Abstract: Certain aspects of the present disclosure provide techniques for making armored cables. An example method for making an armored cable includes forming a strip stock into an armor tubing; welding a seam of the armor tubing in a welding zone; inserting at least one of a first optical fiber or a first wire into a first end of a first guide tube, wherein: the first guide tube extends through the welding zone; the first guide tube protects the at least one of the first optical fiber or the first wire during the welding of the seam; and the first guide tube is not part of the armored cable after the making of the armored cable; and supporting the first guide tube within the armor tubing by a plurality of support legs such that the first guide tube does not contact the armor tubing.

Abstract: Certain aspects of the present disclosure provide techniques for making armored cables. An example method for making an armored cable includes forming a strip stock into an armor tubing; welding a seam of the armor tubing in a welding zone; inserting at least one of a first optical fiber or a first wire into a first end of a first guide tube, wherein: the first guide tube extends through the welding zone; the first guide tube protects the at least one of the first optical fiber or the first wire during the welding of the seam; and the first guide tube is not part of the armored cable after the making of the armored cable; and supporting the first guide tube within the armor tubing by a plurality of support legs such that the first guide tube does not contact the armor tubing.

Abstract: Certain aspects of the present disclosure provide techniques for making armored cables. An example method for making an armored cable includes forming a strip stock into an armor tubing; welding a seam of the armor tubing in a welding zone; inserting at least one of a first optical fiber or a first wire into a first end of a first guide tube, wherein: the first guide tube extends through the welding zone; the first guide tube protects the at least one of the first optical fiber or the first wire during the welding of the seam; and the first guide tube is not part of the armored cable after the making of the armored cable; and supporting the first guide tube within the armor tubing by a plurality of support legs such that the first guide tube does not contact the armor tubing.

Abstract: Certain aspects of the present disclosure provide techniques for making armored cables. An example method for making an armored cable includes forming a strip stock into an armor tubing; welding a seam of the armor tubing in a welding zone; inserting at least one of a first optical fiber or a first wire into a first end of a first guide tube, wherein: the first guide tube extends through the welding zone; the first guide tube protects the at least one of the first optical fiber or the first wire during the welding of the seam; and the first guide tube is not part of the armored cable after the making of the armored cable; and supporting the first guide tube within the armor tubing by a plurality of support legs such that the first guide tube does not contact the armor tubing.

Abstract: An optical waveguide feedthrough assembly passes at least one optical waveguide through a bulk head, a sensor wall, or other feedthrough member. The optical waveguide feedthrough assembly comprises a cane-based optical waveguide that forms a glass plug sealingly disposed in a feedthrough housing. For some embodiments, the optical waveguide includes a tapered surface biased against a seal seat formed in the housing. The feedthrough assembly can include an annular gold gasket member disposed between the tapered surface and the seal seat. The feedthrough assembly can further include a backup seal. The backup seal comprises an elastomeric annular member disposed between the glass plug and the housing. The backup seal may be energized by a fluid pressure in the housing. The feedthrough assembly is operable in high temperature and high pressure environments.

Abstract: Certain aspects of the present disclosure provide techniques for making armored cables. An example method for making an armored cable includes forming a strip stock into an armor tubing; welding a seam of the armor tubing in a welding zone; inserting at least one of a first optical fiber or a first wire into a first end of a first guide tube, wherein: the first guide tube extends through the welding zone; the first guide tube protects the at least one of the first optical fiber or the first wire during the welding of the seam; and the first guide tube is not part of the armored cable after the making of the armored cable; and supporting the first guide tube within the armor tubing by a plurality of support legs such that the first guide tube does not contact the armor tubing.

Abstract: Fiber optic cables suitable for use in downhole applications, with one or more features for inhibiting flow of any fluid breaching an armor layer of the optical cable are provided. By preventing, or at least impeding, fluid flow along the cable length, any breaching fluid may be confined to a small region of the cable, which may significantly reduce the deleterious effects (e.g., hydrogen darkening) of an armor layer breach. One example optical cable generally includes one or more optical fibers, an inner tube surrounding the one or more optical fibers, an outer tube surrounding the inner tube, and one or more polymer sealing features disposed in an annulus between the outer tube and the inner tube and bonded to at least one of the inner tube or the outer tube to prevent fluid flow in the annulus along at least a portion of a length of the optical cable.

Abstract: A sensing device is used for measuring physical characteristics. The sensing device may include an optical fiber disposed in a tube. The optical fiber may have a section containing a fiber Bragg grating (FBG) sensor. A support member may be coupled to the ends of the section, such that the section includes a length greater than a length of the portion of the support member disposed between the ends of the section. The support member is configured to isolate the FBG sensor from strain in the optical fiber.

Abstract: Fiber optic cables suitable for use in downhole applications, with one or more features for inhibiting flow of any fluid breaching an armor layer of the optical cable are provided. By preventing, or at least impeding, fluid flow along the cable length, any breaching fluid may be confined to a small region of the cable, which may significantly reduce the deleterious effects (e.g., hydrogen darkening) of an armor layer breach. One example optical cable generally includes one or more optical fibers, an inner tube surrounding the one or more optical fibers, an outer tube surrounding the inner tube, and one or more polymer sealing features disposed in an annulus between the outer tube and the inner tube and bonded to at least one of the inner tube or the outer tube to prevent fluid flow in the annulus along at least a portion of a length of the optical cable.

