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Seismic geophysical surveying

  • US 9,465,126 B2
  • Filed: 07/12/2012
  • Issued: 10/11/2016
  • Est. Priority Date: 07/15/2011
  • Status: Active Grant
First Claim
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1. A fibre optic distributed sensing apparatus for use in geophysical surveying involving stimulating an area of interest with a seismic source, said apparatus comprising:

  • a source of electromagnetic radiation arranged to, in use, repeatedly launch interrogating electromagnetic radiation into an optic fibre deployed in said area of interest;

    a sampling detector for sampling electromagnetic radiation back-scattered from said optic fibre; and

    a processor arranged to process the back-scattered radiation to provide, for each of a plurality of longitudinal sensing portions of optic fibre, an indication of any incident acoustic signals affecting that sensing portion,wherein the sampling detector is arranged to acquire a plurality of diversity samples for each said longitudinal sensing portion from each launch of interrogating electromagnetic radiation and the processor is configured to, for each said longitudinal sensing portion;

    divide said diversity samples into a plurality of diversity channels;

    process each of said diversity channels to determine a measurement signal indicative of any acoustic disturbance;

    correlate the measurement signal from each channel with a signal indicative of a seismic stimulus applied; and

    combine the correlated measurement signals to provide an overall measurement signal for the longitudinal sensing portion.

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