VSP imaging of CO₂ injection with rapid-repeat time lapse full waveform inversion

Xiaohui Cai, Kristopher A. Innanen, Qi Hu, Matthew Eaid, Scott Keating, Kevin W. Hall, Donald C. Lawton

We use FWI to quantitatively interpret the anomaly in rapid-repeat time-lapse VSP data. We present an elastic FWI workflow for indentifying and estimating time-lapse changes introduced by injection of CO₂ at a depth of 300 m, where log-derived P-wave velocity parameterization FWI, effective source estimation and time-lapse strategy are introduced. Applying the workflow to field data shows that our time-lapse inversion scheme is able to detect and quantify the time-lapse anomaly in P wave velocities with the magnitude of 0–150 m/s and a depth of approximately 287.5 m. The inversion of a synthetic data also demonstates the effectiveness of our time-lapse inversion scheme.