| Patent application number | Description | Published |
|---|
| 20080246947 | Optical Pulse Generator for Distributed Temperature Sensing Operating at a Characteristic Wavelength in a Range Between 1050 Nm and 1090 Nm - An improved laser source for use in a distributed temperature sensing (DTS) system (and DTS systems employing the same) includes a laser device and drive circuitry that cooperate to emit an optical pulse train at a characteristic wavelength between 1050 nm and 1090 nm. An optical amplifier, which is operably coupled to the laser device, is adapted to amplify the optical pulse train for output over the optical fiber sensor of the DTS system. In the preferred embodiment, the laser device operates at 1064 nm and outputs the optical pulse train via an optical fiber pigtail that is integral to its housing. The optical power of the optical pulse train generated by the laser source is greater than 100 mW, and preferably greater than 1 W, at a preferred pulse repetition frequency range between 1 and 50 kHz, and at a preferred pulse width range between 2 and 100 ns. | 10-09-2008 |
| 20090008536 | DISTRIBUTED SENSING IN AN OPTICAL FIBER USING BRILLOUIN SCATTERING - To perform distributed sensing with an optical fiber using Brillouin scattering, a light pulse is transmitted into the optical fiber, where the transmitted light pulse has a first frequency. Backscattered light and optical local oscillator light are combined, where the backscattered light is received from the optical fiber in response to the transmitted light pulse, and where the optical local oscillator light has a second frequency. A frequency offset is caused to be present between the first frequency of the transmitted light pulse and the second frequency of the optical local oscillator light, where the frequency offset is at least 1 GHz less than a Brillouin frequency shift of the backscattered light. Spectra representing Stokes and anti-Stokes components of the backscattered light are acquired, where the Stokes and anti-Stokes components are separated by a frequency span that is based on the frequency offset. | 01-08-2009 |
| 20090097015 | MEASURING A CHARACTERISTIC OF A MULTIMODE OPTICAL FIBER - To measure a characteristic of a multimode optical fiber, a light pulse source produces a light pulse for transmission into the multimode optical fiber. A spatial filter passes a portion of Brillouin backscattered light from the multimode optical fiber that is responsive to the light pulse. Optical detection equipment detects the portion of the Brillouin backscattered light passed by the spatial filter. | 04-16-2009 |
| 20090114386 | SYSTEMS AND METHODS FOR DISTRIBUTED INTERFEROMETRIC ACOUSTIC MONITORING - This disclosure relates in general to a method and system for monitoring a conduit, a wellbore or a reservoir associated with hydrocarbon production or transportation and/or carbon dioxide sequestration. More specifically, but not by way of limitation, embodiments of the present invention provide for using an optical fiber as a distributed interferometer that may be used to monitor the conduit, wellbore or reservoir. In certain aspects, the distributed interferometric monitoring provides | 05-07-2009 |
| 20090132183 | SYSTEM AND METHOD FOR MONITORING STRUCTURES - A technique facilitates the monitoring of elongate structures. An elongate structure is combined with an optical fiber deployed along the structure. An interrogation system is operatively joined with the optical fiber to input and monitor optical signals to determine any changes in parameters related to the structure. | 05-21-2009 |
| 20090304322 | DISTRIBUTED VIBRATION SENSING SYSTEM USING MULTIMODE FIBER - An optical time domain reflectometry (OTDR) system is configured to detect Rayleigh backscatter reflected from a multimode sensing optical fiber. The system includes a single spatial mode filtering system to select a single speckle of the Rayleigh backscatter produced in response to an optical pulse launched into the multimode fiber. The detected single speckle may be used for distributed disturbance (vibration) detection. | 12-10-2009 |
| 20100014071 | FREQUENCY-SCANNED OPTICAL TIME DOMAIN REFLECTOMETRY - A frequency-scanned optical time domain reflectometry technique includes launching a plurality of interrogating pulses into an optical fiber at a plurality of optical carrier frequencies. A Rayleigh backscatter signal is detected for each interrogating pulse as a function of time between the launching of the pulse and the detection of the backscatter signal. The time resolved Rayleigh backscatter signal at each optical frequency may then be examined to determine a distribution of a physical parameter along the length of the optical fiber. | 01-21-2010 |
| 20100085572 | TIME DOMAIN MULTIPLEXING OF INTERFEROMETRIC SENSORS - An optical sensor array includes a plurality of interferometric sensors that are disposed at a plurality of locations in a region of interest. To determine a physical parameter at the plurality of locations, the array is interrogated with a plurality of optical pulses covering a range of optical wavelengths. The signals returned in response to the interrogating pulses are analyzed to determine an optical path imbalance associated with each sensor, where the optical path imbalance bears a relationship to the physical parameter of interest. Each sensor's contribution to the returned signals is determined by measuring the transit time between the launching of the interrogating pulses and the detection of the returned signals. By determining each sensor's contribution, the physical parameter may be determined at each of the plurality of locations. | 04-08-2010 |
| 20100107754 | DISTRIBUTED ACOUSTIC WAVE DETECTION - A distributed acoustic wave detection system and method is provided. The system may include a fiber optic cable deployed in a well and configured to react to pressure changes resulting from a propagating acoustic wave and an optical source configured to launch interrogating pulses into the fiber optic cable. In addition, the system may include a receiver configured to detect coherent Rayleigh noise produced in response to the interrogating pulses. The CRN signal may be use to track the propagation of the acoustic wave in the well. | 05-06-2010 |
| 20100207019 | OPTICAL MONITORING OF FLUID FLOW - A distributed vibration sensor is positioned in a wellbore to measure fluid flow. The output of the sensor is monitored to acquire a distribution of vibration along a region of interest in the wellbore. An indication of the effectiveness of a well treatment to stimulate fluid flow in the wellbore may be provided based on the acquired vibration distribution. In some embodiments, the well treatment may be adjusted based on the indication of effectiveness. | 08-19-2010 |
| 20110134940 | NARROW LINEWIDTH BRILLOUIN LASER - A Brillouin laser having a narrowed linewidth, reduced relative intensity noise, and increased output power includes a pump laser that provides pump energy to an optical fiber resonant cavity to stimulate Brillouin emission. The output of pump laser is stabilized and its linewidth is narrowed by locking the frequency and phase of the optical signal generated by the pump laser to a longitudinal mode of the optical fiber resonant cavity. In addition, the resonant cavity is temperature and/or strain-tuned so that the Brillouin gain is substantially centered on a longitudinal mode of the cavity, thereby ensuring that the Brillouin frequency shift is substantially equal to an integer number of the free spectral range of the cavity. | 06-09-2011 |
| 20110163891 | METHODS AND SYSTEMS FOR DOWNHOLE TELEMETRY - Subterranean oilfield high-temperature devices configured or designed to facilitate downhole monitoring and high data transmission rates with remotely pumped lasers that are configured for operation downhole, within a borehole, at temperatures in excess of 115 degrees Celsius. | 07-07-2011 |
