The Tern Field, Block 210/25a, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 191-198 ◽  
Author(s):  
M. Van Panhuys-Sigler Van ◽  
A. Baumann ◽  
T. C. Holland
Keyword(s):  
North Sea ◽  
Water Contact ◽  
Shetland Islands ◽  
The North ◽  
Initial Stage ◽  
Cumulative Production ◽  
Oil Water ◽  
Northern North Sea ◽  
The Uk ◽  
Complex Faulting

AbstractThe Tern Oilfield is situated 150 km northeast of the Shetland Islands in Block 210/25a in the UK sector of the northern North Sea. The discovery well 210/25-1 was drilled in 1975 in a water depth of about 541 ft. The trap is defined at around 8000 ft TVSS by a tilted horst-structure. The hydrocarbons are contained in reservoirs belonging to the Middle Jurassic Brent Group sands deposited by a wave-dominated delta system in the East Shetland Basin. Complex faulting of the structure is responsible for the division of the field into two areas with different original oil-water contacts: the Main Area of the field with an oil-water contact at 8260 ft TVSS, and the Northern Area with a possible oil-water contact at 8064 ft TVSS. Reservoir quality is good with average porosities ranging from 20-24% and an average permeability of 350 md. The expected STOIIP and ultimate recovery of oil are 452 and 175 MMBBL, respectively which represents a recovery factor of 39%.The initial stage of the development plan calls for ten wells, five oil producers and five water injectors, to be drilled from a single platform, Tern Alpha. Development drilling started in February 1989 and first oil was produced on 2 June 1989. The oil is evacuated via the North Cormorant and Cormorant Alpha platforms into the Brent System pipeline for export to the Sullom Voe terminal.To date, two producers have b een drilled and total cumulative production is 6.4 MMBBL (1 January 1990). Ultimate recovery is estimated to be some 175 MMBBL.

The Flora Field, Blocks 31/26a, 31/26c, UK North Sea

2003 ◽  
Vol 20 (1) ◽  
pp. 549-555 ◽  
Author(s):  
R. D. Hayward ◽  
C. A. L. Martin ◽  
D. Harrison ◽  
G. Van Dort ◽  
S. Guthrie ◽  
...  
Keyword(s):  
North Sea ◽  
Upper Jurassic ◽  
Water Contact ◽  
Upper Carboniferous ◽  
The North ◽  
Recoverable Reserves ◽  
The North Sea ◽  
Oil Water ◽  
The Uk ◽  
Clay Formation

AbstractThe Flora Field straddles Blocks 31/26a and 31/26c of the UK sector of the North Sea on the southern margin of the Central Graben. The field is located on the Grensen Nose, a long-lived structural high, and was discovered by the Amerada Hess operated well 31/26a-12 in mid-1997.The Flora Field accumulation is reservoired within the Flora Sandstone, an Upper Carboniferous fluvial deposit, and a thin Upper Jurassic veneer, trapped within a tilted fault block. Oil is sourced principally from the Kimmeridge Clay Formation of the Central Graben and is sealed by overlying Lower Cretaceous marls and Upper Cretaceous Chalk Group.Reservoir quality is generally good with average net/gross of 85% and porosity of 21%, although permeability (Kh) exhibits a great deal of heterogeneity with a range of 0.1 to <10000mD (average 300 mD). The reservoir suffers both sub-horizontal (floodplain shales) and vertical (faults) compartmentalization, as well as fracturing and a tar mat at the oil-water contact modifying flow and sweep of the reservoir. Expected recoverable reserves currently stand at 13 MMBBL

The MacCulloch Field, Block 15/24b, UK North Sea

2003 ◽  
Vol 20 (1) ◽  
pp. 453-466 ◽  
Author(s):  
C. Gunn ◽  
J. A. MacLeod ◽  
P. Salvador ◽  
J. Tomkinson
Keyword(s):  
North Sea ◽  
Water Contact ◽  
Northern Flank ◽  
Recoverable Reserves ◽  
Average Porosity ◽  
Oil Water ◽  
The Witch ◽  
The Uk ◽  
Clay Formation ◽  
Central North Sea

AbstractThe MacCulloch Field lies within Block 15/24b in the UK Central North Sea and is located on the northern flank of the Witch Ground Graben. It was discovered by Conoco well 15/24b-3 in 1990.MacCulloch Field is a four-way dip closure at Top Paleocene over a deeper Mesozoic structure. The reservoir consists of Upper Balmoral Sandstones containing 32-37° API oils derived from Kimmeridge Clay Formation shales and sealed by shales belonging to the Sele Formation. The field contains recoverable reserves of 60-90 MMBOE.Reservoir quality is generally very good, with an average porosity of 28% and core permeabilities (Kh) between 200 mD and 2D. AVO anomalies and a seismic flat spot are associated with oil filled reservoir and the oil-water contact in certain areas of the field.

