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

Alan F Baird, Anna L Stork, S Horne, G Naldrett, J M Kendall, James M Wookey, A Clarke, James P Verdon

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)

4 Citations (Scopus)
173 Downloads (Pure)


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.
Original languageEnglish
Title of host publication 81st EAGE Conference and Exhibition 2019
Subtitle of host publicationMicro and Passive Seismic I
PublisherEuropean Association of Geoscientists and Engineers, EAGE
Number of pages5
Publication statusPublished - 3 Jun 2019
EventEAGE Annual Conference and Exhibition - London, United Kingdom
Duration: 3 Jun 20196 Jun 2019
Conference number: 81


ConferenceEAGE Annual Conference and Exhibition
Abbreviated titleEAGE2019
Country/TerritoryUnited Kingdom
Internet address


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