting the WDM method.
  • a plurality of the amplifying units are provided, and the plurality of amplifying units amplify optical signals in the same wavelength region. May be.
  • the measurement distance can be extended without being limited by the optical loss while adopting the TDM method, the BOTDR method, or the BOCDA method.
  • the optical fiber part has a fiber Bragg rating formed in the core as the sensor part. May be.
  • the FBG method can be supported.
  • the first side to which the incident light signal of the amplification unit is input and the reflected light signal. May be provided on at least one of the second sides to which the light is input, and an optical switch unit capable of selectively connecting the amplification unit and the plurality of optical fiber units.
  • the riser tube according to the seventh aspect of the present invention has a cylindrical shape with one of the optical fiber sensing systems according to any one of the first to sixth aspects, and a surface of the optical fiber portion of the optical fiber sensing system.
  • a plurality of main riser pipe main bodies arranged in a tube, and an amplification riser pipe main body having a cylindrical shape on which an amplification part of the optical fiber sensing system is arranged on the surface, the end of the main riser pipe main body and the The optical fiber part and the amplifying part are connected by connecting the end part of the amplifying riser tube body in series.
  • the optical fiber part and the amplifying part can be continuously provided along the riser tube.
  • the distortion of the riser tube can be directly converted to the distortion of the optical fiber portion to correspond to the reflected light signal, and the light intensity of the reflected light signal at the stage of receiving light by the measuring device can be maintained by the amplifier.
  • the response of each part in the riser pipe from the ship to the seabed can be measured.
  • the present invention it is possible to amplify both the incident light signal and the reflected light signal even if the bidirectional optical signal is propagated through the single optical fiber portion.
  • the riser pipe 2 is used to excavate offshore platforms (for oil development, scientific research, etc.) and to lift crude oil collected from the offshore oil field to the offshore platforms.
  • the riser pipe 2 of the present embodiment has one end connected to the ship 1.
  • the ship 1 arranges the riser pipe 2 in the sea S and extends the other end of the riser pipe 2 to the seabed G.
  • the riser tube 2 has an optical fiber sensing system 3. As shown in FIG. 2, the riser pipe 2 has a structure in which a plurality of riser pipe main bodies 20 are connected in series.
  • the riser pipe body 20 has a cylindrical shape.
  • the riser tube main body 20 of the present embodiment has a cylindrical shape.
  • the riser pipe body 20 includes a drill pipe, a muddy water flow path, and a measuring device, and is covered with a protective member including a floating body (not shown).
  • the riser pipe 2 of the present embodiment includes a main riser pipe main body 21 and an amplification riser pipe main body 22 as the riser pipe main body 20.
  • the main riser tube main body 21 is attached with an optical fiber portion 31 of an optical fiber sensing system 3 to be described later.
  • the amplification riser tube main body 22 is attached with an amplification unit 32 of the optical fiber sensing system 3 described later.
  • the amplification riser tube main body 22 has the same shape as the main riser tube main body 21. That is, the amplification riser tube main body 22 is different from the main riser tube main body 21 in that an amplification unit 32 is attached instead of the optical fiber unit 31.
  • the end portion of the main riser tube body 21 and the end portion of the amplification riser tube body 22 are connected in series, whereby the optical fiber portion 31 and the amplification portion 32 are connected. Moreover, the optical fiber parts 31 are connected by the end parts of the main riser pipe main bodies 21 being connected in series.
  • the optical fiber sensing system 3 measures a physical quantity change such as a distortion of a measurement target and a temperature change at a remote point.
  • the optical fiber sensing system 3 of the present embodiment is attached to the riser pipe 2 to accurately grasp the response of the riser pipe 2 to the flow of seawater.
  • the optical fiber sensing system 3 accurately measures various vibrations including vortex induced vibration (VIV: Vortex Induced Vibration) generated in the riser tube 2 by seawater, or buckling occurs in the riser tube 2 due to these various vibrations. Accurately grasp the possibilities.
  • VIV Vortex Induced Vibration
  • the optical fiber sensing system 3 of this embodiment is provided with the optical fiber part 31, the amplification part 32, and the measuring device 33, as shown in FIG.
  • the optical fiber unit 31 is capable of propagating a bidirectional optical signal so as to guide the incident optical signal S1 input from the light source and the reflected optical signal S2 generated by the sensor unit 311.
  • the reflected light signal S2 is generated by at least one of the sensor units 311 of the optical fiber unit 31.
  • the reflected light signal S2 is generated by being reflected by a physical change in the surrounding environment of the sensor unit 311.
  • a plurality of optical fiber sections 31 are connected in series.
  • the optical fiber portion 31 is attached in close contact with the surface of the main riser tube main body 21.
  • the optical fiber portion 31 extends along the axial direction that is the longitudinal direction of the main riser tube main body 21.
  • the optical fiber portion 31 is bonded to the surface of the main riser tube main body 21 with an adhesive, for example.
  • the optical fiber portion 31 has a first end portion 31 a that is one end portion and a second end portion 31 b that is the other end portion extending from both end portions of the main riser tube main body 21.
  • the first end portion 31 a in the present embodiment is an end portion on the side where the incident optical signal S ⁇ b> 1 is input in the optical fiber portion 31.
  • the second end portion 31b is an end portion on the side where the reflected light signal S2 is input in the optical fiber portion 31.
  • the optical fiber portions 31 of the present embodiment are arranged one by one at a plurality of locations on the surface of the main riser tube main body 21.
  • the optical fiber portions 31 are arranged one by one in the circumferential direction of the main riser tube main body 21 so as to be arranged at predetermined intervals, for example, at equal intervals.
  • the optical fiber portion 31 is formed such that the first end portion 31 a and the second end portion 31 b protrude from the end portion of the main riser tube main body 21.
  • the first end portion 31 a and the second end portion 31 b of the optical fiber portion 31 are not fixed to the main riser pipe body 21 for connection work with the adjacent optical fiber portion 31.
  • the protruding portion of both ends of the optical fiber portion 31 and the protruding portion of the adjacent optical fiber portion 31 are connected by fusion, mechanical splice, connector, or the like. In this way, the protruding portions are connected by fusion, mechanical splices, connectors, or the like, so that a plurality of optical fiber portions 31 are easily provided continuously over the entire length of the long riser tube 2.
  • optical fiber portions 31 may use a fusion connection or a mechanical splice that are permanently connected, or a connector connection that can be repeatedly attached and detached.
  • the optical fiber unit 31 has a fiber Bragg grating (Bragg grating) formed in the core as the sensor unit 311.
  • a plurality of sensor units 311 are provided at a predetermined interval with respect to a plurality of optical fiber units 31 connected so as to be continuous. That is, the optical fiber part 31 of this embodiment has a part that functions as the sensor part 311 and a part that propagates an optical signal.
  • the sensor units 311 of the plurality of optical fiber units 31 correspond to different Bragg wavelengths. Thereby, the optical fiber sensing system 3 can be made to correspond to the wavelength multiplexing (WDM: Wavelength Division Multiplexing) method.
  • WDM Wavelength Division Multiplexing
  • the sensor unit 311 can be provided at intervals of several tens of cm, for example.
  • the sensor unit 311 When the riser pipe main body 20 is arranged on the seabed G with a depth of 3000 m and a water depth of 3000 m, the sensor unit 311 can be provided with several thousand measurement points. Thereby, a higher order response (mode node 20 m or less interval, several tens of Hz or more) can be measured.
  • the sensor part 311 may each have all the optical fiber parts 31, and may have only some optical fiber parts 31.
  • the amplifying unit 32 is connected to the optical fiber unit 31.
  • the amplifying unit 32 amplifies both the incident light signal S1 and the reflected light signal S2 separately.
  • a plurality of amplifying units 32 are provided.
  • the amplifying unit 32 of the present embodiment is provided at a ratio of one to a plurality of optical fiber units 31 connected in series.
  • the plurality of amplifying units 32 amplify optical signals in different wavelength ranges. That is, the plurality of amplifying units 32 correspond to different Bragg wavelengths.
  • the amplifying unit 32 includes a first optical waveguide 321, a second optical waveguide 322, a first optical path converter 323, and a second optical path converter 324.
  • the first optical waveguide 321 amplifies only the incident optical signal S1.
  • the first optical waveguide 321 is an optical fiber provided with an optical amplifier 320 on the way.
  • the optical amplifier 320 amplifies the optical signal passing therethrough.
  • an optical fiber amplifier or a semiconductor optical amplifier SOA: Semiconductor-Amplifier
  • the second optical waveguide 322 is provided in parallel with the first optical waveguide 321.
  • the second optical waveguide 322 amplifies only the reflected light signal S2.
  • the second optical waveguide 322 is an optical fiber provided with an optical amplifier 320 on the way.
  • the optical amplifier 320 used for the second optical waveguide 322 of the present embodiment is the same as the optical amplifier 320 used for the first optical waveguide 321.
  • the first optical path converter 323 connects the first side to which the incident optical signal S1 of the first optical waveguide 321 and the second optical waveguide 322 arranged in parallel is input.
  • the first side in the present embodiment is a side to which the incident optical signal S1 is input in the first optical waveguide 321.
  • the first optical path changer 323 is connected to the optical fiber unit 31 disposed on the first side, which is the side where the incident optical signal S1 is input to the amplifier unit 32.
  • the first optical path converter 323 guides the incident optical signal S1 to the first optical waveguide 321.
  • the first optical path changer 323 of this embodiment is an optical circulator.
  • the first optical path changer 323 separates or branches the incident optical signal S ⁇ b> 1 that has propagated through the optical fiber unit 31 and guides it only to the first optical waveguide 321.
  • the second optical path converter 324 connects the first optical waveguide 321 and the second side to which the reflected light signal S2 of the second optical waveguide 322 is input in parallel.
  • the second side in the present embodiment is a side to which the reflected optical signal S2 is input in the second optical waveguide 322. That is, the second optical path converter 324 is disposed on the opposite side of the first optical path converter 323 with respect to the first optical waveguide 321 and the second optical waveguide 322.
  • the second optical path converter 324 is connected to the optical fiber unit 31 disposed on the second side, which is the side on which the reflected light signal S ⁇ b> 2 to the amplifier unit 32 is input.
  • the second optical path converter 324 guides the reflected light signal S ⁇ b> 2 to the second optical waveguide 322.
  • the second optical path converter 324 of the present embodiment is the same optical circulator as the first optical path converter 323.
  • the second optical path changer 324 separates or branches the reflected light signal S ⁇ b> 2 that has propagated through the optical fiber portion 31 and guides it only to the second optical waveguide 322.
  • the measuring device 33 is connected to an optical fiber portion 31 disposed on the surface of the main riser tube main body 21.
  • the measuring device 33 is a light source that outputs an incident light signal S1 such as pulsed laser light having a predetermined frequency to the plurality of optical fiber portions 31.
  • the measuring device 33 receives the reflected light signal S2 generated by the sensor unit 311.
  • the measuring device 33 calculates the response distribution of the riser tube 2 by a known method based on the received reflected light signal S2. For example, for one optical fiber unit 31, the reflection position of each reflected light signal S2 (the position of the Bragg grating) is determined from the difference between the time when the incident light signal S1 is output and the time when each of the plurality of reflected light signals S2 is received. ) Is calculated. Further, due to the difference between the frequency (distribution) of the output incident light signal S1 and the frequency (distribution) of the received reflected light signal S2, the tensile stress (or the tensile length) generated in the optical fiber portion 31 at each reflection position. ) Or compressive stress (compressed length). The stress generated in the riser tube 2 can be calculated from these calculation results in the plurality of optical fiber portions 31 and the material property values of the riser tube 2 in close contact with the optical fiber portions 31. As this calculation method, a known method can be used.
  • the incident optical signal S1 can be amplified by the first optical waveguide 321 and the reflected optical signal S2 can be amplified by the second optical waveguide 322. That is, the incident light signal S1 and the reflected light signal S2 propagated through the optical fiber section 31 can be amplified by the amplification section 32, respectively.
  • the optical loss of both the incident light signal S1 and the reflected light signal S2 can be compensated. Therefore, both the incident optical signal S1 and the reflected optical signal S2 can be amplified even when the bidirectional optical signal is propagated through the single optical fiber portion 31.
  • the light intensity required for receiving the reflected light signal S2 by the measuring device 33 can be stably maintained. Thereby, the measurement distance can be extended without being limited by the optical loss.
  • the incident light signal S1 output from the measuring device 33 by the first optical path converter 323 is guided to the first optical waveguide 321, and the reflected light signal S2 generated by the sensor unit 311 by the second optical path converter 324 is used as the second optical signal.
  • the light can be guided to the optical waveguide 322. Therefore, the incident light signal S1 and the reflected light signal S2 can be amplified individually and stably.
  • the Bragg grating is formed as the sensor unit 311 in the optical fiber unit 31, it can be made compatible with a fiber Bragg grating (FBG) system.
  • FBG fiber Bragg grating
  • the plurality of optical fiber units 31 and the amplifying units 32 can amplify different wavelength ranges, thereby supporting the WDM system. Therefore, the measurement distance can be extended without being limited by optical loss while adopting the WDM method.
  • the optical fiber portion 31 fixed to the surface of the main riser tube main body 21 and the amplification unit 32 fixed to the surface of the amplification riser tube main body 22 are connected to the main riser tube main body 21 and the amplification riser tube main body 22. It is connected by being done. Therefore, the optical fiber part 31 and the amplifying part 32 can be provided continuously along the riser tube 2. As a result, the distortion of the riser tube 2 is directly converted into the distortion of the optical fiber portion 31 to correspond to the reflected light signal S2, and the light intensity of the reflected light signal S2 at the stage of being received by the measuring device 33 by the amplifier 32 is maintained. be able to. Thereby, the response of each part in the riser pipe 2 from the ship 1 to the seabed G can be measured.
  • Second Embodiment the optical fiber sensing system 3A of the second embodiment will be described with reference to FIG.
  • the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
  • the optical fiber sensing system 3A of the second embodiment is different from the first embodiment in the configuration of the optical fiber portion 31A and the amplification portion 32A.
  • a fiber Bragg grating (Bragg grating) is formed in the core as the sensor portion 311A, as in the first embodiment.
  • a plurality of sensor units 311A are provided at a predetermined interval with respect to a plurality of optical fiber units 31A connected in series.
  • the plurality of sensor units 311A respectively correspond to the same Bragg wavelength.
  • the optical fiber sensing system 3 can be made to correspond to a time division multiplexing (TDM: Time
  • TDM Time
  • the amplifying unit 32A is connected to the optical fiber unit 31A.
  • the amplifying unit 32A amplifies both the incident light signal S1 and the reflected light signal S2 separately.
  • a plurality of amplifying units 32A are provided.
  • One amplifying unit 32A of this embodiment is provided for a plurality of optical fiber units 31A connected in series.
  • the plurality of amplifying units 32A amplify optical signals in the same wavelength region. That is, the plurality of amplifying units 32A correspond to the same Bragg wavelength.
  • the plurality of optical fiber units 31A and the amplifying units 32A each amplify the same Bragg wavelength, thereby making it possible to correspond to the TDM system. Therefore, the measurement distance can be extended without being restricted by the optical loss while adopting the TDM method. Further, the optical fiber sensing system 3A can be constructed with a simple configuration by using the same type of optical fiber part 31A and amplifying part 32A.
  • optical fiber sensing system 3A of the second embodiment is not limited to having a Bragg grating, and the amplification unit 32A only has to amplify the same wavelength.
  • the Bragg grating may not be formed in the sensor unit 311B of the optical fiber unit 31A. That is, as shown in FIG. 6, in the optical fiber sensing system 3B of the first modification, the entire optical fiber portion 31B has a function as the sensor portion 311B.
  • the optical fiber sensing system 3B according to the first modification corresponds to BOTDR (Brillouin Optical Time Domain Reflectometry) using Brillouin scattered light.
  • BOTDR Brillouin Optical Time Domain Reflectometry
  • an optical signal is incident only from one side of the optical fiber portion 31B.
  • the incident light signal S1 and the reflected light signal S2 are amplified by the amplifying unit 32B.
  • the measurement distance can be extended without being limited by optical loss while adopting the BOTDR method.
  • BOCDA BrillouinloOptical Correlation-Domain Analysis
  • the entire optical fiber portion 31C has a function as the sensor portion 311C.
  • BOCDA as shown in FIG. 7, optical signals are not incident only from one side of the optical fiber portion 31C, but optical signals having a frequency difference are incident from both ends.
  • the pump light S3 is output from the measuring device 33C as the incident light signal S1
  • the probe light S4 is output in the opposite direction to the pump light S3.
  • the optical fiber sensing system 3C amplifies the pump light S3 and the probe light S4 by the amplifying unit 32C. In such an optical fiber sensing system 3C, the measurement distance can be extended without being limited by optical loss while adopting the BOCDA method.
  • a plurality of optical fiber portions 31D are arranged at a plurality of locations on the surface of the main riser tube main body 21.
  • the plurality of optical fiber portions 31D are arranged in the circumferential direction of the main riser tube main body 21 so as to be at a predetermined interval, for example, at equal intervals.
  • four are arranged in four places.
  • the optical fiber sensing system 3D includes an optical switch unit 34 that connects the amplification unit 32 and the plurality of optical fiber units 31D.
  • the optical switch unit 34 can selectively connect the amplification unit 32 and the plurality of optical fiber units 31D.
  • the optical switch unit 34 is disposed on at least one of the first side to which the incident light signal S1 is input and the second side to which the reflected light signal S2 is input.
  • the optical switch unit 34 of the third embodiment is disposed on both the first side and the second side of the amplification unit 32.
  • the optical switch unit 34 can switch the optical path by any one of electric, mechanical, thermal, and optical control methods.
  • the optical fiber part 31D and the one amplifying part 32 can be selectively connected to the four on both sides. Accordingly, the measurement distance can be extended while increasing the number of measurement points as the entire optical fiber system.
  • the optical amplifiers 320 of the first optical waveguide 321 and the second optical waveguide 322 of the amplifying unit 32 are not limited to being the same as in this embodiment, and may be different from each other. Good.
  • first optical path converter 323 and the second optical path converter 324 of the amplifying unit 32 are not limited to being the same as in the present embodiment, and may be different from each other. .
  • the optical switch unit 34 is not limited to four optical fiber units 31D connected to the amplifying unit 32, but includes a plurality of optical fiber units 31D and one amplifying unit 32. It only has to be connected. Therefore, the number of optical fiber portions 31D connected to the amplifying portion 32 via the optical switch portion 34 may be two or more.
  • the optical switch unit 34 is not limited to the structure arranged on both sides of the amplifying unit 32 as in the present embodiment, and may be arranged at least on one side. Therefore, the optical switch unit 34 may be disposed only on the first side where the incident light signal S1 is input to the amplifier unit 32, and is disposed only on the second side where the reflected light signal S2 is input. May be.
  • the optical switch unit 34 is configured by configuring the first side optical switch unit 34 with a WDM optical circuit and the second side optical switch unit 34 as an optical switch. You may comprise with a wavelength separation (DWDM) type optical circuit.
  • DWDM wavelength separation
  • both the incident optical signal and the reflected optical signal can be amplified even when the bidirectional optical signal is propagated through the single optical fiber portion.

