Basin Modeling of Exhumation in the Petroleum Systems of the Southwestern Barents Sea

Cavanagh, Andrew J., R. diPrimio, B. Horsfield, GeoForschungsZentrum-Potsdam, Potsdam, Germany

The south-western Barents Sea is a frontier area for exploration on the Norwegian Margin. The juxtaposition of the North Atlantic rift system with the northern borderlands of the Eurasian continental shelf makes for an unusual basin evolution with oil- and gas-prone petroleum systems. The area is home to giant gas fields and one of the largest known ocean floor gas hydrate deposits in the world. Since exploration began in the early 1980’s, some 60 wells and 250,000 km of seismic have defined seven distinct plays in the petro­leum systems of the region. Prospective drilling has largely concentrated on the three prin­cipal plays of the Hammerfest Basin, i.e. the sandstones of the Triassic, Lower-Middle Jurassic and Upper Jurassic-Lower Cretaceous. These have yielded giant gas discoveries, very little oil and evidence of significant inversion during the Cenozoic. These findings are typical of peripheral North Atlantic basins that have undergone exhumation. At present, there is a consensus on the three principal episodes of Cenozoic exhumation in the region as having occurred during the Paleocene, Oligo-Miocene, and Quaternary respectively, and the amount of total erosion within the Hammerfest Basin as approximating 1000-1500 metres. However, the relative severity of each individual episode and associated impact on fluid dynamics within the basin are poorly constrained. This modelling study aims to estab­lish the sensitivity of the south-western Barents Sea petroleum systems to thermal, ice loading and isostatic changes during the Late Cenozoic. Here we report our initial findings for the Hammerfest Basin.