Exploring Seismic Detection and Resolution Thresholds of Fault Interpretations in the Shallow Subsurface Using Seismic Modelling

Abstract

Summary This study focuses on limitations in imaging of fault geometries explored by combined seismic interpretation and modelling. The challenges and pitfalls related to interpreting normal faults are addressed by evaluating objective and subjective uncertainties. Geological models with different architecture were made based on fault interpretations on 2D seismic section by a test-panel of 20 geoscientists. More detailed and realistic fault architectures, based on published knowledge from outcrop studies including damage zones and fracture corridors, are included in refined geological models. The geological fault models, both with and without damage zones, were explored with 2(3)D point-spread function (PSF)-based convolution seismic modelling to investigate the potential of seismic data to image detailed fault architectures and associated fluids. The high-resolution seismic data show more details that combined with seismic modelling can add confidence to interpretation of conventional data. Synthetic seismic sections from the refined geological models are used to address detection thresholds for structural details in seismic data, both conventional and high-resolution. The results show that: (1) The fault is characterized by brighter reflection(s) when adding a damage zone; (2) There are stronger amplitudes for the models with CO2-filled fractures; and (3) Fracture corridors are clearly visible as dipping reflections crossing continuous horizons/layers.