Elastic Full Waveform Inversion with Coiled Distributed Acoustic Sensing Fibres

Summary Distributed acoustic sensing (DAS) is a a powerful technology for seismic data acquisition. Employing optical fibres, DAS senses strain induced by seismic wavefields along the tangent of the fibre. The noninvasive nature of DAS allows for its use in borehole applications not accessible by traditional geophones, including producing wells, injecting wells, and treatment wells during hydraulic fracture treatment. The complementary data supplied by DAS at transmission angles holds the potential to improve parameter estimates provided by inversion frameworks like full waveform inversion (FWI). Little work has focused on the inclusion of the data supplied by DAS in FWI, usually assuming a straight fibre in a vertical well. Here we present a method for full waveform inversion of DAS data that is flexible in its ability to consider data from arbitrarily shaped DAS fibres. The approach we propose here also offers the ability for simultaneous inversion of complementary DAS and geophone datasets, improving the quality of parameter estimates over considering either dataset alone.