Baker Hughes Corporation

Rutgers, The State University of New Jersey

Baker Huges Incorporated

Luna Energy LLC

Baker Hughes, a Ge Compnay, LLC

Daniel Scott Homa

Brooks A Childers

Robert M Harman

Christopher H Lambert

Roger Glen Duncan

Alexander Michael Barry

George H Sigel

John Guarniere

Justin Crusse

Paul Samuel Zerwekh

Philip Robin Couch

Ajit Balagopal

Robert Harman

Stephen H Poland

Malcolm S Laing

Charles A Giebner

Lance A Beckner

Brian S Lucas

Alexander M Barry

Alexander Barry

Justin W Crusse

Brian Lucas

Stephen Poland

A method, apparatus and system for forming a fiber optic cable is disclosed. A first pattern of a phase mark is formed at a first location in the fiber optic cable. A relational parameter between the fiber optic cable and the phase mask is changed and a second pattern of the phase mask is formed at a second location in the fiber optic cable. The second pattern is related to the first pattern via the change in the relational parameter between the fiber optic cable and the phase mask. A controller can be used to control the relational parameter.

Phase mask period control

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.

Sensing assembly

An optical fiber includes: a core including a photosensitive material disposed therein, the core having a first index of refraction; a depressed cladding surrounding the core and having a second index of refraction that is lower than the first index of refraction; and an outer cladding surrounding the depressed cladding and having a third index of refraction that is higher than the depressed cladding.

Bend insensitive optical fiber with improved hydrogen resistance

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.

Extended temperature fiber optic cable design

An apparatus for estimating a property includes a hollow core tube and an input light guide disposed at least partially within hollow core tube. The apparatus also includes a second gap disposed within the hollow core tube and separated from the input light guide by an air gap width. The second gap is formed of a first solid material and has a second gap width. The apparatus also includes a third gap disposed at least partially within the hollow core tube and being further from the input light guide than the second gap. The third gap is formed of a second solid material and has a third gap width.

Multi-gap interferometric sensors

A method for estimating a distance includes: generating an optical signal having a wavelength that is within a wavelength range, the optical signal modulated via a modulation signal having a modulation frequency; transmitting the modulated optical signal from a light source into the optical fiber, the optical fiber in contact with a moveable strain inducing element located at the position along the optical fiber, the optical fiber including a plurality of sensing locations configured to reflect light within the wavelength range when under strain from the strain inducing element and transmit light within the wavelength range when not under strain from the strain inducing element; receiving a reflected signal including light reflected from at least one of the sensing locations; demodulating the reflected signal with a reference signal to generate reflected signal data; and determining the distance to the position along the optical fiber based on the reflected signal data.

Distance measurement using incoherent optical reflectometry

A method, system and apparatus for obtaining a parameter of interest relating to a wellbore is disclosed. A fiber optic cable having a plurality of sensors is disposed in the wellbore, wherein the plurality of sensors have reflectivity values configured to provide improved signal-to-noise ratio compared to signal-to-noise ratio of a plurality of sensors having substantially same reflectivity values. Light is propagated into the fiber optic cable from a light source and signals are received at a detector from the plurality of sensors in response to interaction of the propagated light with the plurality of sensors. A processor may be used to obtain the parameter of interest from the received signals. The fiber optic cable may be coupled to a member in the wellbore, wherein the parameter of interest is related to the member.

Sensor array configuration for swept-wavelength interferometric-based sensing systems

An apparatus for estimating a shape, the apparatus including: an optical fiber configured to conform to the shape and having a first core offset from a centerline of the optical fiber, the first core having an optical characteristic configured to change due to a change in shape of the optical fiber wherein a change in the optical characteristic is used to estimate the shape. A method for estimating a shape is also disclosed.

Rotated single or multicore optical fiber

An apparatus for estimating a property, the apparatus includes: a hollow core tube having a first opening and a second opening; a first optical waveguide disposed within the first opening; and a second optical waveguide disposed within the second opening and spaced a distance from the first optical waveguide, the distance being related to the property; wherein a portion of at least one of the optical waveguides within the tube is perimetrically isolated from the tube.

EFPI sensor

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.

Method and apparatus for stripping optical fibers and optical fiber assemblies

A hydrogen-resistant optical fiber particularly well-suitable for downhole applications comprises a relatively thick pure silica core and a depressed-index cladding layer. Interposed between the depressed-index cladding layer and the core is a relatively thin germanium-doped interface. By maintaining a proper relationship between the pure silica core diameter and the thickness of the germanium-doped interface, a majority (preferably, more than 65%) of the propagating signal can be confined within the pure silica core and, therefore, be protected from hydrogen-induced attenuation problems associated with the presence of germanium (as is common in downhole fiber applications). The hydrogen-resistant fiber of the present invention can be formed to include one or more Bragg gratings within the germanium-doped interface, useful for sensing applications.

Hydrogen-resistant optical fiber/grating structure suitable for use in downhole sensor applications

An apparatus for determining a property, the apparatus including: an optical fiber having a series of fiber Bragg gratings, each fiber Bragg grating in the series being characterized by a light reflection frequency at which the fiber Bragg grating reflects light; wherein: the light reflection frequency for each fiber Bragg grating is different from the light reflection frequency of each adjacent fiber Bragg grating to minimize resonance of light between at least two of the fiber Bragg gratings in the series; at least two fiber Bragg gratings in the series have light reflection frequencies that overlap; and a change in the light reflection frequency of each fiber Bragg grating in the series is related to the property at the location of the each fiber Bragg grating.

On-line fiber Bragg grating dithering

A method of forming an optical fiber preform using, for example, an MCVD process, is modified to reduce the presence of hydrogen-induced transmission losses in an optical fiber drawn from the preform. A relatively porous, unsintered soot layer is first formed (similar to the initial soot layer commonly associated with the solution-doped process of the prior art) and then subjected to a flow of a metal halide (such as SiCl) to reduce the presence of excess oxygen. It is imperative that the metal halide treatment occur in the absence of oxygen. Sintering of the treated layer, followed by a conventional collapsing process is then used to form the inventive preform. In accordance with the present invention, both the sintering and collapsing steps are performed in a non-oxygen based ambient. When the drawn fiber is then later exposed to hydrogen, the lack of oxygen thus eliminates the formation of Si&#x2014;OH and the associated attenuation problems.

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Blacksburg, VA, United States of America

Daniel Scott Homa