Landscapes

  • Engineering & Computer Science (AREA)
  • Geology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Fluid Mechanics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Remote Sensing (AREA)
  • Mechanical Engineering (AREA)
  • Electromagnetism (AREA)
  • Geophysics (AREA)
  • Optical Transform (AREA)
  • Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)

Abstract

An optical fiber sensing system is provided with a plurality of optical fiber parts (31) connected in series and configured to be capable of propagating a bidirectional optical signal so as to induce an incident light signal (S1) inputted from a light source and a reflected light signal generated by a sensor part (311), and an amplification part (32) connected to the optical fiber parts (31). The amplification part (32) has a first optical waveguide for amplifying only the incident light signal (S1), and a second optical waveguide (322) for amplifying only the reflected light signal, the second optical waveguide (322) being provided in parallel with the first optical waveguide (321).

Description

光ファイバセンシングシステム及びライザー管Optical fiber sensing system and riser tube
　本発明は、光ファイバセンシングシステム及びライザー管に関する。
　本願は、２０１６年４月１９日に出願された特願２０１６－０８３５０６号について優先権を主張し、その内容をここに援用する。 The present invention relates to an optical fiber sensing system and a riser tube.
This application claims priority on Japanese Patent Application No. 2016-083506 filed on Apr. 19, 2016, the contents of which are incorporated herein by reference.
　海底資源の採掘する海中生産システムでは、海底から数千ｍの深さまで掘削した生産井から原油や天然ガス等が混在した生産流体が汲み上げられている。海中生産システムでは、汲み上げた生産流体は、スクラバーのようなセパレータによって天然ガス等の気体と原油等の液体とに分離される。その後、生産流体は、海中を延びるライザー管を介して海上の船まで送られる。 In an undersea production system that mine submarine resources, production fluid mixed with crude oil, natural gas, etc. is pumped from a production well drilled to a depth of several thousand meters from the seabed. In the undersea production system, the pumped production fluid is separated into a gas such as natural gas and a liquid such as crude oil by a separator such as a scrubber. The production fluid is then sent to a ship at sea via a riser tube that extends under the sea.
　ライザー管は、海上から海底までの達するように、非常に長い構造を有している。そのため、ライザー管が破損する場合、局部的な座屈が主要な破壊モードとなる。また、ライザー管は、高潮流下に配置されることで、局部的な座屈だけでなく、振動による疲労破壊も問題となる。 The riser pipe has a very long structure that reaches from the sea to the sea floor. Therefore, when the riser tube breaks, local buckling becomes the main failure mode. Further, the riser pipe is disposed under a high tide, so that not only local buckling but also fatigue failure due to vibration becomes a problem.
　そこで、例えば、特許文献１には、海水の流れに対するライザー管の応答を精密に計測するために、光ファイバを用いた計測手法を適用する構造が記載されている。特許文献１に記載のライザー管は、複数のライザー管本体が接続されることで構成されている。このライザー管本体には、端部がはみ出すように配置された双方向に光信号を送信可能な光ファイバが表面に取り付けられている。光ファイバは、ライザー管本体同士を接続することで接続されている。これにより、ライザー管の表面に沿って長距離にわたって延びる光ファイバセンシングシステムを構築している。 Therefore, for example, Patent Document 1 describes a structure in which a measurement technique using an optical fiber is applied in order to precisely measure the response of the riser pipe to the flow of seawater. The riser pipe described in Patent Document 1 is configured by connecting a plurality of riser pipe main bodies. An optical fiber capable of transmitting an optical signal in both directions is disposed on the surface of the riser tube main body so that the end portion protrudes. The optical fibers are connected by connecting the riser tube bodies together. Thereby, an optical fiber sensing system extending over a long distance along the surface of the riser tube is constructed.
　ところで、遠隔地点における被計測対象の歪みや温度の変化のような物理量の変化を計測する方法として光ファイバを用いた場合、光ファイバ中の光損失が問題となる。そこで、光損失を補うために光信号を増幅する中継器型の光増幅器が用いられている。 By the way, when an optical fiber is used as a method for measuring a physical quantity change such as a distortion of a measurement target or a temperature change at a remote point, optical loss in the optical fiber becomes a problem. Therefore, a repeater type optical amplifier that amplifies the optical signal is used to compensate for the optical loss.
特許第５６１９５７１号公報Japanese Patent No. 5619571
　しかしながら、光増幅器は、基本的に光ファイバを伝送される光信号のうち、一方向に伝送される光信号のみしか増幅できない。そのため、増幅器が配置されている地点で入射光信号のみを増幅させたとしても、反射光信号を十分に増幅させることができない場合がある。具体的には、計測箇所が測定部から離れていることで反射光信号の発生位置が遠くなってしまうと、入射光信号を増幅しても測定機で受光するために必要な光強度を保たせることがむずかしい。そこで、双方向の光信号が単一の光ファイバを伝播する構造であっても、入射光信号と反射光信号との両方を増幅させることが求められている。 However, the optical amplifier can basically amplify only the optical signal transmitted in one direction among the optical signals transmitted through the optical fiber. Therefore, even if only the incident light signal is amplified at the point where the amplifier is disposed, the reflected light signal may not be sufficiently amplified. Specifically, if the position where the reflected light signal is generated becomes far because the measurement location is away from the measurement unit, the light intensity necessary for receiving the light by the measuring instrument is maintained even if the incident light signal is amplified. It is difficult to give. Therefore, it is required to amplify both the incident optical signal and the reflected optical signal even when the bidirectional optical signal is propagated through a single optical fiber.
　本発明は、双方向の光信号が単一の光ファイバ部を伝播する構造であっても、入射光信号と反射光信号との両方を増幅させることが可能な光ファイバセンシングシステム及びライザー管を提供する。 The present invention provides an optical fiber sensing system and a riser tube capable of amplifying both an incident optical signal and a reflected optical signal even when a bidirectional optical signal propagates through a single optical fiber section. provide.
　上記課題を解決するために、本発明は以下の手段を提案している。
　本発明の第一の態様における光ファイバセンシングシステムは、光源から入力された入射光信号と、センサ部で生成された反射光信号とを誘導するよう双方向の光信号を伝搬可能とされ、直列に複数接続された光ファイバ部と、前記光ファイバ部に接続された増幅部とを備え、前記増幅部は、前記入射光信号のみを増幅する第一光導波路と、前記第一光導波路と並列に設けられて前記反射光信号のみを増幅する第二光導波路と、を有する。 In order to solve the above problems, the present invention proposes the following means.
The optical fiber sensing system according to the first aspect of the present invention is capable of propagating a bidirectional optical signal so as to guide an incident optical signal input from a light source and a reflected optical signal generated by a sensor unit, and is serially connected. A plurality of optical fiber units connected to the optical fiber unit, and an amplification unit connected to the optical fiber unit, wherein the amplification unit amplifies only the incident optical signal, and is parallel to the first optical waveguide. And a second optical waveguide that amplifies only the reflected light signal.
　このような構成によれば、入射光信号だけでなく、反射光信号を増幅させることで、入射光信号及び反射光信号の両方の光損失を補うことができる。 According to such a configuration, the optical loss of both the incident light signal and the reflected light signal can be compensated by amplifying not only the incident light signal but also the reflected light signal.
　また、本発明の第二の態様における光ファイバセンシングシステムでは、第一の態様において、前記増幅部は、並列に配置された前記第一光導波路及び前記第二光導波路の前記入射光信号が入力される第一側を繋ぐ第一光路変換器と、並列に配置された前記第一光導波路及び前記第二光導波路の前記反射光信号が入力される第二側を繋ぐ第二光路変換器と、を有し、前記第一光路変換器は、前記入射光信号を前記第一光導波路に導き、前記第二光路変換器は、前記反射光信号を前記第二光導波路に導いてもよい。 In the optical fiber sensing system according to the second aspect of the present invention, in the first aspect, the amplification unit receives the incident optical signals of the first optical waveguide and the second optical waveguide arranged in parallel. A first optical path converter connecting the first side, a second optical path converter connecting the second side to which the reflected light signal of the first optical waveguide and the second optical waveguide arranged in parallel is input, and The first optical path converter may guide the incident optical signal to the first optical waveguide, and the second optical path converter may guide the reflected optical signal to the second optical waveguide.
　このような構成によれば、入射光信号及び反射光信号をそれぞれ個別に安定して増幅させることができる。 According to such a configuration, the incident light signal and the reflected light signal can be amplified individually and stably.
　また、本発明の第三の態様における光ファイバセンシングシステムでは、第一または第二の態様において、前記増幅部を複数備え、複数の前記増幅部は、それぞれ異なる波長域の光信号を増幅していてもよい。 In the optical fiber sensing system according to the third aspect of the present invention, in the first or second aspect, the optical fiber sensing system includes a plurality of the amplifying units, and the plurality of amplifying units amplify optical signals in different wavelength ranges. May be.
　このような構成によれば、ＷＤＭ方式に対応させることができる。したがって、ＷＤＭ方式を採用しながら、光損失の制限を受けずに計測距離を伸ばすことができる。 According to such a configuration, it is possible to correspond to the WDM system. Therefore, the measurement distance can be extended without being limited by optical loss while adopting the WDM method.
　また、本発明の第四の態様における光ファイバセンシングシステムでは、第一または第二の態様において、前記増幅部を複数備え、複数の前記増幅部は、それぞれ同じ波長域の光信号を増幅していてもよい。 In the optical fiber sensing system according to the fourth aspect of the present invention, in the first or second aspect, a plurality of the amplifying units are provided, and the plurality of amplifying units amplify optical signals in the same wavelength region. May be.
　このような構成によれば、ＴＤＭ方式やＢＯＴＤＲ方式やＢＯＣＤＡ方式に対応させることができる。したがって、ＴＤＭ方式やＢＯＴＤＲ方式やＢＯＣＤＡ方式を採用しながら、光損失の制限を受けずに計測距離を伸ばすことができる。 According to such a configuration, it is possible to correspond to the TDM system, the BOTDR system, and the BOCDA system. Therefore, the measurement distance can be extended without being limited by the optical loss while adopting the TDM method, the BOTDR method, or the BOCDA method.
