Ammonite occurrences in North Sea cores: implications for Jurassic Arctic–Mediterranean marine seaway connectivity

2020 ◽  
Vol 56 (2) ◽  
pp. 175-195
Author(s):  
Nicol Morton ◽  
Vasily V. Mitta ◽  
John R. Underhill
Keyword(s):  
North Sea ◽  
The Arctic ◽  
Migration Routes ◽  
Content Type ◽  
Upper Bajocian ◽  
Moray Firth ◽  
Extensional Faulting ◽  
Supplementary Material ◽  
The Uk ◽  
Uplift And Erosion

The paucity of ammonite recovery from North Sea wells has meant that offshore correlations are largely dependent upon microfossil assemblages. While rare, ammonites have been found in a few boreholes during the course of oil exploration activities. The occurrence of ammonites in ten wells in the UK sector of the Viking Graben and the Moray Firth rift arms provides a new basis by which to demonstrate that there was a distinct separation between Arctic and sub-Mediterranean species that lasted from Bajocian to Early Callovian times. Five wells contain ‘Boreal Bathonian' ammonites from the Arctic Realm. Arctocephalites from the Boreal Arcticus Zone (uppermost Bajocian) correlates basinal partly anoxic mudstones in the Beryl Embayment (9/13b) with both bioturbated siltstones in the southern Viking Graben (9/10b), and calcareous mudstones in the East Shetland Basin (211/21). Upper Bajocian Pompeckji Zone Cranocephalites and younger Arcticoceras from Lower to Middle Bathonian Greenlandicus, Ishmae and Cranocephaloide zones are confined to 211/21 demonstrating that the marine transgression began earlier and lasted longer. A Cadoceras from well 3/3-8 dates to the Lower Callovian Koenigi and Calloviense zones during which renewed extensional faulting re-established ammonite migration routes between the Boreal and sub-Mediterranean realms. A Middle Oxfordian (Densiplicatum Zone) Perisphinctes from well 22/5b-8 confirms an episode of northward migration from the sub-Mediterranean into the Boreal Realm. Upper Oxfordian (Regulare to Rosenkantzi zones) Amoeboceras in wells 211/21-1 and 9/13b-19 are close to Upper Bajocian/Lower Bathonian faunas, suggesting an absence of Upper Bathonian to Middle Oxfordian strata as a result of rift-related footwall uplift and erosion. In four wells from Block 15/21 (-4, -11, -12A and -25) Lower Kimmeridgian ammonites have been documented, including Rasenia, Amoebites, Aulacostephanoides and Zenostephanoides, from the Baylei (?), Cymodoce, Mutabilis and Eudoxus zones, the latter (confirmed at well 13/28b-8) dating a widespread regional marine flooding surface in the Inner Moray Firth.Supplementary material: The detailed measurements of dimensions of the ammonites described are available at: https://doi.org/10.6084/m9.figshare.c.5087313

scholarly journals Evolution of a sand-rich submarine channel-lobe system and impact of mass-transport and transitional flow deposits on reservoir heterogeneity: Magnus Field, northern North Sea

2021 ◽  
pp. petgeo2020-095
Author(s):  
Michael J. Steventon ◽  
Christopher A-L. Jackson ◽  
Howard D. Johnson ◽  
David M. Hodgson ◽  
Sean Kelly ◽  
...  
Keyword(s):  
Mass Transport ◽  
North Sea ◽  
Fluid Pressure ◽  
Transitional Flow ◽  
Rock Properties ◽  
Sweep Efficiency ◽  
Content Type ◽  
Supplementary Material ◽  
Northern North Sea ◽  
The Impact

