1. by D. J. Went, R. V. Hamilton, N. H. Platt, and J. R. Underhill
Role of forced regression in controlling Brent Group reservoir architecture and prospectivity in the northern North Sea
by D. J. Went, R. V. Hamilton, N. H. Platt, and J. R. Underhill
Petroleum Geoscience
Volume 19(4):
November 28, 2013
© 2013 The Authors

2. Location and regional setting.
Location and regional setting. (a) Timing of major structural events relative to Brent Group deposition; (b) regional setting of the study area, position of precursor Triassic rift basins and faults active during Brent deposition; (c) study area showing the present-day faults and well locations on Brent top depth map.
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© 2013 The Authors

3. Summary of study area facies characteristics and interpretation.
D. J. Went et al. Petroleum Geoscience 2013;19:
© 2013 The Authors

4. Core photographs of key facies: (a) lower shoreface facies, 15440–15452', 211/18a-N7; (b) upper shoreface facies, 12211–12229', 211/13-8; (c) fluvio-estuarine channel facies, 3790–3796 m, 211/18a-N3; (d) distal sharp-based shoreface facies, 11545–11554', 211/18-21; (e) lagoon and lagoon margin facies, 11589–11596', 211/13-8; (f) distal shelf and bioturbated shelf facies, 11541–11574', 211/13-8.
Core photographs of key facies: (a) lower shoreface facies, 15440–15452', 211/18a-N7; (b) upper shoreface facies, 12211–12229', 211/13-8; (c) fluvio-estuarine channel facies, 3790–3796 m, 211/18a-N3; (d) distal sharp-based shoreface facies, 11545–11554', 211/18-21; (e) lagoon and lagoon margin facies, 11589–11596', 211/13-8; (f) distal shelf and bioturbated shelf facies, 11541–11574', 211/13-8.
D. J. Went et al. Petroleum Geoscience 2013;19:
© 2013 The Authors

5. Core descriptions and facies: (a) stacked HCS in Rannoch but with local intervals with wave ripple and Skolithos burrows (arrowed), 211/18-N3; (b) coarse-grained, cross-bedded fluvio-estuarine channel sandstones (arrowed) overlying lower shoreface strata showing HCS, 211/18-22; (c) core to log calibration, showing associated wireline log responses; (d) thin section photomicrograph, Facies EC, containing mechanically infiltrated, detrital clay, 211/18-N4, 12284ft.
Core descriptions and facies: (a) stacked HCS in Rannoch but with local intervals with wave ripple and Skolithos burrows (arrowed), 211/18-N3; (b) coarse-grained, cross-bedded fluvio-estuarine channel sandstones (arrowed) overlying lower shoreface strata showing HCS, 211/18-22; (c) core to log calibration, showing associated wireline log responses; (d) thin section photomicrograph, Facies EC, containing mechanically infiltrated, detrital clay, 211/18-N4, 12284ft. Facies colour coded as in Figure 2.
D. J. Went et al. Petroleum Geoscience 2013;19:
© 2013 The Authors

6. Gross depositional environment for the Dons area of the Brent Delta: (a) at sea level lowstand emphasizing the lowstand fluvio-estuarine channels; and (b) at sea-level highstand emphasizing the progradational shoreface and back barrier facies.
Gross depositional environment for the Dons area of the Brent Delta: (a) at sea level lowstand emphasizing the lowstand fluvio-estuarine channels; and (b) at sea-level highstand emphasizing the progradational shoreface and back barrier facies.
D. J. Went et al. Petroleum Geoscience 2013;19:
© 2013 The Authors

7. Saloum Delta, Senegal, West Africa, illustrating the regional distribution of environments described in Figure 2.
Saloum Delta, Senegal, West Africa, illustrating the regional distribution of environments described in Figure 2. Inset shows the area illustrated in Figure 7. Map data courtesy of Google Earth 2011, Tracks4Africa.
D. J. Went et al. Petroleum Geoscience 2013;19:
© 2013 The Authors

