The Aquistore carbon storage project, located near Estevan, Saskatchewan, Canada, aims to employ 3D time-lapse seismic techniques to monitor injected CO 2 at depths of 3100-3350 m. During early stages of the injection schedule, vertical seismic profiling (VSP) will primarily be utilized, given its inherent advantages in imaging close to the borehole. Distributed acoustic sensing (DAS) possesses the capability of providing a cost-efficient, high-resolution alternative to traditional geophone methods in VSP. In this study, an evaluation is made of baseline DAS and traditional geophone VSP data from an observation well located 150 m away from the injection well. Comparative images are analyzed for quantities of injected CO 2, ranging from 27 kt to 330 kt to determine the visibility of the CO 2 plume over time. The study demonstrated that DAS VSP is a feasible technique for reservoir monitoring at the Aquistore site. The CO 2 plume should be visible near the borehole after 90 days (27 kt of CO 2) of injection, with increasing clarity over a three-year duration.

Aquistore is a geologic [Formula: see text] storage project that is using a deep saline formation as a storage reservoir. From April 2015 to February 2016, approximately 36 kilotonnes of [Formula: see text] were injected into the reservoir at a depth of 3130–3350 m. We have developed an analysis of distributed acoustic sensing (DAS) 3D vertical seismic profiling data acquired in February 2016, marking the first seismic survey since injection began. The VSP data were processed in parallel with baseline preinjection data from a November 2013 survey, with the objective of detecting and characterizing the subsurface [Formula: see text] plume and evaluating the repeatability of DAS in a reservoir monitoring project. A single processing sequence was devised that (1) accurately imaged the reservoir for the baseline and monitor data and (2) attained adequate repeatability to observe time-lapse differences related to the presence of [Formula: see text]. Repeatability was somewhat compromised by the less advanced noise cancellation methodology of the DAS system used for the baseline survey. In the final cross-equalized migrated data volumes, normalized root-mean-square ([Formula: see text]rms) difference values of [Formula: see text] were attained at the reservoir level indicating good repeatability compared with most surface seismic studies. An injection-related amplitude anomaly with maximum [Formula: see text]rms values of approximately 0.7 is apparent in the Deadwood Formation of the reservoir, whereas no significant [Formula: see text]rms anomalies were observed near the injection and monitoring wells in the Black Island Member or above the reservoir.

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