The Armada development, UK Central North Sea: The Fleming, Drake and Hawkins Gas-Condensate Fields

2003 ◽  
Vol 20 (1) ◽  
pp. 139-151 ◽  
Author(s):  
I. A. Stuart
Keyword(s):  
Maximum Yield ◽  
Upper Jurassic ◽  
Salt Dome ◽  
Gas Condensate ◽  
Project Design ◽  
Surface Site ◽  
Shallow Marine ◽  
The North ◽  
Fault Block ◽  
Central North Sea

abstractIn 1994 the Armada partnership sanctioned the simultaneous development of the Fleming, Drake and Hawkins Gas-condensate Fields by means of shared facilities; the overall project was called the Armada Development. The operator is BG International (formerly British Gas). The development was interesting because the component fields are not only separate accumulations, but are of completely different geological type.The Fleming Field is a Palaeocene, Maureen Formation high-density turbidite reservoir, sourced from the north but pinching out eastwards against the N S Utsira/Jaeren High and Hawking-Varg Ridge, and therefore forming a 20 km long, continuous, but very narrow reservoir. The drake Field is an Upper Jurassic. Fulmar Formation, shallow marine, shore-face reservoir, with excellent reservoir quality in a compact fault block. The Hawkins Field reservoir is poorer quality Fulmar Formation, typical of a more distal setting; the trap is formed by closure over a salt dome, and the structure is consequently quite heavily faulted.The challenge was to develop these disparate reservoirs from a single surface site. to capture the askward shape of Fleming and the distance between Drake and Hawkins. This was achieved by means of extended each drilling; although the high cost of such wells meant that every one had to be designed for maximum yield. Overall eifht wells were drilled, five to Fleming, two to Drake and one to Kawkins (these numbers being approximately proportional to gas-in-place). These wells are capable of delivering the project design peak rate of 450 mmscfd off-platform (equivalent to about 480 mmscfd reservoir gas), and up to 24000 BOPD condensate. Armada began production on schedule in October 1997.

scholarly journals Sedimentology and sequence stratigraphy of paralic and shallow marine Upper Jurassic sandstones in the northern Danish Central Graben

2003 ◽  
Vol 1 ◽  
pp. 367-402 ◽  
Author(s):  
Peter N. Johannessen
Keyword(s):  
Sea Level ◽  
Upper Jurassic ◽  
High Energy ◽  
Salt Dome ◽  
The South ◽  
The West ◽  
Relative Sea Level ◽  
Shallow Marine ◽  
The North ◽  
Plateau Area

Paralic and shallow marine sandstones were deposited in the Danish Central Graben during Late Jurassic rifting when half-grabens were developed and the overall eustatic sea level rose. During the Kimmeridgian, an extensive plateau area consisting of the Heno Plateau and the Gertrud Plateau was situated between two highs, the Mandal High to the north, and the combined Inge and Mads Highs to the west. These highs were land areas situated on either side of the plateaus and supplied sand to the Gertrud and Heno Plateaus. Two graben areas, the Feda and Tail End Grabens, flanked the plateau area to the west and east, respectively. The regressive–transgressive succession consists of intensely bioturbated shoreface sandstones, 25–75 m thick. Two widespread unconformities (SB1, SB2) are recognised on the plateaus, forming the base of sequence 1 and sequence 2, respectively. These unconformities were created by a fall in relative sea level during which rivers may have eroded older shoreface sands and transported sediment across the Heno and Gertrud Plateaus, resulting in the accumulation of shoreface sandstones farther out in the Feda and Tail End Grabens, on the south-east Heno Plateau and in the Salt Dome Province. During subsequent transgression, fluvial sediments were reworked by high-energy shoreface processes on the Heno and Gertrud Plateaus, leaving only a lag of granules and pebbles on the marine transgressive surfaces of erosion (MTSE1, MTSE2). The sequence boundary SB1 can be traced to the south-east Heno Plateau and the Salt Dome Province, where it is marked by sharp-based shoreface sandstones. During low sea level, erosion occurred in the southern part of the Feda Graben, which formed part of the Gertrud and Heno Plateaus, and sedimentation occurred in the Norwegian part of the Feda Graben farther to the north. During subsequent transgression, the southern part of the Feda Graben began to subside, and a succession of backstepping back-barrier and shoreface sediments, 90 m thick, was deposited. In the deep Tail End and Feda Grabens and the Salt Dome Province, sequence boundary SB2 is developed as a conformity, indicating that there was not a significant fall in relative sea level in these grabens, probably as a result of high subsidence rates. Backstepping lower shoreface sandstones overlie SB2 and show a gradual fining-upwards to offshore claystones that are referred to the Farsund Formation. On the plateaus, backstepping shoreface sandstones of sequence 2 are abruptly overlain by offshore claystones, indicating a sudden deepening and associated cessation of sand supply, probably caused by drowning of the sediment source areas on the Mandal, Inge and Mads Highs. During the Volgian, the Gertrud Plateau began to subside and became a graben. During the Late Kimmeridgian – Ryazanian, a long-term relative sea-level rise resulted in deposition of a thick succession of offshore claystones forming highstand and transgressive systems tracts on the Heno Plateau, and in the Gertrud, Feda and Tail End Grabens.

