Ahmed Alghuraybi, Rebecca E. Bell, Christopher Jackson

The growth of normal faults can influence subsurface fluid flow and entrapment within rift basins. However, fault seal studies typically view faults as static structures, with their growth and the potential related temporal changes in hydraulic properties being ignored. In this study, we use borehole data and a high-quality 3D full-stack depth migrated seismic reflection volume to analyse the growth history of the normal fault network in the Samson Dome area, SW Barents Sea. We specifically focus on how the kinematic history of normal faults impacts their sealing properties, whilst also considering their origin and implications for regional salt tectonics. We show that the faults formed during two distinct phases in the Late Triassic and Middle Jurassic-to-Early Cretaceous, and two phases of dome growth occurred in the Late Triassic and Late Cretaceous, challenging existing proposals for the timing of the development of structure. The salt-tectonic origin of the Samson Dome itself remains enigmatic, although mechanical considerations suggest existing models require refinement. Our fault seal analysis reveals a correlation between displacement patterns and sealing potential, as reflected in the Shale Gouge Ratio (SGR) values of different fault groups. More specifically, faults that grew via vertical linkage of initially isolated segments and experienced potential reactivation exhibit lower SGR values, implying a higher likelihood of across and along-fault leakage. Conversely, faults lacking evidence for reactivation or vertical linkage show higher SGR values, suggesting better sealing potential. Notably, the accuracy of our fault seal analysis is greatly influenced by the calculation methods used for Vshale, particularly for faults with low displacement. Our study provides valuable insights into the faulting, development, and sealing potential of the Samson Dome area. We also highlight the importance of careful consideration of Vshale calculation methods when conducting fault seal analysis.