Norwegian Petroleum Directorate

Stavanger, Norway

Norwegian Petroleum Directorate

Stavanger, Norway
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Glorstad-Clark E.,University of Oslo | Faleide J.I.,University of Oslo | Lundschien B.A.,Norwegian Petroleum Directorate | Nystuen J.P.,University of Oslo
Marine and Petroleum Geology | Year: 2010

A sequence stratigraphic framework of the Triassic on the Norwegian Barents shelf is presented. The Triassic succession was subdivided into five second-order sequences based on facies analysis of 2D seismic data constrained by well data. The sequences were separated by maximum flooding surfaces that correlate seismically for hundreds of kilometers.The Mesozoic succession in the Barents Sea was deposited in a shallow epicontinental seaway, and shows a gradual infill of the basin throughout the Triassic, progressively prograding further west and northwest with time. The NW Barents Sea remained distal to main sediment supply until accommodation space was filled in further south, and prograding seismic clinoforms from the south and east are observed from Ladinian times. Accommodation space east of Bjørnøya-Sørkapp High was filled during the Late Triassic, sourced from the east, but possibly also from the west. The paleo-Loppa High controlled sediment distribution until early Ladinian times, with one major uplift event in latest Permian and several subsequent minor events of renewed uplift and creation of local source areas as observed from aerially restricted systems prograding from the west to the east. In the Late Triassic, paleo-Loppa High area became one of the main depocenters, responding to extension in the North Atlantic system to the west. Clinoform geometries were developed west of the high and towards the Bjørnøya Basin. Multiple clinoform units prograding from west to east was identified on top of the paleo-Loppa High in the Upper Triassic, representing a source area to the west.Within each sequence, maximum progradation and retrogradation were mapped out and discussed in terms of reservoir, seal and source rock development. Sediment accommodation space was locally controlled by salt mobilization and differential subsidence across Late Paleozoic faults. The Triassic second-order flooding surfaces are interpreted to be controlled by global and/or regional tectonics. © 2010 Elsevier Ltd.

Furnes H.,University of Bergen | de Wit M.J.,University of Cape Town | Robins B.,University of Bergen | Sandsta N.R.,Norwegian Petroleum Directorate
Precambrian Research | Year: 2011

The volcanic stratigraphy of the upper Onverwacht Suite in the southeastern part of the Paleoarchean Barberton Greenstone Belt has been investigated in 18 sections through parts of the Hooggenoeg, Kromberg, and lower Mendon Complexes. The ca. 2700. m thick volcanic sequence of the lowest tectonostratigraphic unit - the Hooggenoeg Complex (HC) - can be subdivided into 9 stratigraphic units representing major eruptive phases, each separated by silicified sedimentary and volcaniclastic rocks. The thicknesses of the units vary from <100. m to ∼700. m. Some units are wedge-shaped and die out over distances of a few kilometre along strike. The volcanic rocks are predominantly basaltic lavas, with minor basaltic komatiite and komatiite in the middle part of the HC. The basaltic lavas of the overlying tectonostratigraphic unit, the Kromberg Complex (KC), occur as screens within intrusives, or are in tectonic contact with adjacent rocks. The basal part (Ncakini section) of the tectonostratigraphically uppermost Mendon Complex (MC), consists of Mg-rich basalt lava. The lavas of the HC and KC are predominantly pillowed and massive flows, whereas those of the Ncakini section are exclusively massive. The massive and pillowed lava are commonly organized in cyclic units from 3. m to 32. m thick, and consisting of massive lava or large pillows that are succeeded by progressively smaller pillows. Cyclic units are inferred to have resulted from individual eruptions with decreasing rates of effusion. The pillow lavas of both the HC and KC contain <3-5% vesicles indicating eruption at greater depths than ∼2000. m. In general vesicular pillows occur in the lower part of both the HC and KC, and non-vesicular (and variolitic) lavas are found at the top, suggesting increasing water depths, and hence eruption in a subsiding basin. The chert layers within the HC include silicified tuffs derived from explosive subaerial or shallow-marine eruptions distant from the deep-water lavas of the HC and KC. © 2010 Elsevier B.V.

Halland E.,Norwegian Petroleum Directorate
4th EAGE CO2 Geological Storage Workshop 2014: Demonstrating Storage Integrity and Building Confidence in CCS | Year: 2014

Carbon capture and storage (CCS) is a critical component in a portfolio of low-carbon energy technologies aimed at combating climate change. Given the dominant role that fossil fuels continue to play in primary energy consumption, the urgency of CCS deployment is only increasing. It is important to enable a good understanding for safe design and operation across the whole CCS value chain, with a special focus on the environmental aspects. Copyright © (2014) by the European Association of Geoscientists & Engineers. All rights reserved.

