The West Sole Field, Block 48/6, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 517-523 ◽  
Author(s):  
D. A. Winter ◽  
B. King
Keyword(s):  
Continental Shelf ◽  
North Sea ◽  
Gas Production ◽  
Permian Basin ◽  
The West ◽  
Depositional Facies ◽  
Reservoir Sandstones ◽  
Sandstone Formation ◽  
The Uk ◽  
Coal Measures

AbstractWest Sole is located in the Sole Pit area of the Southern North Sea Permian Basin in UK Block 48/6. The field was discovered in 1965 and was the first commercial discovery in the UK Continental Shelf. Gas Production commenced in 1967. Initial reserves are 1.873 TCF of which 1.335 TCF had been produced by the end of 1989. Gas is trapped in aeolian sandstones of the Permian Lower Leman Sandstone Formation. Three depositional facies are recognized, comprising aeolian dune, fluvial and sabkha. The aeolian dune facies form the principal reservoir sandstones, in units up to 40 m (131 ft) thick. However, permeability is reduced due to pervasive illite cementation, such that it averages 3 md in the dune sandstones. Productivity is enhanced in the southern part of the field by 'open' gas-filled fractures, generated during the Alpine inversion. The trap was also amplified at this stage and comprises a faulted inversion anticline trending NW-SE. The source rock is the Westphalian Coal Measures, lying directly beneath the reservoir.

The Tolmount Field, Block 42/28d, UK North Sea

2020 ◽  
Vol 52 (1) ◽  
pp. 262-272 ◽  
Author(s):  
A. Miles ◽  
M. Allen ◽  
L. Fairweather ◽  
J. Hilton ◽  
H. Sloan ◽  
...  
Keyword(s):  
North Sea ◽  
Burial History ◽  
Reservoir Properties ◽  
Water Contact ◽  
Diagenetic Alteration ◽  
Reservoir Sandstones ◽  
Sandstone Formation ◽  
The Uk ◽  
Continental Basin ◽  
Gas Bearing

AbstractThe Tolmount Field is a lean gas condensate accumulation located in Block 42/28d of the UK Southern North Sea. The field was discovered in 2011 by well 42/28d-12, which encountered good-quality gas-bearing reservoir sandstones of the Permian Leman Sandstone Formation. The discovery was appraised in 2013 by wells 42/28d-13 and 42/28d-13Z, which logged the gas–water contact on the eastern flank of the field. The Tolmount structure is a four-way, dip-closed, faulted anticline, orientated NW to SE. The reservoir comprises mixed aeolian dune and fluvial sheetflood facies deposited within an arid continental basin. Dune sands display the best reservoir properties with porosities around 22% and permeabilities exceeding 100 mD. Only minor diagenetic alteration has occurred, primarily in the form of grain-coating illite. Superior reservoir quality is observed at Tolmount compared to adjacent areas, due to the preservation of dune facies, a hypothesized early gas emplacement and a relatively benign burial history. Current mapped gas initially-in-place estimates for the field are between 450 bcf and 800 bcf, with an estimated recovery factor between 70 and 90%. An initial four-well development is planned, with first gas expected in 2020.

The Esmond, Forbes and Gordon Fields, Blocks 43/8a, 43/13a, 43/15a, 43/20a, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 425-432 ◽  
Author(s):  
F. J. Ketter
Keyword(s):  
North Sea ◽  
Arid Environment ◽  
Gas Production ◽  
Alluvial Fan ◽  
Southern North Sea ◽  
Offshore Installations ◽  
Porosity And Permeability ◽  
Sandstone Formation ◽  
The Uk

AbstractThe 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.

The Kraken and Kraken North fields, Block 9/2b, UK North Sea

2020 ◽  
Vol 52 (1) ◽  
pp. 863-874 ◽  
Author(s):  
L. Parkes ◽  
P. Wood ◽  
C. Macdonald
Keyword(s):  
Continental Shelf ◽  
North Sea ◽  
Reservoir Quality ◽  
The West ◽  
Injection Wells ◽  
Stock Tank ◽  
The Uk

AbstractThe Kraken and Kraken North fields lie in the UK Continental Shelf Block 9/2b on the East Shetland Platform. Hydrocarbons are stratigraphically trapped within Heimdal Sandstone Member of the Lista Formation. The fields lie at around 3900 ft true vertical; depth subsea and the oil is heavy (13–15°API) and viscous.The field is developed via a waterflood scheme with long horizontal production and injection wells, alternating across the field. To date, 21 development wells have been drilled, with further wells planned. Reservoir quality is extremely good with porosity around 36% and permeabilities in the range of 2–10 D. The field is produced via the Armada Kraken floating production storage and offloading vessel. Developed stock tank oil originally in place is in the region of 400 MMbbl, with further currently undeveloped resources to the west of the field.

