Skjold oil field explained

Skjold oil field
Location Map:North Sea
Coordinates:55.5314°N 4.9094°W
Relief:yes
Country:Denmark
Region:North Sea
Block:5504/16
Offonshore:Offshore
Operator:Maersk, TotalEnergies
Owner:BlueNord
Nordsøfonden
TotalEnergies
Discovery:1977
Start Production:November 1982
Peak Year:1991
Peak Production:47.08 thousand barrels per day
Expectedabandonment:2038
Oil Production Bbl/D:7152
Production Gas Mmscm/D:4.45
Currentproductionoilyear:2022
Api:30
Formations:Danian and Upper Cretaceous chalk

The Skjold oil field (Danish: Skjoldfeltet) is a crude oil and associated gas production field in the Danish sector of the central North Sea, close to the Danish-German median line. Production of oil started in 1982, peak oil was achieved in 1991 and production is expected to continue until 2038.

The field

The Skjold oil field is located in Block 5504/16 of the Danish North Sea. The name Skjold translates as 'shield' in English.[1] The field was discovered in March 1977 and is a Danian and Upper Cretaceous chalk anticline with salt tectonics.[2] The reservoir has the following characteristics:

Skjold reservoir properties
ParameterValue
Field delineation33 km2
Reservoir depth1,600 m
API gravity30°
Gas/oil ratio510 scf/bbl
Sulfur0.30%
Recoverable reserves30-45 million barrels

Owners and operators

The field was originally licensed to a joint venture called Dansk Undergrunds Consortium (DUC) comprising Shell (40.0%), A.P. Moeller (30.0%), Chevron (15.0%), and Texaco (15.0%). The field was originally operated by Maersk Oil & Gas A/S.

By 2013 ownership of the Skjold field was by Norwegian Energy (37.0%), TotalEnergies (43.0%) and Nordsøfonden (20.0%). The field was operated in 2013 by Maersk Olle og Gas A/S.[3]

As of 2023, it is owned by BlueNord (36.8 %), Nordsøfonden (20.0 %) and TotalEnergies (43.2%).[4] The field is operated by TotalEnergies.

Development

The field was originally developed by a single unattended wellhead platform. No processing was undertaken on the Skjold, and well fluids were routed via an 11km, 6-inch pipeline to the Gorm complex for processing. The Skjold platform was remotely operated from the Gorm installation.

In 1988 a system for the treatment and injection of water into the reservoir was installed on a jack-up rig adjacent to Skjold. This was later replaced by permanent water injection facilities on Gorm with injection water piped to Skjold.[5]

Further infrastructure was subsequently added to the field.[6] This comprised two installations, designated Skjold B and Skjold C, bridge linked to the original installation now designated Skjold A. Skjold B is a wellhead platform allowing further wells to be drilled to reach outlying areas of the reservoir. Skjold C is an accommodation platform. Outline details of the Skjold field platforms are summarised in the table.

Skjold field infrastructure
PlatformSkjold ASkjold B[7] [8] Skjold C
Coordinates55°31’53”N 04°54’34”E55°31'52"N 4°54'32"E55°31'52"N 4°51'24"E
Water depth, metres40 40 40
FabricationJacket: Monberg & Thersen, Aalborg

Topsides: Volund Energiteknik, Essbjerg

Jacket / substructure weight, tonnes1308545830
Topside weight, tonnes90011001200
FunctionWellheadWellhead, bridge link to A platformAccommodation, bridge link to A platform
Accommodation8 (emergency)Nil16
TypeSteel jacketSTAR (see note)STAR
Legs433
Piles433
Well slots97Nil
HelideckS61 helicopterYes
InstalledMay 198219941994
Production startNovember 19821994
Oil and gas production toGorm DA platform
Note: STAR (Slim Tripod Adapted for Rig) is a concept developed by Maersk comprising a three-leg base piled to the seabed supporting a single large diameter column above sea level.[9]

In 1994 a second 11 km pipeline from Skjold to Gorm was laid, this was associated with the increased production from the Skjold field.

As of 2023, there are 16 oil-producing wells and seven water injection wells.

Production

Peak oil production was in 1991 at 47.08 thousand barrels of oil per day.[10]

To maintain production the reservoir pressure is kept high by water injection. Injection water is obtained from the Gorm complex. By 2014 there were 19 production wells and nine water injection wells.

Total fluid production to January 2014 was 45.38 million cubic metres of oil, 3.75 billion normal cubic metres of gas, and 70.65 million cubic metres of water. Water injection was 126.04 million cubic metres of water. The estimated reserves were 6.4 million cubic metres of oil, sufficient to sustain economic production until 2038.

The Danish Energy Agency publishes tables and bar charts of oil, gas and water production from the field, from commissioning in 1982 to the present day.[11]

See also

External links

Notes and References

  1. Web site: Danish to English Dictionary . 23 September 2023 . bab.la.
  2. Book: Gallimore . David . The North Sea Platform Guide . Madsen . Tony . Oilfield Publications Limited . 1985 . 9789995350512 . Ledbury . 613–15.
  3. Web site: 28 July 2023 . Oil & gas field profile: Skjold Conventional Oil Field, Denmark . 20 September 2023 . Offshore Technology.
  4. Web site: Nordsoefonden . Oil and gas producing fields . 24 September 2023.
  5. Book: 1989 . Oil and gas in Denmark, Exploration and Production 1989 . 24 September 2023 . Danish Energy Agency . 8789072243.
  6. Book: Danish Energy Agency . Oil and gas production in Denmark in December 2013 . Danish Energy Agency . 2014 . -978-87-93071-71-1 . Copenhagen . 88–89.
  7. Web site: OSPAR (Convention for the Protection of the Marine Environment of the North East Atlantic) . 2013 . Offshore Installations Inventory . 20 September 2023 . OSPAR.
  8. Web site: Maersk . March 1994 . Maersk Post 3/1994 . 20 September 2023 . Maersk.
  9. Web site: Maersk Oil DBU . 2016 . ESIA Maersk Oil DBU Technical Sections . 24 September 2023.
  10. Web site: A Barrel Full . Skjold Oil Field . 20 September 2023 . A Barrel Full.
  11. Web site: Statistics data, key figures and energy maps . 20 September 2023 . Danish Energy Agency. 25 August 2016 .