The Barque Field, Blocks 48/13a, 48/14, UK North Sea

2003 ◽  
Vol 20 (1) ◽  
pp. 661-670 ◽  
Author(s):  
M. J. Sarginson
Keyword(s):  
North Sea ◽  
Late Cretaceous ◽  
Natural Fracture ◽  
Lower Permian ◽  
Reservoir Performance ◽  
Well Stimulation ◽  
Reservoir Permeability ◽  
Initial Area ◽  
Sandstone Formation ◽  
Two Phases

AbstractThe 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 generally 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 two 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 dictated 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 from horizontal wells led to later development of the whole field.

The Barque Field, Blocks 48/13a, 48/14, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 395-400 ◽  
Author(s):  
R. T. Farmer ◽  
A. P. Hillier
Keyword(s):  
North Sea ◽  
Late Cretaceous ◽  
Natural Fracture ◽  
Lower Permian ◽  
Reservoir Performance ◽  
Well Stimulation ◽  
Reservoir Permeability ◽  
Initial Area ◽  
Sandstone Formation ◽  
Coal Measures

AbstractThe 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 Clipper Field, Blocks 48/19a, 48/19c, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 417-423 ◽  
Author(s):  
R. T. Farmer ◽  
A. P. Hillier
Keyword(s):  
North Sea ◽  
Upper Permian ◽  
Lower Permian ◽  
Reservoir Properties ◽  
Gas Field ◽  
Initial Development ◽  
Reservoir Performance ◽  
Matrix Permeability ◽  
Reservoir Permeability ◽  
Sandstone Formation

AbstractThe Clipper Gas Field is a moderate-sized faulted anticlinal trap located in Blocks 48/19a and 48/19c within the Sole Pit area of the southern North Sea gas basin. The reservoir is formed by the Lower Permian Leman Sandstone Formation, lying between truncated Westphalian Coal Measures and the Upper Permian evaporitic Zechstein Group which form source and seal respectively. Reservoir permeability is very low, mainly as a result of compaction and diagenesis which accompanied deep burial of the Sole Pit Trough, a sub-basin within the main gas basin. The Leman Sandstone Fm. is on average about 715 ft thick, laterally heterogeneous and zoned vertically with the best reservoir properties about the middle of the formation. Porosity is fair with a field average of 11.1%. Matrix permeability, however, is less than 1 millidarcy on average and is so low that some intervals in the field will not flow gas unless stimulated. Steep dipping zones of natural fractures occur in certain areas of the field; these commonly allow high flow rates to be achieved from large blocks of low-permeability matrix. Expected recoverable reserves from the most favourable part of the field are 558 BCF and Clipper Field is now being developed in conjunction with part of the adjacent Barque Gas Field. Later development of the remainder of Clipper Field will depend upon reservoir performance in the initial development area.

The Clipper Field, Blocks 48/19a, 48/19c, UK North Sea

2003 ◽  
Vol 20 (1) ◽  
pp. 691-698
Author(s):  
M. J. Sarginson
Keyword(s):  
North Sea ◽  
Upper Permian ◽  
Lower Permian ◽  
Reservoir Properties ◽  
Gas Field ◽  
Field Development ◽  
Matrix Permeability ◽  
Recoverable Reserves ◽  
Reservoir Permeability ◽  
Sandstone Formation

AbstractThe Clipper Gas Field is a moderate-sized faulted anticlinal trap located in Blocks 48/19a, 48/19c and 48/20a within the Sole Pit area of the southern North Sea Gas Basin. The reservoir is formed by the Lower Permian Leman Sandstone Formation, lying between truncated Westphalian Coal Measures and the Upper Permian evaporitic Zechstein Group which form source and seal respectively. Reservoir permeability is very low, mainly as a result of compaction and diagenesis which accompanied deep burial of the Sole Pit Trough, a sub basin within the main gas basin. The Leman Sandstone Formation is on average about 715 ft thick, laterally heterogeneous and zoned vertically with the best reservoir properties located in the middle of the formation. Porosity is fair with a field average of 11.1%. Matrix permeability, however, is less than one millidarcy on average. Well productivity depends on intersecting open natural fractures or permeable streaks within aeolian dune slipface sandstones. Field development started in 1988. 24 development wells have been drilled to date. Expected recoverable reserves are 753 BCF.