8. Saloum Delta, showing barrier migration and destruction, and their effects on channel evolution and sediment supply offshore.
Saloum Delta, showing barrier migration and destruction, and their effects on channel evolution and sediment supply offshore. Image courtesy of the Image Science & Analysis Laboratory, NASA Johnson Space Center,
D. J. Went et al. Petroleum Geoscience 2013;19:
© 2013 The Authors

9. (a) Summary of the age and lithostratigraphic significance of the main sequence boundaries and flooding surfaces identified and used in this study.
(a) Summary of the age and lithostratigraphic significance of the main sequence boundaries and flooding surfaces identified and used in this study. The sequence boundary terminology is modified from Hampson et al. (2004). Comparison is made with the sequence stratigraphy, lithostratigraphy and chronostratigraphy of the studies of Johannesson et al. (1995) and Hampson et al. (2004). (b) Early lithostratigraphic model for the Brent (after Deegan & Scull 1977; Brown et al. 1987).
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© 2013 The Authors

10. Stratal surface characteristics and relationship to facies and lithostratigraphy.
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© 2013 The Authors

11. North–south correlation through the Penguin and Don NE fields.
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© 2013 The Authors

12. North–south correlation through West Don.
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© 2013 The Authors

13. West–east correlation through southern SW Don.
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© 2013 The Authors

14. West–east correlation through West Don, SW Don, NE Don and East Penguin.
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15. Brent, Tarbert and Rannoch–Etive–Ness isopach maps (PHH, proto Halibut High; PH, Penguin Horst).
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© 2013 The Authors

16. Depositional model showing the environmental and sequence stratigraphic setting of the principal facies identified in the Don fields area: (a) Sequence 100 lower (Broom); (b) Sequence 300 lower (lower Etive); (c) Sequence 300 upper; (d) Sequence 400 lower; (e) Sequence 400 upper (mid-Ness shale); (f) Sequence 500 lower; (g) Sequence 500 upper; (h) SB1000–FS1000 (lower Tarbert); (i) FS1000–FS1050 (upper Tarbert).
Depositional model showing the environmental and sequence stratigraphic setting of the principal facies identified in the Don fields area: (a) Sequence 100 lower (Broom); (b) Sequence 300 lower (lower Etive); (c) Sequence 300 upper; (d) Sequence 400 lower; (e) Sequence 400 upper (mid-Ness shale); (f) Sequence 500 lower; (g) Sequence 500 upper; (h) SB1000–FS1000 (lower Tarbert); (i) FS1000–FS1050 (upper Tarbert). The regional facies distributions (left-hand of map pairs) are adapted from those shown in Hampson et al. (2004) with conceptual incised fluvial channel systems. Emergent areas are shown by clear polygons.
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© 2013 The Authors

17. Cross-plot of conventional core analysis data from the NE Don area showing a strong facies control on porosity and permeability, and a reduced permeability associated with the water leg (blue crosses).
Cross-plot of conventional core analysis data from the NE Don area showing a strong facies control on porosity and permeability, and a reduced permeability associated with the water leg (blue crosses).
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© 2013 The Authors

18. Model of facies architecture in dip section.
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© 2013 The Authors

19. Facies architecture in strike section showing the influence of the proto-Halibut High in controlling deposition.
Facies architecture in strike section showing the influence of the proto-Halibut High in controlling deposition.
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© 2013 The Authors

20. (a) Regression of the Brent Delta driven by thermal doming, evidence of which is also seen in the pattern of subcrop; (b)–(f) stylized sequential development of stratigraphic sequences in the north of the Brent Delta, illustrating the significant process of forced regression.
(a) Regression of the Brent Delta driven by thermal doming, evidence of which is also seen in the pattern of subcrop; (b)–(f) stylized sequential development of stratigraphic sequences in the north of the Brent Delta, illustrating the significant process of forced regression. Note that deposition occurs in HST, FSST and LST at the delta front. The repeated ‘squeezing’ of up-dip accommodation space causes long distance build out of the delta. Note that the Ness Formation (delta plain) is expected to contain multiple extensive discontinuities (b), and the Rannoch (Facies 2) is deduced to be an amalgam of multiple systems tracts (c, d, e).
D. J. Went et al. Petroleum Geoscience 2013;19:
© 2013 The Authors