The geometry, distribution, and rock properties (i.e. porosity and permeability) of turbidite reservoirs, and the processes associated with turbidity current deposition, are relatively well known. However, less attention has been given to the equivalent properties resulting from laminar sediment gravity-flow deposition, with most research limited to cogenetic turbidite-debrites (i.e. transitional flow deposits) or subsurface studies that focus predominantly on seismic-scale mass-transport deposits (MTDs). Thus, we have a limited understanding of the ability of sub-seismic MTDs to act as hydraulic seals and their effect on hydrocarbon production, and/or carbon storage. We investigate the gap between seismically resolvable and sub-seismic MTDs, and transitional flow deposits on long-term reservoir performance in this analysis of a small (<10 km radius submarine fan system), Late Jurassic, sandstone-rich stacked turbidite reservoir (Magnus Field, northern North Sea). We use core, petrophysical logs, pore fluid pressure, quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN), and 3D seismic-reflection datasets to quantify the type and distribution of sedimentary facies and rock properties. Our analysis is supported by a relatively long (c. 37 years) and well-documented production history. We recognise a range of sediment gravity deposits: (i) thick-/thin- bedded, structureless and structured turbidite sandstone, constituting the primary productive reservoir facies (c. porosity = 22%, permeability = 500 mD), (ii) a range of transitional flow deposits, and (iii) heterogeneous mud-rich sandstones interpreted as debrites (c. porosity = <10%, volume of clay = 35%, up to 18 m thick). Results from this study show that over the production timescale of the Magnus Field, debrites act as barriers, compartmentalising the reservoir into two parts (upper and lower reservoir), and transitional flow deposits act as baffles, impacting sweep efficiency during production. Prediction of the rock properties of laminar and transitional flow deposits, and their effect on reservoir distribution, has important implications for: (i) exploration play concepts, particularly in predicting the seal potential of MTDs, (ii) pore pressure prediction within turbidite reservoirs, and (iii) the impact of transitional flow deposits on reservoir quality and sweep efficiency.Supplementary material:https://doi.org/10.6084/m9.figshare.c.5313860

Carboniferous records of the Zoophycos group of trace fossils from England, Wales, the Isle of Man and the North Sea

2020 ◽  
Vol 63 (2) ◽  
pp. 135-145
Author(s):  
Duncan McLean ◽  
Matthew Booth ◽  
David J. Bodman ◽  
Finlay D. McLean
Keyword(s):  
North Sea ◽  
Trace Fossils ◽  
Depositional Environments ◽  
Common Component ◽  
Content Type ◽  
Clastic Rocks ◽  
Isle Of Man ◽  
The North ◽  
The North Sea ◽  
Supplementary Material

The Zoophycos group of trace fossils is common in Carboniferous to recent marine strata and sediments, and is a common component of ichnofaunas in the Visean and Namurian stages of England and Wales. A review of new and published records indicates that it is often present in limestones and sandstones of Chadian to Arnsbergian age. Thereafter it is less common, and restricted to clastic rocks. There are no known records within Carboniferous strata above the lowest Westphalian. The form is most common and often abundant in limestones of the Yoredale facies in the upper Visean and lower Namurian stages of northern England, particularly so in northern Northumberland. Where detailed sedimentological data exist, they indicate that the organisms responsible for the Zoophycos group burrowed into unconsolidated carbonate substrate that was deposited under low accumulation rates, often affected by storm wave action and where seawater flow provided a nutrient supply. However, in mixed carbonate–clastic settings, the deep-tier nature of Zoophycos may indicate that the organism lived in overlying shallow-marine, clastic-dominated depositional environments and burrowed down into the carbonate substrate. The same may be true of siliciclastic depositional settings where the presence of Zoophycos in some sandstones may reflect the palaeoenvironment of the overlying, finer-grained transgressive marine (prodelta and distal mouth bar) deposits.Supplementary material: A spreadsheet with details of Carboniferous records of Zoophycos group fossils from England, Wales, the Isle of Man and the North Sea is available at https://doi.org/10.6084/m9.figshare.c.4994636

Field map

2003 ◽  
Vol 20 (1) ◽  
pp. 132-132
Keyword(s):  
North Sea ◽  
Oil And Gas ◽  
Median Line ◽  
Moray Firth ◽  
The Uk ◽  
Central North Sea ◽  
International Border

AbstractMap depicting the position and names of the main oil and gas producing fields located in the Viking Graben and eastern parts of the Outer Moray Firth rift arms, Northern and Central North Sea. The international border (median line) between the UK and Norway is highlighted as are the producing fields in the Norwegian sector. The boxed areas show the extent of licensed acreage in the region.

Exploration well failures from the UK North Sea

2016 ◽  
Vol 8 (1) ◽  
pp. 267-272 ◽  
Author(s):  
Christian J. H. Mathieu
Keyword(s):  
Peer Review ◽  
North Sea ◽  
Primary Reason ◽  
Success Rates ◽  
Moray Firth ◽  
The Uk ◽  
Central North Sea ◽  
Exploration Well ◽  
Play Context

