Unravelling the nature of deep-marine sandstones through the linkage of seismic geomorphologies to sedimentary facies; the Hermod Fan, Norwegian North Sea - From Depositional Systems to Sedimentary Successions on the Norwegian Continental Margin - page 665

25/2 - 6 25/2 - 14 25/5 - 1

25/5 - 2

1

25/5 - 1 25/5 - 1

Balder Fm Balder Fm

Odin Mbr Sandstone
4

-INTRA_BALDER_FM_SS

15m

Sele Fm

Sele Fm

3

2

Lista Fm Lista Fm

0 250m 0 250m

30 Hz Ricker GR

Fig. 12. above: oblique 3d view of edge attribute map draped onto an auto-tracked Top Sele Formation time-structure
map. The edge attribute is a combination of different quantitative measures of the dip and continuity of seismic reflectors.
The green colours are therefore an objective illustration of edges. Well 25/5-1 is located in a small circular depression.
Below: the seismic lines with well tie and lithology-filled GR curves and the edge map illustrate four characteristic features
of the well 25/5-1 depression: (1) circular to oval map view shape; (2) contracted Sele Formation with no Hermod Member
sandstone; (3) steep-sided contact to elevated shoulder and; (4) expanded Balder Formation with an extra high acoustic
impedance reflector representative of Odin Member sandstone.

a nucleation of smaller, circular, depressions
(Fig. 13). Seismic edge attributes suggest that small
circular depressions can also define the steep
sides of large sand-injection mounds (Fig. 12). The

nucleation of circular depressions detected by the
use of edge attributes can easily be mistaken for
scallops in an isochron map (compare structure
drilled by well 25/5-2 in Figs 12 and 14).