bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Petronella Field, Block 14/20b, UK North Sea
Authors: Waddams P. , Clark N. M. 
Published: April 2008

Abstract
Petronella Field is a small oil and gas accumulation located 110 miles northeast of Aberdeen in UK Block 14/20b. The field lies on the highest part of the east-west-trending Petronella Ridge approximately 6 miles southwest of the Witch Ground Graben axis. The reservoir is Upper Jurassic in age and lies some 7500 ft below sea level. It comprises shallow marine sandstone of the Piper Formation ('Principal Reservoir Sequence') overlain by deeper marine turbidites ('Hot Lens Equivalent') of the Kimmeridge Clay Formation. The structure is a tilted fault block which is bounded to the north by a major fault system, downthrown to the north. Sandstone units dip to the south and thin or are truncated to the north as a result of erosion of the crest of the structure. Seal is effected by Upper Jurassic siltstone and Lower Cretaceous calcareous claystone. The accumulation has been sourced from maturation of the Kimmeridge Clay Formation below approximately 10000 ft in adjacent basins. The Field was discovered in February 1975 and is delineated by six wells. Current production of 13 000 BOPD comes from one well and uses an innovative remote subsea system controlled from, and with pipelines to, the Tartan Platform 6.4 miles to the east. Ultimate recoverable reserves from the main portion of the Field are 17 MMBBL of crude oil.
The Amethyst Field, Blocks 47/8a, 47/9a, 47/13a, 47/14a, 47,15a, UK North Sea
Authors: Garland C. R. 
Published: April 2008

Abstract
The Amethyst gas field was discovered in 1970 by well 47/13-1. Subsequently it was appraised and delineated by 17 wells. It consists of at least five accumulations with modest vertical relief, the reservoir being thin aeolian and fluviatile sandstones of the Lower Leman Sandstone Formation. Reservoir quality varies from poor to good, high production rates being attained from the aeolian sandstones. Seismic interpretation has involved, in addition to conventional methods, the mapping of several seismic parameters, and a geological model for the velocity distribution in overlying strata.
Gas in place is currently estimated at 1100 BCF, with recoverable reserves of 844 BCF. The phased development plan envisages 20 development wells drilled from four platforms, and first gas from the 'A' platforms was delivered in October 1990. A unitization agreement is in force between the nine partners, with a technical redetermination of equity scheduled to commence in 1991.
The Barque Field, Blocks 48/13a, 48/14, UK North Sea
Authors: Farmer R. T. , Hillier A. P. 
Published: April 2008

Abstract
The Barque Field is associated with some of the earliest gas discoveries in the southern North Sea. In the Sole Pit area the reservoir, the Rotliegend Group Leman Sandstone Formation of Lower Permian age, occurs between Carboniferous Coal Measures, which source the gas, and Zechstein evaporites which form an excellent seal. Primarily aeolian, the sandstone has very low permeability resulting from deep burial of the Sole Pit Trough. The deepest burial and hence the maximum diagenetic damage to the reservoir was achieved in the early Late Cretaceous prior to the two-fold main phases of inversion in Late Cretaceous and Mid-Tertiary.
Compaction and diagenesis reduced reservoir permeability to such an extent that parts of the field would be non-productive were it not for the presence of effective natural fracture zones and well stimulation by hydraulic fracturing techniques. Though appraisal and evaluation have been relatively extensive, remaining uncertainties dictate a conservative development in conjunction with the adjacent Clipper Field. A selected initial area was developed for first gas in October 1990. Good reservoir performance may lead to later development of the whole field.
The Esmond, Forbes and Gordon Fields, Blocks 43/8a, 43/13a, 43/15a, 43/20a, UK North Sea
Authors: Ketter F. J. 
Published: April 2008

Abstract
The three separate fields, Esmond, Forbes and Gordon form the Esmond Gas Complex in Quadrant 43 in the UK Southern North Sea. The Bunter Sandstone Formation is the reservoir in each of the separate, seismically defined, simple, anticlinal structures. The Bunter Sandstone correlates well across the three structures and is composed of a 400-500 ft thick interval containing individual channel sandstones deposited in an arid environment on an alluvial fan. Porosity and permeability are controlled by original texture and by subsequent diagenesis. Reservoir communication within the Bunter reservoir is good though locally tortuous.
First gas production started in July 1985. Four offshore installations have allowed gas to be produced at full contract (plateau) rates of 200 MMSCFD without major interruption. Ultimate sales gas reserves are approximately 530 BCF.
Ravenspurn South Field, Blocks 42/29, 42/30, 43/26, UK North Sea
Authors: Heinrich R. D. 
Published: April 2008