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.

Diagenesis of the shallow marine Fulmar Formation in the Central North Sea

Clay Minerals ◽  
1986 ◽  
Vol 21 (4) ◽  
pp. 537-564 ◽  
Author(s):  
D. J. Stewart
Keyword(s):  
Clay Mineral ◽  
North Sea ◽  
Large Scale ◽  
Shear Zones ◽  
Upper Jurassic ◽  
Burial Diagenesis ◽  
Secondary Porosity ◽  
Shallow Marine ◽  
History Of ◽  
Central North Sea

AbstractThe diagenetic history of the Upper Jurassic Fulmar Formation of the Central North Sea is described with emphasis on the Fulmar Field. The Fulmar Formation was deposited on a variably subsiding shallow-marine shelf under the influence of halokinetic and fault movements. The sediments are extensively bio-destratified although large-scale cross-bedding is locally preserved. The dominant mechanism of deposition is thought to have been storm-generated currents. Soft-sediment deformation structures are common and are attributed to syn- and post-depositional dewatering of the sandstones. The dewatering was associated with fractures and shear zones which reflect tectonic instability resulting from periodic salt withdrawal and/or graben fault movements. The dewatering may have been initiated by repacking of the sediments during earth movements or by the gradual build-up and sudden release of overpressures due to compaction and/or clay mineral dehydration during rapid burial at the end of the Cretaceous. The formation is composed of arkosic sandstone of similar composition to Triassic sandstones from which it was probably derived. The sandstones also contain limited amounts of marine biogenic debris including sponge solenasters, bivalve shells, rare ammonites and belemnites. Initial diagenesis began with an environment-related phase during which quartz and feldspar overgrowths and chalcedony and calcite cements were precipitated. These cements appear to form concretions adjacent to local concentrations of sponge debris and shell debris, respectively, and were disturbed after their formation by fracturing and dewatering. This was followed by an early burial stage of diagenesis which resulted in extensive dolomite cementation and minor clay mineral authigenesis (illite and chlorite). The last phase of mineral growth was probably pyrite. During early burial diagenesis, secondary porosity after feldspar and/or carbonate was produced, although the exact timing is not clear. The lack of both stylolitic developments and extensive illitization indicates that the late burial diagenesis stage was never reached, although sufficient clay diagenesis occurred to destroy all traces of mixed-layer illite-smectite (present in some shallower wells). The main control on reservoir behaviour is primary depositional fabric. Diagenesis only overprints these controls. Locally-cemented fracture sets act as baffles to fluid flow, but they are not extensive and the reservoir acts as one unit.

