Stratigraphic architecture of the Knarr Field, Norwegian North Sea: sedimentology and biostratigraphy of an evolving tide- to wave-dominated shoreline system

Abstract

The Knarr Field is located on the Tampen Spur, Norwegian continental shelf and was discovered in 2008 by the Jordbær well (34/3-1S), with additional resources later added to the field by the Jordbær Vest well (34/3-3S) in 2011. Within the Knarr Field, the Cook Formation is informally divided into the Lower Cook and Upper Cook successions and appears to have prograded from east to west. The Lower Cook consists of Sands 1, 2 and 3 and the Upper Cook consists of Sands 4 and 5, with the sands separated by intraformational mudstones that are commonly chronostratigraphically constrained; the J15 maximum flooding surface separates the Lower and Upper Cook. The tide-dominated Lower Cook is notably heterolithic, with intricate intercalations of sandstone and mudrock lithologies representing tidal channel, tidal bar and intertidal bar facies. The Upper Cook represents a series of coarsening-upwards cycles that displays the systematic changes in facies and ichnology expected for a shoreface succession, consisting of offshore, offshore transition zone and shoreface facies. Palynomorphs confirm these observations and suggest that the Lower Cook was deposited in brackish-water conditions, whereas the presence of more marine fossils in the Upper Cook suggests an increase in marine influence. The integration of the sedimentology and biostratigraphy described herein enabled the establishment of a robust reservoir zonation that has been utilized during the development and ongoing exploitation of the Knarr Field.

Palynofacies classification of submarine fan depositional environments: Outcrop examples from the Marnoso-Arenacea Formation, Italy

“…Fungal material was not subdivided (sensu Boulter and Riddick, 1986), and well-preserved wood and parenchyma were also grouped (sensu van der Zwan, 1990 (Gary et al, 2009). This is important for large, gradational palaeoentological datasets, which often include samples that are transitional between hard clusters (Gary et al, 2009;Daly et al, 2011;Erbs-Hansen et al, 2011Churchill et al, 2016;McArthur et al, 2016b). This methodology is particularly appropriate for the Marnoso-Arenacea dataset, which aims to examine the changes in sedimentation from turbidity currents that graded across an area in excess of 3600 km 2 ( Fig.…”

Impact of the lower Jurassic Dunlin Group depositional elements on the Aurora CO2 storage site, EL001, northern North Sea, Norway

“…The unit has been interpreted as a highly heterogeneous tidal-and wave-influenced succession (Livbjerg and Mjøs, 1989;Steel, 1993 1995; Marjanac and Steel, 1997) organized in a series of regional regressivetransgressive cycles (Marjanac and Steel, 1997). Churchill et al (2017) observed tidal deposits in the lower part and wave deposits in the upper part, while Dreyer and Wiig (1995) and Folkestad et al (2012) recognized wave-deposits in the lower part followed by tidal deposits.…”

“…2B). Available literature (Dreyer and Wiig, 1995;Folkestad et al, 2012;Churchill et al, 2017) focuses mostly on the Tampen Spur, a different structural element in the Norwegian North Sea ca. 100 km to the NW of the Horda Platform.…”

Clay‐coat diversity in marginal marine sediments

“…() on the Cook Formation, Knarr Field, Norway, reported that total sediment chlorite abundance and mean grain coat coverage are greatest in estuarine facies compared to fully marine facies. There is therefore broad concurrence between the modern Ravenglass Estuary and the Jurassic Cook Formation (Churchill et al ., ; Skarpeid et al ., ).…”