Abstract: A sensing apparatus includes a sheath, a central member disposed in the sheath, at least one optical fiber disposed with the central member, and a film adhesive disposed between the central member and the sheath, the film adhesive provided in one or more sheets or strips and disposed in one or more layers between the central member and the sheath, and the film adhesive attached to the sheath.

Abstract: A sensing apparatus includes a sheath, a central member disposed in the sheath, at least one optical fiber disposed with the central member, and a film adhesive disposed between the central member and the sheath, the film adhesive provided in one or more sheets or strips and disposed in one or more layers between the central member and the sheath, and the film adhesive attached to the sheath.

Abstract: Disclosed herein is a method for sensing one or more selected parameters related to a structure of interest, for example, the shape of an isolated structure. A cable is attached to the structure of interest at one or more attachment points. The cable contains one or more optical fibers. One or more light signals are transmitted into the one or more optical fibers and then detected to form a data set. The data set is compared with information known about the one or more attachment points to determine error values. The error values are then combined with the data set to determine the selected parameters associated with the structure.

Abstract: An apparatus for estimating a parameter includes: an optical fiber sensor including at least one optical fiber configured to be disposed in a downhole location and including at least one sensing location configured to generate measurement signals; at least one light source configured to transmit a measurement signal having a wavelength to interrogate a sensing location and cause the sensing location to return a reflected measurement signal indicative of a measured parameter, and configured to transmit a reference signal and cause a reflected reference signal to be returned from a location associated with the sensing location, the reflected reference signal having a known relationship to hydrogen concentration; and a processor configured to receive the reflected measurement signal and the reflected reference signal, estimate the hydrogen concentration based on the reflected reference signal, and calibrate the first reflected signal based on the estimated hydrogen concentration.

Abstract: A fiber optic cable arrangement includes a core, a sheath surrounding the core and being strain locked to the core, and at least one optical fiber positioned within the sheath being strain locked to the core.

Abstract: Disclosed herein is a method for sensing one or more selected parameters related to a structure of interest, for example, the shape of an isolated structure. A cable is attached to the structure of interest at one or more attachment points. The cable contains one or more optical fibers. One or more light signals are transmitted into the one or more optical fibers and then detected to form a data set. The data set is compared with information known about the one or more attachment points to determine error values. The error values are then combined with the data set to determine the selected parameters associated with the structure.

Abstract: A distributed sensing apparatus and system including one or more optical fibers disposed in a channel on the surface of a central member. A layer of film adhesive is disposed between the central member and a sheath. The film adhesive is circumferentially wrapped around the central member prior to arranging the sheath around the central member. The film adhesive is then cured and expanded to firmly attach the optical fiber to the sheath.

Abstract: A sensing assembly including a fiber for monitoring at least one condition or parameter and a strip formed from a pair of laminae disposed with the fiber. The laminae are arranged parallel to each other and engaged longitudinally along the fiber for enabling the strip to secure the fiber in place. A method of monitoring a parameter or condition with a sensing assembly is also included.

Abstract: An apparatus for estimating a parameter includes: an optical fiber sensor including at least one optical fiber configured to be disposed in a downhole location and including at least one sensing location configured to generate measurement signals; at least one light source configured to transmit a measurement signal having a wavelength to interrogate a sensing location and cause the sensing location to return a reflected measurement signal indicative of a measured parameter, and configured to transmit a reference signal and cause a reflected reference signal to be returned from a location associated with the sensing location, the reflected reference signal having a known relationship to hydrogen concentration; and a processor configured to receive the reflected measurement signal and the reflected reference signal, estimate the hydrogen concentration based on the reflected reference signal, and calibrate the first reflected signal based on the estimated hydrogen concentration.

Abstract: A fiber optic cable for use in a downhole environment is disclosed. The fiber optic cable includes a tube having an interior region; an optical fiber disposed in the interior region of the tube; a gas in the interior region; and a gel in the interior region, wherein the gel is configured to reduce stress on the optical fiber in the presence of the gas at a temperature substantially near the flashpoint of the gel. One or more seals can be used to seal the gel and the inert gas in the interior region. In various aspects, the fiber optic cable can be used in a downhole environment.

Abstract: An apparatus for performing a downhole operation includes: a carrier configured to be deployed in a borehole in an earth formation; and an optical fiber assembly disposed at the carrier, the optical fiber assembly including an optical fiber and a polymer material bonded to a length of the optical fiber. A portion of the polymer material has been removed by: disposing a liquid metallic material proximate to the polymer material, the polymer material being bonded to the optical fiber; heating the liquid metallic material to a temperature sufficient to burn the polymer material and de-bond the polymer material from a surface of the optical fiber; and removing the polymer material and liquid metal from the surface of the optical fiber.

Abstract: An apparatus for estimating at least one parameter in a downhole environment includes: an optical fiber configured to be disposed in a borehole, the optical fiber including a core having a first index of refraction and a cladding surrounding the core and having a second index of refraction that is lower than the first index of refraction, at least a portion of the core being made from a hydrogen resistant material; at least one fiber Bragg grating (FBG) formed within the hydrogen resistant material; a light source configured to send an optical signal into the optical fiber; and a detector configured to receive a return signal generated by the at least one FBG and generate data representative of the at least one parameter.

Abstract: A sensing cable, including an outer cladding; and at least one sensing bundle contained within the cladding, each sensing bundle having a sensing fiber wrapped strain-transmissively by at least one strand. A method of sensing strain is also included.

Abstract: A method of removing a polymer material from an optical fiber assembly includes: disposing a liquid metallic material proximate to the polymer material, the polymer material being bonded to the optical fiber; heating the liquid metallic material to a temperature sufficient to burn the polymer material and de-bond the polymer material from a surface of the optical fiber; and removing the polymer material and liquid metal from the surface of the optical fiber.

Abstract: A sensing assembly including a fiber for monitoring at least one condition or parameter and a strip formed from a pair of laminae disposed with the fiber. The laminae are arranged parallel to each other and engaged longitudinally along the fiber for enabling the strip to secure the fiber in place. A method of monitoring a parameter or condition with a sensing assembly is also included.

Abstract: A method of producing a coated FBG optical fiber involves coating the optical fiber prior to writing the Bragg grating. A system for producing the coated FBG optical fibers includes a high temperature furnace from which to draw the fiber, a coating applicator that may be a carbon coating applicator, a cooling station, and a grating writing station.

Abstract: An optical fiber sensing apparatus includes: a substrate configured to deform in response to an environmental parameter; an optical fiber sensor including a core having at least one measurement location disposed therein and a protective coating surrounding the optical fiber sensor, the protective coating made from a polyimide material; and an adhesive configured to adhere the optical fiber sensor to the substrate, the adhesive made from the polyimide material.

Abstract: A method of removing a polymer material from an optical fiber assembly includes: disposing a liquid metallic material proximate to the polymer material, the polymer material being bonded to the optical fiber; heating the liquid metallic material to a temperature sufficient to burn the polymer material and de-bond the polymer material from a surface of the optical fiber; and removing the polymer material and liquid metal from the surface of the optical fiber.

Abstract: A fiber optic cable for use in a downhole environment is disclosed. The fiber optic cable includes a tube having an interior region; an optical fiber disposed in the interior region of the tube; a gas in the interior region; and a gel in the interior region, wherein the gel is configured to reduce stress on the optical fiber in the presence of the gas at a temperature substantially near the flashpoint of the gel. One or more seals can be used to seal the gel and the inert gas in the interior region. In various aspects, the fiber optic cable can be used in a downhole environment.