The Camelot Fields, Blocks 53/1a, 53/2, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 401-408
Author(s):  
A. J. Holmes
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
North Sea ◽  
Lower Permian ◽  
Southern North Sea ◽  
Recoverable Reserves ◽  
Sandstone Formation ◽  
Two Phases ◽  
Gas Fields ◽  
Central South

AbstractThe Camelot Gas Fields (Camelot North, Northeast and Central-South) lie in Blocks 53/la and 53/2 in the Southern North Sea, some 30 miles (48 km) east of Great Yarmouth. Initial sub commercial discovery wells were drilled in 1967, 1969 and 1972. Further exploration and appraisal drilling was carried out in 1987 and 1988. This paper covers the Field history up to the 53/la-10 appraisal well in June 1988. The Lower Permian, Leman Sandstone Formation is the reservoir, with the gas accumulations trapped in tilted fault terraces. The Leman Sandstone Fm. in the Camelot area is 800 ft thick with a gas column up to 200 ft. Development of the fields will be in two phases. Phase I will consist of 5 wells deviated from the Camelot 'CA' platform to produce reserves from the Camelot North and Central-South Fields. Production commenced in October 1989. Phase II scheduled for 1991/92 will tie-in the Camelot Northeast Field. Gas is exported from the unmanned 'CA' gathering platform via pipeline to Amoco's Leman 'A' complex, from where the gas is transported to shore via the existing Amoco pipeline from Leman to Bacton. Total recoverable reserves for the Camelot Fields are estimated at 215 BCF.

The Ensign Field, Blocks 48/14a, 48/15a and 48/15b, UK North Sea

2020 ◽  
Vol 52 (1) ◽  
pp. 172-179 ◽  
Author(s):  
V. W. J. Verlinden ◽  
H. Basford
Keyword(s):  
North Sea ◽  
Regional Scale ◽  
Fracture Network ◽  
Natural Fracture ◽  
Well Performance ◽  
Gas Recovery ◽  
Production Wells ◽  
Sandstone Formation ◽  
Low Offset

AbstractThe Ensign Field is located in UK offshore licence Blocks 48/14a, 48/15a and 48/15b. The field is located 100 km east of the Humberside coast within the Sole Pit area of the Southern North Sea. The reservoir consists of sandstones of the Permian Rotliegend Group (Leman Sandstone Formation). Reservoir quality has been impacted by diagenesis during deep burial, whereby illitization has reduced permeability to sub-millidarcy scale. The field has been developed with two horizontal production wells, both completed with five hydraulic fracture stages. First gas from the field was achieved in 2012 via the Ensign normally unmanned installation and exported through the Lincolnshire Offshore Gas Gathering System. The field is compartmentalized by multiple regional-scale De Keyser fault zones. A heterogeneous natural fracture network exists with only a limited contribution to flow. Well performance and ultimate gas recovery have been lower than originally anticipated due to sub-optimal completions and a higher degree of compartmentalization than originally expected. The volume of gas that is connected to the wells is limited by low-offset faults, which have been identified by integrating long-term production data, and core, log and reprocessed seismic data. Production ceased in 2018 when the original export route was decommissioned.

