Advanced Methods for Geological Interpretation of Depositional Environments and Lithofacies: Insights into Hydrocarbon Potential in the Northern Norwegian North Sea

Ali Al Janabi¹Camelia Cristina Knapp¹Ziyad Albesher^2*

• ¹School of Geology, College of Arts and Sciences, Oklahoma State University, Stillwater, Oklahoma, United States
• ²King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia

The exploration of hydrocarbon resources in deep-marine environments of the northern Norwegian North Sea is hindered by the complex stratigraphy and poorly understood depositional architecture of Paleogene formations, particularly the Sele and Lista formations. This study addresses the critical scientific challenge of accurately characterizing these formations to assess their hydrocarbon potential. Although structural traps have been widely studied in the region, stratigraphic traps formed by subtle lithological variations remain underexplored and difficult to predict due to ambiguous well-log signatures and limited core data. To resolve this problem, the study integrates gamma-ray log motifs, high-resolution core imagery, and lithofacies analysis from thirty-nine wells across quadrants 31, 32, 35, 36, and 6204. Eleven stratigraphic cross-sections were constructed in both dip and strike directions to analyze vertical stacking patterns, depositional environments, and key stratigraphic surfaces such as sequence boundaries and maximum flooding surfaces. Thirteen distinct lithofacies were identified and grouped into four depositional types: low-energy mudstones, turbidites, sandy debris flows, and muddy debris flows. These facies were further assessed for reservoir quality attributes including porosity, permeability, and net-to-gross ratio. The findings reveal that the Lista Formation contains laterally extensive, sand-rich turbidites and debris flows with significant reservoir potential, while the Sele Formation is predominantly mud-rich, serving as a regional seal. A key contribution of this study is the development of a 3D structural depth model that enhances the spatial understanding of lithofacies distribution and reservoir connectivity. The integrated methodology presented here improves geological interpretation and supports de-risking of exploration in deep-water stratigraphic plays. This work not only advances the geoscientific understanding of post-rift basins in the Norwegian North Sea but also offers transferable insights for similar offshore systems worldwide.