2/11-5
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General information
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Wellbore history
GeneralWell 2/11-5 was drilled on the western lobe of the Hod Field to test the Late Cretaceous Chalk section. The well was located 1.8 km SSE of 2/11-2 which tested oil from a very thin Chalk section of the Lower Hod Formation. Structural interpretations were made showing a NW-SE trending graben traversing the West Hod lobe. Based on a model from East Hod, it was expected that the porous Tor Formation should be preserved below the unconformity within this structure.Operations and resultsWell 2/11-5 was spudded with the semi-submersible installation Dyvi Alpha on 18 May 1979 and drilled to TD at 2945 m in the Early Cretaceous Rødby Formation. No significant problem was encountered in the operations, however six days were spent repairing the BOP stack before it could be run and two days were spent while mixing oil-based mud. The well was drilled with seawater, bentonite and CMC EHV down to 1285 m, with gyp/CMC mud from 1285 m to 2320 m, with lignosulphonate mud from 2320 m to 2765 m, and with oil based "Oilfaze" mud from 2765 m to TD.The Paleocene Ash Marker (Balder Formation) was encountered at 2715 m; 105 m low to prognosis. The top of the Chalk Group, Ekofisk Formation was encountered at 2822 m; 117 m low to prognosis. In total, the Chalk section was found to be 98 m thick, whereas 300 m was predicted. These discrepancies reflect the effects of the shallow gas in the area on the seismic data. The velocity corrections which were applied to the seismic were too large. As a consequence, the Chalk Group within the Graben was found below the oil-water contact of the area and no moveable hydrocarbons were encountered. Frequent oil shows were reported however, starting in the upper part of the Hordaland Group:1470 - 1575 m: Appr.100% dull yellow fluorescence w/slow white streaming cut, strong odour.1575 - 1760 m: 20-100% dull yellow fluorescence w/slow white streaming cut, large pieces bleeding gas.1760 - 2050 m: 5-20% dull yellow fluorescence w/slow white streaming cut.2050 - 2715 m: 100% dull to golden yellow fair to good fluorescence; moderate to fast streaming white cut; fair to good oil stain.2715 - 2737 m: 20-50%, fair dull golden fluorescence and fair cut.2825 - 2900 m: 20-80%, dull yellow/ orange fluorescence. No to fair cut.No conventional cores were cut in well 2/11-5. Out of 25 sidewall cores 17 were recovered in the Late Cretaceous chalk. No wire line fluid samples were taken.The well was permanently abandoned on 5 July 1979 as a well with shows.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]165.002867.50 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit941475271527152737282228222835285529202920 -
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]pdf1.95pdf14.15pdf0.73 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]BHC AL IEL GR SP168356BHC AL IEL GR SP295766BHC AL IEL GR SP12742777BHC AL IEL GR SP26902943CBL VDL GR CCL11250CBL VDL GR CCL20002723CDL CDN GR CAL00DIP12772645DIP27652943VELOCITY1462901 -
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 typeCONDUCTOR30170.036172.00.00LOTSURF.COND.20351.026358.01.48LOTINTERM.13 3/81278.017 1/21278.01.92LOTINTERM.9 5/82768.012 1/42781.01.84LOTOPEN HOLE2945.08 1/22945.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3581.0435.0waterbased11701.0730.0waterbased16831.5938.0waterbased19801.7275.0waterbased23871.7595.0waterbased27071.8052.0waterbased27811.7456.0waterbased