THE PERSEUS FIELD, NORTH WEST SHELF, AUSTRALIA: A GIANT GAS ACCUMULATION IN A COMPLEX STRUCTURAL/STRATIGRAPHIC TRAP

1998 ◽  
Vol 38 (1) ◽  
pp. 52
Author(s):  
M.L. Taylor ◽  
N.B. Thompson ◽  
N.C. Taylor
Keyword(s):  
Lower Cretaceous ◽  
Upper Jurassic ◽  
Fault Scarp ◽  
North West ◽  
The North ◽  
Fault Block ◽  
Engineering Data ◽  
Production History ◽  
Complex Structural ◽  
Multi Disciplinary Team

The Perseus Field contains reported expectation (proven plus probable) dry gas and condensate reserves of 6.48 TCF (183 × 109 m3) and 165.7 MMBBL (26.3 × 106 m3), respectively, in a complex structural/stratigraphic trap. Gas is predominantly reservoired in Bathonian shallow marine sandstones of the Legendre Formation which subcrop the Upper Jurassic-Lower Cretaceous 'Main Unconformity' in a graben separating the Goodwyn and North Rankin horsts. The Lower Cretaceous Muderong Shale forms the main regional top seal. The Lower-Middle Jurassic Athol Formation forms the seat seal for the Perseus trap and subcrops the Main Unconformity northwest of North Rankin. The maximum gross gas column for the field is approximately 360 m. The Athol Formation and underlying Murat Siltstone also form the topseal for the small Searipple Field, which underlies Perseus.The Perseus trap is dip-closed to the northwest. A steep fault scarp forms the southern margin of the trap. Trap integrity is dependent upon fault seal along the western flank of the field, where the reservoir section is juxtaposed against Athol Formation claystones in a long narrow fault block downthrown from the Goodwyn block. At the southwestern corner of the field this fault block is absent and the Perseus reservoir is juxtaposed against Triassic reservoir section in the Goodwyn block.The NRA22 well, drilled from the North Rankin A platform, has been producing gas from the Perseus Field since mid-1991. Reservoir pressure measurements and production history data have been of immense value in the exploration and appraisal of this field, both in driving further drilling and in understanding the results. Integration of geoscientific and engineering data and expertise within a multi-disciplinary team was essential for the efficient appraisal and evaluation of the field.

The Magnus Field, Block 211/7a, 12a, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 153-157 ◽  
Author(s):  
M. Shepherd
Keyword(s):  
North Sea ◽  
Upper Jurassic ◽  
Hydrocarbon Source Rock ◽  
Submarine Fan ◽  
Oil Accumulation ◽  
The North ◽  
Fault Block ◽  
The North Sea ◽  
The Uk ◽  
Clay Formation

abstractMagnus is the most northerly producing field in the UK sector of the North Sea. The oil accumulation occurs within sandstones of an Upper Jurassic submarine fan sequence. The combination trap style consists of reservoir truncation by unconformity at the crest of the easterly dipping fault block structure and a stratigraphic pinchout element at the northern and southern limits of the sand rich fan. The reservoir is enveloped by the likely hydrocarbon source rock, the organic rich mudstones of the Kimmeridge Clay Formation.

The Auk Field, Block 30/16, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 227-236 ◽  
Author(s):  
Nigel H. Trewin ◽  
Mark G. Bramwell
Keyword(s):  
North Sea ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
The South ◽  
Well Control ◽  
Western Margin ◽  
The North ◽  
Fault Block ◽  
Definition Of ◽  
Central North Sea

