Upper Cenozoic channels and fans on 3D seismic data in the northern Norwegian North Sea

Abstract

Miocene-Pliocene deposits of the northern Norwegian North Sea, quadrant 35, have been analysed on three 3D seismic surveys, 2D seismic sections and well logs to interpret the detailed stratigraphy, morphology and facies of regionally defined depositional systems. The interpretations might serve as analogues for subtle stratigraphic hydrocarbon traps in older deposits. A major Miocene channel system, possibly submarine formed, has been mapped. Analyses of the reflection heterogeneity attribute suggest sandy channel-fills and crevasse splays. Time-slices show pronounced Miocene-Pliocene incision close to the Norwegian continental North Sea margin. In a basinward direction mounded fans of high reflection intensity are identified at the mouths of narrow, sinuous feeder channels in the earliest Pliocene depositional sequence. Facies changes through prograding, deltaic systems tracts of the succeeding Pliocene sequence are identified from the reflection intensity attribute and logs. The systems were generally forced westward by Scandinavian uplift, while higher-order glacio-eustatic sea-level changes punctuated the westward prograding systems and formed high-frequency sequences.