Schlumberger Technology Corporation

Onesubsea IP UK Limited

Bookham Technology Limited

Bp Exploration Operating Company Limited

Gareth P Lees

Arthur H Hartog

Andrew Strong

Rogerio Tadeu Ramos

Colin Allan Wilson

Peter C Wait

Paul Frederick Cilgrim Dickenson

Stephen Mullens

Graeme Hilton

Ashley Bernard Johnson

Cheng-Gang Xie

Gary Martin Oddie

Douglas E Miller

Andrew Meredith

Paul Simon Hammond

Kamal Kader

Dylan H Davies

Franck Bruno Jean Monmont

Paul Dickenson

Theo Cuny

Russell Smith

Surya Perdana Simanjuntak

Roger Hampson

Michael John Duffield

Nicholas John Parsons

Kevin Williams

Jakub Szypicyn

A system and technique for obtaining two or more distributed measurements from an optical sensing fiber deployed along a desired measuring path are disclosed. Interrogating probes from two or more different distributed measuring systems are combined and launched into the sensing fiber. Backscattered light generated in response to the combined interrogating probes is separated into portions and each portion is provided to a respective distributed measuring instrument. In this manner, distributed measurements corresponding to different parameters of interest, such as temperature and pressure, along the measuring path can be measured simultaneously using the same sensing fiber.

Simultaneous distributed measurements on optical fiber

Monitoring one or more items of equipment associated with a borehole or other conduit. A sensor system includes a vibration sensor for sensing vibrations at one or more sensor locations associated with one or more items of the equipment and/or the borehole or other conduit. A processing system processes the sensor information to determine a characteristic of the operation of the one or more items of equipment and/or the borehole or other conduit.

Monitoring of equipment associated with a borehole/conduit

A technique facilitates monitoring of flow conditions with respect to flow through a tubing. A distributed sensor is routed along an interior of the tubing to monitor flow conditions. For example, the distributed sensor may be routed over a length of the tubing having a lateral opening. Fluid is flowed along the distributed sensor and within the interior of the tubing. The distributed sensor is operated to measure strain which results from flow of the fluid along the distributed sensor. The strain may then be evaluated to determine a change in a flow condition, such as a change in a flow condition related to the lateral opening.

Flow monitoring using distributed strain measurement

An optical fiber sensor system and method for monitoring a condition of a linear structure such as a pipeline is provided which is capable of providing continuous monitoring in the event of a break in the sensing optical fiber or fibers. The system includes at least one sensing fiber provided along the length of the linear structure, and first and second interrogation and laser pumping sub-systems disposed at opposite ends of the sensing fiber, each of which includes a reflectometer. The reflectometer of the first interrogation and laser pumping sub-system is connected to one end of the sensing fiber. The reflectometer of the second interrogation and laser pumping sub-system is coupled to either (i) an end of a second sensing fiber provided along the length of the linear structure which is opposite from the one end of the first sensing fiber, or (ii) the opposite end of the first sensing fiber. Before any break of the sensing fiber or fibers occurs, each reflectometer redundantly monitors the condition of the linear structure over its entire length. After any such break occurs, each reflectometer will continue to receive signals up to the point of the break from opposite ends of the structure.

Redundant optical fiber system and method for remotely monitoring the condition of a pipeline

A cable for monitoring a tubular structure. The cable comprising a fiber optic bundle arranged for simultaneously sensing a plurality of parameters along a length of the tubular structure that the cable is interfaced with.

Fiber-optic monitoring cable

A system and method for detecting breakage, rupture or malfunctioning of a pipe or cable structure, including sensing elements for monitoring the structure and placed in, on or around the structure for monitoring the breakage, rupture or malfunctioning of the structure. The sensing elements provide sensing data regarding events related to breakage, rupture or malfunctioning and are placed near the structure so as to perform a breakage, rupture or malfunction detection function, and within a distance sufficient to obtain a measureable strain, tension, torsion, vibration, acceleration, and/or temperature response signal based on the breakage, rupture or malfunctioning of the structure. One of the sensing elements is based on Coherent Rayleigh Noise (CRN) sensing techniques, and the system is configured to interpret the sensed data for determining the breakage, rupture or malfunctioning of the structure.

System and method for detection of flexible pipe armor wire ruptures

A leak detection system and method is provided for a structure having a first barrier to a first fluid and a second barrier to a second fluid, the first barrier and the second barrier defining a space therebetween. The system includes at least one sensor, such as a fiber optic sensor, placed in the space and configured to detect presence of the first fluid or the second fluid in the space due to a fluid leak in the first barrier or the second barrier. The fiber optic sensor may further be configured to measure one or more characteristics of an acoustic emission caused by the leak, and the system and method may be able to estimate the orifice diameter of the fluid leak based on the measured one or more characteristics, and to calculate a leak rate based on the estimated orifice diameter.

Method and system for estimating fluid leak flow rates using distributed optical fiber sensors

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.

Distributed acoustic wave detection

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.

Measuring a characteristic of a multimode optical fiber

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.

Optical pulse generator for distributed temperature sensing operating at a characteristic wavelength in a range between 1050 nm and 1090 nm

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.

Distributed sensing in an optical fiber using brillouin scattering

An optical signal demodulator for demodulating an M-ary phase shift key (PSK) optical signal comprises a plurality of interferometers arranged such that the optical signal is divided between the interferometers. Each interferometer comprises a plurality of interferometer arms, each arm for transmitting a portion of the signal between an input and an output of the interferometer, the interferometer including an optical delay in one arm relative to another arm thereof. The optical delay between arms of an interferometer may be provided by an optical path length difference between the arms. The optical delay between arms of an interferometer may be different for one interferometer to that of another interferometer.

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Romsey, United Kingdom

Gareth P Lees