Siri, Nini and Cecilie oil fields

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. It is in Block 5604/20 in the far north of the Danish sector near the Denmark-Norway median line. 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.

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. +Siri, Nini and Cecilie fields propertiesFieldSiriNiniCecilleReservoir rockSandstoneSandstomeSandstoneTrapStructural trapStructural and stratigraphic trapStructural and stratigraphic trapGeological agePaleoceneEocene/Paleocene PaleoceneDepth2060 m1700 m 2200 mDiscovery199520002000Field delineation63 km245 km223 km2Oil reserves1.1 million m31.1 million m30.2 million m3Gas 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. +Siri, Nini and Cecilie installationsNameSiri (SCA)Stine SCB-1Stine SCB-2Nini A (Nini West)Nini B

(Nini East)CecilieBlock5604/205604/205604/205605/10 & 145605/10 & 145604/19 & 20Coordinates56.482686°N

4.911144°E56.505947N

5.040943E56.640805N

5.321124E56.674771N

5.412430E56.402115N

4.759621EWater depth, m606060606060Commissioned19992004200320102003TypeFixed steelSubseaSubseaFixed steelFixed steelFixed steelFunctionWellheads, processing, accommodation (60 beds)WellheadWellheadWellheadsWellheadsWellheadsWells, production61183 oil, 1 gasWells, injection21060Substructure weight, tonnes2000160200020002000Topside 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 pipelinesFromToFluidLength, kmDiameter, inchesNoteSCB-1SCAWell fluids98SCB-1SBC-2Injection wateradjacentSCASCB-1Lift gas93SCASALCrude oil16Nini BNini AWell fluids78Nini ASCAWell fluids3214CecilieSCAWell fluids1312SCANini AInjection water3210Nini ANini BInjection water710SCANini ALift gas324Nini ANini BLift gas74SCACecilieLift gas134SCACecilieInjection water1310

Oil production The oil produced across the fields is shown in the tables. +Siri, Nini and Cecilie oil production (1000 m3) 1999-2010199920002001200220032004200520062007200820092010Siri1,5932,1181,7611,487925693703595508598326286Cecilie000016631018311688663833Nini00003911,477624377323355159544 +Siri, Nini and Cecilie oil production (1000 m3) 2011-22201120122013201420152016201720182019202020212022Siri16123213194200206189162124796053Cecilie393217102339323128252323Mini569454268336299310208141117898375 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 consortium has identified the Nini West subsea reservoir as a feasible carbon dioxide (CO2) storage facility. 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.

Siri, Nini and Cecilie oil fields

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