Ahmed Alghuraybi, Rebecca E. Bell, Christopher Jackson, Melissa Sim, Shuhan Jin

Understanding the physical properties of fault zones is essential for various subsurface applications, including carbon capture and geologic storage, geothermal energy, and seismic hazard assessment. Despite improvements in fault imaging and visualisation, predicting the physical properties of faults and fault zones in the subsurface remains challenging, even with high-quality seismic reflection data. In this study, we use borehole and high-quality Post-Stack Depth Migrated (PSDM) seismic reflection and Full-Waveform Inversion (FWI) velocity data to investigate the characteristics of fault zones in the Samson Dome in the SW Barents Sea. We analyse the variance attribute of the PSDM and FWI volumes, revealing linear features that consistently appear in both datasets. These features correspond to locations of rapid velocity changes and seismic trace distortions, which we interpret as faults. These observations demonstrate the capability of FWI in recovering fault zone velocity structures. Our findings also reveal the natural heterogeneity and complexity of fault zones, with varying P-wave velocity anomalies within the studied fault network. We propose that these anomalies may indicate differences in fault transmissibility. Our study highlights the potential of FWI velocity models in predicting fault zone physical properties and improving subsurface interpretations. By integrating seismic reflection data and FWI models, we can enhance our understanding of fault zone architecture, which has implications for energy transition policies, carbon storage, geothermal energy development, waste disposal, and seismic hazard mitigation.