New Insights into the Structure, Geology and Hydrocarbon Prospectivity along the Central-Northern Corona Ridge, Faroe-Shetland Basin

Acknowledgements This paper forms part of the lead author’s Ph.D. research conducted as part of the Natural Environment Research Council (NERC) Centre for Doctoral Training (CDT) in Oil and Gas at the University of Aberdeen. It is funded by the University of Aberdeen and sponsored by Total E&P UK Limited, whose support is gratefully acknowledged. PGS are thanked for the generous provision of the FSB MegaSurveyPlus seismic dataset to the Ph.D. project and also for permission to publish part of the dataset (Fig. 3). This paper contains information provided by the North Sea Transition Authority and/or other third parties. Seismic data used throughout this paper were purchased from the UK North Sea Transition Authority (NSTA) National Data Repository (NDR) portal. Well data used throughout this paper are freely available and can be downloaded from the UK NSTA NDR portal. Core photographs were obtained from the BGS Offshore well database. Seismic interpretation was undertaken using Schlumberger Petrel software and well log interpretation was performed using Schlumberger Techlog software, of which academic licenses were kindly provided by Schlumberger and are gratefully acknowledged. Thanks to Conrado Climent, Ole-Petter Hansen, Michael Hertle, Anders Madsen, and Stuart Archer for invaluable discussions during the lead author’s time spent working with TotalEnergies in Copenhagen. Thanks also to Christopher Bugg and Matthew Rowlands at TotalEnergies in Aberdeen. Reviewers Tony Doré, Peter Dromgoole and Clayton Grove are thanked for their detailed constructive reviews which improved this manuscript. The views held within this paper do not necessarily represent the views of Schlumberger, TotalEnergies and Ørsted. Funding: The University of Aberdeen (grant number: RT10121-14), Natural Environment Research Council Centre for Doctoral Training (CDT) in Oil and Gas (grant number: NE/M00578X/1) and Total E&P UK Limited. Principal award-recipient: Lucinda Kate Layfield.Peer reviewedPublisher PD

3D Seismic reflection evidence for lower crustal intrusions beneath the Faroe–Shetland Basin, NE Atlantic Margin

Lower crustal intrusion is considered to be a common process along volcanic or magma-rich passive margins, including the NE Atlantic Margin, where it is thought to have occurred during phases of Paleogene magmatism, both prior to and during continental break-up between NW Europe and Greenland. Evidence of Paleogene magmatism is prevalent throughout the sub-basins of the Faroe–Shetland Basin as extensive lava flows and pervasive suites of igneous intrusions. However, in contrast with other areas located along the NE Atlantic Margin, no lower crustal reflectivity indicative of lower crustal intrusion has been documented beneath the Faroe–Shetland Basin. The nearest documentation of lower crustal reflectivity and interpretation of lower crustal intrusion to the Faroe–Shetland Basin is NW of the Fugloy Ridge, beneath the Norwegian Basin of the Faroese sector. Despite this, the addition of magma within the lower crust and/or at the Mohorovičić discontinuity is thought to have played a part in Paleogene uplift and the subsequent deposition of Paleocene–Eocene sequences. Advances in sub-basalt seismic acquisition and processing have made significant improvements in facilitating the imaging of deep crustal structures along the NE Atlantic Margin. This study used broadband 3D seismic reflection data to map a series of deep (c. 14–20 km depth) high-amplitude reflections that may represent igneous intrusions within the lower crust beneath the central-northern Corona Ridge. We estimate that the cumulative thicknesses of the reflections may be >5 km in places, which is consistent with published values of magmatic underplating within the region based on geochemical and petrological data. We also estimate that the total volume of lower crustal high-amplitude reflections within the 3D dataset may be >2000 km3. 2D gravity modelling of a seismic line located along the central-northern Corona Ridge supports the interpretation of lower crustal intrusions beneath this area. This study provides evidence of a potential mechanism for Paleogene uplift within the region. If uplift occurred as a result of lower crustal intrusions emplaced within the crust during the Paleogene, then we estimate that c. 300 m of uplift may have been generated within the Corona Ridge area

Halokinetic modulation of sedimentary thickness and architecture: A numerical modelling approach

