Thermal evolution of the Nordkapp Basin and implications for its petroleum system

Abstract

The Nordkapp Basin is an elongated salt-bearing basin that developed during Late Palaeozoic-Early Mesozoic rifting in the southwestern Barents Sea. The presence of salt structures within the basin modified its temperature distribution and evolution. This thesis focuses on two sections across the eastern and east-central sub-basins of the Nordkapp Basin. By using a paleo-stepping approach, the modeling enables integrating structural restoration and thermal modelling of the sections to determine the impact of salt related structures on the geothermal history of the Basin and implications on its petroleum system. The results show that salt diapirs induced a significant negative thermal anomaly, retarding maturation and generation of neighboring source rocks, as a function of the overlying sediments and salt structural evolution. Furthermore, salt structures enabled optimum reservoir temperatures for hydrocarbon preservation. Essential elements of the petroleum system include source rock limestones and shales from Late Permian and Early Triassic age, Middle to Late Triassic siliciclastic reservoirs, and Jurassic to Cenozoic overburden strata. Traps include reservoir beds pinching towards the salt structures, and traps at the basin boundaries associated with suprasalt faults, both sealed at the top by Cenozoic shales. Modeling the thermal influence of salt structures in the Nordkapp Basin allows generating new exploration models for the basin, and salt-related basin alike in the Barents Sea.