Abstract: A fiber optic sensing (FOS) system may include a Brillouin Optical Time Domain Analyzer (BOTDA) unit, a first fiber optical cable optically connected to the BOTDA interrogator unit at a first end, and an optical feedthrough system (OFS) optically connected the first fiber optical cable at a second end of the first fiber optical cable. The FOS system may further comprise a fiber optic cable forming a loop within a wellbore that is optically connected to the first fiber optical cable at the OFS and a second fiber optical cable optically connected to the loop at the OFS and wherein the second fiber optical cable is optically connected to the BOTDA interrogator unit.

Abstract: A method, includes: detecting one or more properties of a waveguide having a downhole end and an uphole end; and responsive to the detected one or more properties, positioning into a passage of a wellbore the waveguide to minimize tension thereof.

Abstract: A fiber optic sensing (FOS) system may include a Brillouin Optical Time Domain Analyzer (BOTDA) unit, a first fiber optical cable optically connected to the BOTDA interrogator unit at a first end, and an optical feedthrough system (OFS) optically connected the first fiber optical cable at a second end of the first fiber optical cable. The FOS system may further comprise a fiber optic cable forming a loop within a wellbore that is optically connected to the first fiber optical cable at the OFS and a second fiber optical cable optically connected to the loop at the OFS and wherein the second fiber optical cable is optically connected to the BOTDA interrogator unit.

Abstract: There is provided a method and an apparatus of fiber optic distributed acoustic sensing (DAS) which can use low-cost coherent laser as well as low-cost acquisition and processing electronics and which can still provide reliable monitoring results for optical fiber monitoring and troubleshooting applications in optical fiber telecommunication networks. Such low-cost solution is made possible by employing grouped data signal processing. Data is processed over independent groups of data to provide an independent DAS signal for each group. This allows measurements to be less sensitive to laser fluctuations and thereby reduces coherent laser technical specification requirements and allows the use of a low-cost coherent laser (thereby reducing the cost of the laser) as well as low-cost acquisition and processing electronics.

Abstract: A well system includes a fiber-optic cable that can be positioned downhole along a wellbore. The well system further includes a plurality of opto-electrical interfaces to communicatively couple to the fiber-optic cable to monitor temperature and strain along the fiber-optic cable. Additionally, the well system includes a processing device and a memory device that includes instructions executable by the processing device to cause the processing device to perform operations. The operations include receiving data representing frequency or phase shift measurements from the opto-electrical interfaces using at least two frequency or phase shift measurement techniques. Further, the operations include generating a temperature shift output and a strain change output using an inversion comprising sensitivity ratios and the data representing the frequency or phase shift measurements from the plurality of opto-electrical interfaces.

Abstract: A fiber optic cable in the present disclosure comprises: an outer tube having an inner surface and an outer surface; a fiber in metal tube (FIMT) comprising one or more optical fibers, wherein the FIMT is disposed within the outer tube, and wherein the outer surface of the FIMT and the inner surface of the outer tube form an annular space; and a cured gelling material in the annular space. By incorporating the cured gelling material into the annular space, fluid migration through the annular space can be reduced, and sheer stress for strain coupling of the FIMT and the outer tube can be increased.

Abstract: A system may include a sensing fiber that can receive interrogation data via a coil of reference fiber, the coil of reference fiber configurable to be of a same type of fiber as the sensing fiber, and the sensing fiber configurable to be coupled in series with the coil of reference fiber. A known temperature and a known strain can be received from the coil of reference fiber. The known temperature, the known strain, and the interrogation data can be outputted for calibrating a measurement of the interrogation data.

Abstract: A well system includes a fiber-optic cable that can be positioned downhole along a wellbore. The well system further includes a plurality of opto-electrical interfaces to communicatively couple to the fiber-optic cable to monitor temperature and strain along the fiber-optic cable. Additionally, the well system includes a processing device and a memory device that includes instructions executable by the processing device to cause the processing device to perform operations. The operations include receiving data representing frequency or phase shift measurements from the opto-electrical interfaces using at least two frequency or phase shift measurement techniques. Further, the operations include generating a temperature shift output and a strain change output using an inversion comprising sensitivity ratios and the data representing the frequency or phase shift measurements from the plurality of opto-electrical interfaces.

Abstract: A system may include a splice housing positioned along a portion of tubing in a wellbore and a splice housing protector around the splice housing. An uphole fiber optic cable may extend through the splice housing protector. The uphole fiber optic cable may mate with a first port of the splice housing at a downhole end of the splice housing protector. A downhole fiber optic cable may mate with a second port of the splice housing in the splice housing protector. The splice housing may splice the uphole fiber optic cable and the downhole fiber optic cable.

Abstract: A wellbore optical fiber measurement system for measuring data in a lateral wellbore that includes a flexible optical fiber. The optical fiber includes a waveguide coated with a coating, wherein the optical fiber has an effective density ?efffiber and an effective axial Young modulus Eefffiber and wherein the product ( ? eff f ? i ? b ? e ? r E eff f ? i ? b ? e ? r ) · ( 1 - ? w ? a ? t ? e ? r ? eff f ? i ? b ? e ? r ) is greater than 50 kg/m3/GPa. The system also includes a data acquisition unit with a processor operable to obtain strain measurement data of the wellbore from the optical fiber.