AbstractThe Auk field is located in Block 30/16 at the western margin of the Central Graben. Oil is contained in a combination stratigraphic and structural trap which is sealed by Cretaceous chalk and Tertiary claystones. An oil column of up to 400 ft is contained within Rotliegend sandstones, Zechstein dolomites, Lower Cretaceous breccia and Upper Cretaceous chalk. Production has taken place since 1975 with 80% coming from the Zechstein, in which the best reservoir lithology is a vuggy fractured dolomite where porosity is entirely secondary due to the dolomitization process and leaching of evaporites. Both Rotliegend dune slipface sandstones, and the Lower Cretaceous breccia comprising porous Zechstein clasts in a sandy matrix, also contribute to production. Poor seismic definition of the reservoir results in reliance on well control for detailed reservoir definition. The field has an estimated ultimate recovery of 93 MMBBL with 13 MMBBL remaining at the end of 1988.The Auk field is situated in Block 30/16 of the Central North Sea about 270 km ESE from Aberdeen in 240-270 ft of water (Fig. 1). The field covers an area of about 65 km2 and is a combination of tilted horst blocks and stratigraphic traps, located at the western margin of the South West Central Graben. The Auk horst is about 20 km long and 6-8 km wide, with a NNW-SSE trend. It is bounded on the west by a series of faults with throws of up to 1000 ft, and the eastern boundary fault has a throw of 5000 ft in the north reducing to zero in the south (Fig. 2). The horst is a westward tilted fault block in the north which grades into a faulted anticline in the south. The Auk accumulation is largely contained within Zechstein dolomites and is ultimately sealed by Cretaceous chalk which overlies the base Cretaceous erosion surface. An E-W cross-section of the field is illustrated by Fig. 3. Auk was the first of the alphabetical sequence of North Sea sea-bird names used for Shell/ Esso fields.

scholarly journals Correlation of Hydrocarbon Reservoir Sandstones Using Heavy Mineral Provenance Signatures: Examples from the North Sea and Adjacent Areas

Minerals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 564 ◽  
Author(s):  
Andrew Morton ◽  
Paula McGill
Keyword(s):  
North Sea ◽  
Upper Jurassic ◽  
Heavy Mineral ◽  
Hydrocarbon Reservoir ◽  
The North ◽  
The North Sea ◽  
Reservoir Sandstones ◽  
Northern North Sea ◽  
Heavy Mineral Analysis ◽  
Central North Sea

Correlation of hydrocarbon reservoir sandstones is one of the most important economic applications for heavy mineral analysis. In this paper, we review the fundamental principles required for establishing correlation frameworks using heavy mineral data, and illustrate the applications of a wide variety of heavy mineral techniques using a number of case studies from hydrocarbon reservoirs in the North Sea and adjacent areas. The examples cover Triassic red-bed successions in the central North Sea and west of Shetland, which have been subdivided and correlated using provenance-sensitive ratio data and mineral morphologies; Middle Jurassic paralic sandstones in the northern North Sea, correlated using garnet geochemistry; Upper Jurassic deep water sandstones in the northern North Sea, discriminated using rutile geochemistry and detrital zircon age data; and the “real-time” application of the technique at well site in Devonian-Carboniferous fluvio-lacustrine sandstones of the Clair Field, west of Shetland.

scholarly journals Jurassic lithostratigraphy and stratigraphic development onshore and offshore Denmark

2003 ◽  
Vol 1 ◽  
pp. 145-216 ◽  
Author(s):  
Olaf Michelsen ◽  
Lars H. Nielsen ◽  
Peter N. Johannessen ◽  
Jan Andsbjerg ◽  
Finn Surlyk
Keyword(s):  
North Sea ◽  
Middle Jurassic ◽  
Upper Jurassic ◽  
Lower Jurassic ◽  
Coarse Grained ◽  
Late Triassic ◽  
New Members ◽  
Shallow Marine ◽  
Central North Sea ◽  
Sea Area

