Fluvial Geometries and Reservoir Characteristics of a Triassic Coastal Plain System in the Norwegian Barents Sea — 3-D Seismic Imaging of the Ladinian to Early Norian Snadd Formation

The Barents Sea, today the site of a continental shelf and the islands of the Svalbard archipelago, once hosted a vast low-gradient prograding deltaic plain that stretched from the Ural and Caledonian mountain belts in the south and southeast, north to Spitsbergen. Progradation was made possible by high sediment yield, and conduits for sediment transport from source to sink were huge trunk river systems fed by a significant drainage area that comprised most of the northern margin of Pangaea. Parts of these river systems have since become the focus for hydrocarbon exploration and as a consequence are now well covered by a variety of subsurface data, including high-resolution 3D seismic data.

Analysis of five 3D seismic volumes that span the southwestern Barents Sea samples the succession at different locations along an oblique-to depositional dip profile. Using a variety of seismic imaging techniques, e.g. spectral decomposition and RGB-blending, the project aims to understand the palaeogeographic extent and significance of this fluvial system in order to explain geometric properties and reservoir characteristics of the fluvial channels, their spatial variability and stratigraphic evolution. Preliminary studies show that there is a variety of seismic geomorphological features within and between discrete fluvial sequences, including large scale point bar systems followed by ribbon channel sandstone bodies. Towards the top of the Snadd Formation an increase in tidal influence associated with more heterogeneous deposits and elongate reservoir sandstone bodies is interpreted to reflect an overall autogenic response to progressively gentler gradients and a broader coastal plain as the system prograded. This increased understanding of the Snadd fluvial succession within the study area can be used to predict its trend and architecture in the underexplored areas of the Barents Sea.
 

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California