Cristin-resultat-ID: 2042869
Sist endret: 14. august 2022, 23:10
Resultat
Vitenskapelig foredrag
2022

Array signal processing on distributed acoustic sensing data: directivity effects in slowness space

Bidragsytere:
  • Sven Peter Näsholm
  • Kamran Iranpour
  • Andreas Wüstefeld
  • Benjamin Dando
  • Alan F. Baird og
  • Volker Oye

Presentasjon

Navn på arrangementet: European Geosciences Union General Assembly
Sted: Vienna, Austria
Dato fra: 23. mai 2022
Dato til: 27. august 2022

Arrangør:

Arrangørnavn: EGU

Om resultatet

Vitenskapelig foredrag
Publiseringsår: 2022

Beskrivelse Beskrivelse

Tittel

Array signal processing on distributed acoustic sensing data: directivity effects in slowness space

Sammendrag

Distributed Acoustic Sensing (DAS) involves the transmission of laser pulses along a fiber-optic cable. These pulses are backscattered at fiber inhomogeneities and again detected by the same interrogator unit that emits the pulses. Elastic deformation along the fiber causes phase shifts in the backscattered laser pulses which are converted to spatially averaged strain measurements, typically at regular fiber intervals. DAS systems provide the potential to employ array processing algorithms. However, there are certain differences between DAS and conventional sensors. The current paper is focused on taking these differences into account. While seismic sensors typically record the directional particle displacement, velocity, or acceleration, the DAS axial strain is inherently proportional to the spatial gradient of the axial cable displacement. DAS is therefore insensitive to broadside displacement, e.g., broadside P-waves. In classical delay-and-sum beamforming, the array response function is the far-field response on a horizontal slowness (or wavenumber) grid. However, for geometrically non-linear DAS layouts, the angle between wavefront and cable varies, requiring the analysis of a steered response that varies with the direction of arrival. This contrasts with the traditional array response function which is given in terms of slowness difference between arrival and steering. This paper provides a framework for DAS steered response estimation accounting also for cable directivity and gauge-length averaging – hereby demonstrating the applicability of DAS in array seismology and to assess DAS design aspects. It bridges a gap between DAS and array theory frameworks and communities, facilitating increased employment of DAS as a seismic array.

Bidragsytere

Sven Peter Näsholm

  • Tilknyttet:
    Forfatter
    ved NORSAR
  • Tilknyttet:
    Forfatter
    ved Digital signalbehandling og bildeanalyse ved Universitetet i Oslo

Kamran Iranpour

  • Tilknyttet:
    Forfatter
    ved NORSAR

Andreas Wüstefeld

  • Tilknyttet:
    Forfatter
    ved NORSAR

Benjamin Dando

  • Tilknyttet:
    Forfatter
    ved NORSAR

Alan F. Baird

  • Tilknyttet:
    Forfatter
    ved NORSAR
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