Halliburton Energy Services, Inc.

Input/output, Inc.

Ziebel (US), Inc.

Han-Sun Choi

Tasneem Mandviwala

Etienne M Samson

David Andrew Barfoot

Mikko K Jaaskelainen

John L Maida

Xinwei Lan

Michel J Leblanc

Greyson Orval Knapp

Lee E Siems

Andrew David Barfoot

Tom O'Brien

Reinis Kanders

An interrogation system may be coupled to a fiber-optic cable positioned in a wellbore to interrogate a plurality of optical sensors coupled to the fiber-optic cable. The interrogation system may include an optical frequency comb source having a plurality of narrowband optical carriers transmitting light to the plurality of optical sensors. Each of the plurality of optical sensors may include a pair of partial reflectors to reflect the light transmitted by the optical frequency comb to one or more optical receivers to receive the reflection signals In some aspects, the interrogation system may include a de-interleaver device for separating reflected light signals having adjacent wavelength into separate optical waveguides. In additional aspects, interrogation system may also include a data processing system having a processing device for performing interferometric measurements using the reflected light signals.

Optical frequency comb source for fiber sensor interferometer arrays

A disclosed subsurface electromagnetic field monitoring system includes at least one fiberoptic cable to optically communicate measurements from an array of electromagnetic field sensors in a borehole. The array of electromagnetic field sensors includes a distributed feedback fiber laser strain sensor with electromagnetic field sensitivity.

Distributed feedback fiber laser strain sensor systems and methods for subsurface EM field monitoring

A system for measuring subterranean physical properties, in some embodiments, comprises a source of broadband light, an input optical fiber coupled to the source of broadband light, a wavelength division demultiplexer coupled to the input optical fiber, a plurality of detectors arranged in parallel and coupled to the demultiplexer, a wavelength division multiplexer coupled to the plurality of detectors, and an output optical fiber coupled to the multiplexer.

Modifying optical signals output by a wavelength division demultiplexer to detect subterranean physical properties

A method and apparatus for magnetic sensing is described. The apparatus includes a strain-sensing fiber coupled to a conducting strip. The strain-sensing fiber may be, for example, a distributed feedback fiber with Bragg gratings. A current may be induced to flow on the conducting strip by electrically coupling a photodiode to the conducting strip and then activating a laser optically coupled to the photodiode. In the presence of a magnetic field, a Lorentz force will be exerted on the conducting strip, causing a displacement of the conducting strip that will induce strain on the strain-sensing fiber. The strain on the strain-sensing fiber may be measured by laser-pumping the strain-sensing fiber and measuring the reflected waves. The measured strain may be used to calculate the magnitude of the magnetic field. Multiple strain-sensing fibers may be optically coupled in series and deployed into a borehole for distributed magnetic field measurements. The magnetic field measurements may be used to determine the resistivity of formations surrounding the borehole and, for example, to monitor the movement of relatively-low resistivity water fronts.

Fiber optic magnetic field sensing system based on lorentz force method for downhole applications

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.

Apparatus and method for characterization of FBG rellector array

Multiplexed microvolt sensor systems and methods are described. An example system may include a pulsed light source, a first optical waveguide segment operatively coupled to the pulsed light source, an optical circulator including a first port, a second port, and a third port, the first port being operatively coupled to the first optical waveguide segment, a second optical waveguide segment operatively coupled to the second port of the optical circulator, and an array of sensor elements. Each of the sensor elements may include a detector and an electro-optical modulator, the electro-optical modulator being operatively coupled to the second optical waveguide segment. The example system may further include a third optical waveguide segment operatively coupled to the third port of the optical circulator, a compensating interferometer operatively coupled to the third optical waveguide segment, and a time division multiplexed demodulator operatively coupled to the compensating interferometer and the pulsed light source.

Multiplexed microvolt sensor systems

A sensing system includes plurality of sensors along the lengths of input and output optical fibers. Each sensor receives broadband pulses from the input fiber, dynamically senses a plurality of physical parameters in a one-to-one correspondence with a plurality of predefined wavelength bands, and forms signal pulses from the broadband pulses by transmitting only a single wavelength within each wavelength band. Each single wavelength has a dynamically-varying peak wavelength value indicative of the corresponding sensed physical parameter. The signal pulses from the output optical fiber are directed into one or more interferometers, which produce a phase deviation corresponding to each dynamically-varying peak wavelength value.

Multiplexed fiber optic sensing system and method

A method for demodulating signals from a dispersive, white light interferometer includes generating test interferometry spectra from an interferometer forming part of a sensor for various values of interferometer sensor optical path length. The various test spectra are correlated to a measured spectrum from the sensor to generate a correlation function. The sensor optical path length resulting in the correlation function value reaching a maximum is selected as the optical path length.

Method for demodulating signals from a dispersive white light interferometric sensor and its application to remote optical sensing

A fiber optic acoustic sensor system including an optical conductor having low reflectivity mirrors is provided. Optical sensors are provided by sections of the optical conductor bounded by pairs of the low reflectivity mirrors. Pulses of light are injected into the optical conductor and reflected by the low reflectivity mirrors. The reflected pulses of light are processed using a compensating interferometer to generate interference patterns representative of the environmental conditions acting upon the optical conductor.

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Houston, TX, United States of America

Han-Sun Choi