Abstract: Fiber optic cables suitable for use in downhole applications, with one or more features for inhibiting flow of any fluid breaching an armor layer of the optical cable are provided. By preventing, or at least impeding, fluid flow along the cable length, any breaching fluid may be confined to a small region of the cable, which may significantly reduce the deleterious effects (e.g., hydrogen darkening) of an armor layer breach. One example optical cable generally includes one or more optical fibers, an inner tube surrounding the one or more optical fibers, an outer tube surrounding the inner tube, and one or more polymer sealing features disposed in an annulus between the outer tube and the inner tube and bonded to at least one of the inner tube or the outer tube to prevent fluid flow in the annulus along at least a portion of a length of the optical cable.

Abstract: Small profile apparatus for pressure and/or temperature sensing within a wellbore are provided. The apparatus may include optical sensing assemblies designed for inclusion in traditional or coiled production tubing deployments and suitable for use in high pressure, high temperature environments. One example assembly generally includes an outer housing, an inner housing at least partially disposed in the outer housing, a port for fluid communication between an internal volume of the inner housing and a volume external to the outer housing, and a large diameter optical waveguide disposed in the internal volume of the inner housing. The waveguide includes a first portion with a first grating and a second portion with a second grating, wherein the outer diameter of the large diameter optical waveguide is at least 300 ?m.

Abstract: Methods and apparatus for performing Distributed Acoustic Sensing (DAS) using fiber optics with increased acoustic sensitivity are provided. Acoustic sensing of a wellbore, pipeline, or other conduit/tube based on DAS may have increased acoustic sensitivity through fiber optic cable design and/or increasing the Rayleigh backscatter property of a fiber's optical core. Some embodiments may utilize a resonant sensor mechanism with a high Q coupled to the DAS device for increased acoustic sensitivity.

Abstract: Small profile apparatus for pressure and/or temperature sensing within a wellbore are provided. The apparatus may include optical sensing assemblies designed for inclusion in traditional or coiled production tubing deployments and suitable for use in high pressure, high temperature environments. One example assembly generally includes an outer housing, an inner housing at least partially disposed in the outer housing, a port for fluid communication between an internal volume of the inner housing and a volume external to the outer housing, and a large diameter optical waveguide disposed in the internal volume of the inner housing. The waveguide includes a first portion with a first grating and a second portion with a second grating, wherein the outer diameter of the large diameter optical waveguide is at least 300 ?m.

Abstract: Small profile apparatus for pressure and/or temperature sensing within a wellbore are provided. The apparatus may include optical sensing assemblies designed for inclusion in traditional or coiled production tubing deployments and suitable for use in high pressure, high temperature environments. One example assembly generally includes a housing having a divider for separating a first volume from a second volume inside the housing, a compressible element disposed in the first volume, wherein a first end of the compressible element is coupled to the divider and a second of the compressible element is sealed, and a large diameter optical waveguide disposed in an internal volume of the compressible element. The waveguide typically includes a first portion with a first grating and a second portion with a second grating, wherein the first portion has a greater outer diameter than the second portion.

Abstract: An optical transducer is provided. A “measuring” portion of the transducer may be exposed to a high pressure and fluids when the optical transducer is deployed (e.g., in a wellbore or other industrial setting). The transducer may include an optical waveguide with a first portion that forms a first seal that isolates an “instrumentation” portion of the transducer from exposure to the high pressure and fluids to which the measuring portion may be exposed. The transducer may also include a second seal with a “stack” of material elements that contact a second portion of the optical waveguide to also isolate the instrumentation portion of the transducer from exposure to the high pressure and fluids to which the measuring portion may be exposed.

Abstract: An optical waveguide feedthrough assembly passes at least one optical waveguide through a bulk head, a sensor wall, or other feedthrough member. The optical waveguide feedthrough assembly comprises a cane-based optical waveguide that forms a glass plug sealingly disposed in a feedthrough housing. For some embodiments, the optical waveguide includes a tapered surface biased against a seal seat formed in the housing. The feedthrough assembly can include an annular gold gasket member disposed between the tapered surface and the seal seat. The feedthrough assembly can further include a backup seal. The backup seal comprises an elastomeric annular member disposed between the glass plug and the housing. The backup seal may be energized by a fluid pressure in the housing. The feedthrough assembly is operable in high temperature and high pressure environments.

Abstract: Embodiments of the present invention provide methods and apparatus for cables having one or more fibers that may function as a sensing device within a wellbore, wherein the fibers do not adhere to each other or to an inner wall of the cable during a high temperature operation, such as in a thermal recovery operation that may last over 30 days.

Abstract: Methods and apparatus for interrogating sets of optical elements having characteristic wavelengths spanning a sweep range while avoiding overlapping reflections from the different sets when performing a wavelength sweep are provided. One example method generally includes introducing a pulse of light, by an optical source, into an optical waveguide to interrogate at least first and second sets of optical elements, wherein the optical elements within each set have different characteristic wavelengths and wherein the first and second sets are separated in time such that a first time window over which light is reflected from the optical elements in the first set and reaches a receiver does not overlap with a second time window over which light is reflected from the optical elements in the second set and reaches the receiver; and processing the reflected light to determine one or more parameters corresponding to the optical elements.

Abstract: Purging interior regions of a cable reduces or prevents hydrogen darkening of an optical fiber located in the cable. While hydrogen may permeate through an outer surface of the cable, fluid circulating through the cable purges the hydrogen from within the cable. This circulation of the fluid occurs between an inner tube containing the fiber and an outer tube surrounding the inner tube.

Abstract: Methods and apparatus for performing Distributed Acoustic Sensing (DAS) using fiber optics with increased acoustic sensitivity are provided. Acoustic sensing of a wellbore, pipeline, or other conduit/tube based on DAS may have increased acoustic sensitivity through fiber optic cable design and/or increasing the Rayleigh backscatter property of a fiber's optical core. Some embodiments may utilize a resonant sensor mechanism with a high Q coupled to the DAS device for increased acoustic sensitivity.