The Osprey Field, Blocks 211/18a & 211/23a, UK North Sea*

1991 ◽  
Vol 14 (1) ◽  
pp. 183-189 ◽  
Author(s):  
John W. Erickson ◽  
C. D. Van Panhuys
Keyword(s):  
Crude Oil ◽  
North Sea ◽  
Water Depth ◽  
Middle Jurassic ◽  
Reservoir Quality ◽  
Shetland Islands ◽  
Delta System ◽  
Reservoir Sandstones ◽  
Northern North Sea ◽  
The Uk

AbstractThe Osprey Oilfield is located 180 km northeast of the Shetland Islands in Blocks 211/23a and 211/18a in the UK sector of the northern North Sea. The discovery well 211/23-3 was drilled in January 1974 in a water depth of 530 ft. The trap is defined at around 8500 ft TVSS by two dip and fault closed structures, the main 'Horst Block' and the satellite 'Western Pool'. The hydrocarbons are contained in reservoir sandstones belonging to the Middle Jurassic Brent Group which was deposited by a wave-dominated delta system in the East Shetlands Basin. The expected STOIIP and ultimate recovery are estimated at 158 MMBBL and 60 MMBBL of oil respectively, which represents a recovery factor of 38%. The 'Horst Block' contains 85% of the reserves with an OOWC about 150 ft shallower than in the 'Western Pool'. Reservoir quality is excellent, with average porosities varying from 23-26% and average permeabilities varying from 35-5300 md. The development plan envisages eleven satellite wells, six producers and five water injectors, closely clustered around two subsea manifolds. First production is expected in late 1990/early 1991. The wet crude oil will be piped to the Dunlin 'A' platform for processing and from there to the Cormorant Alpha platform into the Brent System pipeline for export to the Sullom Voe terminal.

The Cormorant Field, Blocks 211/21a, 211/26a, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 73-82 ◽  
Author(s):  
D. J. Taylor ◽  
J. P. A. Dietvorst
Keyword(s):  
North Sea ◽  
Shetland Islands ◽  
The North ◽  
Stock Tank ◽  
Delta System ◽  
The North Sea ◽  
Reservoir Porosity ◽  
The Uk ◽  
Exploration Well ◽  
Water Depths

AbstractThe Cormorant Oilfield is located approximately 150 km northeast of the Shetland Islands in Blocks 211/2la and 211/ 26a of the UK sector of the North Sea, in water depths of 500-550 ft. The field was discovered in 1972 by exploration well 211/ 26-1 and consists of four discrete accumulations spread along a major, north-south trending fault terrace. Hydrocarbons are produced from Middle Jurassic (Bajocian) sands of the Brent Group, which was deposited in a wave-dominated delta system. The reservoir has a typical gross thickness of 250-300 ft, locally increasing to 550 ft over faults active during sedimentation. Reservoir porosity varies from 16-28%, with average permeabilities ranging from tens of md to 1300md. The accumulation contains under-saturated 34-36° API oil which was initially overpressured by some 1000-1270 psi. The stock tank oil initially in place and ultimate recovery are estimated at 1568 MMBBL and 623 MMBBL, respectively, reflecting a recovery factor of 39%. The reserves are produced through crestally-located wells supported by down-dip water injectors, and exported via two fixed platforms and an underwater manifold centre. To date, 59 wells have been drilled and 324 MMBBL (52%) of the estimated reserves have been produced.

scholarly journals Resolving the spatial distributions of Dipturus intermedius and Dipturus batis—the two taxa formerly known as the ‘common skate’

