Tectonic controls on the spatial distribution and stratigraphic architecture of a net-transgressive shallow-marine synrift succession in a salt-influenced rift basin: Middle to Upper Jurassic, Norwegian Central North Sea

2016 ◽  
Vol 173 (6) ◽  
pp. 901-915 ◽  
Author(s):  
Aruna S. Mannie ◽  
Christopher A.-L. Jackson ◽  
Gary J. Hampson ◽  
Alastair J. Fraser
Keyword(s):  
Spatial Distribution ◽  
North Sea ◽  
Upper Jurassic ◽  
Rift Basin ◽  
Shallow Marine ◽  
Stratigraphic Architecture ◽  
Central North Sea

Diagenesis of the shallow marine Fulmar Formation in the Central North Sea

Clay Minerals ◽  
1986 ◽  
Vol 21 (4) ◽  
pp. 537-564 ◽  
Author(s):  
D. J. Stewart
Keyword(s):  
Clay Mineral ◽  
North Sea ◽  
Large Scale ◽  
Shear Zones ◽  
Upper Jurassic ◽  
Burial Diagenesis ◽  
Secondary Porosity ◽  
Shallow Marine ◽  
History Of ◽  
Central North Sea

AbstractThe diagenetic history of the Upper Jurassic Fulmar Formation of the Central North Sea is described with emphasis on the Fulmar Field. The Fulmar Formation was deposited on a variably subsiding shallow-marine shelf under the influence of halokinetic and fault movements. The sediments are extensively bio-destratified although large-scale cross-bedding is locally preserved. The dominant mechanism of deposition is thought to have been storm-generated currents. Soft-sediment deformation structures are common and are attributed to syn- and post-depositional dewatering of the sandstones. The dewatering was associated with fractures and shear zones which reflect tectonic instability resulting from periodic salt withdrawal and/or graben fault movements. The dewatering may have been initiated by repacking of the sediments during earth movements or by the gradual build-up and sudden release of overpressures due to compaction and/or clay mineral dehydration during rapid burial at the end of the Cretaceous. The formation is composed of arkosic sandstone of similar composition to Triassic sandstones from which it was probably derived. The sandstones also contain limited amounts of marine biogenic debris including sponge solenasters, bivalve shells, rare ammonites and belemnites. Initial diagenesis began with an environment-related phase during which quartz and feldspar overgrowths and chalcedony and calcite cements were precipitated. These cements appear to form concretions adjacent to local concentrations of sponge debris and shell debris, respectively, and were disturbed after their formation by fracturing and dewatering. This was followed by an early burial stage of diagenesis which resulted in extensive dolomite cementation and minor clay mineral authigenesis (illite and chlorite). The last phase of mineral growth was probably pyrite. During early burial diagenesis, secondary porosity after feldspar and/or carbonate was produced, although the exact timing is not clear. The lack of both stylolitic developments and extensive illitization indicates that the late burial diagenesis stage was never reached, although sufficient clay diagenesis occurred to destroy all traces of mixed-layer illite-smectite (present in some shallower wells). The main control on reservoir behaviour is primary depositional fabric. Diagenesis only overprints these controls. Locally-cemented fracture sets act as baffles to fluid flow, but they are not extensive and the reservoir acts as one unit.

scholarly journals Jurassic lithostratigraphy and stratigraphic development onshore and offshore Denmark

2003 ◽  
Vol 1 ◽  
pp. 145-216 ◽  
Author(s):  
Olaf Michelsen ◽  
Lars H. Nielsen ◽  
Peter N. Johannessen ◽  
Jan Andsbjerg ◽  
Finn Surlyk
Keyword(s):  
North Sea ◽  
Middle Jurassic ◽  
Upper Jurassic ◽  
Lower Jurassic ◽  
Coarse Grained ◽  
Late Triassic ◽  
New Members ◽  
Shallow Marine ◽  
Central North Sea ◽  
Sea Area

