Abstract: In some embodiments, a distributed nondestructive inspection method for slickline cable structural defect detection transmits a light pulse along an optical waveguide in the slickline cable. A reflected light signal is 5 received from the optical waveguide in response to the light pulse. Defects can then be determined in the slickline cable based on variations in scattering intensity, phase shift, specific spectral signature, power spectral density, strain amplitude, and/or transmission loss of the reflected light signal as compared to the light pulse.

Abstract: A polymer composite wireline cable comprising: a polymeric matrix material; at least one reinforced fiber embedded in the polymeric matrix material; and at least one optical fiber disposed in the polymeric matrix material, the at least one optical fiber having at least one pair of Bragg grating sensors, wherein one of the pair of Bragg grating sensors is configured to experience loading strain and the other of the pair of Bragg grating sensors is configured not to experience loading strain.

Abstract: A disclosed system for downhole time domain reflectometry (TDR) includes a surface electro-optical interface, a downhole electro-optical interface, a fiber-optic cable that couples the surface electro-optical interface and the downhole electro-optical interface, and an electrical transmission line that extends from the downhole electro-optical interface into a wellbore environment to enable TDR operations. A described method for downhole TDR includes transmitting an optical signal to a downhole environment, converting the optical signal to an electrical signal in the downhole environment, reflecting the electrical signal using an electrical transmission line in the downhole environment, analyzing data corresponding to the reflected electrical signal, and displaying a result of the analysis.

Abstract: Pipeline segments can contain cables, such as communication cables (e.g., fiber optic cables) within insulation material surrounding the pipeline segments. Cables can be embedded within the insulation material, run through conduits embedded within the insulation material, placed in channels formed in the insulation material, or otherwise. Channels containing one or more cables can be filled with supplemental insulation material, thus securing the cables within the channels. Pipelines created as disclosed herein can enable data transfer between distant points without the need to lay fiber optic cable in addition to the pipeline. Further, fiber optic cable embedded thusly can be used to sense conditions in the pipeline, such as leaks, seismic activity, strain, and temperature information.

Abstract: An illustrative distributed acoustic sensing system includes a multi-mode optical fiber cable for distributed sensing and a distributed acoustic sensing interrogator coupled to the multi-mode optical fiber cable via a single mode optical fiber. The interrogator derives distributed acoustic measurements from Rayleigh backscattering light that is initiated with a substantially under-filled launch configuration that is designed to excite only the lowest-order modes of the multi-mode optical fiber. Mode conversion within the multi-mode optical fiber is anticipated to be negligible. For elastic scattering (i.e., Rayleigh scattering), it is further anticipated that the scattered light will be primarily returned in the incident propagation mode, thereby escaping the extraordinarily large coupling loss that would otherwise be expected from coupling a single-mode optical fiber to a multi-mode optical fiber for distributed sensing. Experiments with graded index multi-mode optical fiber have yielded positive results.

Abstract: Systems and methods for determining whether mechanical fatigue exists in a downhole cable using thermally-induced acoustic waves are disclosed herein. A cable fatigue monitoring system includes a thermal source, one or more light sources, one or more photodetector arrays, and a computing system comprising a processor, a memory, and a cable distortion module.

Abstract: Method and apparatus are disclosed for use of a fiber-optic sensor loop for use within a wellbore; with a plurality of light sources optically coupled to the fiber-optic sensor loop; at least one electromagnetically sensitized region within the fiber-optic sensor loop; and a plurality of detectors optically coupled to the fiber-optic sensor loop; and using the sensing system to detect changes in a magnetic field within the wellbore.

Abstract: Downhole slickline cable including a polymer matrix having reinforcing fibers embedded therein. A plurality of integrity-sensing optical fibers are embedded within the polymer composite and extend along an axial length of the downhole slickline cable that enables slickline cable structural and mechanical integrity self-diagnosis. The cable may include energy transmission lines that include one or more integrity-sensing optical fibers.

Abstract: An illustrative distributed acoustic sensing system includes a multi-mode optical fiber cable for distributed sensing and a distributed acoustic sensing interrogator coupled to the multi-mode optical fiber cable via a single mode optical fiber. The interrogator derives distributed acoustic measurements from Rayleigh backscattering light that is initiated with a substantially under-filled launch configuration that is designed to excite only the lowest-order modes of the multi-mode optical fiber. Mode conversion within the multi-mode optical fiber is anticipated to be negligible. For elastic scattering (i.e., Rayleigh scattering), it is further anticipated that the scattered light will be primarily returned in the incident propagation mode, thereby escaping the extraordinarily large coupling loss that would otherwise be expected from coupling a single-mode optical fiber to a multi-mode optical fiber for distributed sensing. Experiments with graded index multi-mode optical fiber have yielded positive results.

Abstract: A method of optical communication in a well can include launching light having substantially coherent phase into an optical waveguide extending in a wellbore, modulating light having substantially coherent phase in the wellbore, and receiving the modulated light transmitted via the same optical waveguide. A well system can include at least one optical waveguide extending in a wellbore, and a downhole optical modulator which modulates light transmitted via the optical waveguide, the optical modulator comprising a potassium titanyl phosphate crystal. Another method of optical communication in a well can include launching light into an optical waveguide extending in a wellbore, the light launched into the optical waveguide having information modulated thereon using a carrier, modulating light in the wellbore, the modulating comprising modulating information using a subcarrier of the carrier, and transmitting the light modulated in the wellbore via the same optical waveguide.

