Method of measuring acoustic energy impinging upon a cable

Patent metadata

Field	Value
Publication number	US-2016274064-A1
Application number	US-201514661364-A
Country	US
Kind code	A1
Filing date	Mar 18, 2015
Priority date	Mar 18, 2015
Publication date	Sep 22, 2016
Grant date	—

Abstract

A method of measuring acoustic energy impinging upon a cable includes, interrogating at least one optical fiber of the cable with electromagnetic energy, the at least one optical fiber is nonconcentrically surrounded by and strain locked to a sheath of the cable, monitoring electromagnetic energy returned in the at least one optical fiber, and determining acoustic energy impinging on the cable.

First claim

What is claimed is:

1 . A method of measuring acoustic energy impinging upon a cable, comprising:
interrogating at least one optical fiber of the cable with electromagnetic energy, the at least one optical fiber being nonconcentrically surrounded by and strain locked to a sheath of the cable; monitoring electromagnetic energy returned in the at least one optical fiber; and determining acoustic energy impinging on the cable.

2 . The method of measuring acoustic energy impinging upon a cable of claim 1 , wherein the interrogating includes sweeping a laser between two wavelengths.

3 . The method of measuring acoustic energy impinging upon a cable of claim 2 , further comprising sweeping the laser between wavelengths of about 1520 nm and 1560 nm.

4 . The method of measuring acoustic energy impinging upon a cable of claim 2 , further comprising sweeping the laser at a rate of between about 100 nm/s and 10,000 nm/s.

5 . The method of measuring acoustic energy impinging upon a cable of claim 1 , further comprising interrogating lengths of the at least one optical fiber of few meters to hundreds of meters.

6 . The method of measuring acoustic energy impinging upon a cable of claim 1 , further comprising interrogating fiber Bragg grating sensors.

7 . The method of measuring acoustic energy impinging upon a cable of claim 1 , further comprising interrogating an optical frequency domain reflectometer.

8 . The method of measuring acoustic energy impinging upon a cable of claim 1 , further comprising monitoring electromagnetic energy returning from Rayleigh scatterings.

9 . The method of measuring acoustic energy impinging upon a cable of claim 1 , further comprising interrogating with coherent optical time domain reflectometer.

10 . The method of measuring acoustic energy impinging upon a cable of claim 9 , further comprising interrogating with pulses of electromagnetic energy.

11 . The method of measuring acoustic energy impinging upon a cable of claim 1 , further comprising interrogating with wavelength division multiplexed sensors.

12 . The method of measuring acoustic energy impinging upon a cable of claim 1 , further comprising determining time varying displacement of the cable while the cable is strain locked to a tool.

13 . The method of measuring acoustic energy impinging upon a cable of claim 1 , further comprising determining acoustically induced displacements in three-dimensions at distributed points on the cable.

14 . The method of measuring acoustic energy impinging upon a cable of claim 1 , further comprising determining parameters of acoustic energy impinging the cable in directions not parallel to a longitudinal axis of the cable.

15 . The method of measuring acoustic energy impinging upon a cable of claim 14 , wherein the parameters include at least one of acoustic spectrum, phase, and amplitude of the acoustic energy.

16 . The method of measuring acoustic energy impinging upon a cable of claim 14 , wherein the parameters includes a location of a source of the acoustic energy.

17 . The method of measuring acoustic energy impinging upon a cable of claim 14 , wherein the parameters includes a direction of travel of the acoustic energy.

18 . The method of measuring acoustic energy impinging upon a cable of claim 14 , wherein the parameters includes an image of what the acoustic energy has passed through.

19 . The method of measuring acoustic energy impinging upon a cable of claim 14 , wherein the at least one optical fiber is positioned within the sheath in a helical pattern.

Assignees

• Wysocki Paul F
• Mitchell Ian
• Raum Matthew Thomas
• Baker Hughes Inc

Inventors

• Wysocki Paul F
• Mitchell Ian
• Raum Matthew Thomas

Classifications

• G01N29/2418 Primary

  using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics (photoacoustic cells G01N21/1702; measuring characteristics of vibrations by using radiation-sensitive means G01H9/00; acousto-optical conversion techniques for short-range imaging G01S15/8965; sound-producing devices using laser bundle G10K15/046) · CPC title

• G01N29/04

  Analysing solids (using acoustic emission techniques G01N29/14) · CPC title