　また、本発明の第五の態様における光ファイバセンシングシステムでは、第一から第四の態様のいずれか一つにおいて、前記光ファイバ部は、前記センサ部として、コアにファイバブラッグレーティングが形成されていてもよい。 Moreover, in the optical fiber sensing system according to the fifth aspect of the present invention, in any one of the first to fourth aspects, the optical fiber part has a fiber Bragg rating formed in the core as the sensor part. May be.
　このような構成によれば、ＦＢＧ方式に対応させることができる。 According to such a configuration, the FBG method can be supported.
　また、本発明の第六の態様における光ファイバセンシングシステムでは、第一から第五の態様のいずれか一つにおいて、前記増幅部の前記入射光信号が入力される第一側及び前記反射光信号が入力される第二側の少なくとも一方に配置され、前記増幅部と複数の前記光ファイバ部とを選択的に接続可能な光スイッチ部とを備えていてもよい。 In the optical fiber sensing system according to the sixth aspect of the present invention, in any one of the first to fifth aspects, the first side to which the incident light signal of the amplification unit is input and the reflected light signal. May be provided on at least one of the second sides to which the light is input, and an optical switch unit capable of selectively connecting the amplification unit and the plurality of optical fiber units.
　このような構成によれば、複数の光ファイバ部と一つの増幅部とを選択に接続可能な状態で繋ぐことができる。したがって、光ファイバシステム全体として計測点数を増やしつつ、計測距離を伸ばすことができる。 According to such a configuration, it is possible to connect a plurality of optical fiber units and one amplifying unit in a connectable state. Accordingly, the measurement distance can be extended while increasing the number of measurement points as the entire optical fiber system.
　また、本発明の第七の態様におけるライザー管では、第一から第六の態様のいずれか一つの光ファイバセンシングシステムと、筒状をなし、表面に前記光ファイバセンシングシステムの光ファイバ部の一つが配置された複数の主ライザー管本体と、筒状をなし、表面に前記光ファイバセンシングシステムの増幅部が配置された増幅ライザー管本体と、を備え、前記主ライザー管本体の端部と前記増幅ライザー管本体の端部とが直列的に接続されることで、前記光ファイバ部と前記増幅部とが接続される。 The riser tube according to the seventh aspect of the present invention has a cylindrical shape with one of the optical fiber sensing systems according to any one of the first to sixth aspects, and a surface of the optical fiber portion of the optical fiber sensing system. A plurality of main riser pipe main bodies arranged in a tube, and an amplification riser pipe main body having a cylindrical shape on which an amplification part of the optical fiber sensing system is arranged on the surface, the end of the main riser pipe main body and the The optical fiber part and the amplifying part are connected by connecting the end part of the amplifying riser tube body in series.
　このような構成によれば、ライザー管に沿って光ファイバ部及び増幅部を連続して設けることができる。その結果、ライザー管のひずみを光ファイバ部のひずみに直接変換して反射光信号に対応させ、増幅部によって計測装置で受光する段階の反射光信号の光強度を維持することができる。これにより、船舶から海底までのライザー管における各部分の応答を計測することができる。 According to such a configuration, the optical fiber part and the amplifying part can be continuously provided along the riser tube. As a result, the distortion of the riser tube can be directly converted to the distortion of the optical fiber portion to correspond to the reflected light signal, and the light intensity of the reflected light signal at the stage of receiving light by the measuring device can be maintained by the amplifier. Thereby, the response of each part in the riser pipe from the ship to the seabed can be measured.
　本発明によれば、双方向の光信号が単一の光ファイバ部を伝播する構造であっても、入射光信号と反射光信号との両方を増幅させることができる。 According to the present invention, it is possible to amplify both the incident light signal and the reflected light signal even if the bidirectional optical signal is propagated through the single optical fiber portion.
本発明の実施形態のライザー管を説明する模式図である。It is a mimetic diagram explaining a riser pipe of an embodiment of the present invention. 本発明のライザー管同士を接続する様子を説明する模式図である。It is a schematic diagram explaining a mode that the riser pipe | tube of this invention is connected. 本発明の第一実施形態における光ファイバセンシングシステムを説明する概念図である。It is a conceptual diagram explaining the optical fiber sensing system in 1st embodiment of this invention. 本発明の第一実施形態における増幅器を説明する概念図である。It is a conceptual diagram explaining the amplifier in 1st embodiment of this invention. 本発明の第二実施形態における光ファイバセンシングシステムを説明する概念図である。It is a conceptual diagram explaining the optical fiber sensing system in 2nd embodiment of this invention. 本発明の第二実施形態の第一変形例における光ファイバセンシングシステムを説明する概念図である。It is a conceptual diagram explaining the optical fiber sensing system in the 1st modification of 2nd embodiment of this invention. 本発明の第二実施形態の第二変形例における光ファイバセンシングシステムを説明する概念図である。It is a conceptual diagram explaining the optical fiber sensing system in the 2nd modification of 2nd embodiment of this invention. 本発明の第三実施形態における光スイッチ部を説明する概念図である。It is a conceptual diagram explaining the optical switch part in 3rd embodiment of this invention.
《第一実施形態》
　以下、本発明の第一実施形態のライザー管２及び光ファイバセンシングシステム３について図１から図４を参照して説明する。
　ライザー管２は、洋上プラットフォーム（石油開発用、科学調査用等）の掘削や、洋上プラットフォームへ海底油田から採取した原油を持ち上げるために用いられる。本実施形態のライザー管２は、図１に示すように、船舶１に一方の端部が接続されている。船舶１は、ライザー管２を海Ｓ中に配設し、ライザー管２の他方の端部を海底Ｇまで伸ばしている。 << first embodiment >>
Hereinafter, the riser pipe 2 and the optical fiber sensing system 3 according to the first embodiment of the present invention will be described with reference to FIGS.
The riser pipe 2 is used to excavate offshore platforms (for oil development, scientific research, etc.) and to lift crude oil collected from the offshore oil field to the offshore platforms. As shown in FIG. 1, the riser pipe 2 of the present embodiment has one end connected to the ship 1. The ship 1 arranges the riser pipe 2 in the sea S and extends the other end of the riser pipe 2 to the seabed G.
　ライザー管２は、光ファイバセンシングシステム３を有している。ライザー管２は、図２に示すように、複数のライザー管本体２０を直列的に接続した構造を有している。ライザー管本体２０は、筒状をなしている。本実施形態のライザー管本体２０は、円筒状をなしている。ライザー管本体２０は、ドリルパイプと、泥水流路と、計測機器とを含み、浮体を含む保護部材で覆われている（以上、図示せず）。なお、ライザー管本体２０同士を接続するための接続構造（例示：フランジやボルトやナットなど）など本発明に直接関係ない部分（前述のドリルパイプ、泥水流路、計測機器、浮体を含む保護部材）は従来の技術と同様であり記載を省略している。本実施形態のライザー管２は、ライザー管本体２０として、主ライザー管本体２１と、増幅ライザー管本体２２とを有している。 The riser tube 2 has an optical fiber sensing system 3. As shown in FIG. 2, the riser pipe 2 has a structure in which a plurality of riser pipe main bodies 20 are connected in series. The riser pipe body 20 has a cylindrical shape. The riser tube main body 20 of the present embodiment has a cylindrical shape. The riser pipe body 20 includes a drill pipe, a muddy water flow path, and a measuring device, and is covered with a protective member including a floating body (not shown). In addition, the parts not directly related to the present invention such as a connection structure for connecting the riser pipe main bodies 20 to each other (example: flange, bolt, nut, etc.) (protective member including the above-described drill pipe, muddy water flow path, measuring device, floating body) ) Is the same as in the prior art and is not shown. The riser pipe 2 of the present embodiment includes a main riser pipe main body 21 and an amplification riser pipe main body 22 as the riser pipe main body 20.
　主ライザー管本体２１は、後述する光ファイバセンシングシステム３の光ファイバ部３１が取り付けられている。増幅ライザー管本体２２は、後述する光ファイバセンシングシステム３の増幅部３２が取り付けられている。増幅ライザー管本体２２は、主ライザー管本体２１と同じ形状をなしている。つまり、増幅ライザー管本体２２は、光ファイバ部３１の代わりに増幅部３２が取り付けられている点で主ライザー管本体２１と異なる。 The main riser tube main body 21 is attached with an optical fiber portion 31 of an optical fiber sensing system 3 to be described later. The amplification riser tube main body 22 is attached with an amplification unit 32 of the optical fiber sensing system 3 described later. The amplification riser tube main body 22 has the same shape as the main riser tube main body 21. That is, the amplification riser tube main body 22 is different from the main riser tube main body 21 in that an amplification unit 32 is attached instead of the optical fiber unit 31.
　主ライザー管本体２１の端部と増幅ライザー管本体２２の端部とが直列的に接続されることで、光ファイバ部３１と増幅部３２とが接続されている。また、主ライザー管本体２１同士の端部が直列的に接続されることで、光ファイバ部３１同士が接続されている。 The end portion of the main riser tube body 21 and the end portion of the amplification riser tube body 22 are connected in series, whereby the optical fiber portion 31 and the amplification portion 32 are connected. Moreover, the optical fiber parts 31 are connected by the end parts of the main riser pipe main bodies 21 being connected in series.
　光ファイバセンシングシステム３は、遠隔地点における被計測対象の歪みや温度の変化のような物理量の変化を計測する。本実施形態の光ファイバセンシングシステム３は、ライザー管２に取り付けられることで、海水の流れに対するライザー管２の応答を的確に把握する。光ファイバセンシングシステム３は、例えば、海水によりライザー管２に発生する渦励振（ＶＩＶ：Ｖｏｒｔｅｘ　Ｉｎｄｕｃｅｄ　Ｖｉｂｒａｔｉｏｎ）を含む各種振動を精密に計測し、あるいはそれら各種振動によりライザー管２に座屈が発生する可能性を的確に把握する。本実施形態の光ファイバセンシングシステム３は、図３に示すように、光ファイバ部３１と、増幅部３２と、計測装置３３とを備えている。 The optical fiber sensing system 3 measures a physical quantity change such as a distortion of a measurement target and a temperature change at a remote point. The optical fiber sensing system 3 of the present embodiment is attached to the riser pipe 2 to accurately grasp the response of the riser pipe 2 to the flow of seawater. The optical fiber sensing system 3 accurately measures various vibrations including vortex induced vibration (VIV: Vortex Induced Vibration) generated in the riser tube 2 by seawater, or buckling occurs in the riser tube 2 due to these various vibrations. Accurately grasp the possibilities. The optical fiber sensing system 3 of this embodiment is provided with the optical fiber part 31, the amplification part 32, and the measuring device 33, as shown in FIG.
　光ファイバ部３１は、光源から入力された入射光信号Ｓ１と、センサ部３１１で生成された反射光信号Ｓ２とを誘導するよう双方向の光信号を伝搬可能とされている。反射光信号Ｓ２は、光ファイバ部３１のセンサ部３１１の少なくとも一つで生成される。反射光信号Ｓ２は、センサ部３１１の周囲環境の物理的変化により反射することで生成される。 The optical fiber unit 31 is capable of propagating a bidirectional optical signal so as to guide the incident optical signal S1 input from the light source and the reflected optical signal S2 generated by the sensor unit 311. The reflected light signal S2 is generated by at least one of the sensor units 311 of the optical fiber unit 31. The reflected light signal S2 is generated by being reflected by a physical change in the surrounding environment of the sensor unit 311.
