Acoustic Anisotropic Time-Lapse Full-Waveform Inversion Based on Elliptical Anisotropic Assumption at the Sleipner Site

Given the potential influence of seismic anisotropy on multichannel seismic data acquired over sedimentary basins, applying an optimal anisotropic time-lapse seismic imaging technique to accurately estimate the injected CO2 plume is imperative. This study conducts acoustic multiparameter assumption full-waveform inversion (FWI) based on the elliptical anisotropy to enhance the accuracy of time-lapse seismic monitoring results at the Sleipner field. The Sleipner project is the pioneering commercial-scale offshore carbon capture and storage (CCS), marking the successful implementation of time-lapse seismic surveys to monitor the injected CO2 plume. To validate the necessity of anisotropic time-lapse FWI at the Sleipner field, we construct an initial anisotropic velocity model using Backus averaging. Subsequently, we compare the accuracy of the velocity structure obtained with isotropic and anisotropic FWI starting from the same initial model. Consequently, we confirm that the elliptical anisotropic time-lapse FWI significantly enhances accuracy, as demonstrated by the improved matching of synthetic data derived from anisotropic FWI to the real data, compared to the isotropic FWI results.