Chiswick and Kew fields, Blocks 49/4a, 49/4b, 49/4c, 49/5a and 49/5b, UK North Sea

2020 ◽  
Vol 52 (1) ◽  
pp. 142-150 ◽  
Author(s):  
W. Smit
Keyword(s):  
North Sea ◽  
Primary Objective ◽  
Permian Basin ◽  
Current Estimate ◽  
Gas Field ◽  
Gas Recovery ◽  
Domal Structure ◽  
Exploration Drilling ◽  
Sandstone Formation ◽  
The Uk

AbstractThe Chiswick Field is a Carboniferous gas field located in UK Blocks 49/4a and 49/4b in the Southern North Sea, approximately 18 km NW of the Markham Field, close to the UK–Netherlands median line. The Kew Field is situated approximately 3 km NE of the Chiswick Field. The Kew structure is a NW–SE-trending horst separated from the Chiswick Field, a large anticlinal domal structure, by a major NW–SE fault and a structural low. The productive reservoir units are Carboniferous (Westphalian A and B) fluvial sandstones.Both fields are situated on the eastern edge of the Silverpit Basin (part of the Southern Permian Basin). The initial exploration drilling had Leman Sandstone Formation as the primary objective, but the first wells encountered a tight Permian reservoir with gas-bearing Carboniferous reservoirs, subsequently appraised and developed.The current estimate for the gas initially in place of Chiswick and Kew is respectively 687 bcf and 85 bcf in the Carboniferous reservoir. The fields to date (Q4 2018) have produced respectively 220 bcf and 33 bcf sales gas. Gas recovery is through natural depletion from hydraulically fractured, horizontal development wells.

Petroleum geology of the Cygnus gas field, UK North Sea: from discovery to development

2017 ◽  
Vol 8 (1) ◽  
pp. 307-318 ◽  
Author(s):  
Ross Catto ◽  
Samantha Taggart ◽  
Gareth Poole
Keyword(s):  
North Sea ◽  
High Water ◽  
Poor Quality ◽  
Log Analysis ◽  
Permian Basin ◽  
Gas Field ◽  
Flow Rates ◽  
Southern North Sea ◽  
Sandstone Formation ◽  
The Uk

AbstractThe Cygnus Field, operated by ENGIE E&P UK Limited, is located in UK Southern North Sea blocks 44/11 and 44/12. The reservoir comprises sandstones of the Permian Leman Sandstone Formation and Carboniferous Ketch Formation.Cygnus was first drilled in 1988 by well 44/12-1, which encountered gas shows in sandstones in the Leman Sandstone Formation whilst targeting a Carboniferous objective. The initial evaluation indicated the presence of poor-quality reservoir with conventional log analysis indicating high water saturations. Further appraisal activity ceased until 2002 when a group led by ENGIE E&P UK Limited were awarded the licence in the 20th round having recognized the missed pay potential. Through appraisal drilling, a second reservoir (the Carboniferous Ketch Formation) was discovered and the Leman Sandstone Formation was proven to be capable of achieving stabilized flow rates greater than 30 MMscf/d.The Cygnus discovery now proves that a northern-sourced Leman Sandstone Formation play fairway exists, establishing an extension of the Rotliegend play to the northern feather edge of the Southern Permian Basin. The Cygnus Field's estimated ultimate recoverable volume is forecast to be 760 Bscf, making it the largest field discovered in the UK Southern North Sea in the last 30 years.

The Ravenspurn North Field, Blocks 42/30, 43/26a, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 459-467 ◽  
Keyword(s):  
North Sea ◽  
Clay Content ◽  
Gas Production ◽  
Commercial Production ◽  
Reservoir Rock ◽  
Normal Faults ◽  
Well Drilling ◽  
Variable Permeability ◽  
Porosity And Permeability ◽  
Sandstone Formation

AbstractThe Ravenspurn North Field is a gas accumulation located in the Southern North Sea, Permian Gas Basin which was discovered in October 1984. It has undergone four years of appraisal well drilling culminating in the approval of the development plan in 1988. Development wells are currently being drilled and three offshore installations are planned; first gas production began in July 1990.The Ravenspurn North Field is a combined structural and stratigraphic trap. The reservoir is fault closed along a series of anastomosing oblique strike-slip and normal faults. Seals along the faults are provided by the Silverpit Formation mudstones and Zechstein Group evaporites. The reservoir deteriorates to the northwest because of thinning, facies change and increasing authigenic clay content.The Lower Leman Sandstone Formation of the Rotliegendes Group forms the reservoir. It consists of a sequence of aeolian dune, fluvial sheetflood, fluvial channels and lake margin sabkha deposits. Non-reservoir intervals are formed by playa lake mudstone sequences. Fluvial and sabkha facies dominate in the northwest while aeolian facies dominate in the southeast parts of the Field.Reservoir quality was initially controlled by lithofacies distribution. Subsequent diagenesis further modified the reservoir rock resulting in variations in the porosity and permeability. Deliverability is a function of variable permeability with two areas identified; the high deliverability area where gas wells have tested sufficient quantities for commercial production without artificial stimulation and a low deliverability area where gaswells require hydraulic fracture stimulation before significant commercial production rates are achieved.