Abstract: The present disclosure describes gain stabilization techniques for scintillation devices which do not require use of an intrinsic reference radiation source. Reference light pulses are emitted into the scintillation device to obtain a signal having a given magnitude. The magnitude of the signal is compared to the magnitude of a reference signal computed as a function of temperature and a degradation factor. A gain adjustment is computed with causes the magnitude of the signal to match the target reference magnitude. The gain adjustment is then used to adjust the system gain so that subsequent output signal amplitudes, measured when energetic photons interact in the scintillator, always correspond to the same energy.

Abstract: Optical sensors having one or more soluble coatings thereon are used to detect the presence of a degrading fluid. In a generalized embodiment, the fiber optic sensor includes a fiber optic cable having two strain sensor positioned therein. A soluble layer is positioned over one of the strain sensor. Due to the presence of the soluble layer, the covered strain sensor optically responds differently than the other strain sensor to changes in pressure, strain and temperature. In the presence of a degrading fluid, the soluble layer degrades and ultimately dissolves, thereby changing the optical response of the previously covered strain sensor. When the soluble layer is dissolved, the strain induced by the soluble layer relaxes, thus causing a wavelength shift in the signal of the grating. By monitoring the wavelength shifts of both strain sensors, the fiber optic sensor acts as a detector for the presence of the degrading fluid.

Abstract: Methods and systems for effectively sealing a fiber optic line to a pressure gauge device are disclosed. A pressure gauge device has an outer body, a reference volume within the outer body and a pressure sensor having a first side and a second side. The first side of the pressure sensor is exposed to a pressure inlet and the second side of the pressure sensor is exposed to the reference volume. A fiber optic line is coupled to the pressure gauge device using a feedthrough device. The fiber optic line comprises a first fiber optic line portion located within the feedthrough device, a second fiber optic line portion located within the reference volume and a third fiber optic line portion located within a cable located outside the pressure gauge device and coupled to the feed through device. The first fiber optic line portion comprises a first Fiber Bragg Grating (“FBG”).

Abstract: Optical sensors having one or more soluble coatings thereon are used to detect the presence of a degrading fluid. In a generalized embodiment, the fiber optic sensor includes a fiber optic cable having two strain sensor positioned therein. A soluble layer is positioned over one of the strain sensor. Due to the presence of the soluble layer, the covered strain sensor optically responds differently than the other strain sensor to changes in pressure, strain and temperature. In the presence of a degrading fluid, the soluble layer degrades and ultimately dissolves, thereby changing the optical response of the previously covered strain sensor. When the soluble layer is dissolved, the strain induced by the soluble layer relaxes, thus causing a wavelength shift in the signal of the grating. By monitoring the wavelength shifts of both strain sensors, the fiber optic sensor acts as a detector for the presence of the degrading fluid.

Abstract: An OTDR device and method for characterizing one or more events in an optical fiber link are provided. A plurality of light acquisitions is performed. For each light acquisition, test light pulses are propagated in the optical fiber link and the corresponding return light signals from the optical fiber link are detected. The light acquisitions are performed under different acquisition conditions, for example using different pulsewidths or wavelengths. Parameters characterizing the event are derived using the detected return signal from at least two of the plurality of light acquisitions.

Abstract: The reflectometric method for measuring an optical loss value of an optical fiber link generally comprises: obtaining at least one bias value being indicative of a bias induced by differing backscattering characteristics of a first optical fiber length and a second optical fiber length; propagating at least one test signal serially into the first optical fiber length, the optical fiber link and the second optical fiber length; monitoring at least one return signal resulting respectively from the propagation of the at least one test signal; and determining the optical loss value based on the at least one return signal and the at least one bias value.

Abstract: An OTDR device and method for characterizing one or more events in an optical fiber link are provided. A plurality of light acquisitions is performed. For each light acquisition, test light pulses are propagated in the optical fiber link and the corresponding return light signals from the optical fiber link are detected. The light acquisitions are performed under different acquisition conditions, for example using different pulsewidths or wavelengths. Parameters characterizing the event are derived using the detected return signal from at least two of the plurality of light acquisitions.

Abstract: An OTDR device and method for characterizing one or more events in an optical fiber link are provided. A plurality of light acquisitions is performed. For each light acquisition, test light pulses are propagated in the optical fiber link and the corresponding return light signals from the optical fiber link are detected. The light acquisitions are performed under different acquisition conditions, for example using different pulsewidths or wavelengths. Parameters characterizing the event are derived using the detected return signal from at least two of the plurality of light acquisitions.

Abstract: Methods and systems for effectively sealing a fiber optic line to a pressure gauge device are disclosed. A pressure gauge device has an outer body, a reference volume within the outer body and a pressure sensor having a first side and a second side. The first side of the pressure sensor is exposed to a pressure inlet and the second side of the pressure sensor is exposed to the reference volume. A fiber optic line is coupled to the pressure gauge device using a feedthrough device. The fiber optic line comprises a first fiber optic line portion located within the feedthrough device, a second fiber optic line portion located within the reference volume and a third fiber optic line portion located within a cable located outside the pressure gauge device and coupled to the feed through device. The first fiber optic line portion comprises a first Fiber Bragg Grating (“FBG”).

Abstract: An OTDR device and method for characterizing one or more events in an optical fiber link are provided. A plurality of light acquisitions is performed. For each light acquisition, test light pulses are propagated in the optical fiber link and the corresponding return light signals from the optical fiber link are detected. The light acquisitions are performed under different acquisition conditions, for example using different pulsewidths or wavelengths. Parameters characterizing the event are derived using the detected return signal from at least two of the plurality of light acquisitions.