From Wiley via Jisc Publications RouterHistory: received 2021-02-12, rev-recd 2021-04-23, accepted 2021-04-27, pub-electronic 2021-07-03Article version: VoRPublication status: PublishedFunder: Natural Environment Research Council; Id: http://dx.doi.org/10.13039/501100000270; Grant(s): NEM00578X/1Abstract: Subsurface salt flow can deform overlying strata and influence contemporaneous sedimentary systems. Studying salt‐sediment interactions is challenging in the subsurface due to poor imaging adjacent to salt, and in the field due to the dissolution of halite. Discrete Element Modelling provides an efficient and inexpensive tool to model stratigraphy and deformation around salt structures, which is advantageous over other modelling techniques as it realistically recreates brittle processes such as faulting. Six 2D experiments were run representing 4.6 Myr to determine the effect of salt growth on syn‐kinematic stratigraphy. Halokinetic deformation of stratigraphic architecture was assessed by varying sediment input rates through time. Results show the realistic formation and evolution of salt‐related faults which define a zone of halokinetic influence ca. 3 times the width of the initial diapir. Outside of this, early diapiric and syn‐kinematic stratigraphy are undeformed. Within this zone, syn‐kinematic strata are initially isolated into primary salt withdrawal basins, onlapping and thinning towards the salt‐cored high. In most models, syn‐kinematic strata eventually thin across and cover the diapir roof. Thinning rates are up to six times greater within 350 m of the diapir, compared to further afield, and typically decrease upwards (with time) and laterally (with distance) from the diapir. Outputs are compared to a subsurface example from the Pierce field, UK North Sea, which highlights the importance of considering local fluctuations in diapir rise rate. These can create stratigraphic architectures that may erroneously be interpreted to represent increases/decreases in sedimentation rate. Exposed examples, such as the Bakio diapir, northern Spain, can be used to make inferences of the expected depositional facies, below model resolution. Our models aid the prediction of sedimentary unit thickness and thinning rates and can be used to test interpretations arising from incomplete or low‐resolution subsurface and outcrop data when building geological models for subsurface energy

An integrated characterisation of the Paleocene Submarine Fan Systems (Lista and Maureen Formations) in the central Graben of the North Sea

The Paleocene submarine fans of the Central Graben represent important petroleum reservoir units recording the cyclic input of sand-rich turbidity flows into the post-rift basin. Provision of extensive seismic (a subset of ~l5000 km" of the PGS Central North Sea MegaSurvey), well (n = 549) and core (n = 28, totalling ~2760 feet/84l m) datasets by Shell UI Europe enabled a regional-scale re-evaluation of these deposits. This thesis presents new models illustrating the distribution and quality of the Maureen and Lista Formation sandstones and the syn- and post-depositional controls on these deposits. The Lista Formation sandstones occur within northwest (channelised, proximal, ~300 feet net) to southeast (sheet-like, distal, ~50 feet net) trending (axial) fans with western/eastern fairways and minor sidefan sedimentation (west/east). Four sand-rich to sand-poor facies are defined, with distinct grain size distributions. Mean grain size is the main control on porosity and permeability. Progradation occured between the Ll and L2 units with retrogradation in the L3. This variability, and internal porosity trends, is linked to global sea level change. Characterisation of the Maureen Formation sandstones is complicated by the presence of variable chalk facies derived from turbidite, debris flow and pelagic processes. However, these deposits can still be classified in a similar manner to the Lista Formation and exhibit similar spatial distributions, although the sandstones are thinner ~125 feet in the northwest to 25 feet in the southeast, suggesting that similar depositional controls were active. Sandstone quality is controlled by grain size (with calcitisation also important) although the porosity/permeability values are lower than in the Lista Formation. Progradation occured between the TlO and T20/30 sequences with retrogradation in the T35. The current MlIM2 divisions do not describe the complexity of this formation. The routing of the sandstones was defined by the relict graben structure with offset stacking an additional local control. Routing from the shelf to the basin was controlled by global sea level change. Although these systems are often labelled as basin floor fans they do not resemble classical examples, thanks to their confined nature.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The spatial distribution of igneous centres along the Norwegian Atlantic Margin (Møre and Vøring) and their relationship to magmatic plumbing systems

ACKNOWLEDGEMENTS The authors would like to thank A/S Norske Shell for permission to publish this work. Kari Berge, Petter Frantzen, Christian Gibson, and John Keating are thanked for their support, and Sonya Eide is recognised for her mapping help. Tony Doré, Craig Magee and Christian Berndt are thanked for their constructive reviews which greatly improved the manuscript and Douglas Watson is acknowledged for his input on seminal papers. Workers such as Sverre Planke and Laurent Gernigon are thanked for their fundamental contributions to the literature which has made this work possible. All observation and interpretation work were undertaken in Schlumberger‟s Petrel 2018 software with supporting material in ESRI‟s ArcMap 10.4.1. Seismic data examples are from released datasets. Bouguer gravity residual products are sourced from TGS (licenced by A/S Norske Shell) and the Gravimetric Bureau (freely available to the University of Aberdeen). Magnetic regional grids are sourced from Frogtech Geoscience (licenced by A/S Norske Shell). Funding was provided by A/S Norske Shell.Peer reviewedPostprin

The Impacts of Igneous Systems on Sedimentary Basins and their Energy Resources

Igneous processes within sedimentary basins impact energy resource plays across a range of scales from regional tectonics to reservoir porosity. Understanding these interactions has a direct influence on hydrocarbon, carbon capture, geothermal, hydrogen and helium projects. This volume demonstrates state of the art thinking around these often complex systems