Siri, Nini and Cecilie oil fields explained

Siri oil field
Coordinates:56.482686N 4.911144E
Country:Denmark
Region:North Sea
Blocks:5604/20
Offonshore:Offshore
Operators:DONG E & P A/S
Discovery:1995
Start Production:1999
Peak Year:2000
Peak Of Production:2.188 million cubic metres per year
Formations:Paleocene sandstone structural trap

The Siri oil field and its satellites, Nini and Cecille, are oil producing fields in the Danish sector of the southern North Sea. Operating since 1999 and 2003 they are the most northerly of Denmark's offshore oil assets located close to the Denmark-Norway median line.

The fields

The Siri field comprises a sandstone reservoir of oil with a low gas content.[1] It is in Block 5604/20 in the far north of the Danish sector near the Denmark-Norway median line.[2] The Siri reservoir comprises four areas: Siri Central; Siri North; to the north east Stine segment 2; and Stine segment 1. The field is developed through a single installation (designated SCA) located over the Siri Central formation with subsea wells exploiting Stine1 & 2.[3]

The Nini field is to the north east of the Siri field and is a sandstone oil reservoir. It has been developed through two platforms (Nini A and Nini B also known as Nini East and Nini West) with well fluids piped to Siri SCA installation for processing.

The Cecilie field is located south west of the Siri field, it too is a sandstone oil reservoir. It has been developed by a wellhead platform with well fluids routed to Siri SCA for processing.

Key parameters of the fields are given in the table.

Field!Siri!Nini!Cecille
Reservoir rockSandstoneSandstomeSandstone
TrapStructural trapStructural and stratigraphic trapStructural and stratigraphic trap
Geological agePaleoceneEocene/Paleocene               Paleocene
Depth2060 m1700 m 2200 m
Discovery199520002000
Field delineation63 km245 km223 km2
Oil reserves1.1 million m31.1 million m30.2 million m3
Gas reserves000

Owners and operators

The licence for the Siri field was originally owned by Dong Energy (50%), Altinex (20%) and Talisman (30%). The operator licence was taken over by Dong Energy from Statoil in 2002. The Siri, Nini and Cecilie fields are currently owned and operated by DONG E & P A/S.

Production infrastructure

The fields have been exploited by several subsea and topside installations, as shown in the table.

Name!Siri (SCA)!Stine SCB-1!Stine SCB-2!Nini A (Nini West)!Nini B

(Nini East)!Cecilie

Block5604/205604/205604/205605/10 & 145605/10 & 145604/19 & 20
Coordinates56.482686°N

4.911144°E

56.505947N

5.040943E

56.640805N

5.321124E

56.674771N

5.412430E

56.402115N

4.759621E

Water depth, m606060606060
Commissioned19992004200320102003
TypeFixed steelSubseaSubseaFixed steelFixed steelFixed steel
FunctionWellheads, processing, accommodation (60 beds)WellheadWellheadWellheadsWellheadsWellheads
Wells, production61183 oil, 1 gas
Wells, injection21060
Substructure weight, tonnes2000160200020002000
Topside weight, tonnes80000700700700
The Siri, Nini and Cecilie fields are stranded assets remote from export infrastructure such as pipelines. Oil from SCA is routed to a 50,000 m3 storage tank on the seabed. The tank is 50 m x 66 m and  17.5 m high. It is emptied periodically by tanker via a Single Anchor Loading (SAL) buoy mooring system.

Pipelines

In addition to the offshore installations there are a number of pipelines connecting and transferring fluids within the fields

Siri, Nini and Cecilie and connected pipelines!From!To!Fluid!Length, km!Diameter, inches!Note
SCB-1SCAWell fluids98
SCB-1SBC-2Injection wateradjacent
SCASCB-1Lift gas93
SCASALCrude oil16
Nini BNini AWell fluids78
Nini ASCAWell fluids3214
CecilieSCAWell fluids1312
SCANini AInjection water3210
Nini ANini BInjection water710
SCANini ALift gas324
Nini ANini BLift gas74
SCACecilieLift gas134
SCACecilieInjection water1310

Oil production

The oil produced across the fields is shown in the tables.

199920002001200220032004200520062007200820092010
Siri1,5932,1181,7611,487925693703595508598326286
Cecilie000016631018311688663833
Nini00003911,477624377323355159544
201120122013201420152016201720182019202020212022
Siri16123213194200206189162124796053
Cecilie393217102339323128252323
Mini569454268336299310208141117898375
Water and recovered gas are co-injected into the Siri and Nini reservoirs to increase oil recovery. An average of 2.98 million m3 of water per year is injected.

The future

The Project Greensand[4] consortium has identified the Nini West subsea reservoir as a feasible carbon dioxide (CO2) storage facility.[5] The reservoir is suitable for injecting 0.45 million tonnes CO2 per year per well for a 10-year period and that it can safely contain the CO2 in compressed form. If successful the project could be extended to the whole Siri field. Work on the project is ongoing.

See also

Notes and References

  1. Web site: Danish Energy Agency . 2013 . Oil and gas production in Denmark . 9 November 2023 . Copenhagen.
  2. Web site: 2021 . Danish oil and gas fields . 10 November 2023.
  3. Web site: Statoil Oil and Gas Field Project . 9 November 2023.
  4. Web site: Project Greensand . 11 November 2023.
  5. Web site: 2023 . Denmark Starting signal for successful CCS .