The Malory Field, Block 48/12d, UK North Sea

2003 ◽  
Vol 20 (1) ◽  
pp. 771-776
Author(s):  
R. E. O'Brien ◽  
M. Lappin ◽  
F. Komlosi ◽  
A. Loftus
Keyword(s):  
North Sea ◽  
Upper Permian ◽  
Reservoir Quality ◽  
Lower Permian ◽  
Burial Depth ◽  
Recoverable Reserves ◽  
Adjacent Structures ◽  
Sandstone Formation ◽  
The Uk ◽  
Hydrocarbon Charge

AbstractThe Malory Field straddles blocks 48/12d and 48/12c of the UK Sector of the Southern North Sea on the western margin of the Sole Pit Trough. The field is located within an upthrown part of the Dowsing Fault Zone and was discovered by the Mobil operated well 48/12d-9 in early 1997.The Malory Field is a small fault-bounded horst structure with expected recoverable reserves of 75 BSCF. The reservoir consists of a 249 ft-section of Lower Permian, Rotliegendes Leman Sandstone Formation sandstones, is sourced from the Carboniferous Westphalian Coal Measures below, and is sealed by overlying Upper Permian Zechstein evaporites.Reservoir quality is generally good with an average porosity of 14.7% and core permeabilities (Kh) between 0.2 and 1651 mD. This preservation of reservoir quality is attributed to a combination of the structure being located on a broad palaeostructural high, with a lower maximum burial depth than adjacent structures and associated lower compactional porosity loss, the presence of an early hydrocarbon charge and the preferential precipitation of chlorite over illite cements.

The Viking Fields, Blocks 49/11d, 49/12a, 49/16a, 49/16c, 49/17a, UK North Sea

2020 ◽  
Vol 52 (1) ◽  
pp. 273-287 ◽  
Author(s):  
S. E. Anston-Race ◽  
D. Ganesh
Keyword(s):  
North Sea ◽  
Water Depth ◽  
Reservoir Rocks ◽  
Development History ◽  
Sandstone Formation ◽  
Two Phases ◽  
And Performance ◽  
The Uk ◽  
The Phoenix ◽  
Porosity Range

AbstractThe Viking Fields were a gas development in the UK Southern North Sea, c. 130 km east of the Lincolnshire coast in 30 m water depth and covering Blocks 49/11d, 49/12a, 49/16a, 49/16c, 49/17a. The area comprised the Viking A, B, C, D and E Fields.The Viking Fields were discovered in 1965 and started producing in 1972. The development was in two phases from 1971 to 1994 and from 1995 to 2000; the latter phase included the ‘Phoenix development’. The fields continued to produce until September 2015. Plugging and abandonment of the Viking Field wells was complete in 2017, with final decommissioning planned for 2021.The Viking Fields have produced 3.3 tcf of gas from the Rotliegend Group, Leman Sandstone Formation, aeolian-dominated reservoir rocks with a porosity range of 7–25% and average permeability of >100 mD. The Viking reservoirs are impacted by NE--SW De Keyser faults which often delineate and compartmentalize the reservoirs. The final recovery factor for the Viking Fields was 90%. This paper summarizes the geology, development history and performance of these legacy assets.

The Cleeton Field, Block 42/29, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 409-415 ◽  
Keyword(s):  
North Sea ◽  
Lower Permian ◽  
Early Permian ◽  
Desert Environment ◽  
Reservoir Properties ◽  
Peak Shaving ◽  
Gas Field ◽  
Southern North Sea ◽  
Sandstone Formation

AbstractThe Cleeton Gas Field is located in the Sole Pit Basin in the Southern North Sea in UK Block 42/29. The gas is trapped in sandstones of the Lower Permian Lower Leman Sandstone Formation, which was deposited by wind and occasional fluvial action in a desert environment. In contrast to nearby Ravenspurn South, the sands have excellent reservoir properties, particularly in the aeolian sandstones, with porosities around 22% and permeabilities between 10 and 100 md. The trap is a NW-SE-striking faulted anticline, in which the top seal is provided by the early Permian Silverpit shales directly overlying the reservoir. The field has been producing since October 1988 and its use in the Villages Field Project is as a peak shaving producer to the Ravenspurn South Field main output. The initial reserves are 280 BCF and the field life is expected to be 9 years.

