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Paleozoic structural framework in the northern Dutch offshore • Recent 2D and 3D seismic data allow for a more detailed interpretation of Paleozoic strata. • This has led to a new structural framework which is used to assess the hydrocarbon potential at Paleozoic levels. A 5 A 8 A7 A 9 A 1 2 A 1 1 A 1 0 B 1 0 B 1 4 B 1 3 A 1 5 A 1 4 A 1 3 B 1 8 B 1 7 B 1 6 A 1 8 A 1 7 A 1 6 F 3 F 2 F 1 E 3 E 2 E 1 F 6 F 5 F 4 E 6 E 5 E 4 D6 F 9 F 8 F 7 E 9 E 8 E 7 D 9 G7 F 1 1 F 1 0 E 1 2 E 1 5 F10-03 E12-04 F04-02-A A15-01 B17-04 F07-02 A14-01 E12-02 A16-01 E02-01 F04-03 E12-03 A11-01 E06-01 F10-02 E09-01 A17-01 E02-02 5°E 5°E 4°E 4°E 3°E 3°E 55°N 55°N 0 10 20 30 40 50 5 Kilometers S S t t e e p p G G r r a a b b e e n n C C e e n n t t r r a a l l G G r r a a b b e e n n E E l l b b o o w w S S p p i i t t H H i i g g h h Coordinate System: ED 1950 UTM Zone 31N Un i t e d K in gdo m T h e N e t h e r la n ds Ge rma ny The Nether land s DEF 3D Survey Public 3D Survey 2D Seismic Survey 13-5-2015 13:09:45 Legend Fault activity Jurassic - Palaeogene Permian - Jurassic Devonian - Carboniferous Well into pre-Permian Non-NL Well DEFAB area International Border Saalian unconformity -1500 -2500 -3500 ms TWT -4500 -5500 5°E 5°E 4°E 4°E 3°E 3°E 2°E 2°E 56°N 56°N 55°N 55°N 0 20 40 60 80 100 Kilometers Map datum/projection: ED 1950 UTM Zone 31N 8-5-2015 9:59:51 Legend Carboniferous High Carboniferous Low Lower Carboniferous present DEFAB area International Border A B D E F 31 38 37 44 43 30 29 Elbow Spit Elbow Spit High High Dogger Dogger High High Auk-Flora Auk-Flora Ridge Ridge Norway Denmark Germany The Netherlands United Kingdom Mid-North Sea Mid-North Sea Carboniferous Basin Carboniferous Basin 39 Devonian – Carboniferous • Two clear fault trends; N120E and N040E • Extension less intensive above basement highs (e.g., Elbow Spit High). • North and South of the high: significant basins. • The two trends seem to have been acvated during mulple phases, prior to the Permian. The N120E-trend- ing faults were predominantly acve during the Devoni- an and Dinanan, the N040E-trending aſterwards. • Most of these faults show no offset in post- Carboniferous strata. • Again, Paleozoic basement highs (e.g., Elbow Spit High) are less strongly affected by extension. • Deformaon ‘avoids’ the Elbow Spit High. This results in the ‘stepping’ of the Step Graben. • Stepping is accomodated along pre-exisng (Devonian-Carboniferous) faults, now reacvated as oblique slip (transfer) faults. • Predominantly dextral strike-slip faulng along N060-N080 trending faults. • Timing: Jurassic-Cretaceous. Minor acvity during the Upper Cretaceous, and possibly the Paleogene. • Clearly expressed only below Zechstein salt, or where salt is absent. • Locally, Carboniferous faults were reacvated, result- ing in the formaon of pop-up structures/pull-apart basins. (Permian) Triassic – Jurassic Jurassic – Palaeogene N of high: extension in wide zone E of high: extension in narrower zone Basin configuraon of the Mid North Sea High area during the Dinanan (Early Carboniferous), with selected Paleozoic structural elements (UK interpretaon aſter Milton-Worssell et al., 2010). During the Dinanan sediment influx was from the north, and the Mid-North Sea Carboniferous Basin was the main sediment sink. The transion to deeper water environments occurred south of the Elbow Spit High. Deposion occurred both on the highs and in the lows, and Lower Carboniferous deposits have since been preserved in a significant part of the Dutch northern offshore. Structural map of the Dutch northern offshore. Shown are faults that affect pre-Permian strata, on top of a surface that shows the two way travel me to the Saalian unconformity (~Base Permian). Where the Permian is absent the base of the oldest post-Carboniferous deposits is shown. Presentaon of the project in the Exploraon - plays, Prospects and Prospects Evaluaon session, We 03-06 / 12:20 / N103.
