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Modelling of fibre-optic DAS response to microseismic arrivals in anisotropic media

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Original languageEnglish
Title of host publication 81st EAGE Conference and Exhibition 2019
Subtitle of host publicationMicro and Passive Seismic I
Publisher or commissioning bodyEuropean Association of Geoscientists and Engineers, EAGE
Number of pages5
DOIs
DateAccepted/In press - 3 Feb 2019
DatePublished (current) - 3 Jun 2019
EventEAGE Annual Conference and Exhibition - London, United Kingdom
Duration: 3 Jun 20196 Jun 2019
Conference number: 81
https://eage.eventsair.com/81st-eage-annual-conference-and-exhibtion/

Conference

ConferenceEAGE Annual Conference and Exhibition
Abbreviated titleEAGE2019
CountryUnited Kingdom
CityLondon
Period3/06/196/06/19
Internet address

Abstract

Fibre-optic Distributed Acoustic Sensing (DAS) cables are now used to monitor microseismicity during hydraulic fracture stimulations of unconventional gas reservoirs. Unlike geophone arrays, DAS systems are sensitive to uniaxial strain along the fibre direction and thus provide a single-component recording, which makes identifying the directionality of incoming waves difficult to infer. Using synthetic examples, we show some fundamental characteristics of microseismic recordings on DAS systems for purposes of hydraulic fracture monitoring in a horizontal well in anisotropic (VTI) shales. We demonstrate that SH arrivals dominate the recorded signals since their polarization is aligned along the horizontal cable at near offset. The amplitude of the SH phase along the cable exhibits a characteristic pattern with bimodal peaks, the width of which relates to the distance of the event from the cable. Furthermore, we find that shear-wave splitting recorded on DAS systems can be used to infer the inclination of the incoming waves, overcoming a current limitation of event locations which have constrained events to lie in a horizontal plane. Low amplitude qSV arrivals suggest an event depth similar to that of the DAS cable. Conversely, steep arrivals produce higher amplitude qSV waves, with shear-wave splitting increasing with offset along the cable.

Event

EAGE Annual Conference and Exhibition

Abbreviated titleEAGE2019
Conference number81
Duration3 Jun 20196 Jun 2019
CityLondon
CountryUnited Kingdom
Web address (URL)
Degree of recognitionInternational event

Event: Conference

Documents

Documents

  • Full-text PDF (submitted manuscript)

    Rights statement: This is the submitted manuscript (SM). The accepted author manuscript version (AAM) will be made available online via Earthdoc . Please refer to any applicable terms of use of the publisher.

    Submitted manuscript, 1 MB, PDF document

DOI

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