Patent application number | Description | Published |
20080232425 | LOCATION DEPENDENT CALIBRATION FOR DISTRIBUTED TEMPERATURE SENSOR MEASUREMENTS - A method for calibrating distributed temperature sensing (DTS) systems is disclosed. The method includes: receiving temperature data associated with one or more locations along a length of an optical fiber; calculating a set of unique calibration coefficients specific to each of the one or more locations along the fiber length; and applying the set of calibration coefficients specific to each of the one or more locations along the fiber length to the temperature data for calibrated correction thereof. Also disclosed is a system for calibrating DTS data and a wellbore for providing calibrated DTS data. | 09-25-2008 |
20090051905 | Optical Inclination Sensor - An optical inclination sensor is provided having at least one reflective surface and at least two separate optical fibers having ends spaced from a reflective surface. As the reflective surface tilts with respect to a pre-determined reference position the gap lengths between the fiber ends and the reflective surface change and the differences in these gap lengths is used to calculate an angle of inclination with respect to a reference position. The optical inclination sensor can include at least one mass attached to a housing and moveable with respect to the housing as the mass and housing are rotated about one or more axes. Optical strain sensors are disposed a various locations between the mass and housing so that as the mass moves with respect to the housing, each one of the optical strain sensors are placed in compression or tension. The housing can be a generally u-shaped housing having two arms and a base section with the mass disposed within the housing. Alternatively, the housing includes a first beam, and the mass is a second beam arranged generally orthogonal to the first beam and pivotally attached thereto. The optical strain sensors are disposed between the first beam and the second beam. The optical strain sensors are placed in tension or compression as the second beam pivots with respect to the first beam. | 02-26-2009 |
20110110620 | ROTATED SINGLE OR MULTICORE OPTICAL FIBER - An apparatus for estimating a shape, the apparatus including: an optical fiber configured to conform to the shape and having a first core offset from a centerline of the optical fiber, the first core having an optical characteristic configured to change due to a change in shape of the optical fiber wherein a change in the optical characteristic is used to estimate the shape. A method for estimating a shape is also disclosed. | 05-12-2011 |
20110110621 | NOVEL SENSOR ARRAY CONFIGURATION FOR EXTENDING USEFUL SENSING LENGTH OF A SWEPT-WAVELENGTH INTERFEROMETRY BASED SYSTEM - An apparatus for estimating a parameter at distributed locations, the apparatus including: an optical fiber having: a first series of fiber Bragg gratings (FBGs) and configured to measure the parameter at a portion of the distributed locations; a second series of FBGs and configured to measure the parameter at another portion of the distributed locations; and an optical interrogator configured to illuminate the optical fiber and to receive light signals resulting from the illumination, the light signals including first light signals from the first series of FBGs within a first range of wavelengths, second light signals from the second series of FBGs within a second range of wavelengths, and other light signals within a third range of wavelengths, the ranges of wavelengths being distinct from each other; wherein the first light signals and the second light signals are used to estimate the parameter at the distributed locations. | 05-12-2011 |
20110172959 | MULTI-GAP INTERFEROMETRIC SENSORS - An apparatus for estimating a property includes a hollow core tube and an input light guide disposed at least partially within hollow core tube. The apparatus also includes a second gap disposed within the hollow core tube and separated from the input light guide by an air gap width. The second gap is formed of a first solid material and has a second gap width. The apparatus also includes a third gap disposed at least partially within the hollow core tube and being further from the input light guide than the second gap. The third gap is formed of a second solid material and has a third gap width. | 07-14-2011 |
20110181871 | COMBINED SWEPT-CARRIER AND SWEPT-MODULATION FREQUENCY OPTICAL FREQUENCY DOMAIN REFLECTOMETRY - An apparatus for estimating a parameter, the apparatus includes: an optical fiber; a component in communication with the optical fiber and configured to interact with light at a wavelength related to the parameter; and an optical interrogator in communication with the optical fiber and configured to: illuminate the optical fiber with a series of light inputs, each light input in the series having a substantially constant unique optical wavelength and swept-frequency amplitude modulation; and receive a resulting light signal associated with each light input in the series; wherein the resulting light signals associated with the series of light inputs are used to estimate the parameter. | 07-28-2011 |
