2/6-4 S
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General information
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Wellbore history
GeneralWell 2/6-4 S is located in the northwest part of the Søgne Basin in the North Sea. It was drilled on the flank of a salt dome. The objectives were to evaluate the potential of the Late and Middle Jurassic series, which were supposed to accommodate three reservoirs; turbiditic sands in the Mandal-Farsund Formations, shallow marine Ula Formation sands of Kimmeridgian to Volgian age, and fluvial sands of the Middle Jurassic. Oil was expected with only small amounts of associated gas.Operations and resultsWildcat well 2/6-4 S was spudded with the semi-submersible installation West Vanguard on 8 April 1990 and drilled to TD at 3627 m (3617 m drillers depth, 3584 m TVD MSL drillers depth) in the Late Permian Zechstein Group. The well was drilled deviated down to 2330 m to avoid possible shallow gas pockets seen on seismic. No shallow gas was encountered. From 2330 m it was drilled with an average of 15 deg dip to the target at 3402 m, then dropping of to less than 10 deg dip for the rest of the well down to TD. No significant drilling problems occurred during drilling operations, but due to a problem of tie-in with gamma ray drillers depth was 10 m shallower than logger's depth in the lower part of the well.The results of the well were disappointing since the Ula formation was missing, and only two meters of Kimmeridgian sands were encountered at 3537 m (3527 m driller's depth). These sands were very glauconitic, silty and well cemented with porosity estimated around 5-7%. The Bryne formation was thicker than expected, but had limited reservoir quality with only some thin sand beds separated by shaley layers towards the base of the Formation. All Jurassic sands were water bearing without shows, except for some fluorescence in fissures in a coal at the top of the Bryne Formation. Small shows at 2930 to 3040 m (in upper Tor Formation) were described as: "- background gas increases and remains between 1 to 7.7 % (max at 2970 m) with presence of C1 to traces of C5. On this interval, direct fluorescence was observed on cuttings (10 to 20 % light yellow spots) with a slow to moderate streaming pale milky cut fluorescence."One core was cut at 3530 m in the Middle-Late Jurassic with 67% recovery 67%, (4 m). Two runs of SWC were run with a recovery 50 SWC. Since no significant reservoir was encountered no RFT pressures or fluid samples were acquired.The well was permanently abandoned on 2 June 1990 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]520.003617.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13530.03534.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]4.0Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory3430.0[m]DCAPT3440.0[m]DCAPT3450.0[m]DCAPT3465.0[m]DCAPT3470.0[m]DCAPT3480.0[m]DCAPT3490.0[m]DCAPT3500.0[m]DCAPT3510.0[m]DCAPT3517.5[m]DCAPT3527.5[m]DCAPT3540.0[m]DCAPT3550.0[m]DCAPT -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit7714422755275527672799282628582858292331713402353735423542360636063615 -
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]pdf2.62pdf7.87 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL GR8002267CST GR12002203CST GR34043611DIL DDBHC GR AMS SP33343627DIL LDL DDBHC GR AMS SP10012286DIL LDL DDBHC GR AMS SP22673345FMS GR33343628LDT CNL AMS NGT33343628MWD1393617VSP9303320VSP33403610 -
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 typeCONDUCTOR30137.036140.00.00LOTINTERM.201002.0261007.01.75LOTINTERM.13 3/82267.017 1/22270.01.92LOTINTERM.9 5/83331.012 1/43331.01.96LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured12041.2922.014.7DUMMY19.04.199022251.4033.015.6DUMMY23.04.199022831.4531.018.6DUMMY24.04.199023141.5520.09.8WATER BASED30.04.199025231.5524.010.7WATER BASED30.04.199034871.6024.09.8WATER BASED21.05.199035301.6023.09.8WATER BASED22.05.199035361.6020.09.8WATER BASED23.05.1990