Acoustic inversion of high-resolution seismic data applied to geotechnical characterization of marine sediments in the Campos Basin

This study investigates the potential of acoustic impedance inversion of Sub-Bottom Profiler (SBP) data to support the geotechnical characterization of marine sediments in the Jubarte Field, Campos Basin. Envelope amplitudes extracted from SBP records were converted into acoustic impedance using log–linear models calibrated with MSCL-S measurements. The predicted impedance was then used as input for local regression models designed to estimate cone resistance ( q c ), sleeve friction ( f s ), and pore pressure ( u 2 ) from CPT data. The main objective was to evaluate whether impedance predicted from high-resolution seismic data can reproduce the vertical geotechnical trends observed in shallow sediment columns.Global impedance–CPT regressions showed limited explanatory power due to lithological variability among boreholes, highlighting the need for borehole-specific models. Local formulations tested for each borehole demonstrated substantially improved performance. Among them, the quadratic model (LM-2) provided the most consistent results, yielding R 2 = 0 . 28 –0.89 for q c and R 2 = 0 . 69 –0.95 for u 2 within the upper 10–15 m, where SBP signal quality is highest. Predictions of f s showed lower agreement ( R 2 = 0 . 26 –0.70), reflecting its greater natural variability.Although the method cannot resolve thin sandy or silty layers due to the vertical resolution of SBP data, the predicted impedance successfully captured the low-frequency mechanical gradients associated with sediment compaction. These results demonstrate that acoustic impedance inversion can generate physically coherent synthetic CPT profiles and serve as a practical tool to support borehole planning and preliminary geotechnical assessment in deep-water settings.