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Summary Monitoring hydraulic fracturing is important for optimizing well-completion and well-spacing. Monitoring efforts, so far, are limited to observing micro-seismic activity, shear-wave shadowing and velocity changes from a neighboring monitoring well. The advent of Distributed Acoustic Sensing (DAS) has allowed us to monitor changes from the treatment well itself. We describe a novel active-source seismic experiment with DAS in a treatment well and discuss time-lapse changes due to hydraulic fracturing. We observe amplification and attenuation of direct P-waves above and below the plug for each stage, respectively. These strong time-lapse changes appear to be long-lived, at least over a period of 10 days. The time-lapse phase changes are small and hard to interpret. We believe that the amplification in the stimulated zone is related to formation changes and the attenuation is probably related to fiber coupling changes. Though the current geometry is not ideal, DAS is promising for hydraulic fracture monitoring.
Bakku et al. (Tue,) studied this question.