Sula Member (new)

updated to follow: Stratigraphic Guide to the Rogaland Group, Norwegian North Sea. Harald Brunstad, Felix M. Gradstein, Jan Erik Lie, Øyvind Hammer, Dirk Munsterman,  Gabi Ogg, and Michelle Hollerbach. Newsletter on Stratigraphy, vol 46/2 pp137-286, 2013.

Rogaland Group, Sele Formation

Unit definition

Sula Member is attributed to the Intra Sele Formation sandstones in Subarea NE in Fig. 1.

Fig 1: Location map of the Members of the Sele Formation.



The Sula Member is defined for first time in this study. The Sula Member is attributed to intra Sele Formation sandstones in the northeastern parts of the North Sea Basin.

Derivatio nominis

The Sula Member is named after one of the largest islands in Hordaland.

Type well

Norwegian well 35/3-2 (new, Fig. 122). Depth 1355-1363 mRKB. Coordinates N61°51'05.98", E 03°46'28.22". No cores.

Fig. 122. Well 35/3-2 Composite log Rogaland Group. Stratigraphic position of the Sula Member is outlined in stratigraphic column to the right.

Reference wells

Norwegian well 35/4-1 (new, Fig. 123). Depth 1795-1803 mRKB. Coordinates N 61°32'00.55", E 03°18'00.26". No cores.

Norwegian Well 35/10-3 (new). Depth 1948-1985 mRKB. Coordinates N 61°02'47.96", E 03°07'40.70". No cores.

Fig. 123. Well 35/4-1 Composite log Rogaland Group. Stratigraphic position of the Sula Member is outlined in stratigraphic column to the right.


The Sula Member consists of friable quartzitic sandstones, clear to white, yellow to green, fine to coarse grained, but mostly medium sized with subrounded to subangular grains. The sandstones are mostly non calcareous with occasional interbeds of grey claystone, and slightly silty. Poorly to well sorted, sub rounded to sub angular, often well sorted. Traces of mica, glauconite and shell debris are common. Non-calcareous.

No cores exist in the Sula Member, and limited information on facies variability is available.

Wireline log characterization

The wireline log response of the Sula Member is blocky to serrated, variably representing thick clean sandstones and series of thinner sandstone layers in alternation with mudstones. Sometimes high velocities and density values are seen, corresponding to zones of calcite cementation in the sandstones.

Upper boundary

The Sula Member is overlain by the shales of the Sele or Balder Formation. When the Sele Formation lies on top, the boundary is generally seen as an upwards increase in gamma-ray response and a decrease in velocity.

Where the Balder Formation directly overlies the Sula Member, the boundary may be seen as an upwards decrease in gamma-ray response and an increase in velocity from the Sele and Lista formations.

Lower boundary

The basal contact of the Sula Member is seen as the boundary between shales of the Sele or Lista Formation below and the coarser sediments of the Sula Member above, but this boundary is often not well defined. The boundary is placed where there is an upwards transition from higher gamma-ray readings and higher velocity.



In wells the Sula sandstones are usually found as series of thin, serrated sandstones with thicknesses of only a few meters. A 37 m thick blocky Sula sandstone is found in well 35/10-3. From seismic there is evidence of thicker development elsewhere.

Seismic characterization

The sandstones belonging to the Sula Member sometimes occur within westward dipping seismic reflectors inside the overall westward thinning wedges (prograding slope) of the Rogaland Group from the Måløy Terrace/Horda Platform into the Sogn Graben.

In some cases the presence of blocky log response in wells corresponds to mounded geometries or channel like lenses, especially in the lower and distal parts of the prograding wedge.

Fig. 124 shows a seismic line through well 35/10-2 where thin stringers of Sula Member sandstones are found, and the well 35/10-3, where a blocky Sula Member sandstone of 37 m thickness is present.

Fig. 124. Seismic section from Sogn Graben to Horda Platform running through 35/10-2 and close to 35/10-3. Inferred presence of Sula Member is highlighted.


Latest Paleocene-Earliest Eocene (Late Thanetian and Earliest Ypresian).


The Sula Member is stratigraphically contained within the Sele Formation, and its biostratigraphic age is thus limited by the same biostratigraphic events that bounds the Sele Formation.

Correlation and subdivision

The Sula Member is stratigraphically divided into Sula S1 and Sula S2 corresponding to Sele 1 and Sele 2 and separated by a high gamma peak. However, the recognition of the boundary between the two sub-units is often difficult in this area because there is generally a less diagnostic development of the high gamma-ray peaks within the Sele formation in this area compared to further south.

Geographic distribution

The Sula Member is present from the area south of Selje High, stretching south to the Horda Platform, and westwards into the Sogn Graben (Fig. 102). It is not known whether the Sula Member is stretching southwards into the Stord Basin Graben due to lack of well control in that area.

Depositional environment

The sandstones of the Sula Member were deposited from sand transported by submarine gravity flow systems. In the eastern areas the Sula Member was largely deposited as proximal turbidites in proximal parts of submarine slope fans on a prograding slope. Further west in the Sogn Graben, the sands were deposited in a basin floor fan setting.

Discoveries with the Sula Member as reservoir

No commercial discovery has been made in the Sula Member.

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