20110199618 | Systems and Methods for Optically Generated Trigger Multiplication - Systems and methods for providing trigger signals in an optical interrogator, wherein multiple triggers are generated within each period of a varying reference signal, and wherein the triggers are evenly spaced according to the wavenumber of the reference signal. In one embodiment, an optical frequency domain reflectometry system provides a laser beam to a reference interferometer to produce a reference signal. This signal is passed through a 4×4 optical coupler which splits the signal into a first signal and a second signal that is 90 degrees out of phase with the first signal. These signals are converted to electrical signals, and a trigger unit generates triggers at points at which the two electrical signals have zero-crossings, and at which the magnitudes of the signals are equal. The resulting triggers remain evenly spaced within the period of the reference signals, even when the period is changed. | 08-18-2011 |
20110261361 | System and Method for Effective Isolation of an Interferometer - An interferometer has its performance enhanced by being suspended in a housing that is optionally evacuated. The frame that supports the interferometer is secured to a cover for the housing with a plurality of studs having mechanical vibration isolators. The frame comprises a support flange with a foam layer beneath the interferometer. An optics tray is disposed above the interferometer and holds the assembly to the support flange. The fibers that are connected to the interferometer enter the side of the housing and the entry is sealed off to allow the interior of the housing to be evacuated. | 10-27-2011 |
20120143524 | Determination of Strain Components for Different Deformation Modes Using a Filter - A method, apparatus and computer-readable medium for determining a strain component for a deformation mode of a member is disclosed. A plurality of measurements is obtained, wherein each of the plurality of measurements relates to a strain at a location of the member. A deformation mode is selected and an adjustable filter is applied to the plurality of strain measurements to determine the strain component for the selected deformation mode. | 06-07-2012 |
20120143525 | Interpretation of Real Time Compaction Monitoring Data Into Tubular Deformation Parameters and 3D Geometry - A method, apparatus and computer-readable medium for determining a deformation strain distribution of a member corresponding to a selected deformation mode is disclosed. Strain measurements are obtained at a plurality of sensors, wherein each strain measurement is related to a strain at a location of the member. A component of the strain related to a selected deformation mode for the obtained strain measurements is determined and a principal strain component and a secondary strain component for each of the determined components of the strain is determined. The determined principal strain component and secondary strain component are mapped to a surface of the member to determine the deformation strain distribution. | 06-07-2012 |
20120175512 | RAYLEIGH SCATTER-BASED LARGE DIAMETER WAVEGUIDE SENSOR SYSTEM - Disclosed is an apparatus for estimating a parameter in a borehole penetrating the earth. The apparatus includes a large diameter waveguide (LDW) sensor configured to be disposed in the borehole and to sense the parameter at one or more locations along the LDW sensor, the LDW sensor having an outer dimension greater than or equal to 0.25 mm and random variations of an optical property. An optical interrogator is coupled to the LDW sensor and configured to illuminate the LDW sensor with incident light at a swept frequency and to receive light from the large diameter waveguide due to Rayleigh scattering of the incident light by the random variations of the optical property along a length of the LDW sensor. The received light provides information for estimating the parameter and a location along the LDW sensor where the parameter was sensed. | 07-12-2012 |
20120175513 | Sensor Array Configuration for Swept-Wavelength Interferometric-Based Sensing Systems - A method, system and apparatus for obtaining a parameter of interest relating to a wellbore is disclosed. A fiber optic cable having a plurality of sensors is disposed in the wellbore, wherein the plurality of sensors have reflectivity values configured to provide improved signal-to-noise ratio compared to signal-to-noise ratio of a plurality of sensors having substantially same reflectivity values. Light is propagated into the fiber optic cable from a light source and signals are received at a detector from the plurality of sensors in response to interaction of the propagated light with the plurality of sensors. A processor may be used to obtain the parameter of interest from the received signals. The fiber optic cable may be coupled to a member in the wellbore, wherein the parameter of interest is related to the member. | 07-12-2012 |