2021 ◽  
Author(s):  
Maisie Bache-Jeffreys ◽  
Bárbara Lins Caldas de Moraes ◽  
Rachel E. Ball ◽  
Gui Menezes ◽  
Jónbjörn Pálsson ◽  
...  
Keyword(s):  
North Sea ◽  
Large Scale ◽  
Species Distribution Modelling ◽  
Distribution Model ◽  
Nominal Species ◽  
Spatial Distributions ◽  
The North ◽  
Control Region Haplotype ◽  
Northern North Sea ◽  
The Uk

AbstractBatoid fishes are among the most endangered marine vertebrates, yet conservation efforts have been confounded by incomplete taxonomy. Evidence suggest that the critically endangered ‘common skate’ actually represents two species: the flapper skate (Dipturus intermedius) and the blue skate (Dipturus batis). However, knowledge of the geographic range of these two nominal species is limited. Here, DNA sequencing is used to distinguish these species, allowing their spatial distributions to be clarified. These records were also used as the basis for species distribution modelling, providing the first broad scale models for each species across the Northeast Atlantic. Samples were obtained from Iceland, the UK (specifically Shetland), the North Sea and the Azores. Results suggest that D. batis was commonly distributed in the Western Approaches and Celtic Sea, extending out to Rockall and Iceland. D. intermedius generally appears to be less abundant, but was most frequent around northern Scotland and Ireland, including the northern North Sea, and was also present in Portugal. Two individuals were also identified from seamounts in remote areas of the Atlantic around the Azores, the furthest south and west the species has been found. This supports reports that the flapper skate historically had a much wider distribution (which was also highlighted in the distribution model), emphasising the large scale over which fisheries may have led to extirpations. Furthermore, these Azorean samples shared a unique control region haplotype, highlighting the importance of seamounts in preserving genetic diversity.

The Chanter Field, Block 15/17, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 261-268 ◽  
Author(s):  
H. R. H. Schmitt
Keyword(s):  
North Sea ◽  
Pressure Measurements ◽  
Water Contact ◽  
Shallow Marine ◽  
Northern Margin ◽  
The North ◽  
Platform Location ◽  
Oil Water ◽  
Sandstone Reservoir ◽  
The Witch

AbstractThe Chanter Field is located 11 krn southeast of the Piper Alpha platform location in Block 15/17. The field was discovered by the 15/17–13 well, which tested 37.8° API crude from Galley sandstone turbidites and 52.1& API gas-condensate from the shallow marine sands of the Piper Formation. The Galley sandstone reservoir is overpressured, whereas the Piper sandstone reservoir is normally pressured. The bulk of the field occupies the culmination of a structural terrace on the downthrown side of the main E-W fault forming the northern margin of the Witch Ground Graben in this area. It has dip closure to the east, south and west and fault closure to the north. The 'main block' gas-water contact of 13 080 ft TVSS in the Piper sandstone and the oil-water contact of 12 240 ft TVSS in the Galley sandstone were deduced from wireline pressure measurements and have not been encountered in wells. Estimated proved reserves of 4.6 MMBBL of crude oil and condensate liquids and 20.8 BCF of gas will be produced through a cluster of wells tied back to the Piper Field by a subsea pipeline.

The Blane Field, Block 30/3a, UK North Sea

2020 ◽  
Vol 52 (1) ◽  
pp. 382-389 ◽  
Author(s):  
K. Robertson ◽  
R. Heath ◽  
R. Macdonald
Keyword(s):  
North Sea ◽  
Oil Production ◽  
Water Contact ◽  
Stock Tank ◽  
Light Oil ◽  
Oil Water ◽  
Water Cut ◽  
The Uk ◽  
Central North Sea ◽  
Structural Closure

AbstractThe Blane Field is located in the central North Sea in Block 30/3a (Licence P.111), approximately 130 km SE of the Forties Field, in a water depth of 75 m (246 ft). It straddles the UK/Norway median line with 82% of the field in the UK and 18% in Norway. Blane produces undersaturated oil from the Upper Forties Sandstone Member of the Sele Formation and contains good quality light oil within a four-way structural closure; it has a hydrodynamically tilted original oil–water contact. The field stock-tank oil initially in place estimate is 93 MMbbl with an expected ultimate recovery of 33 MMbbl. Blane first oil was achieved in September 2007. The field has been developed by two horizontal producers located on the central crest of the field supported by a water injector drilled on the NW flank. Oil production peaked at c. 17 000 bopd in 2007 and the field is currently in decline. By the end of 2018 production was c. 3000 bopd with 55% water-cut. Cumulative oil production to the end of 2018 was 26.6 MMbbl.