Abstract: Various disclosed distributed acoustic sensing (DAS) based systems and methods include embodiments that process the DAS measurements to detect one or more contrasts in acoustic signatures associated with one or more fluids flowing along a tubing string, and determine positions of the one or more contrasts as a function of time. The detected contrasts may be changes in acoustic signatures arising from one or more of: turbulence, frictional noise, acoustic attenuation, acoustic coupling, resonance frequency, resonance damping, and active noise generation by entrained materials. At least some of the contrasts correspond to interfaces between different fluids such as those that might be pumped during a cementing operation.

Abstract: A method of flowing fluid from a formation, the method comprising: sensing presence of a reservoir impairing substance in the fluid flowed from the formation; and automatically controlling operation of at least one flow control device in response to the sensing of the presence of the substance. A well system, comprising: at least one sensor which senses whether a reservoir impairing substance is present; and at least one flow control device which regulates flow of a fluid from a formation in response to indications provided by the sensor.

Abstract: Pipeline segments can contain cables, such as communication cables (e.g., fiber optic cables) within insulation material surrounding the pipeline segments. Cables can be embedded within the insulation material, run through conduits embedded within the insulation material, placed in channels formed in the insulation material, or otherwise. Channels containing one or more cables can be filled with supplemental insulation material, thus securing tbe cables within the channels. Pipelines created as disclosed herein can enable data transfer between distant points without the need to lay fiber optic cable in addition to the pipeline. Further, fiber optic cable embedded thusly can be used to sense conditions in the pipeline, such as leaks, seismic activity, strain, and temperature information.

Abstract: A system for recording metadata is disclosed. The system includes an acoustic vibration sensing system. The system also includes one or more sensors operable to measure characteristic parameters. The sensors are coupled to the acoustic vibration sensing system and include one or more channels for recording metadata. The system further includes one or more optical modulators. The optical modulators modulate a signal received from the one or more sensors and direct the modulated signal to the acoustic vibration sensing system. The system further includes one or more sources of the metadata coupled to the one or more optical modulators.

Abstract: A side-hole optical cane for measuring pressure and/or temperature is disclosed. The side-hole cane has a light guiding core containing a sensor and a cladding containing symmetrical side-holes extending substantially parallel to the core. The side-holes cause an asymmetric stress across the core of the sensor creating a birefringent sensor. The sensor, preferably a Bragg grating, reflects a first and second wavelength each associated with orthogonal polarization vectors, wherein the degree of separation between the two is proportional to the pressure exerted on the core. The side-hole cane structure self-compensates and is insensitive to temperature variations when used as a pressure sensor, because temperature induces an equal shift in both the first and second wavelengths. Furthermore, the magnitude of these shifts can be monitored to deduce temperature, hence providing the side-hole cane additional temperature sensing capability that is unaffected by pressure.

Abstract: A downhole optical sensor system includes at least one optical sensor positioned in a borehole and coupled to an interface via a fiber optic cable. Each of the optical sensors includes a waveguide for conducting light, and a reagent region positioned between the waveguide and a fluid in the borehole to absorb a portion of the light from the waveguide, the portion being dependent upon a concentration of a chemical species in the fluid. A method for operating a well includes deploying one or more downhole optical sensors in a fluid flow path in the well, probing the one or more downhole optical sensors from a surface interface to detect concentrations of one or more chemical species, and deriving a rate of scale buildup or corrosion based at least in part on the detected concentrations.

Abstract: A disclosed system includes a plurality of ion selective fiber sensors configured to measure treatment concentration variance, and a computer in communication with the plurality of ion selective fiber sensors. The computer determines treatment coverage for different downhole zones using information received from the plurality of ion selective fiber sensors. A disclosed method includes collecting data from a plurality of ion selective fiber sensors configured to measure treatment concentration variance. The method also includes determining treatment coverage for different downhole zones using information received from the plurality of ion selective fiber sensors. A disclosed downhole treatment management system includes a data analysis unit that collects data from a plurality of downhole ion selective fiber sensors configured to measure treatment concentration variance, and that determines treatment coverage for different downhole zones using the collected data.

Abstract: Fiber optic enabled casing collar locator systems and methods include a wireline sonde or a coil tubing sonde apparatus configured to be conveyed through a casing string by a fiber optic cable. The sonde includes at least one permanent magnet producing a magnetic field that changes in response to passing a collar in the casing string, a coil that receives at least a portion of the magnetic field and provides an electrical signal in response to the changes in the magnetic field, and a light source that responds to the electrical signal to communicate light along an optical fiber to indicate passing collars.

Abstract: Fiber optic enabled casing collar locator systems and methods including a wireline sonde or a coil tubing sonde apparatus configured to be conveyed through a casing string by a fiber optic cable. The sonde includes at least one permanent magnet producing a magnetic field that changes in response to passing a collar in the casing string. Such magnetic field changes induce voltages changes within associated pick-up electrical coil conductors. Some embodiments include a cylinder configured to change its diameter in response to the changes in the magnetic field and/or impressed voltage, and an optical fiber wound around the cylinder to convert the cylinder diameter change into an optical path length change for light being communicated along the fiber optic cable. The cylinder may include a magnetostrictive material or a piezoelectric material.

Abstract: A disclosed remote work system includes a light source and a nonlinear converter optically coupled to and remote from the light source. The nonlinear light converter converts a narrowband light pulse received from the light source to a converted spectrum light pulse. The system also includes a work element coupled to the nonlinear light converter. The work element performs a work operation using the converted spectrum light pulse. A related remote work method includes generating a narrowband light pulse and conveying the narrowband light pulse to a remote location. The method also includes converting the narrowband light pulse to a converted spectrum light pulse at the remote location. The method also includes performing a sense operation or work operation at the remote location using the converted spectrum light pulse.