Abstract: A method and apparatus for seismic sensing is described. The apparatus includes an outer cable coupled to a formation and an outer fiber component proximate to the outer cable. When seismic P- and S-waves propagate from the formation to the outer cable, strain is placed on the outer fiber cable, which may be measured by a distributed acoustic sensing system coupled to the outer fiber cable. An inner cable positioned within the outer cable includes a corresponding inner fiber component. The innerduct between the outer and inner cables is filled with a gas or fluid which allows only P-waves to propagate to the inner cable. Those P-waves induce strain on the inner fiber component, which may be measured by the distributed acoustic sensing system. By measuring the seismic P- and S-waves at the outer fiber component, and the isolated seismic P-wave at the inner fiber component, it is possible to calculate an isolated seismic S-wave measurement. Methods for deploying the seismic sensing apparatus are also described.

Abstract: A carrier rod having at least one recess extending along at least part of the length of the rod, in which recess a optical fiber assembly for monitoring strain, temperature and/or other physical parameters is arranged, which optical fiber assembly is along at least part of its length bonded within the recess. The carrier rod can be used in a system or 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.

Abstract: An illustrative distributed sensing system includes a fiberoptic cable, a transmitter module, and a receiver module. The transmitter module is coupled to the fiberoptic cable to communicate light in each of multiple independent paths to each of multiple positions along the cable, The receiver module is coupled to the fiberoptic cable to receive backscattered light from said multiple positions along the cable via the multiple independent paths. The receiver module includes at least one receiver for each of said multiple independent paths to obtain simultaneous measurements for each of said multiple positions. The multiple independent paths may be provided by wave division multiplexing, frequency division multiplexing, spatial mode division multiplexing, multicore fiber, and/or multiple fibers.

Abstract: A carrier rod having at least one recess extending along at least part of the length of the rod, in which recess a optical fiber assembly for monitoring strain, temperature and/or other physical parameters is arranged, which optical fiber assembly is along at least part of its length bonded within the recess. The carrier rod can be used in a system or 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.

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. The method includes 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 the assembly's 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 the rod's length to the well equipment; and connecting the optical fiber assembly to an optical signal transmission and reception assembly for monitoring physical parameters of the well equipment.

Abstract: A method and apparatus for seismic sensing is described. The apparatus includes an outer cable coupled to a formation and an outer fiber component proximate to the outer cable. When seismic P- and S-waves propagate from the formation to the outer cable, strain is placed on the outer fiber cable, which may be measured by a distributed acoustic sensing system coupled to the outer fiber cable. An inner cable positioned within the outer cable includes a corresponding inner fiber component. The innerduct between the outer and inner cables is filled with a gas or fluid which allows only P-waves to propagate to the inner cable. Those P-waves induce strain on the inner fiber component, which may be measured by the distributed acoustic sensing system. By measuring the seismic P- and S-waves at the outer fiber component, and the isolated seismic P-wave at the inner fiber component, it is possible to calculate an isolated seismic S-wave measurement. Methods for deploying the seismic sensing apparatus are also described.

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. The method includes 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 the assembly's 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 the rod's length to the well equipment; and connecting the optical fiber assembly to an optical signal transmission and reception assembly for monitoring physical parameters of the well equipment.

Abstract: An illustrative distributed sensing system includes a fiberoptic cable, a transmitter module, and a receiver module. The transmitter module is coupled to the fiberoptic cable to communicate light in each of multiple independent paths to each of multiple positions along the cable, The receiver module is coupled to the fiberoptic cable to receive backscattered light from said multiple positions along the cable via the multiple independent paths. The receiver module includes at least one receiver for each of said multiple independent paths to obtain simultaneous measurements for each of said multiple positions. The multiple independent paths may be provided by wave division multiplexing, frequency division multiplexing, spatial mode division multiplexing, multicore fiber, and/or multiple fibers.

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: 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: 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 system for monitoring subsidence and/or rising of a waterbottom has string of pressure sensors along the interior of a sealed -protective tube(q?) that rests on the waterbottom and is filled with a low pressure liquid, so that any subsidence and/or rising of the can be deduced from subsidence and/or rising of a section of the tube and associated pressure variations measured by the sensors due to variation of the hydrostatic fluid pressure of the liquid in the of the tube. The tube interior is divided into segments by valves during descent to protect the sensors against hydrostatic pressure of the liquid within the tube during installation. The use of a low pressure liquid in the tube allows the use of sensitive pressure sensors which are able to monitor pressure variations of ?0.001 Bar associated with a waterbottom subsidence of ?1 cm, at a water depth of >km where the ambient water pressure may be >100 Bar.

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 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).