Synchronous oil migration and cementation in sandstone reservoirs demonstrated by quantitative description of diagenesis

1993 ◽  
Vol 344 (1670) ◽  
pp. 115-125 ◽  
Keyword(s):  
North Sea ◽  
Quantitative Description ◽  
Rapid Decline ◽  
Time Interval ◽  
Burial Diagenesis ◽  
Water Contact ◽  
Porosity And Permeability ◽  
Oil Water ◽  
Northern North Sea ◽  
And Migration

We present a model that explains the patterns of sandstone burial diagenesis in certain oil reservoirs, in which petroleum migration and burial cementation were synchronous. The coincidence of these two processes controls the chemistry and distribution of major burial cement phases across the field, which in turn controls the distribution of reservoir quality, causing a rapid decline of porosity and permeability with depth. Such a rapid poroperm deterioration is observed in many North Sea sandstone oilfields; we highlight the Magnus Sandstone Member of the Magnus Oilfield, northern North Sea as a type example of such a reservoir. The two most significant elements of the synchronous cementation and migration model are that burial cementation in the reservoir occurs over a restricted time interval, probably less than 10 Ma and that rapid and widespread fluid circulation is not invoked to explain the concentrations of cements observed. We speculate that cementation takes place at, and in a series of zones below, the oil-water contact which descends as oil fills the reservoir, with little change to the bulk chemistry of the reservoir formation waters through time.

The Brechin Field, Block 22/23a, UK North Sea

2020 ◽  
Vol 52 (1) ◽  
pp. 390-398 ◽  
Author(s):  
G. Goffey ◽  
S. Lunn ◽  
J. Seedhouse
Keyword(s):  
North Sea ◽  
Rock Physics ◽  
Seismic Attributes ◽  
Production Well ◽  
Constructive Interference ◽  
Water Contact ◽  
Cumulative Production ◽  
Single Production ◽  
Oil Water ◽  
Opposite Response

AbstractThe Brechin Field was discovered by Paladin Resources in 2004. The reservoir is the Paleocene Forties Sandstone Member, with oil trapped in a small dip closure. The prospect was identified as a bright anomaly on a fluid volume processed as part of a 4D survey. However, the anomaly was not consistent with rock physics modelling, and an earlier processed version of the baseline 3D survey showed the opposite response to the 4D datasets. It was established that the fluid anomaly on the 4D data resulted from constructive interference between reflections from the oil–water contact and from top reservoir. Thus, both versions of the data were responding to the presence of hydrocarbons.The discovery well, 22/23a-7, encountered 137 ft of gross oil-bearing reservoir. Without testing or further appraisal, the field was developed in 2005 with a single production well tieback to the Arbroath platform, via the production manifold at Arkwright Field. Brechin is now operated by Repsol Sinopec Resources and cumulative production to mid-2018 was 4.4 MMbbl. Seismic attributes and well-developed reservoir understanding from neighbouring analogue fields permitted the necessary de-risking of hydrocarbon presence, recovery and volumetric uncertainty, to permit the development of an otherwise economically marginal resource.

The North Cormorant Field, Block 211/21a, UK North Sea

2003 ◽  
Vol 20 (1) ◽  
pp. 315-325
Author(s):  
Louise Bater
Keyword(s):  
North Sea ◽  
Middle Jurassic ◽  
Sedimentary Rocks ◽  
Shetland Islands ◽  
The North ◽  
Delta System ◽  
The Subject ◽  
Northern North Sea ◽  
North And South ◽  
Exploration Well

AbstractThe Cormorant Field was discovered by exploration well 211/26-1 in 1972; the fifth field to be discovered in the Northern North Sea. It straddles blocks 211/21 a and 211/26a and is made up of four discrete accumulations spread along a major N-S trending fault terrace. Oil is produced from the sandstones belonging to the Brent Group. The sedimentary rocks comprising the Brent Group were deposited in a fluvial-wave dominated delta system during the Middle Jurassic. The field is developed from two fixed platforms and an underwater manifold centre and the oil is exported through the Brent system to Sullom Voe in the Shetland Islands. For development purposes the field is split in half; north and south, and it is the northern part, developed by the North Cormorant platform, that is the subject of this review.

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