Geissler W.H.,Alfred Wegener Institute for Polar and Marine Research | Jokat W.,Alfred Wegener Institute for Polar and Marine Research | Brekke H.,Norwegian Petroleum Directorate
Geophysical Journal International | Year: 2011

The separation of Northeast Greenland and Svalbard is the result of large-scale strike slip movements during Cenozoic times. Geological evidence for these movements can be found onshore both on North Greenland and Svalbard. However, the role of the submarine Yermak Plateau (YP) in this process is unclear. The compilation of available multichannel reflection and wide-angle seismic data give new insights into the sedimentary and crustal structure and evolution of the plateau. The flat surface of the present-day plateau is a quite young feature. Up to 2 km of Cenozoic sediments cover a rough basement, which show similarities to the rough topography and strike of geological structures of Spitsbergen Island. In some basins more than 4 km of sedimentary rocks could be mapped. The most pronounced structure is the Sverdrup Bank, which appears to be part of a larger crustal block. P-wave velocities of about 4.5 km s-1 derived from sonobuoy data indicate that its uppermost part is most probably composed of sedimentary or volcanic rocks. We have made a correlation of previously defined seismic units across the YP to outline the history of sediment deposition in the area. The existing graben structures on the plateau might have provided early shallow pathways for water exchange between the Arctic and the Atlantic Oceans. A chaotic sedimentary apron east of the Sverdrup Bank and bright reflections near the Mosby Seamount interpreted as magmatic sills suggest tectonic and magmatic events during the Miocene. © 2011 The Authors Geophysical Journal International © 2011 RAS.

Sandsta N.R.,Norwegian Petroleum Directorate | Robins B.,University of Bergen | Furnes H.,University of Bergen | de Wit M.,University of Cape Town
Contributions to Mineralogy and Petrology | Year: 2011

Exceptionally well-preserved pillowed and massive phenocryst-free metabasaltic lava flows in the uppermost part of the Palae pale and dark green metabasalt and was the result of mingling of two types of basalt (Robins et al. in Bull Volcanol 72:579-592, 2010a). Varioles occur exclusively in the dark chlorite-, MgO- and FeO-rich metabasalt. Varioles are absent in the outermost rinds of pillows and increase in both abundance and size towards the centres of pillows. In the central parts of some pillows, they impinge to form homogeneous pale patches, bands or almost homogenous cores. Individual varioles consist essentially of radially orientated or outwardly branching dendritic crystals of albite. Many varioles exhibit concentric zones and finer-grained rims. Some varioles seem to have grown around tiny vesicles and vesicles appear to have been trapped in others between a core and a finer-grained rim. The matrix surrounding the ocelli contains acicular pseudomorphs of actinolite and chlorite after chain-like, skeletal Ca-rich pyroxenes that are partly overgrown by the margins of varioles. Varioles are enriched in the chemical constituents of feldspar but contain concentrations of immobile TiO2, Cr, Zr and REE that are similar to the host metabasalts. The shape, distribution, texture and composition of the varioles exclude liquid immiscibility and support an origin by spherulitic crystallisation of plagioclase from severely undercooled basalt melt and glass. Nucleation of plagioclase was strongly inhibited and took place on vesicles, on the bases of drainage cavities and along early fractures. Eruption in deep water and retention of relatively high concentrations of volatiles in the melt may be the principal cause of spherulitic crystallisation in the interiors of pillows rather than only in their margins as in younger submarine flows. © 2010 The Author(s).

Hoy T.,Norwegian Petroleum Directorate | Lundschien B.A.,Norwegian Petroleum Directorate
Geological Society Memoir | Year: 2011

Seismic sequence interpretation, analysis of shallow boreholes and outcrop studies at Svalbard strongly indicate that the Triassic basin in the northern Barents Sea and eastern Svalbard was supplied by sediments from the south east by a large complex prograding delta system. The seismic facies interpretation suggests that the black Ladinian and Anisian shale (Botneheia Formation) is an integrated part of the prograding delta system and developed as the bottom sets of large pro-delta clinoforms. The clinoforms and their breaking points define a series of seismically detectable sequences at a shelf edge delta. Provenance areas are suggested to be Siberia, the Kola Peninsula and the Caledonides. Each sequence has a maximum thickness of 200-400 m and is interpreted to represent the water depth range in the basin. Seasonal flooding, stratified salinity and algal blooming are assumed to be important factors generating anoxic bottom conditions in a huge death zone in front of the prograding delta system. The folded and thrusted Triassic rocks in the western part of Svalbard are suggested to be part of an allochthonous nappe ejected from the Greenland region when Greenland moved northwards along the Hornsund Fault complex; their original position is suggested to be further south. © 2011 The Geological Society of London.