A complete updated and revised lithostratigraphic scheme for the Jurassic succession of the onshore and offshore Danish areas is presented together with an overview of the geological evolution. The lithostratigraphies of Bornholm, the Danish Basin and the Danish Central Graben are described in ascending order, and a number of new units are defined. On Bornholm, the Lower–Middle Jurassic coal-bearing clays and sands that overlie the Lower Pliensbachian Hasle Formation are referred to the new Sorthat Formation (Lower Jurassic) and the revised Bagå Formation (Middle Jurassic). In the southern Danish Central Graben, the Middle Jurassic succession formerly referred to the Lower Graben Sand Formation is now included in the revised Bryne Formation. The Lulu Formation is erected to include the uppermost part of the Middle Jurassic succession, previously referred to the Bryne Formation in the northern Danish Central Graben. The Upper Jurassic Heno Formation is subdivided into two new members, the Gert Member (lower) and the Ravn Member (upper). The organic-rich part of the upper Farsund Formation, the former informal ‘hot unit’, is established formally as the Bo Member. Dominantly shallow marine and paralic deposition in the Late Triassic was succeeded by widespread deposition of offshore marine clays in the Early Jurassic. On Bornholm, coastal and paralic sedimentation prevailed. During maximum transgression in the Early Toarcian, sedimentation of organic-rich offshore clays took place in the Danish area. This depositional phase was terminated by a regional erosional event in early Middle Jurassic time, caused by uplift of the central North Sea area, including the Ringkøbing–Fyn High. In the Sorgenfrei–Tornquist Zone to the east, where slow subsidence continued, marine sandy sediments were deposited in response to the uplift. Uplift of the central North Sea area was followed by fault-controlled subsidence accompanied by fluvial and floodplain deposition during Middle Jurassic time. On Bornholm, deposition of lacustrine muds, fluvial sands and peats dominated. The late Middle Jurassic saw a gradual shift to shallow marine deposition in the Danish Central Graben, the Danish Basin and Skåne, southern Sweden. During the Late Jurassic, open marine shelf conditions prevailed with deposition of clay-dominated sediments while shallow marine sands were deposited on platform areas. The Central Graben received sand by means of sediment gravity flows. The clay sediments in the Central Graben became increasingly rich in organic matter at the Jurassic–Cretaceous transition, whilst shallow marine coarse-grained deposits prograded basinwards in the Sorgenfrei– Tornquist Zone.

Disseminated ‘jigsaw piece’ dolomite in Upper Jurassic shelf sandstones, Central North Sea: an example of cement growth during bioturbation?

Sedimentology ◽  
2000 ◽  
Vol 47 (3) ◽  
pp. 631-644 ◽  
Author(s):  
James P. Hendry ◽  
Mark Wilkinson ◽  
Anthony E. Fallick ◽  
Nigel H. Trewin
Keyword(s):  
North Sea ◽  
Upper Jurassic ◽  
Central North Sea

scholarly journals Palaeoecological analysis of maximum flooding zones from the Tithonian (Upper Jurassic) of the Kachchh Basin, western India

Facies ◽  
2020 ◽  
Vol 67 (1) ◽  
Author(s):  
Franz T. Fürsich ◽  
Matthias Alberti ◽  
Dhirendra K. Pandey
Keyword(s):  
Upper Jurassic ◽  
Carbonate Content ◽  
Western India ◽  
Rift Basin ◽  
Benthic Assemblages ◽  
Depositional Sequence ◽  
Sequence Stratigraphic ◽  
Stratigraphic Architecture ◽  
Kachchh Basin ◽  
Rich Fauna

