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 multifunctional end cap assembly for use in terminating the toe end of subsurface coiled tubing strings that include multiple sensors. The assembly includes provisions for turnarounds for DTS or DAS systems as well as provisions for connecting formation pressures with a pressure transducer within the coiled tubing string.

Abstract: Systems and methods for distributed acoustic sensing based on coherent Rayleigh scattering are disclosed herein. A system comprises a pulse generator, an optical fiber coupled to the pulse generator, an interferometer coupled to the optical fiber, a photodetector assembly coupled to the interferometer, and an information handling system, which activates two optical gain elements so as to vary the optical path length of the interferometer. A method comprises sending an optical pulse down an optical fiber, splitting backscattered light from the optical pulse into a first backscattered pulse and a second backscattered pulse, activating a first optical gain element and a second optical gain element, sending the first backscattered pulse into a first arm of an interferometer, sending the second backscattered pulse into a second arm of an interferometer, combining the first and second backscattered pulses to form an interferometric signal, and receiving the interferometric signal at a photodetector assembly.

Abstract: A single-use pressure-controlled actuator for downhole well tools or mechanisms is provided. The actuator is configured for control of activation/deactivation by agency of wellbore fluid pressure (e.g., pressure levels of drilling fluid or drilling mud in the wellbore). The actuator is further configured for hydraulic actuation by agency of the wellbore fluid. The actuator comprises a plunger displaceably mounted on a sealed cylinder body, with a non-reclosable frangible device closing off wellbore fluid access to an interior of the cylinder body. The frangible device is configured for automatic in response to exposure of wellbore fluid pressures exceeding a predetermined activation threshold. Failure of the frangible device causes exposure of the plunger to the wellbore fluid, resulting in actuated movement of the plunger by hydraulic action of the wellbore fluid.

Abstract: A well tool for sensing seismic activity at a downhole location has an anchoring mechanism for mechanically coupling the tool to a formation by contact engagement with a wall of a subterranean cavity in which the well tool is located. The anchoring mechanism is deployable by a pressure-triggered hydraulic actuator incorporated in the tool. The actuator is configured for pressure-triggered activation and for hydraulic actuation by agency of borehole fluids (e.g., drilling mud). The actuator can provide a persistent contacting force urging the anchoring mechanism into contact with the cavity wall, to promote firm coupling with the formation for seismic sensoring purposes.

Abstract: A downhole sensor deployment assembly includes a body attachable to a completion string and one or more arms pivotably coupled to the body. A sensor pad is coupled to each arm and movable from a retracted position, where the sensor pad is stowed adjacent the completion string, and an actuated position, where the sensor pad is extended radially away from the completion string. One or more actuators are pivotably coupled to the body at a first end and pivotably coupled to a corresponding one of the one or more arms at a second end, the one or more actuators being operable to move the sensor pad to the actuated position. One or more sensor devices are coupled to the sensor pad for determining a resistivity of a formation, the one or more sensor devices comprising at least one of a sensing electrode, a transceiver, and a transmitter.

Abstract: A system and method for evaluating individual Fiber Bragg Grating (FBG) sensors in a multiplexed acoustic sensor system, the system comprising: a broadband pulsed source; a circulator that passes a laser pulse to a multiplexed series of N FBG sensors and one reference Fresnel reflector, wherein said circulator also receives a return N+1 reflection pulse train from the N FBG sensors and one reference Fresnel reflector; and an optical switch that receives the return N+1 reflection pulse train from the N FBG sensors and one reference Fresnel reflector.

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 system and method for enhanced acoustic sensing of signals in a pipe using a fiber optic sensing cable that can be interrogated by distributed acoustic sensing (DAS) systems wherein a crescent shaped metallic device is used for attaching to the exterior of the pipe, the crescent shaped metallic device having the one or more fiber optic sensing cables embedded within an upper part of the crescent shaped device, and the crescent shaped metallic device may have one or more cavities or channels that may be empty or partially or completely filled with acoustic filters.

Abstract: A method for making a crescent shaped metallic device for attaching to the exterior of the pipe to provide intimate contact for an enhanced acoustic sensing system using a fiber optic sensing cable that can be interrogated by distributed acoustic sensing (DAS) systems wherein the crescent shaped metallic device is used for attaching to the exterior of the pipe and the method of making includes the use of additive layer-wise manufacturing.