　光ファイバ部３１は、直列に複数接続されている。光ファイバ部３１は、主ライザー管本体２１の表面に密着して取り付けられている。光ファイバ部３１は、主ライザー管本体２１の長手方向である軸方向に沿って延在している。光ファイバ部３１は、例えば、主ライザー管本体２１の表面に対して接着剤によって接合されている。光ファイバ部３１は、図２に示すように、一方の端部である第一端部３１ａから他方の端である第二端部３１ｂが主ライザー管本体２１の両端部にわたって延びている。ここで、本実施形態における第一端部３１ａは、光ファイバ部３１において入射光信号Ｓ１が入力される側の端部である。第二端部３１ｂは、光ファイバ部３１において反射光信号Ｓ２が入力される側の端部である。本実施形態の光ファイバ部３１は、主ライザー管本体２１の表面上の複数箇所に一本ずつ配置されている。光ファイバ部３１は、主ライザー管本体２１の円周方向に所定の間隔、例えば互いに等間隔になるように並んで一本ずつ配置されている。 A plurality of optical fiber sections 31 are connected in series. The optical fiber portion 31 is attached in close contact with the surface of the main riser tube main body 21. The optical fiber portion 31 extends along the axial direction that is the longitudinal direction of the main riser tube main body 21. The optical fiber portion 31 is bonded to the surface of the main riser tube main body 21 with an adhesive, for example. As shown in FIG. 2, the optical fiber portion 31 has a first end portion 31 a that is one end portion and a second end portion 31 b that is the other end portion extending from both end portions of the main riser tube main body 21. Here, the first end portion 31 a in the present embodiment is an end portion on the side where the incident optical signal S <b> 1 is input in the optical fiber portion 31. The second end portion 31b is an end portion on the side where the reflected light signal S2 is input in the optical fiber portion 31. The optical fiber portions 31 of the present embodiment are arranged one by one at a plurality of locations on the surface of the main riser tube main body 21. The optical fiber portions 31 are arranged one by one in the circumferential direction of the main riser tube main body 21 so as to be arranged at predetermined intervals, for example, at equal intervals.
　光ファイバ部３１は、第一端部３１ａ及び第二端部３１ｂが主ライザー管本体２１の端部からはみ出すように形成されている。光ファイバ部３１の第一端部３１ａ及び第二端部３１ｂは、隣接する光ファイバ部３１との接続作業のために主ライザー管本体２１に固着されていない。光ファイバ部３１の両端のはみ出した部分と、隣接する光ファイバ部３１のはみ出した部分とが融着やメカニカルスプライスやコネクタ等により接続されている。このように、はみ出した部分を融着やメカニカルスプライスやコネクタ等により接続することで、容易に長大なライザー管２の全長にわたって複数の光ファイバ部３１を連続して設けている。 The optical fiber portion 31 is formed such that the first end portion 31 a and the second end portion 31 b protrude from the end portion of the main riser tube main body 21. The first end portion 31 a and the second end portion 31 b of the optical fiber portion 31 are not fixed to the main riser pipe body 21 for connection work with the adjacent optical fiber portion 31. The protruding portion of both ends of the optical fiber portion 31 and the protruding portion of the adjacent optical fiber portion 31 are connected by fusion, mechanical splice, connector, or the like. In this way, the protruding portions are connected by fusion, mechanical splices, connectors, or the like, so that a plurality of optical fiber portions 31 are easily provided continuously over the entire length of the long riser tube 2.
　なお、光ファイバ部３１同士は、永久的に接続させる融着接続やメカニカルスプライスを用いてもよく、繰り返し着脱が可能なコネクタ接続を用いてもよい。 It should be noted that the optical fiber portions 31 may use a fusion connection or a mechanical splice that are permanently connected, or a connector connection that can be repeatedly attached and detached.
　光ファイバ部３１は、図３に示すように、センサ部３１１として、コアにファイバブラッグレーティング（ブラッグ格子）が形成されている。センサ部３１１は、連続するよう接続された複数の光ファイバ部３１に対して、所定の間隔で複数設けられている。つまり、本実施形態の光ファイバ部３１は、センサ部３１１として機能する部分と、光信号を伝搬する部分とを有している。複数の光ファイバ部３１のセンサ部３１１は、それぞれ異なるブラッグ波長に対応している。これにより、光ファイバセンシングシステム３を波長多重（ＷＤＭ：Ｗａｖｅｌｅｎｇｔｈ Ｄｉｖｉｓｉｏｎ Ｍｕｌｔｉｐｌｅｘｉｎｇ）方式に対応させることができる。センサ部３１１は、例えば、数十ｃｍ間隔で設けることができる。センサ部３１１は、ライザー管本体２０が３０ｍで水深３０００ｍの海底Ｇに配置される場合、数千箇所程度の計測箇所を設けることができる。それにより、高次の応答（モードの節が２０ｍ又はそれ以下の間隔、数十Ｈｚ以上）を測定することができる。なお、センサ部３１１は、全ての光ファイバ部３１がそれぞれ有していてもよく、一部の光ファイバ部３１のみが有していてよい。 As shown in FIG. 3, the optical fiber unit 31 has a fiber Bragg grating (Bragg grating) formed in the core as the sensor unit 311. A plurality of sensor units 311 are provided at a predetermined interval with respect to a plurality of optical fiber units 31 connected so as to be continuous. That is, the optical fiber part 31 of this embodiment has a part that functions as the sensor part 311 and a part that propagates an optical signal. The sensor units 311 of the plurality of optical fiber units 31 correspond to different Bragg wavelengths. Thereby, the optical fiber sensing system 3 can be made to correspond to the wavelength multiplexing (WDM: Wavelength Division Multiplexing) method. The sensor unit 311 can be provided at intervals of several tens of cm, for example. When the riser pipe main body 20 is arranged on the seabed G with a depth of 3000 m and a water depth of 3000 m, the sensor unit 311 can be provided with several thousand measurement points. Thereby, a higher order response (mode node 20 m or less interval, several tens of Hz or more) can be measured. In addition, the sensor part 311 may each have all the optical fiber parts 31, and may have only some optical fiber parts 31. FIG.
　増幅部３２は、光ファイバ部３１に接続されている。増幅部３２は、入射光信号Ｓ１と反射光信号Ｓ２との両方をそれぞれ別々に増幅させる。増幅部３２は、複数設けられている。本実施形態の増幅部３２は、複数連続して接続された光ファイバ部３１に対して一つの割合で設けられている。複数の増幅部３２は、それぞれ異なる波長域の光信号を増幅している。つまり、複数の増幅部３２は、それぞれ異なるブラッグ波長に対応している。増幅部３２は、図４に示すように、第一光導波路３２１と、第二光導波路３２２と、第一光路変換器３２３と、第二光路変換器３２４とを有する。 The amplifying unit 32 is connected to the optical fiber unit 31. The amplifying unit 32 amplifies both the incident light signal S1 and the reflected light signal S2 separately. A plurality of amplifying units 32 are provided. The amplifying unit 32 of the present embodiment is provided at a ratio of one to a plurality of optical fiber units 31 connected in series. The plurality of amplifying units 32 amplify optical signals in different wavelength ranges. That is, the plurality of amplifying units 32 correspond to different Bragg wavelengths. As illustrated in FIG. 4, the amplifying unit 32 includes a first optical waveguide 321, a second optical waveguide 322, a first optical path converter 323, and a second optical path converter 324.
　第一光導波路３２１は、入射光信号Ｓ１のみを増幅する。第一光導波路３２１は、途中に光増幅器３２０が設けられた光ファイバである。光増幅器は３２０、中を通る光信号を増幅させる。本実施形態における光増幅器３２０は、あらゆる波長に対応可能な光ファイバアンプや半導体光アンプ（ＳＯＡ:Ｓｅｍｉｃｏｎｄｕｃｔｏｒ Ｏｐｔｉｃａｌ Ａｍｐｌｉｆｅｒ）が用いられる。 The first optical waveguide 321 amplifies only the incident optical signal S1. The first optical waveguide 321 is an optical fiber provided with an optical amplifier 320 on the way. The optical amplifier 320 amplifies the optical signal passing therethrough. As the optical amplifier 320 in the present embodiment, an optical fiber amplifier or a semiconductor optical amplifier (SOA: Semiconductor-Amplifier) capable of dealing with any wavelength is used.
　第二光導波路３２２は、第一光導波路３２１と並列に設けられている。第二光導波路３２２は、反射光信号Ｓ２のみを増幅する。第二光導波路３２２は、途中に光増幅器３２０が設けられて光ファイバである。本実施形態の第二光導波路３２２に用いられる光増幅器３２０は、第一光導波路３２１に用いられる光増幅器３２０と同じである。 The second optical waveguide 322 is provided in parallel with the first optical waveguide 321. The second optical waveguide 322 amplifies only the reflected light signal S2. The second optical waveguide 322 is an optical fiber provided with an optical amplifier 320 on the way. The optical amplifier 320 used for the second optical waveguide 322 of the present embodiment is the same as the optical amplifier 320 used for the first optical waveguide 321.
　第一光路変換器３２３は、並列に配置された第一光導波路３２１及び第二光導波路３２２の入射光信号Ｓ１が入力される第一側を繋いでいる。ここで、本実施形態における第一側は、第一光導波路３２１において入射光信号Ｓ１が入力される側である。第一光路変換器３２３は、増幅部３２に対して入射光信号Ｓ１が入力される側である第一側に配置された光ファイバ部３１と接続されている。第一光路変換器３２３は、入射光信号Ｓ１を第一光導波路３２１に導く。本実施形態の第一光路変換器３２３は、光学的サーキュレータである。第一光路変換器３２３は、光ファイバ部３１を伝搬してきた入射光信号Ｓ１を分離又は分岐させて第一光導波路３２１のみに導いている。 The first optical path converter 323 connects the first side to which the incident optical signal S1 of the first optical waveguide 321 and the second optical waveguide 322 arranged in parallel is input. Here, the first side in the present embodiment is a side to which the incident optical signal S1 is input in the first optical waveguide 321. The first optical path changer 323 is connected to the optical fiber unit 31 disposed on the first side, which is the side where the incident optical signal S1 is input to the amplifier unit 32. The first optical path converter 323 guides the incident optical signal S1 to the first optical waveguide 321. The first optical path changer 323 of this embodiment is an optical circulator. The first optical path changer 323 separates or branches the incident optical signal S <b> 1 that has propagated through the optical fiber unit 31 and guides it only to the first optical waveguide 321.
　第二光路変換器３２４は、並列に配置された第一光導波路３２１及び第二光導波路３２２の反射光信号Ｓ２が入力される第二側を繋いでいる。ここで、本実施形態における第二側は、第二光導波路３２２において反射光信号Ｓ２が入力される側である。つまり、第二光路変換器３２４は、第一光導波路３２１及び第二光導波路３２２に対して第一光路変換器３２３の反対側に配置されている。第二光路変換器３２４は、増幅部３２に対しての反射光信号Ｓ２が入力される側である第二側に配置された光ファイバ部３１と接続されている。第二光路変換器３２４は、反射光信号Ｓ２を第二光導波路３２２に導く。本実施形態の第二光路変換器３２４は、第一光路変換器３２３と同じ光学的サーキュレータである。第二光路変換器３２４は、光ファイバ部３１を伝搬してきた反射光信号Ｓ２を分離又は分岐させて第二光導波路３２２のみに導いている。 The second optical path converter 324 connects the first optical waveguide 321 and the second side to which the reflected light signal S2 of the second optical waveguide 322 is input in parallel. Here, the second side in the present embodiment is a side to which the reflected optical signal S2 is input in the second optical waveguide 322. That is, the second optical path converter 324 is disposed on the opposite side of the first optical path converter 323 with respect to the first optical waveguide 321 and the second optical waveguide 322. The second optical path converter 324 is connected to the optical fiber unit 31 disposed on the second side, which is the side on which the reflected light signal S <b> 2 to the amplifier unit 32 is input. The second optical path converter 324 guides the reflected light signal S <b> 2 to the second optical waveguide 322. The second optical path converter 324 of the present embodiment is the same optical circulator as the first optical path converter 323. The second optical path changer 324 separates or branches the reflected light signal S <b> 2 that has propagated through the optical fiber portion 31 and guides it only to the second optical waveguide 322.
