Fault and Fracture Patterns with Linkage to Fluid Migration in the Shallow Subsurface: A 3D Seismic Study along a transect of the Western Barents Sea

Abstract

This thesis investigates shallow subsurface deformation patterns and their relationship to fluid migration and glacial processes in the southwestern Barents Sea. The study focuses on four key areas: Lyngenfjorden, Hammerfest Basin, Bjørnøyrenna, and Storfjordrenna. Using high-resolution P-Cable 3D seismic data and interpretation tools in Petrel, the objective was to identify faults, fractures, and associated features such as pockmarks, mounds, and zones of acoustic blanking.

Seismic attributes including variance and ant tracking were applied to improve visibility of structural discontinuities. Variance proved effective for general structural outlines, while ant tracking provided directional fault detection with greater sensitivity to user-defined parameters.

The findings reveal notable differences between the study areas. Lyngenfjorden displays small pockmarks and minor subsurface anomalies, likely related to earlier fluid release or groundwater flow. Hammerfest Basin contains dense faulting beneath the Upper Regional Unconformity, with depressions aligned to faulted zones suggesting structurally controlled fluid migration. In Bjørnøyrenna, large craters and mounds point toward gas hydrate formation and collapse. Storfjordrenna features domed seafloor mounds interpreted as gas hydrate pingos, associated with post-glacial warming.

This study demonstrates that the interaction between tectonics, glacial history, and sediment dynamics has played a major role in shaping the shallow subsurface. The methodology applied here offers valuable insights into the structural and fluid-related evolution of glaciated continental margins.