Halokinetic initiation of Mesozoic tectonics in the southern North Sea: a regional model

1994 ◽  
Vol 131 (4) ◽  
pp. 559-561 ◽  
Author(s):  
M. R. Allen ◽  
P. A. Griffiths ◽  
J. Craig ◽  
W. R. Fitches ◽  
R. J. Whittington

AbstractThe North Dogger Fault Zone is located at the northern margin of the UK Southern North Sea Basin, at the edge of the mobile Zechstein Supergroup, and was particularly active during late Triassic and early Jurassic times. It resembles geometrically, and is related tectonically to, the Dowsing Fault Zone which was initiated in late Scythian time along the southwestern edge of the mobile salt. It is proposed that both of these basin-bounding fault systems were initiated in response to the buoyant growth of salt swells in the centre of the Southern North Sea Basin. Passive folding of the Triassic strata over the swells, which accommodated the shape changes caused by halokinesis, led to extension on the fault zones at the edge of the mobile Zechstein salt.

2020 ◽  
Vol 52 (1) ◽  
pp. 189-202 ◽  
Author(s):  
J. A. Hook

AbstractThe Hewett Field has been in production for some 50 years. Unusually for a Southern North Sea field in the UK Sector, there has been production from several different reservoirs and almost entirely from intervals younger than the principal Leman Sandstone Formation (LSF) reservoir in the basin. Some of these reservoirs are particular to the Hewett area. This reflects the location of the field at the basin margin bound by the Dowsing Fault Zone, which has influenced structural evolution, deposition and the migration of hydrocarbons. The principal reservoirs are the Permo-Triassic Hewett Sandstone (Lower Bunter), Triassic Bunter Sandstone Formation (BSF) (Upper Bunter) and Permian Zechsteinkalk Formation. There has also been minor production from the Permian Plattendolomit Formation and the LSF. Sour gas is present in the BSF only. Several phases of field development are recognized, ultimately comprising three wellhead platforms with production from 35 wells. Gas is exported onshore to Bacton, where the sour gas was also processed. Peak production was in 1976 and c. 3.5 tcf of gas has been recovered. Hewett has also provided the hub for six satellite fields which have produced a further 0.9 tcf of gas. It is expected that the asset will cease production in 2020.


Author(s):  
David Righton ◽  
Victoria Anne Quayle ◽  
Stuart Hetherington ◽  
Gary Burt

The sub-structure of Atlantic cod (Gadus morhua) stocks in the North Sea has important consequences for fisheries management as the Common Fisheries Policy moves towards a more regional approach. We investigated the movements, distribution and behaviour of cod in the southern North Sea (ICES IVc) and English Channel (ICES VIId) by re-analysing historic data from conventional tagging experiments, and by conducting new experiments with electronic tags. Cod tagged and released in IVc showed a northwards shift in distribution during the feeding season consistent with a homing migration away from spawning grounds along the coasts of the UK and the Netherlands. In contrast, cod tagged and released in VIId did not exhibit a consistent pattern of seasonal movement. Many cod released in VIId were subsequently recaptured close to their release position, although some moved out of the Channel and into the southern North Sea. Overlap between the recapture areas of cod released in the different management areas was no more than 25% in either the spawning or feeding season. Behavioural data from electronic tags suggest that cod in IVc make use of tidal streams to migrate northwards and eastwards in spring, whereas selective tidal stream transport was rarely exhibited by cod tagged and released in VIId. Overall, the evidence suggests that there are behavioural differences between cod in IVc and VIId that limit the mixing of cod from these two areas during the feeding and spawning seasons.


2003 ◽  
Vol 20 (1) ◽  
pp. 723-730 ◽  
Author(s):  
M. Lappin ◽  
D. J. Hendry ◽  
I. A. Saikia

AbstractThe Guinevere Gas Field was discovered in January 1988 by the Mobil-operated well 48/17b-5. The field lies in the UK Sector of the Southern North Sea and occupies Block 48/17b. The field is located within the footwall of the Dowsing Fault Zone on the western flank of the Sole Pit Basin. Guinevere is a compressional northwesterly-trending fault block that comprises Early Permian Leman Sandstone Formation (Rotliegend Group) reservoir, sourced from the Carboniferous below and sealed by Later Permian Zechstein evaporates above.The Guinevere Gas Field is estimated to contain 90 BCF of recoverable gas reserves and was brought on-stream in June 1993 using a single not-normally-manned minimum facilities platform. Field life is predicted to be 13 years. Gas and condensate are evacuated though the Lancelot Area Production System (LAPS) to the onshore Bacton gas terminal in East Anglia.


