30/9-3
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General information
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Wellbore history
GeneralWell 30/9-3 was drilled on the Gamma West structure on the Oseberg Fault Block in the northern North Sea. The primary objective was to find hydrocarbon accumulations in the Middle Jurassic Brent Group. Secondary objective was to find additional hydrocarbon accumulations in the Early Jurassic. Planned TD was ca 75 m below a possible intra Triassic marker to a depth of 4188 +/- 100 mOperations and resultsWildcat well 30/9-3 was spudded with the semi-submersible installation Nortrym on 31 December 1983. The well was drilled to a depth of 3113 m into Drake Formation shales where the pipe got stuck and parted when pulling out of hole for logging. The fish was not recovered and no wire line logs were recorded below 1713.5 m due to fish in hole. All lithostratigraphic interpretation below this point is therefore based on cuttings description, core description, chromatograph data and ROP information. A sidetrack was decided to complete the well programme. The well was drilled with spud mud down to 625 m and with Invermul/EZmul Oil Based Mud from 625 m to TD.The Brent Group (2712-3045 m) consisted of a 259 m thick Ness Formation (2712 - 2971 m) made up of sandstones with stringers of shale, siltstone and coal and 74 m of Etive Formation (2971 - 3045m) sandstones. Based on chromatograph analysis on hydrocarbon samples extracted from core samples a GOC was found at ca 2734 m and an OWC at ca 2815 m, both located in the Ness Formation. From core and chromatograph data the Ness Formation had a gross pay of 103 m. The net gas pay was estimated to 22 m and the net oil pay to 36 m giving a total net pay of 58 m (cut off values porosity < 12%, permeability < l mD). The average porosity was calculated from cores to 22.5 % and average horizontal permeability to 1090 mD. Oil shows were recorded in Maastrichtian limestone in the upper part of the Shetland Group.Fifteen cores were cut in the well, all in the Brent Group, twelve in the Ness Formation and three in the Etive Formation. No wire line fluid samples were taken.The well was plugged back for sidetracking on 26 February as an oil discovery.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]220.003112.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12714.52715.5[m ]22716.02719.3[m ]32719.72735.5[m ]42735.52753.5[m ]52753.52781.0[m ]62781.02800.0[m ]72802.02824.0[m ]82824.02842.3[m ]92842.52860.0[m ]102860.02869.4[m ]112870.02888.0[m ]122888.02906.5[m ]132995.03007.5[m ]143008.53026.5[m ]153026.53030.9[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]223.0Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Oil samples at the Norwegian Offshore Directorate
Oil samples at the Norwegian Offshore Directorate Test typeBottle numberTop depth
MD [m]Bottom depth
MD [m]Fluid typeTest timeSamples availableDST0.000.00YES -
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 typeCONDUCTOR30221.036222.00.00LOTSURF.COND.20616.026625.01.51LOTINTERM.13 3/81699.017 1/21715.01.70LOTOPEN HOLE3113.012 1/43113.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CDL CAL GR6151713DIFL LSBHC GR SP135625DIFL LSBHC GR SP6151712 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit135594843994205120512131222023442354235425782655265526772712297130453045 -
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]pdf3.23pdf16.18 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured8701.1225.030.0OIL BASED12601.0928.016.0OIL BASED13851.12OIL BASED19001.3332.019.0OIL BASED22801.4030.018.0OIL BASED23601.4129.021.0OIL BASED25001.4331.018.0OIL BASED28751.4535.017.0OIL BASED29751.4445.013.0OIL BASED30601.4939.022.0OIL BASED30901.4438.020.0OIL BASED -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory3816.2[m]SWCWESTLB3827.0[m]SWCWESTLB3831.0[m]SWCWESTLB3834.0[m]SWCWESTLB3838.0[m]SWCWESTLB3855.5[m]SWCWESTLB3883.0[m]SWCWESTLB3910.5[m]SWCWESTLB3913.5[m]SWCWESTLB3917.5[m]SWCWESTLB3919.5[m]SWCWESTLB