Kimmeridge Clay: Upper Jurassic present Posidonia: Lower Jurassic present
Zechstein
Upper and Lower Carboniferous Lower Carboniferous
0 40 km
Projec�on: UTM, Zone 31N Map datum: ED50
(c) EBN B.V.
C e n tr a l G ra b e n
St ep
G ra b en
Elb ow
Sp it P
la� orm
A B
E F
Kimmeridge Clay: Upper Jurassic present Posidonia: Lower Jurassic present
Zechstein
Upper and Lower Carboniferous Lower Carboniferous
0 40 km
Projec�on: UTM, Zone 31N Map datum: ED50
(c) EBN B.V.
C e n tr a l G ra b e n
St ep
G ra b en
Elb ow
Sp it P
la� orm
A B
E F
Source rock potential
of the Dutch northern offshore
•
The Posidonia Shale and Westphalian coal measures are proven mature source rocks•
Gas and oil shows also occur in areas where these source rocks are absent (fig. 1)•
The above implies that additional mature source rocks are present•
Principal candidates are Lower CarboniferousScremerston coals, Kimmeridge Clay and intra-Zech- stein source rocks
•
Shallow gas can besourced from biogenic
and thermogenic sources.
Shallow amplitude
anomalies occur throughout the Step Graben and Central Graben (fig. 2)
Shallow Gas field, producing Shallow Gas field, undeveloped
Shallow amplitude anomaly
0 40 km
Projec�on: UTM, Zone 31N Map datum: ED50
(c) EBN B.V.
Central Graben
Step Grab
en
Elbow
Spit P
latfo rm
A B
E F
E06-01 (52 m) E02-02 (49 m)
E02-01 (88 m) 39/07-1
(137 m)
42/10b-2 (339 m)
43/02-1 (99 m)
38/16-1 (256 m)
44/02-1 (84 m) 44/06-1 (503 m)
A09-01 (219 m)
27 28 29 30
35
36
37
38
41 42
43
44
46 47
48 49
4°E 4°E
3°E 3°E
2°E 2°E
1°E 1°E
0°
0°
56°N 56°N
55°N 55°N
54°N 0 510 20 30 40 50 60 70 80 90 100 54°N
Kilometers
Coordinate System: ED 1950 UTM Zone 31N United Kingdom
The Netherlands
Germany The N
etherlands
6-11-2015 16:58:42
Legend
Lithologies lower Asbian (~Scremerston Fm)
Coal Sand Shaly Sand Shale Marl Carbonate DEFAB area
International Border
Denmark
10 km
TWT (s)
-1.0
-2.0
-3.0
-4.0
-5.0
A09-01 NL DE
Elbow Fm./Yoredale Fm. (Lower Carboniferous) (includes NL equivalent of Scremerston Fm)
Upper Old Red Group
(Devonian – Lower Carboniferous)
Kyle Limestone Eqv. (Devonian)
SW NE
Zechstein (Permian) North Sea Group
(Palaeogene – Neogene)
Chalk Triassic
Scremerston coals: a ‘new’ source rock in the Dutch northern offshore
•
Wells show increase in coal content in Scremerston Fm towards the N (fig. 4)•
23 m coal in 39/07-1, 30 m in A09-01•
Coals coincide with high contrast seismic facies in well 39/07-1•
High contrast seismic facies also present in A quadrant (fig. 5)•
Yoredale Fm and Klaverbank Fm (LowerCarboniferous) also contain coal: up to 7.5 m encountered in wells
Fig. 4 Lithologies in the Lower Asbian (rough-
ly equivalent with the Scremerston Formation)
Fig. 5 High contrast seismic facies in the Elbow Fm. (par- tial equivalent of the Scremer- ston Fm.). The projected po- sition of well A09-01 (30 m coal) is shown. Public seismic line NSR32294, available through http://www.nlog.nl/.
Gas show Oil show
Gas field Oil field
0 40 km
Projec�on: UTM, Zone 31N Map datum: ED50
(c) EBN B.V.
Central Graben
Step Grab
en
Elbow
Spit P
latfo rm
A B
E F
Gas show (below NS group) Oil show (below NS group)
Gas field Oil field
0 40 km
Projec�on: UTM, Zone 31N Map datum: ED50
(c) EBN B.V.
Central Graben
Step Grab
en
Elbow Spit P
latfo rm
A B
E F
Fig. 1 Gas and oil shows. Inset: shows in the pre-Tertiary. Fig. 2 Shallow gas fields and shallow seismic anomalies.
Fig. 3 Units with source rock potential. Where formations overlap only the shallowest formation is shown.
•
Oil shows in the A quadrant may be linked to early mature Upper Jurassic ‘hot shale’, similar to Jurassic source rocks in theDanish and German offshore
•
Gas and oil shows indicate that intra- Zechstein source rocks are present and mature in the Step Graben•
Namurian shales may provide additional charge in the southern E and F blocks•
Westphalian coal measures provide gas to Rotliegend and Carboniferous reservoirs•
Lower Carboniferous Scremerston coalsare a promising source rock for gas in the A, B, E and F quadrants (see below)
•
The Lower Jurassic Posidonia shale is a proven oil source rock in the Central Graben•
The Westphalian may be present in the Step and Central GrabenPresence of source rock bearing units
?
mor e coal, mor
e sand
Fig. 5
High contrast seismic facies in Visean
23 m coal
8 m coal
2 m coal
30 m coal
30 m coal