Abstract: A down-hole apparatus comprises a unitary seamless section defining a chamber, a clamping section to engage a fiber optic cable, actuator electronics enclosed in the chamber, and an actuator to acoustically couple the actuator electronics to the fiber optic cable. The apparatus can include a temperature sensor, a microphone, or a geophone, enclosed by the chamber. The actuator can be an acoustic emitter or a piezoelectric device. The apparatus could be battery-operated by a battery enclosed in the chamber. A sensor enclosed within the chamber could be powered by signals propagated within the fiber optic cable. Additional apparatus, methods, and systems are disclosed.

Abstract: An opto-acoustic flowmeter can include an optical waveguide and an emitter that emits acoustic energy in response to flow, the acoustic energy comprising a flow rate dependent parameter. A flow rate measuring method can include configuring an emitter so that flow into or out of a tubular string causes the emitter to emit acoustic energy, arranging an optical line so that the acoustic energy is received by an optical waveguide of the optical line, and detecting optical scatter in the optical waveguide. A well system can include multiple locations where fluid is flowed between an earth formation and a tubular string in a wellbore, multiple emitters that produce an acoustic vibration corresponding to a flow rate of the fluid, an optical line that receives the vibrations, and an optical interrogator that detects optical scatter in an optical waveguide of the line, the scatter being indicative of the vibrations.

Abstract: A system and method for a higher speed auto-correcting temperature measurement in a system using a fiber optic distributed sensor.

Abstract: A flow rate sensing system can include an optical waveguide, an optical interrogator that detects optical scatter in the optical waveguide, and an emitter that produces vibration in response to flow, the optical scatter being influenced by the vibration. A method of measuring flow rate can include detecting optical scattering in an optical waveguide, the optical scattering varying in response to changes in vibration produced by an emitter, and the vibration changing in response to the flow rate changing. A well system can include at least one tubular string positioned in a wellbore, multiple locations at which fluid flows between an interior and an exterior of the tubular string, multiple emitters, each of which produces vibration in response to the flow between the interior and the exterior of the tubular string, and an optical waveguide in which optical scatter varies in response to changes in the vibration.

Abstract: Systems and methods for distributed acoustic sensing based on coherent Rayleigh scattering are disclosed herein. A system comprises a pulse generator, optical fibers coupled to the pulse generator, an interferometer coupled to the optical fibers, a photodetector assembly coupled to the interferometer, and an information handling system configured to detect a difference in backscattered light from the optical fibers. A method comprises sending an optical pulses down optical fibers, receiving backscattered light from the optical pulses, combining the backscattered light from the optical pulses to form an interferometric signal, receiving the interferometric signal at a photodetector assembly, and determining a difference in the interferometric signal at an information handling system.

Abstract: A downhole optical sensing system can include an optical fiber positioned in the well, the optical fiber including multiple cores, and one of the cores having a Brillouin scattering coefficient which is different from another one of the cores. A method of sensing strain and temperature as distributed along an optical fiber can include measuring Brillouin scattering in a core of the optical fiber disposed in a well, and measuring Brillouin scattering in another core of the optical fiber disposed in the well, the optical fiber cores being exposed to a same strain and temperature distribution in the well.

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 monitoring a flood front. The method may comprise installing at least one optical electromagnetic sensor in a wellbore which penetrates an earth formation. The sensor may be a part of an interferometer selected from the group consisting of a Mach Zehnder interferometer and a Michelson interferometer. The method may further comprise inducing an electromagnetic field in the earth formation. A first optical path length in a first optical waveguide of the sensor may increases in response to exposure to the electromagnetic field, and a second optical path length in a second optical waveguide of the sensor may decreases in response to exposure to the electromagnetic field. Additionally, the method may comprise monitoring the flood front by detecting via the sensor the electromagnetic field in the earth formation as the flood front progresses through the earth formation.

Abstract: A method and system for using a distributed electromagnetic sensing system in horizontal hydraulic fracturing wells to monitor fracture growth in real time.

Abstract: Various embodiments include apparatus and methods to measure a parameter of interest using a fiber optic cable. The parameters can be provided by a process that provides for multiplexed or distributed measurements. A multiplexed or a distributed architecture can include acoustic sensor units placed selectively along an optical fiber such that the acoustic sensor units effectively modulate the optical fiber with information regarding a parameter to provide the information to an interrogator coupled to the optical fiber that is separate from the acoustic sensor units.