20120176250 | SYSTEM AND METHOD FOR INTEGRATED DOWNHOLE SENSING AND OPTICAL FIBER MONITORING - A system for measuring downhole parameters is disclosed. The system includes: a carrier configured to be disposed in a borehole in an earth formation; at least one optical fiber sensor in operable communication with the carrier; a measurement assembly including an electromagnetic signal source configured to transmit a first interrogation signal into the optical fiber sensor and a detector configured to receive a reflected signal indicative of a downhole parameter in response to the interrogation signal; and a processor configured to automatically receive scattered signals from the optical fiber sensor, generate distributed scattering data indicative of a condition of the optical fiber sensor and analyze changes in the distributed scattering data to identify changes in the condition of the optical fiber sensor. | 07-12-2012 |
20120179378 | METHOD AND APPARATUS FOR MONITORING VIBRATION USING FIBER OPTIC SENSORS - A apparatus for monitoring a downhole component is disclosed. The apparatus includes: an optical fiber sensor including a plurality of sensing locations distributed along a length of the optical fiber sensor; an interrogation assembly configured to transmit an electromagnetic interrogation signal into the optical fiber sensor and receive reflected signals from each of the plurality of sensing locations; and a processing unit configured to receive the reflected signals, select a measurement location along the optical fiber sensor, select a first reflected signal associated with a first sensing location in the optical fiber sensor, the first sensing location corresponding with the measurement location, select a second reflected signal associated with a second sensing location in the optical fiber sensor, estimate a phase difference between the first signal and the second signal, and estimate a parameter of the downhole component at the measurement location based on the phase difference. | 07-12-2012 |
20120181420 | Programmable Filters for Improving Data Fidelity in Swept-Wavelength Interferometry-Based Systems - A method, system and apparatus for obtaining a parameter of interest from a plurality of sensors in a fiber optic cable deployed in a wellbore are disclosed. Light having variable frequency within a range of frequencies is propagated along the fiber optic cable. Signals are received that are responsive to interaction of the propagated light with the plurality of sensors. The received signals are filtered using a programmable filter. The parameter of interest is obtained from the filtered signals. In one aspect, the fiber optic cable is coupled to a member deployed in the wellbore and the parameter of interest is related to the member. | 07-19-2012 |
20120200422 | Use of Digital Transport Delay to Improve Measurement Fidelity in Swept-Wavelength Systems - A method and apparatus for obtaining a parameter of interest from an optical device placed along a fiber optic cable in a wellbore is disclosed. Light is propagated a light through the fiber optic cable from a light source. A first detector receives a first signal responsive to interaction of the propagated light and the optical device, wherein the first signal has a delay. A second detector receives a second signal and a digital delay device delays the received second signal. A sampling device obtains a selected signal from the first signal using the delayed second signal, and a processor determines the parameter of interest using the selected signal. | 08-09-2012 |
20120237205 | SYSTEM AND METHOD TO COMPENSATE FOR ARBITRARY OPTICAL FIBER LEAD-INS IN AN OPTICAL FREQUENCY DOMAIN REFLECTOMETRY SYSTEM - A method for estimating a parameter includes: generating an optical signal, the optical signal modulated via a modulation signal having a variable modulation frequency over a period of time; transmitting the modulated optical signal from a light source into an optical fiber, the optical fiber including at least one sensing location configured to reflect light; receiving a reflected signal including light reflected from the at least one sensing location; and demodulating the reflected signal with a reference signal, the reference signal including a time delay relative to the modulation signal based on a distance between the light source and the at least one sensing location. | 09-20-2012 |
20120314988 | ROTATED SINGLE OR MULTICORE OPTICAL FIBER - An apparatus for estimating a shape, the apparatus including: an optical fiber configured to conform to the shape and having a first core offset from a centerline of the optical fiber, the first core having an optical characteristic configured to change due to a change in shape of the optical fiber wherein a change in the optical characteristic is used to estimate the shape. A method for estimating a shape is also disclosed. | 12-13-2012 |
