The structural controls on Upper Jurassic and Lower Cretaceous reservoir sandstones in the Witch Ground Graben, UK North Sea

1990 ◽  
Vol 55 (1) ◽  
pp. 299-323 ◽  
Author(s):  
D. O’Driscoll ◽  
A. D. Hindle ◽  
D. C. Long
Keyword(s):  
North Sea ◽  
Lower Cretaceous ◽  
Upper Jurassic ◽  
Structural Controls ◽  
Reservoir Sandstones ◽  
The Witch

Chemostratigraphy of upper Jurassic reservoir sandstones, Danish Central Graben, North Sea

2010 ◽  
Vol 27 (7) ◽  
pp. 1572-1594 ◽  
Author(s):  
R. Weibel ◽  
P.N. Johannessen ◽  
K. Dybkjær ◽  
P. Rosenberg ◽  
C. Knudsen
Keyword(s):  
North Sea ◽  
Upper Jurassic ◽  
Reservoir Sandstones

The Claymore Field, Block 14/19, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 269-278 ◽  
Author(s):  
S. D. Harker ◽  
S. C. H. Green ◽  
R. S. Romani
Keyword(s):  
North Sea ◽  
Water Injection ◽  
Central Area ◽  
Upper Jurassic ◽  
Daily Production ◽  
Northern Area ◽  
Main Area ◽  
Cumulative Production ◽  
The Witch ◽  
Clay Formation

AbstractThe Claymore Field is located in UK North Sea Block 14/19 on the southwest margin of the Witch Ground Graben. The principal structure is a southerly tilted and truncated fault block. The field is divided into three producing areas. Major production is from Upper Jurassic paralic sandstones of the Sgiath Formation and turbidite sandstones of the Claymore Sandstone Member of the Kimmeridge Clay Formation in the downflank Main Area. Minor production is from Permian carbonates of the Halibut Bank Formation and Carboniferous sandstones of the Forth Formation in the crestal Central Area. The Northern Area is a northerly plunging nose, extending graben wards from the Claymore tilt block. Production in the Northern Area is from Lower Cretaceous turbidite sandstones of the Valhall Formation.A small amount of oil was recovered on a wireline test in 1972 from Permian carbonates in the crestally located 14/19-1 well, in what is now termed the Central Area. In 1974 the Main Area was discovered by the southerly downdip well 14/19-2, and the Northern Area was discovered by the northerly downdip well 14/19-6A. Initial oil in place was 1452.9 MMBBL with currently estimated ultimate proved recovery of 511.0 MMBBL of oil. A 36-slot steel platform was installed in 1977. Two subsea water-injection templates were added in 1981 and 1985. Cumulative production to 6 July 1988 was 322.9 MMBBL of oil and daily production was 75 000 BOPD of oil from 28 producers, supported by 16 injectors.

The Highlander Field, Block 14/20b, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 323-329 ◽  
Author(s):  
M. WHITEHEAD ◽  
S. J. PINNOCK
Keyword(s):  
Lower Cretaceous ◽  
Upper Jurassic ◽  
Oil Accumulation ◽  
Shallow Marine ◽  
Oil Development ◽  
The North ◽  
Recoverable Reserves ◽  
Fault Block ◽  
The Witch ◽  
Clay Formation

AbstractHighlander Field, discovered in 1976, is a small oil accumulation located 7½ miles northwest of the Tartan Platform and 114 miles northeast of Aberdeen in UK Block 14/20b. The Field lies on the NW-SE-trending Claymore-Highlander Ridge which forms the southern margin of the Witch Ground Graben. Upper Jurassic sandstones of the shallow marine Piper Formation and deeper marine turbidites (the 'Hot Lens Equivalent') within the Kimmeridge Clay Formation form the principal reservoirs. An additional important reservoir occurs within Lower Cretaceous turbidite sandstone and a small crestal accumulation occurs in Carboniferous deltaic sandstone. The structure is a tilted NW-SE-trending fault block downthrown to the northeast. The sandstone reservoirs all dip to the south and southwest and become thin due to onlap or truncation to the north. The Field has a combined structural-stratigraphic trap configuration. Seal is provided by Upper Jurassic siltstone and Lower Cretaceous calcareous clay stone. The accumulations have been sourced from the Kimmeridge Clay Formation in adjacent basins. Eight wells delineate the structure and production is currently 30 000 BOPD. Ultimate recoverable reserves are 70 million barrels of crude oil. Development has been achieved utilizing an innovative remote subsea system, connected to the Tartan Platform 7½ miles to the southeast.

scholarly journals Diagenetic impact on reservoir sandstones of the Heno Formation in the Ravn-3 well, Danish Central Graben

2018 ◽  
pp. 9-12
Author(s):  
Simone Pedersen ◽  
Rikke Weibel ◽  
Peter N. Johannessen ◽  
Niels H. Schovsbo
Keyword(s):  
North Sea ◽  
Middle Jurassic ◽  
Oil And Gas ◽  
Mineralogical Composition ◽  
Upper Jurassic ◽  
Gas Production ◽  
Oil And Gas Production ◽  
Carbonate Cement ◽  
Porosity And Permeability ◽  
Reservoir Sandstones

Oil and gas production from siliciclastic reservoirs has hitherto been in the Danish Central Graben mostly from Palaeogene and Middle Jurassic sandstone. The Ravn field was the first Upper Jurassic field to start operation. The reservoir is composed of sandstone of the Heno Formation. Production takes place at a depth of 4000 m, which makes Ravn the deepest producing field in the Danish North Sea. The Heno Formation mainly consists of marine shoreface deposits, where foreshore, middle and lower shoreface sandstones constitute the primary reservoir. The results of this study of the diagenetic impact on the mineralogical composition, porosity and permeability are presented here. Microcrystalline quartz has preserved porosity in the sandstone, whereas illite, quartz overgrowth and carbonate cement have reduced both porosity and permeability.

The Miller Field, Blocks 16/7B, 16/8B, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 159-164 ◽  
Author(s):  
S. K. Rooksby
Keyword(s):  
North Sea ◽  
Seismic Data ◽  
Lower Cretaceous ◽  
Upper Jurassic ◽  
Oil Field ◽  
The South ◽  
Submarine Fan ◽  
Western Margin ◽  
Average Porosity ◽  
Slow Velocity

AbstractThe Miller Oil Field is located on the western margin of the South Viking Graben in UKCS Blocks 16/7b and 16/8b. The oil is trapped in Upper Jurassic turbidite sands shed from the Fladen Ground Spur via the Brae complex submarine fan systems. The reservoir sands are of good quality with an average porosity of 16% and permeabilities occasionally in excess of 1 Darcy. The trap is formed within a subtle structural-stratigraphic combination. Overlying slow velocity Lower Cretaceous sediments produce a time flat which, after depth conversion, produces a 3-way dip closed feature. The trap is completed by stratigraphic pinchout of the reservoir sands to the northwest. The most recent (1985) seismic data allow the top reservoir reflector to be picked directly, which was not the case during the exploration and appraisal phase, when only the Top Kimmeridge Clay seismic pick could be made. The estimate of recoverable hydrocarbons is currently 300 MMBBL of oil and 570 BCF of gas. Development drilling commenced early in 1989. No results are yet available.

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