Abstract
The Ravenspurn South Gas Field is located in the Sole Pit Basin of the Southern North Sea in UKCS Block 42/30, extending into Blocks 42/29 and 43/26. The gas is trapped in sandstones of the Permian Lower Leman Sandstone Formation, which was deposited by aeolian and fluvial processes in a desert environment. Reservoir quality is poor, and variations are mostly facies-controlled. The best reservoir quality occurs in aeolian sands wth porosities of up to 23% and permeabilities up to 90 md. The trap is a NW-SE-striking faulted anticline: top seal is provided by the Silverpit Shales directly overlying the reservoir, and by Zechstein halites. Field development began early in 1988 and first gas was delivered in October 1989. Production is in tandem with the Cleeton Field, about 5 miles southwest of Ravenspurn South, as the Villages project. Initial reserves are 700 BCF and field life is expected to be 20 years.
Unravelling dates through the ages: geochronology of the Scottish metamorphic complexes
Authors: Rogers G. , Pankhurst R.J. 
Published: April 2008

Abstract

The paper by Giletti
et al.
(1961) is seen as a major landmark in the evolution of dating techniques in polymetamorphic terrains. We consider certain critical issues from each of the main complexes of the Scottish Highlands studied by Giletti et al. to illustrate how subsequent developments in geochronological methodology have influenced our understanding of metamorphic belts. Lewisian examples focus on the formation of Archaean crust, and the age of the main high-grade metamorphism and the Scourie dyke swarm. The antiquity of Moinian sedimentation, its relationship to the Torridonian sandstones, and the timing of Precambrian metamorphism have been controversial issues. The timing and nature of Caledonian orogenesis, most clearly expressed in the Dalradian complex, have been the focal points for the refinement of radiometric investigation. These complexes have been subject to successive developments in methodology, with ever-tighter constraints from Rb-Sr and K-Ar mineral dating, through Rb-Sr and Pb-Pb whole-rock studies, U-Pb dating of bulk zircon fractions, and Sm-Nd whole-rock and mineral investigation, up to the latest technologies of single-grain zircon and ion microprobe analysis. The rocks have released their secrets reluctantly, and many of the questions posed in 1961 have still not been definitively answered. However, the hope of unambiguous solution leads towards greater efforts, ever more reliable data, and a clearer evolutionary picture.
The Lofoten Drift, Norwegian Sea
Authors: Laberg Jan Sverre , Vorren Tore O. , Knutsen Stig-Morten 
Published: April 2008

Abstract

The Lofoten Contourite Drift is located below

c

. 1000 m water depth on the continental slope off northern Norway. It has a maximum thickness of about 360 m and correlation to published seismic stratigraphy implies a Neogene age. The drift probably originated from the deposition of suspended sediments derived from winnowing of the shelf and upper slope. The geometry of the uppermost part of the drift is characterised by maximum thickness at the mound crest, which implies that it is probably presently active. Within gravity core JM97-950/1 (1160 m water depth), the upper 86 cm represents sediments resulting from Holocene winnowing of the shelf and upper slope. The underlying sediments, to 5.5 m core depth, were deposited in a late Weichselian glacimarine environment as revealed by its content of ice-rafted debris and the dating results. Late Weichselian drift growth is consistent with a circulation system transporting surface water northeastward along the continental margin of Norway also during the Weichselian. The downslope sediment input to the study area was probably relatively low during glacial periods due to the evolution of the nearby mainland area, the Lofoten Islands. These islands may have acted as a sediment barrier causing large fluvial and/or glacial drainage systems from central Fennoscandia to be routed south and north of the study area. As a result, alongslope sediment transport has provided the main sediment input to this part of the continental slope.
Muddy contourites in the Baltic Sea: an example of a shallow-water contourite system
Authors: Sivkov Vadim , Gorbatskiy Vladimir , Kuleshov Alexey , Zhurov Yury 
Published: April 2008

