Frigg Member
Hordaland Group,
Horda Formation
Name
English/ Norwegian
Frigg Member / Friggleddet
Derivatio nominis
Named by Deegan & Scull (1977) after a Norse goddess, the wife of Odin.
Original definition
Deegan, C. E. & Scull, B. J. 1977. A standard lithologic nomenclature for the Central and
Northern North Sea. Institute of Geological Sciences Report 77/25. Norwegian Petroleum
Directorate Bulletin 1, 33 pp.
Lithology
The formation consists of sandstones with some lenses and streaks of silty claystone.
The sandstones are poorly consolidated, light brown to buff, micaceous and
carbonaceous, and very fine to medium, occasionally coarse grained. Some layers have
a calcareous cement. Traces of glauconite are present. The silty claystones are green to
grey and carbonaceous.
Thickness
The member has a thickness of 279 m in the type well and 140 m in the reference
well. A depocentre with a maximum thickness of approximately 300 m lies in
Norwegian block 25/1.
Geographical distribution
The Frigg Member is found in the southwestern part of quadrant 30, the northwestern
part of quadrant 25, and in adjacent areas in the UK sector. The Frigg Member sands
of the Beryl and Bruce Fields just extend into the Norwegian sector at about 59°30'N.
Occurrences of member tops in wells
Isochore map BALDER-FRIGG
Type well
Well name
25/1-1
.
Location
WGS84 coordinates:
UTM coordinates:
UTM zone:
Drilling operator name
Completion date
Interval of type section (m)
In 25/1-1 the member is from 2115 to 1836 m.
Reference wells
Well name
30/7-6
Location
WGS84 coordinates:
UTM coordinates:
UTM zone:
24/12-2:
WGS84 coordinates:
UTM coordinates:
UTM zone:
Drilling operator name
Completion date
Interval of reference section (m)
From 1923 to 1783 m in reference well 30/7-6.
Boundaries
Lower boundary (basal stratotype)
The lower boundary normally shows a decrease in gamma-ray intensity and an
increase in velocity from the
Balder Formation into the Frigg Member (Fig. .).
Upper boundary (characteristics)
The top of the member is placed where the sandstones give way to light grey to
brown, occasionally green claystone of the Hordaland Group. The boundary is seen on
logs as an increase in gamma-ray response and a decrease in velocity (Fig……).
"Reference" seismic sections
Location of section
[figure]
Seismic section
[Colour figure]
Fossil events/zones dating the formation
Age
Early Eocene.
Correlations
[Graph]
Depositional environment
The Frigg Member was deposited as submarine fans, by gravity flows. The mode of
deposition led to the formation varying in thickness over short distances. The source
was the East Shetland Platform to the west.
Remarks
The Frigg Member here defined in the Norwegian sector is equivalent to the Frigg
Sandstone Member in the UK sector.
