25/11-2
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General information
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Wellbore history
GeneralWell 25/11-2 was drilled to appraise the 25/11-1 Balder discovery on the Utsira High in the North Sea. The objective was to define the continuity and reservoir thickness of the Early Eocene oil bearing sands in a northward direction from well 25/11-1 and a southward direction from well 25/8-1.Operations and resultsAppraisal well 25/11-2 was spudded with the vessel Glomar Grand Isle on 13 September 1970 and drilled to TD at 1823 m in the Paleocene Sele Formation. No significant problems occurred during the operations. The well was drilled with seawater/gel down to 175 m, with seawater/Spersene/ XP-20/Salinex from 175 m to 945 m, and with fresh water/ Spersene/XP-20 from 945 to TD.The well penetrated the Utsira Formation and several Skade Formation sand units and then entered a ca 600 m thick section of shales belonging to the lower Hordaland Group before top Balder formation was encountered at 1699 m. The Balder Formation contained several thin Intra Balder Formation sandstones, of which a seven meter thick sandstone at 1727 m was the thickest. The sands were oil bearing down to 1747 m. Hermod sandstones were penetrated from 1780 to 1817 m. They had better reservoir properties than the Intra Balder Formation sands, but were water bearing without shows.No conventional cores were cut in the well. Out of four attempts with the Formation Interval Tester (FIT) three tests were seal failures while test no 4, at 1728.5 m, was successful and recovered 0.33 Sm3 gas, 6.9 l oil, and 3.25 l oil and gas cut mud.The well was permanently abandoned on 24 September as an oil appraisal.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]405.381822.71 -
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 typeCONDUCTOR30175.036180.00.00LOTSURF.COND.13 3/8388.017 1/2405.00.00LOTINTERM.9 5/8945.012 1/4960.00.00LOTOPEN HOLE1856.08 1/21856.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]FDC9441822GR137944IEL9441823NHC SON GR9441819VELOCITY9441824 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1405827167477479399971015108610921699169917271734176517801817 -
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]pdf1.01pdf3.20 -
Documents – Norwegian Offshore Directorate papers
Documents – Norwegian Offshore Directorate papers Document nameDocument formatDocument size [MB]pdf18.56pdf0.48pdf0.41 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1750.00seawater/ge9450.00seawater/sp18230.00water/spers -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory3000.0[ft]DC3090.0[ft]DC3180.0[ft]DC3300.0[ft]DC3390.0[ft]DC3480.0[ft]DC3600.0[ft]DC3690.0[ft]DC3780.0[ft]DC3900.0[ft]DC3990.0[ft]DC4080.0[ft]DC4170.0[ft]DC4290.0[ft]DC4380.0[ft]DC4500.0[ft]DC4590.0[ft]DC4680.0[ft]DC4770.0[ft]DC4890.0[ft]DC4980.0[ft]DC5100.0[ft]DC5190.0[ft]DC5300.0[ft]DC5320.0[ft]DC5360.0[ft]DC5400.0[ft]DC5440.0[ft]DC5460.0[ft]DC5480.0[ft]DC5500.0[ft]DC5520.0[ft]DC5539.0[ft]SWC5554.0[ft]SWC5560.0[ft]SWC5580.0[ft]DC5583.0[ft]SWC5640.0[ft]SWC5654.0[ft]SWC5670.0[ft]DC5722.0[ft]SWC5740.0[ft]SWC5776.0[ft]SWC5788.0[ft]SWC5790.0[ft]DC5800.0[ft]SWC5828.0[ft]SWC5862.0[ft]SWC5880.0[ft]DC5970.0[ft]SWC5970.0[ft]DC