Abstract
Bottom currents in the Baltic Sea have had a pronounced effect on the nature and distribution of sediments throughout the Holocene. Due to the intermittent nature of water exchange between the North and the Baltic Seas, the flow of bottom currents is impermanent. Well-developed nepheloid layers are commonly associated with these bottom currents, and provide evidence that active re-suspension and sediment transport is taking place. Periodically intensified inflow from the North Sea through the Baltic Sea gateway has led to erosion of narrow elongate channels, and associated deposition of small elongate patch drifts and contourite levees. The latter two are best developed on the left flanks of the channels. As a result of strong lateral sediment transport, the overall thickness of muddy contourite layers increases towards the steeper slopes of the sea which are situated on the right-hand side of the inflows. Muddy contourites of the Baltic Sea are predominantly terrigenous in composition, made up of soft, black sulphidic muds that are enriched in organic carbon and manganese. Both enrichments are caused by high biological productivity and periodic stagnation of near-bottom waters. Atypically for most oceanic contourites, these shallow-water organic-rich contourites are finely laminated and generally unbioturbated.
Faro-Albufeira drift complex, northern Gulf of Cadiz
Authors: Stow Dorrik A. V. , Faugères Jean-Claude , Gonthier Eliane , Cremer Michel , Llave Estefania , Hernández-Molina F. J. , Somoza Luis , Díaz-Del-Río V. 
Published: April 2008

Abstract

The northern margin of the Gulf of Cadiz is swept by Mediterranean Outflow Water between about 500 and 1000 m water depth. This warm, saline, thermohaline, bottom current attains velocities in excess of 1 m s
-1
through the narrow and relatively shallow Gibraltar gateway, and then descends and slows as it moves towards the north and west around the Iberian margin. It was established in its present form in the latest Miocene, following tectonic re-opening of the Gibraltar gateway, and has since helped to sculpt the slope region in conjunction with downslope processes and diapiric intrusion. The principal area of contourite deposition, up to 600 m in thickness, is the Faro-Albufeira drift complex in a mid-slope setting some 30 km south of Faro. This comprises an elongate low-mounded drift (Faro-Albufeira) and adjacent broad sheeted drifts (Faro and Bartolomeu Dias Planaltos), flanked and partly dissected by deep, erosional, bottom-current channels and buried channels. The seismic character is one
of progradational-aggradational depositional units with laterally extensive sub-parallel reflectors, widespread discontinuities and a large-scale cyclicity in seismic facies. The upper 10 m of cored section comprises muddy, silty and sandy contourites of mixed terrigenous and biogenic composition, that show small-scale cyclicity in grain size and associated sedimentary features. Rates of accumulation varied from < 1 to 14.5 cm ka
-1
(cores), and 3.5 to 29.5 cm ka
-1
(seismics). The large and small-scale cyclicity noted can be related to fluctuation in bottom current velocity related to climate and sea-level changes, although the precise correlation between these events remains uncertain.
The Vema contourite fan in the South Brazilian basin
Authors: Faugères Jean-Claude , Zaragosi S. , Mézerais M. L. , Massé L. 
Published: April 2008

Abstract

The Vema
contourite fan
is a Neogene mud-rich accumulation (200-400 m thick), fed by Antarctic Bottom Water bottom currents and located downstream of the Rio Grande Rise. It forms one single, mounded, fan-shaped body deposited between two major channels through which the main part of the deep AABW circulation is funneled. A suite of cores and seismic lines have been collected over the whole area. The sediments deposited below the shear zone between the two current branches consist almost exclusively of muddy contourites, either homogeneous in structure or micro-brecciated. Manganiferous deposits occur in the vicinity of the channels and on the channel floors. As a result of the morphological and hydrological background, the contourite drift has prograded mostly downstream. It is composed of several depositional units bounded by widespread discontinuities showing erosional patterns. This geometry results from an alternation of episodes of strong and unstable erosive currents, and periods of relatively weak and stable depositional currents
Mixed biosiliceous-terrigenous sedimentation under the Antarctic Circumpolar Current, Scotia Sea
Authors: Pudsey Carol J. , Howe John A. 
Published: April 2008

