Control on Evolution of Reactivated Structural Highs on the Norwegian Margin and Their Significance in Future Exploration Areas
An understanding of the tectonic ‘boundary conditions' (changing plate motions, orientations of pre-existing structures) is essential when making accurate predictions about kinematics and structural architectures. Previous studies have shown that pre-existing structures in basement rocks were an important control on the evolution of the Norwegian margin. We examine the fault patterns on two reactivated NE-trending structural highs (Lofoten Ridge and Nyk High), and discuss their implication for future hydrocarbon exploration in the region.
The late-Jurassic to early-Cretaceous rifting which lead to the development of the Lofoten Ridge follows Caledonian basement structural trends. Onshore digital mapping techniques have been used to construct fault models which show that this rifting was associated with extension oblique to the ridge (WNW-transtension). Fault patterns appear to be strongly influenced by the location and orientation of pre-existing structures, giving rise to complex, multimodal fault patterns in the basement rocks. Offshore, in the Vøring basin, two later phases of reactivation can be seen on basement-controlled structural highs. On the Nyk High the major rift-bounding faults underwent minor sinistral strike-slip reactivation giving rise to complex, multimodal fault patterns within the sedimentary cover, during the latest phase of continental breakup. Postglacial normal faults then reactivate these basement structures further in recent times.
Our studies demonstrate that pre-existing structures can influence deformation patterns at every stage in the evolution of the margin. These areas generally show complex 3D fault geometries (both at regional and sub-seismic scales), which can impact significantly on trap geometry, integrity and reservoir performance.
Exploring North Atlantic Margins
2005 AAPG Annual Convention (June 19-22, 2005) Technical Program