AbstractThe UK Oil & Gas Authority carried out post-well failure analyses of exploration and appraisal wells in the Moray Firth and the UK Central North Sea to fully understand the basis for drilling the prospects and the reasons why the prospects failed.The data consisted of Tertiary, Mesozoic and Palaeozoic targets/segments associated with 97 wells drilled from 2003 to 2013. Seal was the primary reason for failure followed by trap, reservoir and charge. Root causes for failure were a lack of lateral seal, the absence of the target reservoir and the lack of a trap. The main pre-drill risk was not accurately predicted in over one-third of the cases and a third of the segments were targeted on the basis of perceived Direct Hydrocarbon Indicators.This study identified a number of interpretation gaps and pitfalls that ultimately contributed to the well failures. These included poor integration, improper application of geophysics, lack of regional play context, and absent or ineffective peer review. Addressing these gaps in a comprehensive and systematic way is fundamental to improving exploration success rates.

scholarly journals Evolution of a salt-rich transtensional rifted margin, eastern North Pyrenees, France

2020 ◽  
Vol 178 (1) ◽  
pp. jgs2019-157 ◽  
Author(s):  
M. Ford ◽  
J. Vergés
Keyword(s):  
Sedimentary Cover ◽  
Google Earth ◽  
Rift System ◽  
Content Type ◽  
The North ◽  
Deep Faults ◽  
Supplementary Material ◽  
Uplift And Erosion ◽  
Rifted Margin ◽  
Early Late

In this field study we reinterpret the narrow eastern North Pyrenean Zone, France, as an inverted salt-rich transtensional rift system based on identification of halokinetic depositional sequences across rift platform to distal rift margin domains with a cumulative throw of >2.8 km on steep Cretaceous faults. The rift platform records extension on detached rotational faults above Triassic evaporites from Jurassic to Aptian with uplift and erosion during the Albian. Transtensional Aptian–Albian minibasins align along the salt-rich rift margin fault zone. In the Aptian–Albian main rift large en echelon synclinal minibasins developed between salt walls, although Jurassic diapiric evolution is likely. Upper Cretaceous units locally record continuing diapirism. The Boucheville and Bas Agly depocentres, altered by synrift HT metamorphism, form the distal rift domain terminating south against the North Pyrenean Fault. The narrowness of the Pyrenean rift, shape of minibasins, en echelon oblique synclinal depocentres and folds coupled with a discontinuous distribution and intensity of HT metamorphism support a transtensional regime along the Iberia–Europe plate margin during late Early and early Late Cretaceous. In this model, the distal European margin comprises deep faults limiting laterally discontinuous crustal domains and ‘hot’ pull-apart basins with mantle rocks directly beneath sedimentary cover.Supplementary material: A table summarizing the stratigraphy of the NE Pyrenees and an interpreted Google Earth view of the Quillan syncline and minibasin are available at https://doi.org/10.6084/m9.figshare.c.5100036

scholarly journals Pore scale assessment of subsurface carbon storage potential: implications for the UK Geoenergy Observatories project

2021 ◽  
pp. petgeo2020-092
Author(s):  
Ryan L. Payton ◽  
Mark Fellgett ◽  
Brett L. Clark ◽  
Domenico Chiarella ◽  
Andrew Kingdon ◽  
...  
Keyword(s):  
Carbon Storage ◽  
Co2 Storage ◽  
Rock Physics ◽  
Total Porosity ◽  
Core Material ◽  
Pore Scale ◽  
Content Type ◽  
Link Type ◽  
Supplementary Material ◽  
The Uk

The growing importance of subsurface carbon storage for tackling anthropogenic carbon emissions requires new ideas to improve the rate and cost of carbon capture and storage (CCS) project development and implementation. We assess sandstones from the UK Geoenergy Observatories (UKGEOS) site in Glasgow, UK and the Wilmslow Sandstone Formation (WSF) in Cumbria, UK at the pore scale to indicate suitability for further assessment as CCS reservoirs. We measure porosity, permeability and other pore geometry characteristics using digital rock physics techniques on micro computed tomographic images of core material from each site. We find the Glasgow material to be unsuitable for CCS due to very little porosity—up to 1.65%—whereas the WSF material showed connected porosity up to 26.3% and permeabilities up to 6040 mD. Our results support the presence of a percolation threshold at 10% total porosity, introducing near full connectivity. We find total porosity varies with permeability with an exponent of 3.19. This provides reason to assume near full connectivity in sedimentary samples showing porosities above this threshold without the need for expensive and time consuming analyses.Supplementary material: Information about the boreholes sampled in this study, additional well logs of both boreholes and a summary of the supporting data plotted throughout this article from literature is available at https://doi.org/10.6084/m9.figshare.c.5260074.Thematic collection: This article is part of the Geoscience for CO2 storage collection available at: https://www.lyellcollection.org/cc/geoscience-for-co2-storage

Testing the relationship between marine transgression and evolving island palaeogeography using 3D GIS: an example from the Late Triassic of SW England

