15/12-22
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General information
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Wellbore history
GeneralThe15/12-22 Storkollen well was drilled south of the Sleipner East Field in the south Viking Graben of the North Sea. The objective was test the hydrocarbon and reservoir potential of the Storkollen prospect. Primary target was Oxfordian "Varg Equivalent sandstone" (Hugin Formation) of the Vestland Group, while the Early Tertiary Heimdal/Ty Formations was a secondary target.Operations and resultsWildcat well 15/12-22 was spudded with the semi-submersible installation Bredford Dolphin on 17 April 2010 and drilled to TD at 3035 m in the Late Triassic Skagerrak Formation. A shallow gas influx occurred at 697-700 m while waiting on weather (low wind) after having drilled the 9 7/8" pilot hole to 744 m. The interval had an intermediate shallow gas warning. The gas influx was killed with 1.25 GS mud, and the pilot hole was plugged back for setting the contingent 20" casing with the shoe at 622 m. The well was drilled with seawater/bentonite and hi-vis sweeps down to 622 m, with KCl/polymer/GEM mud from 622 m to 1550 m, and with XP-07 oil based mud from 1550 m to TD.Tertiary sands were penetrated in the Utsira and Skade formations, while the Frigg Formation sandstones were not encountered at the Storkollen location. The secondary target, the Paleocene Heimdal/Ty Formations was not present, and Top Shetland chalks were penetrated at 2320 m, which was 16 m shallower than prognosed. The primary reservoir target, the Hugin Formation of the Vestland Group, was penetrated at 2831 m, which was 22 m shallower than prognosed. The sandstone unit was 154 m thick and had excellent quality with a N/G ratio of 96% and an average porosity of 25%. It was water bearing. GeoTap pressure measurements within the Hugin Formation detected an overpressure of only 42 bars, compared to normal hydrostatic pressure. The low overpressures may indicate compartmentalisation, thus explaining failed migration into the Storkollen 4-way closure. Apart from the shallow gas influx no oil or gas shows are reported from the well.No cores were cut. The well was logged on MWD/LWD and no wire line logs were run. No wire line fluid samples were taken.The well was permanently abandoned on 16 May 2010 as a dry well.TestingNo drill stem test was performed. -
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]630.003035.00 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit10992910941208122921252125215122332317232023202324254126102643267626762683270427302764276427992831283129852985 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]txt0.00txt0.01 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]MWD LWD - DGR EWR ALD CTN BAT PW15503035MWD LWD - DIR108174MWD LWD - DIR PWD174628MWD LWD - EWR GR PWD DIR174744MWD LWD - EWR GR PWD DIR6281550 -
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 typeCONDUCTOR30174.036174.00.00LOTSURF.COND.20622.026628.01.93LOTPILOT HOLE628.09 7/8628.00.00LOTINTERM.13 3/81541.017 1/21550.01.84LOTOPEN HOLE3035.012 1/43035.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1101.04PHB (Sweeps)1781.25Kill Mud4391.04Kill Mud6281.2018.0KCl/GEM6311.2016.0KCl/GEM8631.2017.0KCl/GEM15501.2522.0KCl/GEM16111.2514.0XP-0730351.3519.0XP-07