　計測装置３３は、主ライザー管本体２１の表面上に配置された光ファイバ部３１に接続されている。計測装置３３は、それら複数の光ファイバ部３１へ所定の周波数を有するパルス状のレーザ光のような入射光信号Ｓ１を出力する光源である。計測装置３３は、センサ部３１１で生成された反射光信号Ｓ２を受信する。 The measuring device 33 is connected to an optical fiber portion 31 disposed on the surface of the main riser tube main body 21. The measuring device 33 is a light source that outputs an incident light signal S1 such as pulsed laser light having a predetermined frequency to the plurality of optical fiber portions 31. The measuring device 33 receives the reflected light signal S2 generated by the sensor unit 311.
　計測装置３３は、受信された反射光信号Ｓ２に基づいて、ライザー管２の応答分布を公知の方法で算出する。例えば、一つの光ファイバ部３１について、入射光信号Ｓ１が出力された時刻と複数の反射光信号Ｓ２の各々を受信した時刻との差から、各反射光信号Ｓ２の反射位置（ブラッグ格子の位置）が計算される。また、出力された入射光信号Ｓ１の周波数（分布）と受信された反射光信号Ｓ２の周波数（分布）との相違から、各反射位置で光ファイバ部３１に生じている引っ張り応力（又は引っ張り長さ）又は圧縮応力（圧縮長さ）が計算される。複数の光ファイバ部３１でのこれらの計算結果と、それら光ファイバ部３１に密着しているライザー管２の材料物性値とから、ライザー管２に生じている応力を計算することができる。この計算方法は、公知の方法を用いることができる。 The measuring device 33 calculates the response distribution of the riser tube 2 by a known method based on the received reflected light signal S2. For example, for one optical fiber unit 31, the reflection position of each reflected light signal S2 (the position of the Bragg grating) is determined from the difference between the time when the incident light signal S1 is output and the time when each of the plurality of reflected light signals S2 is received. ) Is calculated. Further, due to the difference between the frequency (distribution) of the output incident light signal S1 and the frequency (distribution) of the received reflected light signal S2, the tensile stress (or the tensile length) generated in the optical fiber portion 31 at each reflection position. ) Or compressive stress (compressed length). The stress generated in the riser tube 2 can be calculated from these calculation results in the plurality of optical fiber portions 31 and the material property values of the riser tube 2 in close contact with the optical fiber portions 31. As this calculation method, a known method can be used.
　上記のような光ファイバセンシングシステム３によれば、第一光導波路３２１によって入射光信号Ｓ１を増幅させ、第二光導波路３２２によって反射光信号Ｓ２を増幅させることできる。つまり、光ファイバ部３１を伝搬される入射光信号Ｓ１及び反射光信号Ｓ２を増幅部３２によってそれぞれ増幅させることができる。入射光信号Ｓ１だけでなく、反射光信号Ｓ２を増幅させることで、入射光信号Ｓ１及び反射光信号Ｓ２の両方の光損失を補うことができる。したがって、双方向の光信号が単一の光ファイバ部３１を伝播する構造であっても、入射光信号Ｓ１と反射光信号Ｓ２との両方を増幅させることができる。その結果、計測装置３３で反射光信号Ｓ２を受光するために必要な光強度を安定して維持することができる。これにより、光損失の制限を受けずに計測距離の延長を図ることができる。 According to the optical fiber sensing system 3 as described above, the incident optical signal S1 can be amplified by the first optical waveguide 321 and the reflected optical signal S2 can be amplified by the second optical waveguide 322. That is, the incident light signal S1 and the reflected light signal S2 propagated through the optical fiber section 31 can be amplified by the amplification section 32, respectively. By amplifying not only the incident light signal S1 but also the reflected light signal S2, the optical loss of both the incident light signal S1 and the reflected light signal S2 can be compensated. Therefore, both the incident optical signal S1 and the reflected optical signal S2 can be amplified even when the bidirectional optical signal is propagated through the single optical fiber portion 31. As a result, the light intensity required for receiving the reflected light signal S2 by the measuring device 33 can be stably maintained. Thereby, the measurement distance can be extended without being limited by the optical loss.
　また、第一光路変換器３２３によって計測装置３３から出力された入射光信号Ｓ１を第一光導波路３２１に導き、第二光路変換器３２４によってセンサ部３１１で生成された反射光信号Ｓ２を第二光導波路３２２に導くことができる。そのため、入射光信号Ｓ１及び反射光信号Ｓ２をそれぞれ個別に安定して増幅させることができる。 Further, the incident light signal S1 output from the measuring device 33 by the first optical path converter 323 is guided to the first optical waveguide 321, and the reflected light signal S2 generated by the sensor unit 311 by the second optical path converter 324 is used as the second optical signal. The light can be guided to the optical waveguide 322. Therefore, the incident light signal S1 and the reflected light signal S2 can be amplified individually and stably.
　また、光ファイバ部３１にセンサ部３１１としてブラッグ格子が形成されていることで、ファイバブラッググレーティング（ＦＢＧ：Ｆｉｂｅｒ Ｂｒａｇｇ Ｇｒａｔｉｎｇ）方式に対応させることができる。 Further, since the Bragg grating is formed as the sensor unit 311 in the optical fiber unit 31, it can be made compatible with a fiber Bragg grating (FBG) system.
　また、複数の光ファイバ部３１及び増幅部３２が異なる波長域をそれぞれ増幅させることで、ＷＤＭ方式に対応させることができる。したがって、ＷＤＭ方式を採用しながら、光損失の制限を受けずに計測距離を伸ばすことができる。 In addition, the plurality of optical fiber units 31 and the amplifying units 32 can amplify different wavelength ranges, thereby supporting the WDM system. Therefore, the measurement distance can be extended without being limited by optical loss while adopting the WDM method.
　また、主ライザー管本体２１の表面に固着された光ファイバ部３１と、増幅ライザー管本体２２の表面に固着された増幅部３２とが、主ライザー管本体２１と増幅ライザー管本体２２とが接続されることで繋がれている。そのため、ライザー管２に沿って光ファイバ部３１及び増幅部３２を連続して設けることができる。その結果、ライザー管２のひずみを光ファイバ部３１のひずみに直接変換して反射光信号Ｓ２に対応させ、増幅部３２によって計測装置３３で受光する段階の反射光信号Ｓ２の光強度を維持することができる。これにより、船舶１から海底Ｇまでのライザー管２における各部分の応答を計測することができる。 Further, the optical fiber portion 31 fixed to the surface of the main riser tube main body 21 and the amplification unit 32 fixed to the surface of the amplification riser tube main body 22 are connected to the main riser tube main body 21 and the amplification riser tube main body 22. It is connected by being done. Therefore, the optical fiber part 31 and the amplifying part 32 can be provided continuously along the riser tube 2. As a result, the distortion of the riser tube 2 is directly converted into the distortion of the optical fiber portion 31 to correspond to the reflected light signal S2, and the light intensity of the reflected light signal S2 at the stage of being received by the measuring device 33 by the amplifier 32 is maintained. be able to. Thereby, the response of each part in the riser pipe 2 from the ship 1 to the seabed G can be measured.
《第二実施形態》
　次に、図５を参照して第二実施形態の光ファイバセンシングシステム３Ａについて説明する。
　第二実施形態においては第一実施形態と同様の構成要素には同一の符号を付して詳細な説明を省略する。この第二実施形態の光ファイバセンシングシステム３Ａは、光ファイバ部３１Ａ及び増幅部３２Ａの構成について第一実施形態と相違する。 << Second Embodiment >>
Next, the optical fiber sensing system 3A of the second embodiment will be described with reference to FIG.
In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The optical fiber sensing system 3A of the second embodiment is different from the first embodiment in the configuration of the optical fiber portion 31A and the amplification portion 32A.
　第二実施形態の光ファイバ部３１Ａは、第一実施形態と同様に、センサ部３１１Ａとしてコアにファイバブラッグレーティング（ブラッグ格子）が形成されている。センサ部３１１Ａは、連続するよう接続された複数の光ファイバ部３１Ａに対して、所定の間隔で複数設けられている。複数のセンサ部３１１Ａは、それぞれ同じブラッグ波長に対応している。これにより、光ファイバセンシングシステム３を時分割多重（ＴＤＭ:Ｔｉｍｅ Ｄｉｖｉｓｉｏｎ Ｍｕｌｔｉｐｌｅｘｉｎｇ）方式に対応させることができる。 In the optical fiber portion 31A of the second embodiment, a fiber Bragg grating (Bragg grating) is formed in the core as the sensor portion 311A, as in the first embodiment. A plurality of sensor units 311A are provided at a predetermined interval with respect to a plurality of optical fiber units 31A connected in series. The plurality of sensor units 311A respectively correspond to the same Bragg wavelength. Thereby, the optical fiber sensing system 3 can be made to correspond to a time division multiplexing (TDM: Time | Division | Multiplexing) system.
　増幅部３２Ａは、光ファイバ部３１Ａに接続されている。増幅部３２Ａは、入射光信号Ｓ１と反射光信号Ｓ２との両方をそれぞれ別々に増幅させる。増幅部３２Ａは、複数設けられている。本実施形態の増幅部３２Ａは、複数連続して接続された光ファイバ部３１Ａに対して一つ設けられている。複数の増幅部３２Ａは、それぞれ同じ波長域の光信号を増幅している。つまり、複数の増幅部３２Ａは、それぞれ同じブラッグ波長に対応している。 The amplifying unit 32A is connected to the optical fiber unit 31A. The amplifying unit 32A amplifies both the incident light signal S1 and the reflected light signal S2 separately. A plurality of amplifying units 32A are provided. One amplifying unit 32A of this embodiment is provided for a plurality of optical fiber units 31A connected in series. The plurality of amplifying units 32A amplify optical signals in the same wavelength region. That is, the plurality of amplifying units 32A correspond to the same Bragg wavelength.
　第二実施形態の光ファイバセンシングシステム３Ａによれば、複数の光ファイバ部３１Ａ及び増幅部３２Ａが同じブラッグ波長をそれぞれ増幅させることで、ＴＤＭ方式に対応させることができる。したがって、ＴＤＭ方式を採用しながら、光損失の制限を受けずに計測距離を伸ばすことができる。また、全て同じ種類の光ファイバ部３１Ａや増幅部３２Ａによって光ファイバセンシングシステム３Ａを簡易な構成で構築できる。 According to the optical fiber sensing system 3A of the second embodiment, the plurality of optical fiber units 31A and the amplifying units 32A each amplify the same Bragg wavelength, thereby making it possible to correspond to the TDM system. Therefore, the measurement distance can be extended without being restricted by the optical loss while adopting the TDM method. Further, the optical fiber sensing system 3A can be constructed with a simple configuration by using the same type of optical fiber part 31A and amplifying part 32A.
　なお、第二実施形態の光ファイバセンシングシステム３Ａは、ブラッグ格子を有することに限定されるものではなく、増幅部３２Ａが同じ波長を増幅していればよい。 Note that the optical fiber sensing system 3A of the second embodiment is not limited to having a Bragg grating, and the amplification unit 32A only has to amplify the same wavelength.
