2/7-9
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General information
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Wellbore history
GeneralWell 2/7-9 is located in the Ål Basin south of the Eldfisk structure in the southern North Sea. The main purpose of the well was to test Danian -Cretaceous limestone and Jurassic sandstone on a north-south trending anticline 6 - 8 km south of Eldfisk, where these intervals had proven commercial oil in several wells.Operations and resultsAppraisal well 2/7-9 was spudded with the jack-up installation Zapata Nordic on 25 December 1973 and drilled to TD 4448 m in Devonian sediments.Appraisal well 2/7-9 was spudded with the jack-up installation Zapata Nordic on 25 December 1973 and drilled to TD 4448 m in Devonian sediments. The Danian Limestone (Ekofisk Formation) came in at 3086 m. It was expected to be 90 m thick while 77 m was found. The Late Cretaceous Chalk (Cromer Knoll Group) was anticipated to be 695 m thick, but a greater thickness of 800 m was found. Good shows were seen in both intervals, but no hydrocarbons were produced when tested. Sands initially dated Late Jurassic were encountered at 4313 m and proved to be hydrocarbon bearing with a 111 m pay section with average porosity of 13% and 55% oil saturation. A clear OWC was found at 4424 m.These sands have later been interpreted as of Devonian age.No cores were cut and no wire line fluid samples were taken.The well was permanently abandoned on 10 April 1974.TestingThree drill stem tests were conducted in the well.DST 1 tested the interval 4313 to 4356 m in the Devonian sandstones. It produced, after acidization, 36 Sm3 oil and 10000 Sm3 gas /day through a 32/64" choke. The GOR was 278 Sm3/Sm3 and the oil gravity was 45 deg API.DST 2 in the interval 3417 to 3436 m in Late Cretaceous limestone (Tor Formation). It produced no hydrocarbons to surface only 1.6 m3 load water. Samples of formation fluid were taken while reversing out the string content.DST 3 in the interval 3098 to 3109 m in Danian Limestone (Ekofisk Formation). It produced no hydrocarbons to surface only 1 m3 load water. -
Cuttings at the Norwegian Offshore Directorate
Cuttings at the Norwegian Offshore Directorate Cuttings available for sampling?YESCuttings at the Norwegian Offshore Directorate Cutting sample, top depth [m]Cutting samples, bottom depth [m]1234.444447.95 -
Casing and leak–off tests
Casing and leak–off tests Casing typeCasing diam.
[inch]Casing depth
[m]Hole diam.
[inch]Hole depth
[m]LOT/FIT mud eqv.
[g/cm3]Formation test typeCONDUCTOR30145.036146.00.00LOTSURF.COND.20501.026511.00.00LOTINTERM.13 3/81226.017 1/21228.00.00LOTINTERM.9 5/82745.012 1/42752.00.00LOTLINER74064.08 1/24075.00.00LOTOPEN HOLE4448.05 7/84448.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0431343560.02.0341734360.03.0309831090.0Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.038.4002.03.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.03699960.8002782.03.0 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]BHC12264454CBL27433450CDM27454455CDM AP27454455FDC30114455IES12264455ML MLL40714454PML C30113970SNP30113970SRS12264454 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit108294929492968301130863086316335783891389839623962407640764311 -
Geochemical information
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Documents – reported by the production licence (period for duty of secrecy expired)
Documents – reported by the production licence (period for duty of secrecy expired) Document nameDocument formatDocument size [MB]pdf2.74pdf26.38 -
Documents – Norwegian Offshore Directorate papers
Documents – Norwegian Offshore Directorate papers Document nameDocument formatDocument size [MB]pdf72.88pdf0.54pdf0.56 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured25231.85waterbased28921.72waterbased29411.72waterbased33531.71waterbased34011.89waterbased