Abstract
Sediment supply to the Scotia Sea is controlled by the east-flowing Antarctic Circumpolar Current (ACC) with some Weddell Gyre influence in the south. Near-bottom flow is unsteady with frequent changes in flow direction and episodic benthic storms. Near the North Scotia Ridge, mounds of sediment up to 1 km thick have accumulated on lower Miocene ocean floor. The basins farther south contain up to 2 km of sediment which is flat-lying or draped rather than mounded. Sediment cores exhibit a biogenic-terrigenous cyclicity related to glacial-interglacial cycles. Grain-size data suggest that ACC flow was stronger during glacials than interglacials.
Current controlled deposition on the Wilkes Land continental rise, Antarctica
Authors: Escutia C. , Nelson C. H. , Acton G. D. , Eittreim S. L. , Cooper A. K. , Warnke D. A. , Jaramillo J. M. 
Published: April 2008

Abstract
Turbidite, contourite and hemipelagic deposition are the main components of Wilkes Land continental rise sedimentation above the regional unconformity WL2. On the continental shelf, unconformity WL2 marks the start of shelf progradation, which is interpreted to correspond with the onset of glacial conditions in this segment of the east Antarctic margin. Unusually large (i.e. up to 900 m relief and 18 km between levee crests) channel-levee deposits, and high relief (up to 490 m) mounded contourite-style deposits develop above unconformity WLlb. Unconformity WLlb overlies unconformity WL2 and is interpreted to have formed under a fully continental glacial regime where ice streams reached the palaeo-continental shelf edge. Based on an analysis of multichannel seismic profiles and sediment cores, we differentiate three phases in the development of the sedimentary unit between WLlb and the present seafloor. From older to younger these are: Phase 1, dominated by turbidite deposition; Phase 2, dominated by turbidite and contourite deposition with significant mound building; and Phase 3, dominated by turbidite and contourite deposition without active mound building. We hypothesize that building of the mounds during Phase 2 corresponded with times of expansion of the Antarctic ice-sheet when vast amounts of sediment were eroded from the continent and continental shelf. The large amount of unsorted glacial sediment supplied to the outer shelf apparently travelled down the slope canyons and rise channels as turbidity current flows to feed the usually large continental rise channel-levee complexes. The suspended fines of the turbidity flows were then entrained in a palaeo-nepheloid layer and carried by the westward flowing palaeo-contour currents until their deposition in the mounds. During Phase 3, sediment supply to the continental rise, although important in volume and capable of turbidite and contour-current deposition, was insufficient to support further building of the mounds. We believe the decrease in sediment supply to the continental rise from Phase 2 to Phase 3 could be the result of a change on sediment depocentres, with most of the sediment supplied to the margin during Phase 3 being trapped on the continental shelf. We believe that ultimately these changes are related to the stage of glacial evolution of the continent.
Neogene contourites, Miura-Boso forearc basin, SE Japan
Authors: Stow Dorrik A. V. , Ogawa Yujiro , Lee In Tae , Mitsuzawa Kyohiko 
Published: April 2008

Abstract
The mid to late Miocene Misaki Formation sediments of the Miura and Boso peninsulas, south central Japan, were deposited in the Pacific-facing forearc region of the proto Izu-Bonin arc at bathyal depths. The hemipelagic background facies, composed mainly of calcareous biogenic and pumiceous voicaniclastic material, are interbedded with thin to thick scoriaceous beds of turbiditic and pyroclastic fall origin. Careful study in the field and in the laboratory of these fine-grained background sediments has revealed the marked influence of bottom currents at certain horizons in producing intervals with distinct muddy contourite characteristics. These include: a general absence of primary structures due to intense bioturbation, some diffuse layering, irregular concentrations of coarser-grained material, sharp and erosive top and bottom lamina contacts, rare micro-cross-lamination disrupted by bioturbation that was continuous with deposition, and a mixed pelagic biogenic (commonly fragmented), volcaniclastic and terrigenous composition. Small-scale cyclicity of variations in grain-size and structural features can be related in part to episodic volcaniclastic input and in part to fluctuation in bottom current strength. Evidence for bottom current reworking of the tops of thin-bedded sandy turbidites is equivocal, and further work is required to resolve this debate. The recognition of Miocene-age contourites from the NW Pacific provides further evidence for the existence of active deep-ocean circulation in the Pacific at this time. However, it is not possible to determine which current system, Antarctic Bottom Water or deep Kuroshio Current, was responsible for these outcrop examples of fossil contourites.
Kuroshio Current-influenced sandy contourites from the Plio-Pleistocene Kazusa forearc basin, Boso Peninsula, Japan
Authors: Ito Makoto 
Published: April 2008