　例えば、第二実施形態の第一変形例として、光ファイバ部３１Ａのセンサ部３１１Ｂにブラッグ格子が形成されていなくてもよい。つまり、第一変形例の光ファイバセンシングシステム３Ｂは、図６に示すように、光ファイバ部３１Ｂ全体がセンサ部３１１Ｂとしての機能を有している。第一変形例の光ファイバセンシングシステム３Ｂは、ブリルアン散乱光を利用したＢＯＴＤＲ（Ｂｒｉｌｌｏｕｉｎ Ｏｐｔｉｃａｌ Ｔｉｍｅ Ｄｏｍａｉｎ Ｒｅｆｌｅｃｔｍｅｔｒｙ）に対応している。第一変形例では、光ファイバ部３１Ｂの片側のみから光信号を入射させている。光ファイバセンシングシステム３Ｂは、入射光信号Ｓ１と反射光信号Ｓ２とを増幅部３２Ｂで増幅している。このような光ファイバセンシングシステム３Ｂでは、ＢＯＴＤＲ方式を採用しながら、光損失の制限を受けずに計測距離を伸ばすことができる。 For example, as a first modification of the second embodiment, the Bragg grating may not be formed in the sensor unit 311B of the optical fiber unit 31A. That is, as shown in FIG. 6, in the optical fiber sensing system 3B of the first modification, the entire optical fiber portion 31B has a function as the sensor portion 311B. The optical fiber sensing system 3B according to the first modification corresponds to BOTDR (Brillouin Optical Time Domain Reflectometry) using Brillouin scattered light. In the first modification, an optical signal is incident only from one side of the optical fiber portion 31B. In the optical fiber sensing system 3B, the incident light signal S1 and the reflected light signal S2 are amplified by the amplifying unit 32B. In such an optical fiber sensing system 3B, the measurement distance can be extended without being limited by optical loss while adopting the BOTDR method.
　また、第二実施形態の第二変形例では、ブリルアン散乱を利用する方式として、ＢＯＣＤＡ（Ｂｒｉｌｌｏｕｉｎ Ｏｐｔｉｃａｌ Ｃｏｒｒｅｌａｔｉｏｎ－Ｄｏｍａｉｎ Ａｎａｌｙｓｉｓ）に対応させてもよい。つまり、第二変形例の光ファイバセンシングシステム３Ｃも、光ファイバ部３１Ｃ全体がセンサ部３１１Ｃとしての機能を有している。ＢＯＣＤＡでは、図７に示すように、光ファイバ部３１Ｃの片側のみから光信号を入射させるのではなく、両端から周波数差を設けた光信号をそれぞれ入射させている。具体的には、光ファイバセンシングシステム３Ｃでは、入射光信号Ｓ１として計測装置３３Ｃからポンプ光Ｓ３を出力するとともに、ポンプ光Ｓ３とは逆方向にプローブ光Ｓ４を出力する。光ファイバセンシングシステム３Ｃは、ポンプ光Ｓ３とプローブ光Ｓ４とを増幅部３２Ｃで増幅している。このような光ファイバセンシングシステム３Ｃでは、ＢＯＣＤＡ方式を採用しながら、光損失の制限を受けずに計測距離を伸ばすことができる。 In the second modification of the second embodiment, BOCDA (BrillouinｌｏOptical Correlation-Domain Analysis) may be used as a method using Brillouin scattering. That is, also in the optical fiber sensing system 3C of the second modified example, the entire optical fiber portion 31C has a function as the sensor portion 311C. In BOCDA, as shown in FIG. 7, optical signals are not incident only from one side of the optical fiber portion 31C, but optical signals having a frequency difference are incident from both ends. Specifically, in the optical fiber sensing system 3C, the pump light S3 is output from the measuring device 33C as the incident light signal S1, and the probe light S4 is output in the opposite direction to the pump light S3. The optical fiber sensing system 3C amplifies the pump light S3 and the probe light S4 by the amplifying unit 32C. In such an optical fiber sensing system 3C, the measurement distance can be extended without being limited by optical loss while adopting the BOCDA method.
《第三実施形態》
　次に、図８を参照して第三実施形態の光ファイバセンシングシステム３Ｄについて説明する。
　第三実施形態においては第一実施形態や第二実施形態と同様の構成要素には同一の符号を付して詳細な説明を省略する。この第三実施形態の光ファイバセンシングシステム３Ｄは、光スイッチ部３４を有する点で第一実施形態及び第二実施形態と相違する。 << Third embodiment >>
Next, the optical fiber sensing system 3D of the third embodiment will be described with reference to FIG.
In 3rd embodiment, the same code | symbol is attached | subjected to the component similar to 1st embodiment and 2nd embodiment, and detailed description is abbreviate | omitted. The optical fiber sensing system 3D according to the third embodiment is different from the first embodiment and the second embodiment in that the optical switch unit 34 is provided.
　第三実施形態の光ファイバセンシングシステム３Ｄでは、光ファイバ部３１Ｄは、主ライザー管本体２１の表面上の複数箇所に複数本ずつ配置されている。複数の光ファイバ部３１Ｄは、主ライザー管本体２１の円周方向に所定の間隔、例えば互いに等間隔になるように並んでいる。第三実施形態では、四本ずつ四カ所に配置されている。 In the optical fiber sensing system 3D of the third embodiment, a plurality of optical fiber portions 31D are arranged at a plurality of locations on the surface of the main riser tube main body 21. The plurality of optical fiber portions 31D are arranged in the circumferential direction of the main riser tube main body 21 so as to be at a predetermined interval, for example, at equal intervals. In the third embodiment, four are arranged in four places.
　光ファイバセンシングシステム３Ｄは、増幅部３２と複数の光ファイバ部３１Ｄとを繋ぐ光スイッチ部３４を有する。光スイッチ部３４は、増幅部３２と複数の光ファイバ部３１Ｄとを選択的に接続可能としている。光スイッチ部３４は、増幅部３２の入射光信号Ｓ１が入力される第一側及び反射光信号Ｓ２が入力される第二側の少なくとも一方に配置されている。第三実施形態の光スイッチ部３４は、増幅部３２の第一側及び第二側の両側に配置されている。光スイッチ部３４は、電気、機械、熱、及び光制御のいずれかの方式で光路を切替可能とされている。 The optical fiber sensing system 3D includes an optical switch unit 34 that connects the amplification unit 32 and the plurality of optical fiber units 31D. The optical switch unit 34 can selectively connect the amplification unit 32 and the plurality of optical fiber units 31D. The optical switch unit 34 is disposed on at least one of the first side to which the incident light signal S1 is input and the second side to which the reflected light signal S2 is input. The optical switch unit 34 of the third embodiment is disposed on both the first side and the second side of the amplification unit 32. The optical switch unit 34 can switch the optical path by any one of electric, mechanical, thermal, and optical control methods.
　第三実施形態の光ファイバセンシングシステム３Ｄによれば、両側の四本に光ファイバ部３１Ｄと一つの増幅部３２とを選択に接続可能な状態で繋ぐことができる。したがって、光ファイバシステム全体として計測点数を増やしつつ、計測距離を伸ばすことができる。 According to the optical fiber sensing system 3D of the third embodiment, the optical fiber part 31D and the one amplifying part 32 can be selectively connected to the four on both sides. Accordingly, the measurement distance can be extended while increasing the number of measurement points as the entire optical fiber system.
　以上、本発明の実施形態について図面を参照して詳述したが、各実施形態における各構成及びそれらの組み合わせ等は一例であり、本発明の趣旨から逸脱しない範囲内で、構成の付加、省略、置換、及びその他の変更が可能である。また、本発明は実施形態によって限定されることはなく、特許請求の範囲によってのみ限定される。 Although the embodiments of the present invention have been described in detail with reference to the drawings, the configurations and combinations of the embodiments in the embodiments are examples, and the addition and omission of configurations are within the scope not departing from the gist of the present invention. , Substitutions, and other changes are possible. Further, the present invention is not limited by the embodiments, and is limited only by the scope of the claims.
　なお、増幅部３２の第一光導波路３２１及び第二光導波路３２２の光増幅器３２０は、本実施形態のように同じものであることに限定されるものでなく、それぞれ別のもであってもよい。 The optical amplifiers 320 of the first optical waveguide 321 and the second optical waveguide 322 of the amplifying unit 32 are not limited to being the same as in this embodiment, and may be different from each other. Good.
　また、増幅部３２の第一光路変換器３２３と第二光路変換器３２４とは、本実施形態のように同じものであることに限定されるものではなく、それぞれ別のものであってもよい。 Further, the first optical path converter 323 and the second optical path converter 324 of the amplifying unit 32 are not limited to being the same as in the present embodiment, and may be different from each other. .
　また、第三実施形態では光スイッチ部３４が増幅部３２に接続する光ファイバ部３１Ｄは四つであることに限定されるものではなく、複数の光ファイバ部３１Ｄと一つの増幅部３２とを接続していればよい。したがって、光スイッチ部３４を介して増幅部３２に接続される光ファイバ部３１Ｄは、二つ以上であればよい。 In the third embodiment, the optical switch unit 34 is not limited to four optical fiber units 31D connected to the amplifying unit 32, but includes a plurality of optical fiber units 31D and one amplifying unit 32. It only has to be connected. Therefore, the number of optical fiber portions 31D connected to the amplifying portion 32 via the optical switch portion 34 may be two or more.
　また、光スイッチ部３４は、本実施形態のように増幅部３２の両側に配置される構造に限定されるものではなく、少なくとも一方に配置されていればよい。したがって、光スイッチ部３４は、増幅部３２に対して入射光信号Ｓ１が入力される第一側のみに配置されていてもよく、反射光信号Ｓ２が入力される第二側のみに配置されていてもよい。 Further, the optical switch unit 34 is not limited to the structure arranged on both sides of the amplifying unit 32 as in the present embodiment, and may be arranged at least on one side. Therefore, the optical switch unit 34 may be disposed only on the first side where the incident light signal S1 is input to the amplifier unit 32, and is disposed only on the second side where the reflected light signal S2 is input. May be.
　また、光スイッチ部３４は、入射光が波長多重の特性を有している場合、第一側の光スイッチ部３４をＷＤＭ方式の光回路で構成し、第二側の光スイッチ部３４を光波長分離（ＤＷＤＭ）方式の光回路で構成してもよい。 Further, when the incident light has wavelength multiplexing characteristics, the optical switch unit 34 is configured by configuring the first side optical switch unit 34 with a WDM optical circuit and the second side optical switch unit 34 as an optical switch. You may comprise with a wavelength separation (DWDM) type optical circuit.
　上記光ファイバセンシングシステム及びライザー管によれば、双方向の光信号が単一の光ファイバ部を伝播する構造であっても、入射光信号と反射光信号との両方を増幅させることができる。 According to the above optical fiber sensing system and riser tube, both the incident optical signal and the reflected optical signal can be amplified even when the bidirectional optical signal is propagated through the single optical fiber portion.
１     船舶
Ｓ     海
Ｇ     海底
２     ライザー管
２０   ライザー管本体
２１   主ライザー管本体
２２   増幅ライザー管本体
３、３Ａ、３Ｂ、３Ｃ、３Ｄ  光ファイバセンシングシステム
Ｓ１   入射光信号
Ｓ２   反射光信号
３１、３１Ａ、３１Ｂ、３１Ｃ、３１Ｄ      光ファイバ部
３１ａ 第一端部
３１ｂ 第二端部
３１１、３１１Ａ、３１１Ｂ、３１１Ｃ、３１１Ｄ   センサ部
３２、３２Ａ、３２Ｂ、３２Ｃ       増幅部
３２１ 第一光導波路
３２２ 第二光導波路
３２３ 第一光路変換器
３２４ 第二光路変換器
３３、３３Ｃ  計測装置
Ｓ３   ポンプ光
Ｓ４   プローブ光
３４   光スイッチ部 DESCRIPTION OF SYMBOLS 1 Ship S Sea G Seabed 2 Riser pipe 20 Riser pipe main body 21 Main riser pipe main body 22 Amplification riser pipe main body 3, 3A, 3B, 3C, 3D Optical fiber sensing system S1 Incident light signal S2 Reflected light signal 31, 31A, 31B, 31C, 31D Optical fiber part 31a First end part 31b Second end part 311, 311A, 311B, 311C, 311D Sensor part 32, 32A, 32B, 32C Amplifying part 321 First optical waveguide 322 Second optical waveguide 323 First optical path Converter 324 Second optical path converter 33, 33C Measuring device S3 Pump light S4 Probe light 34 Optical switch unit