2017 ◽  
Vol 8 (1) ◽  
pp. 47-65 ◽  
Author(s):  
Paul F. Green ◽  
Ian R. Duddy ◽  
Peter Japsen

AbstractWe present a consistent synthesis of palaeothermal (apatite fission track analysis (AFTA) and vitrinite reflectance) data from UK Southern North Sea wells with the regional pattern of exhumation defined from sonic velocity data. Cenozoic exhumation across most of the region began in the Paleocene between 63 and 59 Ma. Amounts of removed section are around 1 km across the offshore platform, increasing to 2 km or more on the Sole Pit axis. Neogene exhumation within this area began between 22 and 15 Ma, and led to removal of up to 1 km of section. Along the eastern flank of the Sole Pit axis, sonic data define a pre-Chalk event, and AFTA data from these wells show that exhumation began between 120 and 93 Ma. This timing correlates with events defined from AFTA data in the Sorgenfrei–Tornquist Zone, further east, presumably reflecting a response to regional tectonic stresses. East of the Sole Pit axis, AFTA and sonic velocities suggest that Neogene exhumation dominates, while further east towards the central parts of the North Sea Mesozoic sediments appear to be at maximum burial today except for local effects related to salt movement. The multiple episodes of exhumation and burial defined here have important implications for exploration.


2003 ◽  
Vol 20 (1) ◽  
pp. 749-759 ◽  
Author(s):  
David E. Lawton ◽  
Paul P. Roberson

abstractThe Johnston Field is a dry gas accumulation located within blocks 43/26a and 43/27a of the UK Southern North Sea. The discovery well was drilled in 1990 and after the drilling of one appraisal well in 1991, a development plan was submitted and approved in 1993. Initially two development wells were drilled from a four slot sub-sea template, with commercial production commencing in October 1994. A further horizontal development well was added to the field in 1997.The field has a structural trap, fault bounded to the SW and dip-closed to the north, east and south. This field geometry has been established using high quality 3D seismic data, enhanced by seismic attribute analysis. The sandstone reservoir interval consists of the Early Permian, Lower Leman Sandstone Formation of the Upper Rotliegend Group. This reservoir consists of a series of interbedded aeolian dune, fluvial, and clastic sabkha lithofacies. The quality of the reservoir is variable and is principally controlled by the distribution of the various lithofacies. The top seal and fault bounding side seal are provided by the overlying clay stone of the Silverpit Shale Formation and the evaporite dominated Zechstein Supergroup.The field has been developed using a phased development plan, with the acquisition of a 3D seismic survey allowing for the optimized drilling of a high deliverability horizontal well.Current mapped gas initially-in-place estimates for the field are between 360 and 403 BCF, with an estimated recovery factor of between 60 and 75%.


2013 ◽  
Vol 92 (2-3) ◽  
pp. 159-164
Author(s):  
F.P. Wesselingh ◽  
A.C. Janse ◽  
M. Vervoenen ◽  
F.A.D. van Nieulande

AbstractThree specimens of the large-sized Eocene campanilid gastropod genus Campanile have been dredged from the modern sea floor in the Bruine Bank area (North Sea, Dutch sector). The material is identified here as Campanile parisiense rarinodosum, a subspecies hitherto unknown from the North Sea Basin. All three shells are strongly abraded, reflecting their secondary derivation. The new finds suggest that fossiliferous strata of probably late Lutetian (middle Eocene) age are represented in the southern North Sea Basin, situated most likely in the southeastern part of the UK sector. The present material of Campanile must have been reworked into the Dutch sector via Quaternary rivers. The occurrence of Campanile parisiense rarinodosum would indicate close biogeographic ties between the North Sea and the western French Atlantic basins during the late Lutetian. These new records thus shed light on the palaeogeography of the area during two widely separated geological time slices.


1993 ◽  
Vol 130 (5) ◽  
pp. 569-574 ◽  
Author(s):  
Richard Rijkers ◽  
Ed Duin ◽  
Michiel Dusar ◽  
Vital Langenaeker

AbstractIn 1991 a deep seismic line, MPNI-9101, was acquired in the southern North Sea. The line runs from the Mesozoic Broad Fourteens Basin in the north, across the West Netherlands Basin, onto the London–Brabant Massif in the south. The London–Brabant Massif is a WNW–ESE trending stable structure located beneath southeastern England, the southern North Sea and Belgium. The London–Brabant Massif represents the most easterly part of the Anglo-Brabant Massif. At the northern margin of the London-Brabant Massif, Devonian and Carboniferous siliciclastic and carbonate rocks onlap the massif. Farther south, shallow parts of the seismic line in the vicinity of the axial zone of the London–Brabant Massif are almost completely devoid of primary reflections. This zone is composed of strongly folded Lower Palaeozoic sedimentary units which have been mapped in the onshore part of Belgium. Numerous seismic reflection multiples from the base of the Cretaceous are observed on this part of the section. The southern limit of the zone is very abrupt and may correspond to a fault belt delimiting an area of magmatic rocks known in the onshore part of Belgium. Unusually the deeper parts of the seismic line show a strongly reflective lower crust beneath the London-Brabant, a phenomenon which has not been observed on other deep seismic sections across the massif. Two-way travel times to the base of the lower crustal reflective zone (corresponding to the Moho), increase from 10 seconds beneath the West Netherlands Basin in the north to 12 seconds beneath the London–Brabant Massif, suggesting a thickening of the crust.


