Abstract: A method using a capstan device and different bonding methods for minimizing undesirable time-dependent effects that occur in sensing devices that use optical fibers placed in tension.

Abstract: A Brillouin system for monitoring both temperature and strain includes either a single or double-ended fiber with multiple fiber Bragg gratings (FBG's) at different wavelengths and a pumped seed laser system tunable over a range substantially larger than a Brillouin shift. The FBG's are distributed along the length of the deployed fiber and serve as wavelength selectable reflectors that enable maintaining system operation even in the case of a fiber break.

Abstract: An apparatus and method for use in distributed temperature sensing (DTS) systems to reduce coherent Rayleigh scattering in fiber optic cables by using photonic crystal fibers.

Abstract: According to one embodiment, the disclosure provides a system for removal of deleterious chemicals from a fiber optic line. The system may a fiber optic line having two ends, an outer tube, an optical fiber, and an inner volume, a fluid operable to move through the inner volume, the fluid operable to remove at least one deleterious chemical other than hydrogen from the fiber optic line, and a fluid controller connected to at least one end of the fiber optic line and operable to control movement of the fluid through the inner volume. According to another embodiment, the disclosure provides a method of removing a deleterious chemical from a fiber optic line. According to a third embodiment, the disclosure provides a method of removing a deleterious chemical from a fiber optic line by introducing a vacuum in an inner volume of a sealed fiber optic line in a static or cyclical manner.

Abstract: A DTS system resistant to radiation induced attenuation losses during the service life of an installation at both low and high temperatures using matched multi-wavelength distributed temperature sensing automatic calibration technology in combination with designed Pure Silica Core (PSC) optical fibers and an in process photo bleaching method provided by the light sources of the distributed temperature sensing system.

Abstract: A DTS system resistant to hydrogen induced attenuation losses during the service life of an installation at both low and high temperatures using matched multi-wavelength DTS automatic calibration technology in combination with designed hydrogen tolerant Pure Silica Core (PSC) optical fibers.

Abstract: A system and method for providing greatly improved linear heat detection using fiber optic distributed temperature systems (DTS). The invention makes use of correction algorithms based on proportional-integral-derivative notions that anticipate exterior temperature increases based on the rate of measured temperature changes.

Abstract: A Brillouin system for monitoring both temperature and strain includes either a single or double-ended fiber with multiple fiber Bragg gratings (FBG's) at different wavelengths and a pumped seed laser system tunable over a range substantially larger than a Brillouin shift. The FBG's are distributed along the length of the deployed fiber and serve as wavelength selectable reflectors that enable maintaining system operation even in the case of a fiber break.

Abstract: A pressure sensor assembly comprises a sensor housing having a flexible wall that is configured to deform in response to a pressure difference between the interior and exterior of the sensor housing; -a first fiber optical cable section that is bonded to the flexible wall of the sensor housing such that the length of the first fiber optical cable section changes in response to deformation of the wall in response to the said pressure difference; a second fiber optical cable section which is bonded to a thermal reference body, which body is connected to the sensor housing by a strain decoupled connection mechanism, such as a tack weld or flexible glue, and is configured to deform substantially solely in response to thermal deformation, such that the length of the second fiber optical cable section solely changes in response to thermal deformation of the thermal reference body.

Abstract: A method of improving sampling resolution in a distributed temperature measurement system using a fiber optic distributed sensor by means of programmed delayed trigger signals to a laser light source in order to improve the spatial resolution of such systems.

Abstract: High resolution distributed temperature sensors using fiber optic distributed temperature sensing systems deployed on various carriers to significantly improve spatial resolution and provide high resolution temperature profile and detection of fluid or fluid interface levels.

Abstract: A method of monitoring deformation and other characteristics of a casing or other tubular or cylindrical well equipment in a well traversing an underground formation, comprises:—providing a carrier rod having at least one recess extending along at least part of the length of the rod, in which recess an optical fiber assembly for monitoring strain, temperature and/or other physical parameters is arranged, which assembly is along at least part of its length bonded within the recess;—lowering the carrier rod and well equipment simultaneously into the well such that the rod is arranged in an annular space between the well equipment and the wellbore;—securing the rod at a plurality of locations distributed along its length to the well equipment; and—connecting the optical fiber assembly to an optical signal transmission and reception assembly for monitoring the physical parameters of the well equipment.

Abstract: A system and method using both static and transient modeling of power cables coupled with real time measurements of distributed temperature profiles of both the cable and it's immediate environment to optimize the current loads of the power cable. The optical fibers used for measuring distributed temperature profiles can be integrated directly into the monitored power cables or be deployed alongside the power cables, including using the optical fibers deployed in optical power ground wire systems.