Claims (7)

  1. 　光源から入力された入射光信号と、センサ部で生成された反射光信号とを誘導するよう双方向の光信号を伝搬可能とされ、直列に複数接続された光ファイバ部と、
    　前記光ファイバ部に接続された増幅部とを備え、
    　前記増幅部は、
    　前記入射光信号のみを増幅する第一光導波路と、
    　前記第一光導波路と並列に設けられて前記反射光信号のみを増幅する第二光導波路と、を有する光ファイバセンシングシステム。     Bidirectional optical signals can be propagated so as to guide the incident optical signal input from the light source and the reflected optical signal generated by the sensor unit, and a plurality of optical fiber units connected in series,
    An amplification unit connected to the optical fiber unit,
    The amplification unit is
    A first optical waveguide for amplifying only the incident optical signal;
    An optical fiber sensing system comprising: a second optical waveguide provided in parallel with the first optical waveguide and amplifying only the reflected optical signal.
  2. 　前記増幅部は、
    　並列に配置された前記第一光導波路及び前記第二光導波路の前記入射光信号が入力される第一側を繋ぐ第一光路変換器と、
    　並列に配置された前記第一光導波路及び前記第二光導波路の前記反射光信号が入力される第二側を繋ぐ第二光路変換器と、を有し、
    　前記第一光路変換器は、前記入射光信号を前記第一光導波路に導き、
    　前記第二光路変換器は、前記反射光信号を前記第二光導波路に導く請求項１に記載の光ファイバセンシングシステム。     The amplification unit is
    A first optical path converter connecting the first side to which the incident optical signal of the first optical waveguide and the second optical waveguide arranged in parallel is input;
    A second optical path converter connecting the second side to which the reflected optical signal of the first optical waveguide and the second optical waveguide arranged in parallel is input, and
    The first optical path converter guides the incident optical signal to the first optical waveguide;
    The optical fiber sensing system according to claim 1, wherein the second optical path converter guides the reflected light signal to the second optical waveguide.
  3. 　前記増幅部を複数備え、
    　複数の前記増幅部は、それぞれ異なる波長域の光信号を増幅している請求項１または請求項２に記載の光ファイバセンシングシステム。     A plurality of amplifying units;
    The optical fiber sensing system according to claim 1, wherein the plurality of amplifying units amplify optical signals in different wavelength ranges.
  4. 　前記増幅部を複数備え、
    　複数の前記増幅部は、それぞれ同じ波長域の光信号を増幅している請求項１または請求項２に記載の光ファイバセンシングシステム。     A plurality of amplifying units;
    The optical fiber sensing system according to claim 1 or 2, wherein each of the plurality of amplification units amplifies an optical signal in the same wavelength region.
  5. 　前記光ファイバ部は、前記センサ部として、コアにファイバブラッグレーティングが形成されている請求項１から請求項４のいずれか一項に記載の光ファイバセンシングシステム。 The optical fiber sensing system according to any one of claims 1 to 4, wherein a fiber Bragg rating is formed in a core of the optical fiber part as the sensor part.
  6. 　前記増幅部の前記入射光信号が入力される第一側及び前記反射光信号が入力される第二側の少なくとも一方に配置され、前記増幅部と複数の前記光ファイバ部とを選択的に接続可能な光スイッチ部とを備える請求項１から請求項５のいずれか一項に記載の光ファイバセンシングシステム。 The amplifying unit is disposed on at least one of the first side to which the incident optical signal is input and the second side to which the reflected optical signal is input, and selectively connects the amplifying unit and the plurality of optical fiber units. The optical fiber sensing system as described in any one of Claims 1-5 provided with a possible optical switch part.
  7. 　請求項１から請求項４のいずれか一項に記載の光ファイバセンシングシステムと、
    　筒状をなし、表面に前記光ファイバセンシングシステムの光ファイバ部の一つが配置された複数の主ライザー管本体と、
    　筒状をなし、表面に前記光ファイバセンシングシステムの増幅部が配置された増幅ライザー管本体と、を備え、
    　前記主ライザー管本体の端部と前記増幅ライザー管本体の端部とが直列的に接続されることで、前記光ファイバ部と前記増幅部とが接続されるライザー管。     An optical fiber sensing system according to any one of claims 1 to 4,
    A plurality of main riser tube bodies, each having a cylindrical shape, on the surface of which one of the optical fiber portions of the optical fiber sensing system is disposed,
    Amplifying riser tube main body having a cylindrical shape and having an amplification unit of the optical fiber sensing system disposed on the surface,
    A riser tube in which the end portion of the main riser tube main body and the end portion of the amplification riser tube main body are connected in series, whereby the optical fiber portion and the amplification portion are connected.
PCT/JP2017/014226 2016-04-19 2017-04-05 Optical fiber sensing system and riser pipe WO2017183455A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2016-083506 2016-04-19
JP2016083506A JP2017194306A (en) 2016-04-19 2016-04-19 Optical fiber sensing system and riser pipe

