3D full waveform inversion of the Snowflake CO₂ injection VSP data

Hyeong-Geun Ji, Sea-Eun Park, Ju-Won Oh, Kristopher A. Innanen

The CaMI FRS is a pilot-scale demonstration carbon capture and storage (CCS) project aimed at validating 4D seismic monitoring. This report focuses on verifying the suitability of 3D acoustic full-waveform inversion (FWI) for inverting Snowflake vertical seismic profile (VSP) data acquired from CaMI FRS both before and after CO₂ injection. The Snowflake data is obtained by a walk-away and walk-around VSP survey, which is applicable to both 2D and 3D FWI. Initially, we present the results of 2D acoustic FWI along each walk-away shot line. Then, we show the results of 3D acoustic FWI utilizing the complete 3D VSP dataset. While the inverted models from 2D FWI did not meet expectations, the inverted model from 3D FWI yields a more satisfactory geological representation in terms of layer continuity and noise reduction. Moreover, the changes in P-wave velocity are partially detected from the individual 3D FWI results for the Snowflake data before and after CO₂ injection.