Session 26. Oral Presentation for: Time-lapse borehole seismic imaging of CO2 plume migration in a heterogeneous saline aquifer: Stage 4 CO2CRC Otway Project

Presented on 21 May 2026: Session 26 The CO2CRC Otway International Test Centre in Victoria is a field laboratory for testing monitoring technologies for safe, effective geological carbon storage. Stage 4 of the Otway Project evaluates continuous and time-lapse seismic monitoring of a controlled carbon dioxide (CO2) injection into a heterogeneous saline aquifer at about 1.5 km depth. Ten kilotonnes of supercritical CO2 were injected via an existing well reperforated roughly 50 m above the previous injection interval to get access to a pristine formation suitable for the experiment. The monitoring uses distributed acoustic sensing (DAS) in multiple wells, permanent surface orbital vibrators and repeat 3D vertical seismic profiling (3D VSP) surveys to image plume evolution. The plume was imaged using 4D DAS VSP using a previously acquired 3D DAS VSP as a baseline and a new monitor survey acquired in February 2025 using two vibroseis trucks and a multi-well DAS array. A dedicated 4D data processing workflow addresses changes in fibre routing and interrogator behaviour while preserving amplitude and traveltime repeatability. Time-lapse images show coherent seismic anomalies near two monitoring wells that are spatially and vertically consistent with the new injection interval and reservoir heterogeneity. The results confirm that permanent DAS-enabled 4D VSP can resolve plume geometry and migration, contributing to the development of cost-effective CO2 storage monitoring solutions. To access the Oral Presentation click ‘Supplementary data’ below. To read the full paper click here