2021 ◽  
pp. jgs2020-158
Author(s):  
Jack Lovegrove ◽  
Andrew J. Newell ◽  
David I. Whiteside ◽  
Michael J. Benton
Keyword(s):  
Geographical Information Systems ◽  
Major Change ◽  
Geographical Information ◽  
Late Triassic ◽  
Irish Sea ◽  
Content Type ◽  
The North ◽  
Species Area ◽  
Supplementary Material ◽  
The Uk

The Rhaetian transgression marked a major change in landscape. The Permian and Triassic had been a time of terrestrial conditions across Europe, including much of mainland UK, as well as the North Sea and Irish Sea, represented by red bed clastic successions. Seas flooded across Europe at 205.7 Ma and the shift from terrestrial to marine environments is marked in the UK by the switch from the red beds of the Mercia Mudstone Group to the black mudstones and shelly limestones and sandstones of the Penarth Group. The area around Bristol was marked by a complex landscape in which an archipelago of islands of Carboniferous limestone was formed in the new shallow seas. The application of new methods in geographical information systems allows a detailed exploration of a number of conformable surfaces, the unconformity between the underlying Paleozoic rocks and the overlying Mesozoic strata, as well as levels within the latest Triassic sediments, marking the advance of the sea and interactions with the coeval tectonics, which caused some islands to rise and some basins to descend. The new geographical information system models show a sequence of palaeogeographical reconstructions of the archipelago and relate this to the island tetrapod faunas, which show strong evidence of the species–area effect.Supplementary material: Supplementary tables S1-S6 and 2D island map GIS files are available at https://doi.org/10.6084/m9.figshare.c.5273256

Field map

2003 ◽  
Vol 20 (1) ◽  
pp. 62.2-62
Keyword(s):  
North Sea ◽  
Oil And Gas ◽  
Median Line ◽  
The South ◽  
Moray Firth ◽  
The Uk ◽  
Central North Sea ◽  
International Border

AbstractMap depicting the position and names of the main oil and gas producing fields located in the South Viking Graben, Inner and Outer Moray Firth Basins and Central Graben areas of the Central North Sea. The international border (median line) between the UK and Norway is highlighted as are the producing fields in the Norwegian sector. The boxed areas show the extent of licensed acreage in the region.

The Captain Field, Block 13/22a, UK North Sea

2020 ◽  
Vol 52 (1) ◽  
pp. 705-716 ◽  
Author(s):  
B. Hodgins ◽  
D. J. Moy ◽  
P. A. Carnicero
Keyword(s):  
North Sea ◽  
Oil Recovery ◽  
Upper Jurassic ◽  
Peak Oil ◽  
Average Production ◽  
Chemical Eor ◽  
Moray Firth ◽  
Continuous Application ◽  
Total Oil ◽  
The Uk

AbstractThe Captain Field in Block 13/22a is in the Moray Firth region of the UK North Sea. The primary reservoirs are Lower Cretaceous turbidite sandstones of the Captain Sandstone Member. Upper Jurassic shallower-marine Heather Formation sandstones of Oxfordian age provide a secondary reservoir. Total oil in place exceeds 1 Bbbl; however, the oil is heavy and viscous, requiring the continuous application of innovative technologies to maximize economic recovery from the field. Captain has been producing since 1997, with reservoir waterflood planned from the outset. Captain has been developed using long horizontal producers to maximize reservoir contact. Water injectors provide pressure support, with the aim of full voidage replacement. The Captain development has been phased with facilities consisting of two bridge-linked platforms, a floating production, storage and offloading vessel, and two subsea manifolds. Peak oil rate (100 000 boepd) was achieved in 2002. Average production in 2019 was 28 000 boepd. Captain is executing a chemical enhanced oil recovery (EOR) project, a first for the UK North Sea. Conventional waterflood yields an estimated ultimate recovery of 30–40%. Chemical EOR is expected to improve this by 5–20% in areas of the reservoir under polymer flood.

Field map

2003 ◽  
Vol 20 (1) ◽  
pp. 394-394
Keyword(s):  
North Sea ◽  
Oil And Gas ◽  
Median Line ◽  
The South ◽  
Moray Firth ◽  
The Uk ◽  
Central North Sea ◽  
International Border

AbstractMap depicting the position and names of the main oil and gas producing fields located in the South Viking Graben, Inner and Outer Moray Firth Basins and Central Graben areas of the Central North Sea. The international border (median line) between the UK and Norway is highlighted as are the producing fields in the Norwegian sector. The boxed areas show the extent of licensed acreage in the region.

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