30/6-11
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General information
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Wellbore history
GeneralWell 30/6-11 was drilled on the Delta structure on the Flatfisk Slope, close to the northwestern end of the Oseberg Fault Block in the North Sea. The primary objective was to find hydrocarbon accumulations in the Brent Group. Secondary objective was to find additional hydrocarbon accumulations within the Early Jurassic Cook Formation and Statfjord Group. The well was placed in an area where a complete Jurassic succession could be expected. Planned TD was 75 m into the Statfjord Group.Operations and resultsWildcat well 30/6-11 was spudded with the semi-submersible installation Nortrym on 20 December 1982 and drilled to TD at 4001 m in the Early Jurassic Statfjord Group. When running casing in the 17 1/2" section at 2165 m the rig had to wait on weather. Cavings accumulated as fill on the bottom and the casing was differentially stuck. Various additives were used to free the casing, including diesel. The well was drilled with seawater and hi-vis pills down to 235 m, with pre-hydrated bentonite and seawater from 235 m to 965 m, and with KCl/polymer mud from 965 m to 2165 m. From 2165 m to 3654 m, the KCl/polymer mud was slowly converted to a dispersed lignosulphonate/lignite mud and in the bottom 8 3/8" section, from 3654 m to TD a dispersed lignosulphonate/lignite mud system was used. From 2165 and downwards the diesel content in the mud was 5%, diminishing to traces below 3265 m.The Brent Group (3351 - 3561m) had a gross thickness of 210 m with 118 m of net sand, giving a net to gross ratio of 0.56. The average porosity of the sandstones were calculated from wireline logs to 16% with an average water saturation of 80%. The Cook Formation (3752.5 - 3768.5m) had a net sand thickness of 3 m, giving a net to gross ratio of 0,19. The average porosity of the sandstones were calculated from wireline logs to 14% with an average water saturation of 55%. The Statfjord Group (3892.5 - 4001 m) had 85 m calculated as net sand giving a net to gross ratio of 0.86. The average porosity was calculated from logs to 11% with a water saturation varying from 60-100%.Oil shows from both cuttings and cores together with high resistivity readings from the logs stated the presence of hydrocarbons in sandstones from the Brent Group, Cook Formation and in the very top of the Statfjord Group. All hydrocarbons were evaluated as residual. Drill stem testing and FMT sampling of the Brent Group produced no hydrocarbons. Otherwise, oil shows were described on limestone stringers in the interval 2515 m to 2635 m and on siltstones in the Late Jurassic between 3265 and 3320 m.Seven cores were cut in this well, one in the Late Jurassic, 5 in the Etive Formation and one in the Cook Formation sandstones. An FMT fluid sample was taken at 3463.5 m. It recovered mud filtrate and water only.The well was permanently abandoned on 30 March 1983 as dry with shows.TestingA drill stem test was performed from the interval 3448.5 to 3454.5 m. The test gave no flow to surface and no samples of formation fluid could be recovered from the test string. -
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]240.004001.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13265.03266.8[m ]23452.03460.0[m ]33461.03465.9[m ]43468.53484.5[m ]53484.53501.7[m ]63502.53508.0[m ]73756.03768.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]65.3Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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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 typeCONDUCTOR30235.036235.00.00LOTSURF.COND.20951.026965.01.76LOTINTERM.13 3/82106.017 1/22165.01.70LOTINTERM.9 5/83639.012 1/43654.01.93LOTOPEN HOLE4000.08 3/84001.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0344934550.0Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.0 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL28503634CCL GR30003504CDL CNL CAL GR9514001DIFL LSBHC GR SP2334001DLL MLL CAL GR32003646FMT32593975HRD21034001SWC14124000VELOCITY9133985 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1467209092055205521272239233323513260326032643351335134593561375237683893 -
Geochemical information
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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]pdf16.56 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured2201.06waterbased7101.1153.0waterbased11901.2150.0waterbased19801.2354.0waterbased25701.3465.0waterbased31101.4450.0waterbased36801.4342.0waterbased40011.4051.0waterbased -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory3262.5[m]SWCRRI3266.8[m]CRRI3303.5[m]SWCRRI3340.5[m]SWCRRI3349.0[m]SWCRRI3415.0[m]SWCRRI3454.5[m]CRRI3458.4[m]CRRI3461.4[m]CRRI3474.8[m]CRRI3484.5[m]CRRI3507.1[m]CRRI3540.0[m]SWCRRI3562.5[m]SWCRRI3570.0[m]DCFUGRO3586.5[m]SWCRRI3619.5[m]SWCRRI3620.0[m]DCFUGRO3635.0[m]SWCRRI3645.5[m]SWCRRI3660.0[m]SWCRRI3660.0[m]DCFUGRO3672.5[m]SWCRRI3710.0[m]DCFUGRO3711.5[m]SWCRRI3727.0[m]SWCRRI3745.0[m]DCFUGRO3756.4[m]CRRI3768.0[m]CRRI3787.0[m]DCFUGRO3798.0[m]SWCRRI3825.0[m]DCFUGRO3875.0[m]DCFUGRO3890.0[m]DCFUGRO3891.0[m]SWCRRI3896.0[m]SWCRRI -
Thin sections at the Norwegian Offshore Directorate
Thin sections at the Norwegian Offshore Directorate DepthUnit3505.75[m ]3503.30[m ]3494.30[m ]3486.50[m ]3482.80[m ]3476.30[m ]3471.80[m ]3464.60[m ]3461.50[m ]3461.20[m ]3453.40[m ]3265.00[m ]