The Britannia Field, Blocks 15/29, 15/30, 16/26 and 16/27, UK North Sea

2020 ◽  
Vol 52 (1) ◽  
pp. 664-678 ◽  
Author(s):  
M. Camm ◽  
L. E. Armstrong ◽  
A. Patel
Keyword(s):  
Continental Shelf ◽  
Development Strategy ◽  
North Sea ◽  
Lower Cretaceous ◽  
Near Field ◽  
Field Development ◽  
Infill Drilling ◽  
To Come ◽  
The Uk

AbstractThe Lower Cretaceous Britannia Field development is one of the largest and most significant undertaken on the UK Continental Shelf. Production started in 1998 via 17 pre-drilled development wells and was followed by a decade of intensive drilling, whereby a further 40 wells were added. In 2000 Britannia's plateau production of 800 MMscfgd supplied 8% of the UK's domestic gas requirements.As the field has matured, so too has its development strategy. Initial near-field development drilling targeting optimal reservoir thickness was followed by extended reach wells into the stratigraphic pinchout region. In 2014 a further strategy shift was made, moving from infill drilling to a long-term compression project to maximize existing production. During its 20-year history the Britannia Platform has undergone numerous changes. In addition to compression, production from five satellite fields has been routed through the facility: Caledonia (2003), Callanish and Brodgar (2008), Enochdhu (2015) and Alder (2016). A new field, Finlaggan, is due to be brought through Britannia's facilities in 2020, helping to maximize value from the asset for years to come.As Britannia marks 20 years of production it has produced c. 600 MMboe – surpassing the original ultimate recoverable estimate of c. 570 MMboe – and is still going strong today.

The Hewett Field, Blocks 48/28a, 48/29a, 48/30a, 52/4a and 52/5a, UK North Sea

2020 ◽  
Vol 52 (1) ◽  
pp. 189-202 ◽  
Author(s):  
J. A. Hook
Keyword(s):  
Fault Zone ◽  
North Sea ◽  
Structural Evolution ◽  
Field Development ◽  
Southern North Sea ◽  
Sandstone Formation ◽  
The Uk ◽  
Basin Margin ◽  
Sour Gas

AbstractThe Hewett Field has been in production for some 50 years. Unusually for a Southern North Sea field in the UK Sector, there has been production from several different reservoirs and almost entirely from intervals younger than the principal Leman Sandstone Formation (LSF) reservoir in the basin. Some of these reservoirs are particular to the Hewett area. This reflects the location of the field at the basin margin bound by the Dowsing Fault Zone, which has influenced structural evolution, deposition and the migration of hydrocarbons. The principal reservoirs are the Permo-Triassic Hewett Sandstone (Lower Bunter), Triassic Bunter Sandstone Formation (BSF) (Upper Bunter) and Permian Zechsteinkalk Formation. There has also been minor production from the Permian Plattendolomit Formation and the LSF. Sour gas is present in the BSF only. Several phases of field development are recognized, ultimately comprising three wellhead platforms with production from 35 wells. Gas is exported onshore to Bacton, where the sour gas was also processed. Peak production was in 1976 and c. 3.5 tcf of gas has been recovered. Hewett has also provided the hub for six satellite fields which have produced a further 0.9 tcf of gas. It is expected that the asset will cease production in 2020.

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 Cygnus Field, Blocks 44/11a and 44/12a, UK North Sea

2020 ◽  
Vol 52 (1) ◽  
pp. 151-162 ◽  
Author(s):  
Ian Dredge ◽  
Gary Marsden
Keyword(s):  
North Sea ◽  
Horizontal Wells ◽  
Third Party ◽  
Production Well ◽  
Field Development ◽  
Fault Block ◽  
Main Fault ◽  
Sandstone Formation ◽  
The Uk ◽  
Gas Bearing

AbstractThe Cygnus Field is located in Blocks 44/11a and 44/12a of the UK Southern North Sea. The field was first discovered in 1988 as a tight lower Leman Sandstone Formation gas discovery by well 44/12- 1. After the licences had sat idle for several years, GDF Britain (now Neptune E&P UK Ltd) appraised the field from 2006 to 2010. During the appraisal phase, the lower Leman Sandstone was found to be of better quality than first discovered and the gas-bearing lower Ketch Member reservoir was also encountered. The field development was sanctioned in 2012.The field has been developed from two wellhead platforms targeting Leman Sandstone and Ketch Member reservoirs. Five main fault blocks have been developed, with two wells in each fault block planned in the field development plan. The wells are long horizontal wells completed with stand-alone sand screens. At the time of writing, the production plateau is 320 MMscfgd (266 MMscfgd when third-party constraints apply), producing from nine wells with the final production well to be drilled.

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