20130016979 | Optical Network Configuration with Intrinsic Delay for Swept-Wavelength Interferometry SystemsAANM Duncan; Roger GlenAACI ChristiansburgAAST VAAACO USAAGP Duncan; Roger Glen Christiansburg VA USAANM Childers; Brooks A.AACI ChristiansburgAAST VAAACO USAAGP Childers; Brooks A. Christiansburg VA US - A method, apparatus and optical network for obtaining a signal from a sensor in a fiber optic cable at a downhole location is disclosed. A reference signal is propagated through the fiber optic cable. A beam of light is received from the fiber optic cable, wherein the beam of light includes the propagated reference signal and the signal from the sensor generated from an interaction of the sensor and the reference signal. The propagated reference signal is obtained from the received beam of light. The signal from the sensors is obtained by sampling the received beam of light using the obtained propagated reference signal. | 01-17-2013 |
20130087937 | Phase Mask Period Control - A method, apparatus and system for forming a fiber optic cable is disclosed. A first pattern of a phase mark is formed at a first location in the fiber optic cable. A relational parameter between the fiber optic cable and the phase mask is changed and a second pattern of the phase mask is formed at a second location in the fiber optic cable. The second pattern is related to the first pattern via the change in the relational parameter between the fiber optic cable and the phase mask. A controller can be used to control the relational parameter. | 04-11-2013 |
20130093598 | ENHANCING FUNCTIONALITY OF REFLECTOMETRY BASED SYSTEMS USING PARALLEL MIXING OPERATIONS - A method for estimating a parameter includes: generating an optical signal, the optical signal modulated via a modulation signal; transmitting the modulated optical signal from a light source into an optical fiber, the optical fiber including a plurality of sensing locations disposed along the optical fiber and configured to reflect light; receiving a reflected signal including light reflected from the plurality of sensing locations; and combining, in parallel, each of a plurality of reference signals with the reflected signal to estimate a value of the parameter. | 04-18-2013 |
20130093599 | INCOHERENT REFLECTOMETRY UTILIZING CHAOTIC EXCITATION OF LIGHT SOURCES - A method for estimating a parameter includes: transmitting a control signal to a coherent optical source, the control signal configured to chaotically vary an output of the optical source and generate a chaotically excited optical signal; transmitting the optical signal from the optical source into an optical fiber, the optical fiber including at least one sensing location; receiving a reflected signal including light reflected from the at least one sensing location; and estimating a value of the parameter using the reflected signal. | 04-18-2013 |
20130094011 | DISTANCE MEASUREMENT USING INCOHERENT OPTICAL REFLECTOMETRY - A method for estimating a distance includes: generating an optical signal having a wavelength that is within a wavelength range, the optical signal modulated via a modulation signal having a modulation frequency; transmitting the modulated optical signal from a light source into the optical fiber, the optical fiber in contact with a moveable strain inducing element located at the position along the optical fiber, the optical fiber including a plurality of sensing locations configured to reflect light within the wavelength range when under strain from the strain inducing element and transmit light within the wavelength range when not under strain from the strain inducing element; receiving a reflected signal including light reflected from at least one of the sensing locations; demodulating the reflected signal with a reference signal to generate reflected signal data; and determining the distance to the position along the optical fiber based on the reflected signal data. | 04-18-2013 |
20130094798 | Monitoring Structural Shape or Deformations with Helical-Core Optical Fiber - A method, apparatus and system for determine a parameter of a structure is disclosed. A fiber optic cable is coupled to a member. The fiber optic cable includes at least a first core helically arranged in the fiber optic cable that includes at least a first sensor and a second sensor. A first measurement related to the parameter is obtained at the first sensor, and a second measurement at the second sensor related to the parameter is obtained at the second sensor. A difference between the first and second measurements is used to determine the parameter. | 04-18-2013 |
20130311095 | MULTI-GAP INTERFEROMETRIC SENSORS - An apparatus for estimating a property includes a hollow core tube and an input light guide disposed at least partially within hollow core tube. The apparatus also includes a second gap disposed within the hollow core tube and separated from the input light guide by an air gap width. The second gap is formed of a first solid material and has a second gap width. The apparatus also includes a third gap disposed at least partially within the hollow core tube and being further from the input light guide than the second gap. The third gap is formed of a second solid material and has a third gap width. | 11-21-2013 |
