The Sorvestsnaget Basin, Southwest Barents Sea

STEWART, DAVID, and ANDREAS LUNDE, A/S Norske Shell, Tananger, Norway

The Sorvestsnaget basin lies to the south of Spitsbergen at the present continental margin of the Barents Sea platform. At present there is little subsurface well data in this area. However, extensive seismic surveys of exceptional quality indicate that a westward thickening wedge of Tertiary sediments is present, with a maximum thickness of some 6 km. The seismic data give a clear picture of the basin's structural and seismic stratigraphic framework, and indicates that strike-slip faulting had a marked influence on Tertiary basin development. Sedimentation possibly follows similar patterns to those observed on the Spitsbergen.

The basal part of the Tertiary section is mainly represented by irregular high amplitude seismic facies thought to indicate the presence of late Paleocene to early Eocene volcanics. The Eocene was a period of tectonic quiescence with the development of a westward prograding passive margin wedge. The base of the Eocene sequence comprises a thick transparent seismic package interpreted to be a clay prone unit possibly with source rock potential. This package is overlain by high amplitude, continuous seismic facies that may represent alternations of sandstone, siltstones, and shale in a shallow marine to deltaic setting. Seismic anomalies in this package suggest the presence of hydrocarbons. From Oligocene times through to the beginning of the Pliocene the area was affected by transpress on with the resulting development of hanging basins with wedge-shaped prograding fills. In several places at this time inversion occurred between these basins leading to the main structures at top Eocene level. The latest phase of evolution of the west Barents Sea was dominated by passive margin sedimentation in the form of a thick progradational wedge. Sedimentation of this wedge was strongly influenced by glacial processes.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)