Tectono-Stratigraphic Development of the Hammerfest Basin (Northern Norway) During the Jurassic to Cretaceous

Signe Ottesen¹, Atle Folkestad², and Robert Gawthorpe^3
1 Statoil, Stavanger, Norway
² Statoil, Bergen, Norway
³ University of Manchester, Manchester, England

The development of the Snøhvit gas-condensate field has led to a renewed interest in the Hammerfest Basin in the Barents Sea. This study emphasized the linkage between tectonics and stratigraphy, and produced a series of paleogeographic maps over the area from Jurassic to Cretaceous time. Analysis of 2D and 3D seismic data combined with a total of 48 wells with cored material shows the importance of tectonically-enhanced accommodation creation during deposition of the studied succession.

The Early Jurassic Stø Fm, the main reservoir on the Snøhvit Field, represents a tectonically controlled wave-dominated estuary that was transgressed while deep marine conditions prevailed in the axial part of the Hammerfest basin. In middle to upper Jurassic time, sedimentation was restricted to both shallow and deep marine deltas along the northern and southern margins of the basin, with mudstone deposits in the central/axial part of the basin. During the Cretaceous, the depositional style changed to include deep marine fans extending far into the basin along structural elements. Subsequently, deep marine fans were also formed by sediments eroded from elevated structural elements in the central/axial part of the basin and slight relative tectonic uplifts of the margins. In the later part of the Early Cretaceous, tectonic activity diminished both in the central part and the southern margin of the basin with some deep marine fan developments on the northern margin. These paleogeographic maps have proven valuable as inputs to prospect evaluation of the Jurassic to Cretaceous succession in the Hammerfest Basin.