Distributed Acoustic Sensing (DAS), a rapidly evolving fiber-optic based technology for permanent in-well and geophysical monitoring, was used to record VSP data in two field trials in Shell assets onshore Canada and USA. Useful in-well velocity data were gathered from the entire length of the well from wellhead to TD (up to 4 km), which compared well with geophone recording and sonic log data. Walk-away VSP data yield images that are nearly equivalent to images from conventional borehole geophones in terms of signal to noise ratio and resolution. Permanently installed fiber-optic infrastructure will enable low-cost non-intrusive geophysical monitoring.
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