Eig K.,Norwegian Petroleum Directorate | Bergh S.G.,University of Tromsø
Tectonophysics | Year: 2011

The Lofoten Ridge is a fault-controlled basement horst residing between Mesozoic basins on the North Norwegian passive margin. This major horst and the adjacent offshore basin-bounding normal faults formed during stages of rifting from the Permian-Jurassic to the Early Cenozoic. Well-exposed, heterogeneous NW-SE striking brittle fracture sets have been studied onshore at Moskenes in the western Lofoten islands. This area provides an excellent frame for understanding onshore-offshore fault-fracture correlations and passive margin evolution as inferred from high-quality offshore seismic data. The fracture sets at Moskenes exhibit geometric and kinematic variability, i.e. systematic bisecting (conjugate) fractures, parallel extensional fractures, and anastomosing relay/stepping (shear) fractures. An incremental NW-SE oriented σ1 compressive stress axis and a NE-SW oriented σ3 was inferred from the attitudes of the conjugate fracture sets. The different fracture sets are interpreted to have formed in isolation and/or in a progression through time, as precursory parallel (Mode I) or conjugate fractures (Mode II) and/or more complex anastomosing shear fracture sets (Mode III) due to varying boundary stress conditions as controlling factors, and not by mechanical weaknesses in the host rock. Whether parallel, conjugate, or anastomosing fractures formed depended on the initial spacing of precursory fractures, the timing of development of complementary fractures, and on the evolving strain-stress conditions. In terms of a North Atlantic passive margin stress field, the NW-SE trend of the heterogeneous fractures in western Lofoten is roughly parallel to the Late Cretaceous-Early Cenozoic regional extension directions but oblique to that of the Permian-Jurassic. A switch of the extension direction from WNW-ESE in the Permian-Jurassic to NNW-SSE in the Late Cretaceous, may have initiated multiple reactivations and, e.g. right-lateral shearing along ENE-WSW striking master faults, producing a block-internal NW-SE σ1 in western Lofoten. Alternatively, the fractures formed by reactivation of transfer fault zones between NNE-SSW right-stepping normal faults. A third possibility is origin by Cenozoic ridge push forces, creating neotectonic fractures as a substitute to inversion structures and arc-shaped domes on the Mid-Norwegian margin farther south. © 2010 Elsevier B.V.

Robins B.,University of Bergen | Sandsta N.R.,Norwegian Petroleum Directorate | Furnes H.,University of Bergen | de Wit M.,University of Cape Town
Bulletin of Volcanology | Year: 2010

Well-preserved pillow lavas in the uppermost part of the Early Archean volcanic sequence of the Hooggenoeg Formation in the Barberton Greenstone Belt exhibit pronounced flow banding. The banding is defined by mm to several cm thick alternations of pale green and a dark green, conspicuously variolitic variety of aphyric metabasalt. Concentrations of relatively immobile TiO2, Al2O3 and Cr in both varieties of lava are basaltic. Compositional differences between bands and variations in the lavas in general have been modified by alteration, but indicate mingling of two different basalts, one richer in TiO2, Al2O3, MgO, FeOt and probably Ni and Cr than the other, as the cause of the banding. The occurrence in certain pillows of blebs of dark metabasalt enclosed in pale green metabasalt, as well as cores of faintly banded or massive dark metabasalt, suggest that breakup into drops and slugs in the feeder channel to the lava flow initiated mingling. The inhomogeneous mixture was subsequently stretched and folded together during laminar shear flow through tubular pillows, while diffusion between bands led to partial homogenisation. The most common internal pattern defined by the flow banding in pillows is concentric. In some pillows the banding defines curious mushroom-like structures, commonly cored by dark, variolitic metabasalt, which we interpret as the result of secondary lateral flow due to counter-rotating, transverse (Dean) vortices induced by the axial flow of lava towards the flow front through bends, generally downward, in the tubular pillows. Other pillows exhibit weakly-banded or massive, dark, variolitic cores that are continuous with wedge-shaped apophyses and veins that intrude the flow banded carapace. These cores represent the flow of hotter and less viscous slugs of the dark lava type into cooled and stiffened pillows. © 2010 Springer-Verlag.

News Article | August 29, 2016

The cost for developing a field on the Norwegian continental shelf has declined by around 45% since autumn 2014, according to the Norwegian Petroleum Directorate.

News Article | December 4, 2015

Norway’s 23rd licensing round received applications on 57 blocks or portions of blocks from 26 oil and gas companies, the Norwegian Petroleum Directorate reported on Dec. 4.

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