Using 3D seismic to understand the structural evolution of the UK Central North Sea

Interpretation of regional 3D seismic data suggests that the structural evolution of the Central North Sea occurred in three successive structural regimes. Two successive extensional tectonic regimes from Late Palaeozoic to Early Cretaceous were followed by a predominantly compressive tectonic regime from the Late Cretaceous into the Tertiary. Tectonic movements were controlled by the relative orientation of the stress fields with respect to the fault strikes of older major Variscan fault trends. The amount and direction of strike-slip movement was controlled by a gradual clockwise rotation of the minimum effective stress in the horizontal plane from approximately NE-SW to E-W in the first two phases. Within this framework, halokinesis is only of local importance, and serves to amplify the tectonically controlled structuration. The structural model developed here explains the observed distribution of fields and structures in the Central Graben, as well as enabling prediction of structural development in its less well explored portions.