20140150548 | DISTRIBUTED DOWNHOLE ACOUSTING SENSING - A method and system to perform distributed downhole acoustic sensing in a borehole are described. The system includes an optical fiber comprising at least one reflector, and a tunable laser configured to perform a transmission of a range of wavelengths through the optical fiber. The system also includes a receiver configured to receive an interferometer signal resulting from the transmission, and a processor configured to determine a component of the interferometer signal. | 06-05-2014 |
20140158877 | HYDROGEN RESISTANT DOWNHOLE OPTICAL FIBER SENSING - An apparatus for estimating at least one parameter in a downhole environment includes: an optical fiber configured to be disposed in a borehole, the optical fiber including a core having a first index of refraction and a cladding surrounding the core and having a second index of refraction that is lower than the first index of refraction, at least a portion of the core being made from a hydrogen resistant material; at least one fiber Bragg grating (FBG) formed within the hydrogen resistant material; a light source configured to send an optical signal into the optical fiber; and a detector configured to receive a return signal generated by the at least one FBG and generate data representative of the at least one parameter. | 06-12-2014 |
20140160483 | POLARIZATION SCRAMBLING IN INTERFEROMETER SYSTEMS - A system and method to obtain and process interferometer output scans is described. The interferometer-based sensor system includes a tunable laser to transmit a transmit signal and a polarization scrambler to produce a polarization state change on the transmit signal. The system also includes an interferometer to provide an output scan based on the transmit signal with the polarization state change and a processor to process the output scan. | 06-12-2014 |
20140161400 | FIBER OPTIC TERMINATION ARRANGEMENT AND METHOD OF MAKING THE SAME - A fiber optic termination arrangement includes a first optical fiber with a core surrounded by cladding having, a first end having a first outer surface and a second end having a second outer surface. The second outer surface is sized to match that of a second optical fiber to facilitate splicing the second end of the first optical fiber to a third end of the second optical fiber. Additionally, the first outer surface is sized and configured to interface with a connector capable of operationally aligning the core of the first optical fiber with a core of a third optical fiber or an optical receiving/transmitting device. The first optical fiber also includes a transition region wherein a third outer surface of the first optical fiber transitions from the first outer surface to the second outer surface. | 06-12-2014 |
20140198823 | TEMPERATURE SENSING ARRANGEMENT, METHOD OF MAKING THE SAME AND METHOD OF SENSING TEMPERATURE - A temperature sensing arrangement includes a member having a first coefficient of thermal expansion, and an optical fiber having a second coefficient of thermal expansion. The optical fiber is strain transmissively mounted to the member. And the second coefficient of thermal expansion is greater than the first coefficient of thermal expansion such that strain measurable in the optical fiber is correlatable to temperature changes in the member. | 07-17-2014 |
20150048243 | OPTICAL FIBER SENSING WITH ENHANCED BACKSCATTERING - An apparatus for estimating at least one parameter in a downhole environment includes: an optical fiber configured to be disposed in a borehole, the optical fiber having a property that causes intrinsic backscattering of signals transmitted therein. The property varies along a length of the optical fiber to generate a variable intensity of the backscattering, the intensity of backscattering varying along the optical fiber as a function of distance from an end of the optical fiber. The apparatus also includes a light source configured to send an optical signal into the optical fiber; and a detector configured to receive a return signal including backscattered signals. | 02-19-2015 |
20150085610 | FIBER OPTIC DISTRIBUTED ACOUSTIC MEASUREMENTS VIA FMCW INTERROGATION - A system and method to obtain acoustic information from a borehole penetrating the earth are described. The system includes a light source to provide a continuous output beam and a modulator to modulate the continuous output beam with a modulation signal to provide a frequency modulated continuous wave (FMCW) to be sent out on an optical fiber disposed along the borehole, the optical fiber including a plurality of reflectors at known locations along the optical fiber. The system also includes a processor to process a light reflection signal from the optical fiber to determine the acoustic information. | 03-26-2015 |