Abstract: A pressure sensor assembly comprises a sensor housing having a flexible wall that is configured to deform in response to a pressure difference between the interior and exterior of the sensor housing; —a first fiber optical cable section that is bonded to the flexible wall of the sensor housing such that the length of the first fiber optical cable section changes in response to deformation of the wall in response to the said pressure difference; a second fiber optical cable section which is bonded to a thermal reference body, which body is connected to the sensor housing by a strain decoupled connection mechanism, such as a tack weld or flexible glue, and is configured to deform substantially solely in response to thermal deformation, such that the length of the second fiber optical cable section solely changes in response to thermal deformation of the thermal reference body.

Abstract: A fiber optical sensing cable is inserted into an underwater well by: connecting a housing (12A) comprising a coiled or spooled U-shaped fiber optical sensing cable (21) to the wellhead (2) of the well (1) such that an opening (14) in the wall of the housing (12A) is connected to a guide tube (15) extending into the underwater well (1); —inserting the U-shaped nose section (21A) of the fiber optical sensing cable (21) via the opening (14) into the guide tube (15), thereby uncoiling at least part of a pair of substantially parallel sections of the fiber optical sensing cable of which the lower ends are interconnected by the U-shaped nose section; and connecting the upper ends (21B) of the substantially parallel sections of the fiber optical sensing cable to an optical signal transmission and/or receiving unit via e.g. a pair of wet mateable connectors that are connected to a pair of underwater fiber optical transmission cables (14).

Abstract: A U-shaped fiber optical cable assembly (11, 21) is arranged in a heated well (1) such that a nose section (13, 23) comprising the bent U-shaped cable section (11C, 21C) is located near the toe (1 A) of the well where the ambient well temperature is lower than the temperature of an intermediate section of the well which is heated by steam injection, electrical heating and/or influx of heated hydrocarbon fluids from a heated section of the surrounding formation to a temperature above 200 degrees Celsius, thereby inhibiting the risk of hydrogen darkening of the bent U-shaped cable section. It is preferred to make the nose section of a glass solder, to arrange the U-shaped fiber optical cable assembly in an aluminium guide tube (22) sealed at its lower end with end cap (31), and to use a heat resistant fiber optical cable to further inhibit the risk of hydrogen darkening of the assembly.

Abstract: A fiber optical sensing cable is inserted into an underwater well by: connecting a housing (12A) comprising a coiled or spooled U-shaped fiber optical sensing cable (21) to the wellhead (2) of the well (1) such that an opening (14) in the wall of the housing (12A) is connected to a guide tube (15) extending into the underwater well (1); —inserting the U-shaped nose section (21A) of the fiber optical sensing cable (21) via the opening (14) into the guide tube (15), thereby uncoiling at least part of a pair of substantially parallel sections of the fiber optical sensing cable of which the lower ends are interconnected by the U-shaped nose section; and connecting the upper ends (21B) of the substantially parallel sections of the fiber optical sensing cable to an optical signal transmission and/or receiving unit via e.g. a pair of wet mateable connectors that are connected to a pair of underwater fiber optical transmission cables (14).

Abstract: A method is disclosed for amplifying a light pulse (S) in an optical fiber (1), wherein a Raman pump signal (RPS) having a lower wavelength than the light pulse (S) is transmitted at a selected interval of time after the light pulse (S) into an end (IA) of an optical fiber(1), with dispersion such that the Raman pump signal (RPS) travels faster through the fiber(1) than the light pulse(S) and reaches and enhances the light pulse (S) after the light pulse has travelled along a selected distance (d1) through the fiber, wherein the Raman pump signal (RPS) is ramped in a substantially linear manner such that the amplification increases with the distance along which the light pulse has travelled along the length of the fiber from A1=S1+RPSmin at a distance d1 to A2=S+RPSmax at a distance d2>d1 from said end (IA) of the fiber 1 and such that the Raman gain increase is substantially similar to the fiber losses of the amplified signal.

Abstract: A system and method are provided for converting an electrical signal to an optical signal for a fiber optic system. The electrical signal produced by a sensor (10) based upon a parameter being measured is connected across a material (12, 34, 40) that changes dimension responsive to an applied electrical signal. An optical fiber (14, 30, 38) is coupled to the material (12, 34, 40) where dimension changes of the material (12, 34, 40) produce strain in the optical fiber (14, 30, 38). This strain is operable to affect light traveling through the optical fiber (14, 30, 38) to produce an optical signal for a fiber optic system. In one embodiment, the sensor (10) can be a geophone sensor that produces an electrical signal proportional to motion of the geophone sensor. In another embodiment, the sensor (10) can be a hydrophone sensor that produces an electrical signal proportional to acoustic pressure incident on the hydrophone sensor.