2021 ◽  
pp. SP494-2020-200
Author(s):  
David G. Quirk ◽  
Stuart G. Archer

AbstractThis paper presents the historical results of onshore and offshore petroleum exploration in the Anglo-Dutch Basin of the Southern North Sea. A total recoverable resource of 220 tcfe has been discovered within a contiguous area of 85,000km2, 73% of which occurs in The Netherlands. The resource is predominantly gas (207 tcf), sourced from Upper Carboniferous coals, although the youngest play is oil, sourced from Lower Jurassic shales.There are five plays, partitioned by late Permian-age (Zechstein) salt. In terms of discovered resource they are ranked 1) Rotliegend aeolian-fluvial sandstones (443 gas discoveries, 417 bcfe average size), 2) Triassic fluvial sandstones (101 gas discoveries, 140 bcfe average), 3) Lower Cretaceous paralic-shallow marine sandstones (61 oil discoveries, 29 MMboe average), 4) Westphalian fluvial sandstones (70 gas discoveries, 88 bcfe average), and 5) Zechstein carbonates (51 gas discoveries, 83 bcfe average). Although the main Rotliegend fairway is mature, there are probably discoveries yet to be made in the Westphalian and Zechstein plays and possibly within the Triassic and Lower Cretaceous plays. There is also potential to extend the Rotliegend play beyond where it is proven, for example along the northern margin of the basin and towards its centre


2019 ◽  
Author(s):  
Oceana ◽  
Silvia García ◽  
Helena Álvarez ◽  
Allison L. Perry ◽  
Jorge Blanco ◽  
...  

Located at the centre of the southern North Sea, Brown Bankridge formed by a series of large-scale sandbanks in Dutch and UK waters. It is a recognised area of ecological interest, due mainly to the high abundance of cetaceans and seabirds in the area. To date, however, Brown Bank has been granted very limited protection. The UK side is protected for a single species (harbour porpoise), within the Southern North Sea MPA. No protection is in place for the Dutch side, although it qualifies for inclusion in the Natura 2000 network due to the high numbers of seabirds that it supports, particularly common guillemot and razorbill. Oceana carried out two research surveys in 2016 and 2017, to gather information about benthic species and communities.In total, 204 taxa were identified. These taxa included nine priority species for conservation, and a range of commercially fished species, including fishes for which Brown Bank provides spawning or nursery habitat. The most noteworthy discovery was the presence of biogenic reefs formed by ross worm (Sabellaria spinulosa), a sedimentary polychaete. These reefs covered a total area of 1023 m2 on the Dutch side of Brown Bank, and hosted a variety of associated species, including various crabs, common dragonet, and lesser spotted dogfish. Such biogenic reefs have nearly disappeared from Dutch waters, and ross worm reefs were previously thought to have been long-extinct in the area.


1991 ◽  
Vol 14 (1) ◽  
pp. 309-316 ◽  
Author(s):  
C. P. Stockbridge ◽  
D. I. Gray

AbstractThe Fulmar Field is located on the southwestern margin of the Central Graben in Blocks 30/16 and 30/11b of the UK sector of the North Sea. The field is a partially eroded anticline with steeply dipping flanks formed by the withdrawal of deeper Zechstein salt. The reservoir consists of thick Upper Jurassic, shallow marine, very bioturbated sandstones of the Fulmar Formation and deep marine turbidites interbedded within the Kimmeridge Clay Formation. Seal to the reservoir is provided by the Kimmeridgian shales in the west and Upper Cretaceous chalks which unconformably overlie the Fulmar Formation in the east.The reservoir section has been subdivided into seven members and 14 reservoir units. Reservoir quality is generally excellent, although there are lower-energy sandstone facies found in the eastern part of the field. The Fulmar oil is highly undersaturated and a secondary gas cap has been created by gas injection.Two exploration wells were drilled before the field was declared commercial. Development is from a 36 slot steel platform and a six slot template. Oil evacuation is by a floating storage unit and gas evacuation is via the Fulmar gas pipeline. Total STOIIP is 815 MMBBL and ultimate recovery is 462 MMBBL oil and 264 BCF gas. Production started in 1982 and 319 MMBBL oil and 121 BCF gas have been produced by year-end 1988. A total of 80 BCF gas has been re-injected for conservation purposes.


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