Abstract
Lithofacies features of bottom current influenced deep-sea sandy deposits (sandy contourites) have been studied by detailed outcrop analyses of the Plio-Pleistocene infill of the Kazusa forearc basin on Boso Peninsula, Japan. Sandy contourites are characterized by traction structures, such as parallel lamination and ripple cross-lamination, together with minor inverse grading and wave ripple-lamination. Ripple cross-lamination is commonly associated with mud drapes and flaser and lenticular bedding. These sedimentary structures do not display any regular vertical sequences. Sandy contourites are commonly associated with turbidites and comprise turbidite-to-contourite continuums. In general, sandy contourites are better sorted than associated turbidites and have sharp or gradational basal contacts with underlying turbidites or hemipelagites, and sharp upper contacts with overlying hemipelagites. The framework composition of sandy contourites, in contrast, is largely equivalent to that of the associated turbidites. Palaeocurrent directions of sandy contourites are variable in time and space and alongslope- and upslope-directed palaeocurrents are dominant. Turbidite-to-contourite continuums show spatial and temporal variation in bed thickness and lithofacies features. These variations suggest varying intensity of deep-sea bottom currents in the Kazusa forearc basin. Analogous flow conditions have been documented from the modern, deep-water mass of the Kuroshio Current. Thus, the observed variations in lithofacies features and palaeocurrents of turbidite-to-contourite continuums can best be interpreted in terms of fluctuating strength of the deep-water palaeo-Kuroshio bottom current during the Pliocene through Pleistocene
UK Oil and Gas Fields - An Overview
Authors: Gluyas J. G. , Hichens H. M. 
Published: April 2008

Abstract

This volume was conceived when one of us (JG) returned to the UK in mid-1996. Having not worked the UK offshore since the late 1980s it was clear that there had been many changes, not least in the number of fields on production. During that first year back in the UK, JG's copy of Abbots (1991)
UK Oil and Gas Fields, 25 Years Commemorative Volume
became exceedingly well used. A casual comment to Wendy Cawthorne of the Geological Society library to this effect solicited the response that JG was not alone in finding Abbots (1991) useful. Memoir 14 was the Geological Society's 'best seller'. However, although Abbots (1991) continues to sell well, it was by 1996 out of date insofar as it contains papers describing only about half of the fields then on production.

A combination of egotistical zeal, wishing for a bestseller and altruism towards the UK industry led us to make an offer to the Geological Society to revise Memoir 14. The offer was accepted and by April 1998, editors had been appointed and letters of invitation to contribute to the memoir were sent to exploration managers in all the UK operating companies. The responses to those letters were for the most part positive. A request was made to authors for manuscripts to be sent to the editors by June 1999. The first to arrive was six months ahead of schedule (thanks A. Yaliz & N. McKim for their paper on the Douglas Field). However, neither the editors
The Beryl Field, Block 9/13, UK North Sea
Authors: Karasek R. M. , Vaughan R. L. , Masuda T. T. 
Published: April 2008

Abstract
The Beryl Field is located within Block 9/13 in the UK North Sea, in the west central part of the Viking Graben. The block was awarded in 1971 to a Mobil operated partnership, and the 9/13-1 discovery well drilled in 1972. The Beryl A platform was installed in 1975 and oil production started up the following year. The Beryl B platform was added in 1983 and production and gas re-injection pressure support commenced in 1984. The first 3D seismic survey was shot over the field in 1986, and the most recent in 1997. As of January 1999, 133 wells have been drilled into the field and development drilling is expected to continue well into the twenty-first century.
Commercial hydrocarbons occur in sandstone reservoirs ranging in age from Triassic to late Jurassic, with the primary reservoir being the Middle Jurassic Beryl Formation (1.4 billion barrels of oil originally in place). Total ultimate recovery for all reservoirs in the field is expected to be about 960 million barrels of oil (MMBBL) and 2.1 trillion cubic feet (TCF) of gas. As of January 1999, the field has produced nearly 710 MMBBL of oil, or almost 75 % of the ultimate oil recovery.
The field has been described previously by Knutson and Munro (1991), and Robertson (1993). Recent drilling data (more than 30 new wells) and new 3D seismic have updated the initial field descriptions. These data allow the mapping of two key unconformities, the Mid Cimmerian (Jt) event and a Base Callovian (Jb3) event. Reservoir facies models and isochore maps have also been developed, which together with the refined structural model, allow a better understanding of the reservoir distributions and will guide future production strategies.