A complete updated and revised lithostratigraphic scheme for the Jurassic succession of the onshore and offshore Danish areas is presented together with an overview of the geological evolution. The lithostratigraphies of Bornholm, the Danish Basin and the Danish Central Graben are described in ascending order, and a number of new units are defined. On Bornholm, the Lower–Middle Jurassic coal-bearing clays and sands that overlie the Lower Pliensbachian Hasle Formation are referred to the new Sorthat Formation (Lower Jurassic) and the revised Bagå Formation (Middle Jurassic). In the southern Danish Central Graben, the Middle Jurassic succession formerly referred to the Lower Graben Sand Formation is now included in the revised Bryne Formation. The Lulu Formation is erected to include the uppermost part of the Middle Jurassic succession, previously referred to the Bryne Formation in the northern Danish Central Graben. The Upper Jurassic Heno Formation is subdivided into two new members, the Gert Member (lower) and the Ravn Member (upper). The organic-rich part of the upper Farsund Formation, the former informal ‘hot unit’, is established formally as the Bo Member. Dominantly shallow marine and paralic deposition in the Late Triassic was succeeded by widespread deposition of offshore marine clays in the Early Jurassic. On Bornholm, coastal and paralic sedimentation prevailed. During maximum transgression in the Early Toarcian, sedimentation of organic-rich offshore clays took place in the Danish area. This depositional phase was terminated by a regional erosional event in early Middle Jurassic time, caused by uplift of the central North Sea area, including the Ringkøbing–Fyn High. In the Sorgenfrei–Tornquist Zone to the east, where slow subsidence continued, marine sandy sediments were deposited in response to the uplift. Uplift of the central North Sea area was followed by fault-controlled subsidence accompanied by fluvial and floodplain deposition during Middle Jurassic time. On Bornholm, deposition of lacustrine muds, fluvial sands and peats dominated. The late Middle Jurassic saw a gradual shift to shallow marine deposition in the Danish Central Graben, the Danish Basin and Skåne, southern Sweden. During the Late Jurassic, open marine shelf conditions prevailed with deposition of clay-dominated sediments while shallow marine sands were deposited on platform areas. The Central Graben received sand by means of sediment gravity flows. The clay sediments in the Central Graben became increasingly rich in organic matter at the Jurassic–Cretaceous transition, whilst shallow marine coarse-grained deposits prograded basinwards in the Sorgenfrei– Tornquist Zone.

A DEPOSITIONAL MODEL FOR THE DUPUY MEMBER AND THE BARROW GROUP IN THE BARROW SUB-BASIN, NORTHWESTERN AUSTRALIA

1985 ◽  
Vol 25 (1) ◽  
pp. 282 ◽  
Author(s):  
A.M. Tait
Keyword(s):  
Debris Flows ◽  
Upper Jurassic ◽  
Regional Model ◽  
Depositional Model ◽  
Shallow Marine ◽  
Exmouth Plateau ◽  
The North ◽  
Structural Growth ◽  
Northwestern Australia ◽  
East West

A detailed sedimentological study of the Dupuy Member and the Barrow Group has resulted in a regional model for the deposition of these Upper Jurassic to Lower Cretaceous reservoir sequences in the Barrow Sub-basin. The Dupuy Member is interpreted as a prograding offshore slope sequence of turbidite sandstones and debris flows, which built laterally into the Barrow Sub-basin from along its eastern margin. This slope sequence contains bentonite markers in its upper part. The overlying Barrow Group was deposited by a delta which prograded along the length of the Barrow Sub-basin from the southwest and onlapped the Dupuy Member along the eastern side of the sub-basin. The topsets of the delta are fluvial to shallow marine sandstones, the foresets are offshore claystones, and the bottomsets are submarine mass-flow sandstones. After 8 million years of progradation, the delta was starved of sediment by continental breakup south of the Exmouth Plateau and stopped with its last foreset trending in an east-west arc from Barrow Island across the Exmouth Plateau. The Barrow Group delta was then gradually transgressed by the sea and blanketed by the Muderong Shale. Structural growth of the Barrow Island anticline took place during deltaic deposition and caused anomalous relationships between foresets and bottomsets under the north of Barrow Island. Known hydrocarbon accumulations and common shows in the Dupuy Member and the Barrow Group make these sequences attractive exploration targets.

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