Processing of DAS and geophone VSP data from the CaMI Field Research Station

Adriana Gordon

The monitoring program of CO₂ injection at the Field Research Station in Newell County Alberta includes diverse surveys and new technologies. The acquisition and processing of Vertical Seismic Profiles (VSP) were undertaken for this thesis. More specifically, the analysis of three different surveys: a walk around VSP for azimuthal anisotropy analysis, zero offset VSPs to test the emerging DAS technology and walk away VSP to obtain imaging results for straight and helical wounded fibre optic cables. From the azimuthal analysis, the fast direction was identified to the northeast with an epsilon value (0.02) indicative of weak anisotropy. For the DAS VSP processing, a calibration step was necessary to register the precise depth of DAS traces; two approaches were completed and yielded similar results. Additionally, DAS strain rate measurements were converted to strain to compare it with geophone data. The excellent correlation between the 3D seismic lines and VSP-CDP stacks and the imaging results shows that DAS is a promising technology for subsurface imaging and monitoring.