AbstractThe siliciclastic Jhuran Formation of the Kachchh Basin, a rift basin bordering the Malagasy Seaway, documents the filling of the basin during the late syn-rift stage. The marine, more than 700-m-thick Tithonian part of the succession in the western part of the basin is composed of highly asymmetric transgressive–regressive cycles and is nearly unfossiliferous except for two intervals, the Lower Tithonian Hildoglochiceras Bed (HB) and the upper Lower Tithonian to lowermost Cretaceous Green Ammonite Beds (GAB). Both horizons represent maximum flooding zones (MFZ) and contain a rich fauna composed of ammonites and benthic macroinvertebrates. Within the HB the benthic assemblages change, concomitant with an increase in the carbonate content, from the predominantly infaunal “Lucina” rotundata to the epifaunal Actinostreon marshii and finally to the partly epifaunal, partly infaunal Eoseebachia sowerbyana assemblage. The Green Ammonite Beds are composed of three highly ferruginous beds, which are the MFZ of transgressive–regressive cycles forming the MFZ of a 3rd-order depositional sequence. The GAB are highly ferruginous, containing berthieroid ooids and grains. GAB I is characterized by the reworked Gryphaea moondanensis assemblage, GAB II by an autochthonous high-diversity assemblage dominated by the brachiopods Acanthorhynchia multistriata and Somalithyris lakhaparensis, whereas GAB III is devoid of fossils except for scarce ammonites. The GAB are interpreted to occupy different positions along an onshore–offshore transect with increasing condensation offshore. Integrated analyses of sedimentological, taphonomic, and palaeoecological data allow to reconstruct, in detail, the sequence stratigraphic architecture of sedimentary successions and to evaluate their degree of faunal condensation.

The Mjølner Field, a deep Upper Jurassic oil field in the central North Sea

First Break ◽  
1991 ◽  
Vol 9 (1242) ◽  
Author(s):  
B. Söderström ◽  
A. Forsberg ◽  
E. Holtar ◽  
B.A. Rasmussen
Keyword(s):  
North Sea ◽  
Upper Jurassic ◽  
Oil Field ◽  
Central North Sea

The Armada development, UK Central North Sea: The Fleming, Drake and Hawkins Gas-Condensate Fields

2003 ◽  
Vol 20 (1) ◽  
pp. 139-151 ◽  
Author(s):  
I. A. Stuart
Keyword(s):  
Maximum Yield ◽  
Upper Jurassic ◽  
Salt Dome ◽  
Gas Condensate ◽  
Project Design ◽  
Surface Site ◽  
Shallow Marine ◽  
The North ◽  
Fault Block ◽  
Central North Sea

abstractIn 1994 the Armada partnership sanctioned the simultaneous development of the Fleming, Drake and Hawkins Gas-condensate Fields by means of shared facilities; the overall project was called the Armada Development. The operator is BG International (formerly British Gas). The development was interesting because the component fields are not only separate accumulations, but are of completely different geological type.The Fleming Field is a Palaeocene, Maureen Formation high-density turbidite reservoir, sourced from the north but pinching out eastwards against the N S Utsira/Jaeren High and Hawking-Varg Ridge, and therefore forming a 20 km long, continuous, but very narrow reservoir. The drake Field is an Upper Jurassic. Fulmar Formation, shallow marine, shore-face reservoir, with excellent reservoir quality in a compact fault block. The Hawkins Field reservoir is poorer quality Fulmar Formation, typical of a more distal setting; the trap is formed by closure over a salt dome, and the structure is consequently quite heavily faulted.The challenge was to develop these disparate reservoirs from a single surface site. to capture the askward shape of Fleming and the distance between Drake and Hawkins. This was achieved by means of extended each drilling; although the high cost of such wells meant that every one had to be designed for maximum yield. Overall eifht wells were drilled, five to Fleming, two to Drake and one to Kawkins (these numbers being approximately proportional to gas-in-place). These wells are capable of delivering the project design peak rate of 450 mmscfd off-platform (equivalent to about 480 mmscfd reservoir gas), and up to 24000 BOPD condensate. Armada began production on schedule in October 1997.

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