Publications (1)

Publication Number Publication Date
WO2017183455A1 true WO2017183455A1 (en) 2017-10-26

Family

ID=60115845

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2017/014226 WO2017183455A1 (en) 2016-04-19 2017-04-05 Optical fiber sensing system and riser pipe

Country Status (2)

Country Link
JP (1) JP2017194306A (en)
WO (1) WO2017183455A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7424391B2 (en) * 2019-12-04 2024-01-30 日本電気株式会社 Optical fiber sensing system, relay device and sensing method
JP7448019B2 (en) 2020-08-27 2024-03-12 日本電気株式会社 Environmental information acquisition system and environmental information acquisition method
JPWO2023100842A1 (en) * 2021-12-02 2023-06-08

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04291525A (en) * 1991-03-19 1992-10-15 Nec Corp Two-way optical repeater
JPH09270750A (en) * 1996-04-03 1997-10-14 Hitachi Ltd Bidirectional optical communication system
JP2002039871A (en) * 2000-07-21 2002-02-06 Hitachi Cable Ltd Sensor for measuring temperature distribution using optical fiber
JP2004334712A (en) * 2003-05-09 2004-11-25 Oki Electric Ind Co Ltd Long-distance transmission fbg sensor system
JP2012098239A (en) * 2010-11-05 2012-05-24 Mitsubishi Heavy Ind Ltd Riser pipe and response distribution measurement system of riser pipe
JP2012184953A (en) * 2011-03-03 2012-09-27 Occ Corp Sensing system
US20140152995A1 (en) * 2012-11-27 2014-06-05 Sentek Instrument LLC Serial weak fbg interrogator
JP2015194433A (en) * 2014-03-31 2015-11-05 株式会社東京精密 Temperature measurement device and temperature measurement method

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04291525A (en) * 1991-03-19 1992-10-15 Nec Corp Two-way optical repeater
JPH09270750A (en) * 1996-04-03 1997-10-14 Hitachi Ltd Bidirectional optical communication system
JP2002039871A (en) * 2000-07-21 2002-02-06 Hitachi Cable Ltd Sensor for measuring temperature distribution using optical fiber
JP2004334712A (en) * 2003-05-09 2004-11-25 Oki Electric Ind Co Ltd Long-distance transmission fbg sensor system
JP2012098239A (en) * 2010-11-05 2012-05-24 Mitsubishi Heavy Ind Ltd Riser pipe and response distribution measurement system of riser pipe
JP2012184953A (en) * 2011-03-03 2012-09-27 Occ Corp Sensing system
US20140152995A1 (en) * 2012-11-27 2014-06-05 Sentek Instrument LLC Serial weak fbg interrogator
JP2015194433A (en) * 2014-03-31 2015-11-05 株式会社東京精密 Temperature measurement device and temperature measurement method

Also Published As

Publication number Publication date
JP2017194306A (en) 2017-10-26

Similar Documents

Publication Publication Date Title
US20100034593A1 (en) Novel deployment technique for optical fibres within pipeline coatings
EP3237936B1 (en) Optical fiber vibration measurement system in multiphase flows with related method to monitor multiphase flows
WO2017009606A1 (en) Improved sensitivity optical fiber sensing systems
JP5904733B2 (en) Deflection measuring equipment using the principle of interferometry
WO2017183455A1 (en) Optical fiber sensing system and riser pipe
RU2573614C2 (en) Sensor and method of measurement
US20090154870A1 (en) Optical Fiber Sensor Connected To Optical Fiber Communication Line
JP5478752B1 (en) Strain measuring method and strain measuring apparatus
JP2012098239A (en) Riser pipe and response distribution measurement system of riser pipe
EP2897310A1 (en) Method and system for monitoring infrastructure using BOTDA
JP2019522206A (en) Brillouin-based distributed bending fiber sensor and method of use thereof
JP4748520B2 (en) Vibration position detection device due to polarization fluctuations
JP2009229134A (en) Optical sensor system
JP2011027533A (en) Optical fiber type acoustic-wave logging system and soil logging structure
US10241230B2 (en) Downhole sensing using solitons in optical fiber
JP5354497B2 (en) Distributed fiber optic pressure sensor system
US11340365B2 (en) Switchable distributed acoustic sensing system for wellbore environment
CN104614093B (en) Bending-insensitive distributed Brillouin optical fiber temperature and strain sensor
US20230039794A1 (en) Apparatus, fiber optic sensor assembly and sensor housing assembly utilizing viscous material composition to mitigate signal attenuation
WO2016084133A1 (en) Acoustic emission wave detector, acoustic emission wave detection system, and acoustic emission wave detection method
US20230283366A1 (en) Environment information acquisition system, environment information acquisition method, and recording medium
KR101388163B1 (en) Deformation measuring apparatus
JP5242142B2 (en) Surface sensor
JP2006343231A (en) Optical fiber sensor
US20230184597A1 (en) Coil of reference fiber for downhole fiber sensing measurement

Legal Events

Date Code Title Description
NENP Non-entry into the national phase

Ref country code: DE

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17785797

Country of ref document: EP

Kind code of ref document: A1

122 Ep: pct application non-entry in european phase

Ref document number: 17785797

Country of ref document: EP

Kind code of ref document: A1