The Banff Field, Blocks 22/27a, 29/2a, UK North Sea

2003 ◽  
Vol 20 (1) ◽  
pp. 497-507 ◽  
Author(s):  
N. Evans ◽  
J. A. MacLeod ◽  
N. Macmillan ◽  
P. Rorison ◽  
P. Salvador
Keyword(s):  
North Sea ◽  
Late Cretaceous ◽  
Production System ◽  
Upper Jurassic ◽  
Oil Field ◽  
Salt Diapir ◽  
Reservoir Performance ◽  
Central North Sea ◽  
Phased Development ◽  
Reservoir Potential

AbstractThe Banff Field is an oil field with a small gas cap containing an estimated 300 MMB0 oil-in place. The structure straddles the boundary between blocks 22/27a and 29/2a in the West Central Graben area of UK Central North Sea. The field was discovered by well 29/2a-6 in 1991. Banff Field is a Steeply dipping raft of fractured Late Cretaceous and Danian Chalk on the flank of a salt diapir. Paleocene sands draped over the raft provide addtional reservoir potential. A vertical oil column of over 3000 ft is present within the reservoir sourced from the underlying upper jurassic Kimmeridge Formation shales. Hydrocarbon migration into the trap is believed to have started in the Eocene.The highest reservoir productivity occurs in the Late Cretaceous Tor Formation, which is expected to yield most of the field's reserves. Chalk porosity ranges from 15% to 35% but matrix permeabilities are generally less than 5 mD. Drainage is achieved through extensive faulting and fracturingInitial uncertainties over reservoir performance and connectivity led to a phased development. Phase i comprised a six month Early Production System (EPS), during which time 5 MMBo were produced and the viability of the field was confirmed. Phase 2 Production is by means of a Floating Production System and Offtake (FPSO) Vessel Named the Ramform Banff. First oil production was achieved on 30 January 1999 and ultimate reserves are expected to be in excess of 75 MMBO.

Radiogenic and stable isotope evidence for age and origin of authigenic illites in the Rotliegend, southern North Sea

Clay Minerals ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 555-565 ◽  
Author(s):  
K. Ziegler ◽  
B. W. Sellwood ◽  
A. E. Fallick
Keyword(s):  
North Sea ◽  
Structural Evolution ◽  
Lower Permian ◽  
Gas Reservoirs ◽  
Gaseous Hydrocarbon ◽  
Oxygen Isotope Exchange ◽  
Basin Inversion ◽  
Southern North Sea ◽  
Evaporative Concentration ◽  
Isotopic Analyses

AbstractAeolian sandstones of the Lower Permian Leman Formation (Rotliegend Group) provide the best gas reservoir in the southern North Sea, but permeability is greatly reduced by the presence of authigenic fibrous illites. New radiogenic (K/Ar) and stable (oxygen and hydrogen) isotope data are presented for fibrous illite cements (<0.1 µm), so that the absolute timing and controlling diagenetic factors for their formation can be more fully evaluated. Thus, the expected quality of gas reservoirs in the southern North Sea might be better predicted. Samples have been analysed from five wells in areas with contrasting structural evolution: the Sole Pit Basin, and the Indefatigable Shelf. The K/Ar ages of between 160 and 190 Ma have been obtained from the Indefatigable Shelf illites, and between 120 and 160 Ma for those from the Sole Pit Basin, reflecting different times of basin inversion. These K/Ar ages are interpreted by reference to burial/thermal models for each well. The temperature of illite precipitation falls between 88 and 140°C. Calculated pore-fluid compositions derived from oxygen and hydrogen isotopic analyses give values of ∼ + 1 to +9‰ (SMOW) δ18O and +1 to −50‰ (SMOW) δD. The illite δD values have probably been affected by isotopic exchange and fractionation with the surrounding gaseous hydrocarbon. The δ18O values reflect the degree to which evaporative concentration had affected Zechstein marine waters which subsequently invaded the Leman Sandstone. Comparisons between δ18O and δD values in clays and in formation water for the Leman Field suggest that oxygen isotope exchange might have taken place, and that the initial K+ and radiogenic 40Ar contents within illites may have been modified.

Sign in / Sign up

Export Citation Format

Share Document