33/12-6
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General information
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Wellbore history
GeneralWell 33/12-6 was drilled on Tampen Spur in the North Sea between the Gullfaks Sør Field area and the UK border. The objective was to test a large structural feature in the southeastern part of Block 33/12, located across a major regional fault bounding the eastern flank of the Brent and Statfjord Fields. The targets were sands in the Early and Middle Jurassic sandstones of the Statfjord and Brent Groups.Operations and resultsWildcat well 33/12-6 was spudded with the semi-submersible installation Norskald on 2 March 1976 and drilled to TD at 4612 m in the Triassic Hegre Group.The Middle Jurassic Brent Group was encountered at 2973. Gross thickness was 312 meters. Only rare fluorescence with minor gas readings were noted in the sands. Higher gas readings encountered were associated with coal beds. Using cutoffs of 40 percent clay volume and 12.5 percent porosity, Schlumberger’s coriband analysis indicates 103 meters of net sand with an average porosity of 20 percent. The coriband analysis showed the sands to be water wet with only 6 m of net pay with water saturations less than 65 percent, scattered throughout the unit. The Early Jurassic Statfjord Group sands were topped at 3721 meters. Gross thickness was 309.5 meters. Using the same cutoff parameters as for the Brent formation, log analysis indicated 149 meters of net sand with an average porosity of 16 percent and showed the sands to be water wet. Only 3 m of scattered thin zones had water saturations less than 65 percent. No shows were seen in the samples. However, the core in the Statfjord sands had residual oil saturation over the 6.51 meters recovered indicating earlier oil migration through the section.The core was cut from 3736 m to 3744 m in the Statfjord Group. Three FIT fluid samples were acquired. One retrieved 10.2 l filtrate and formation water from 3070 m and two were seal failures (3726.5 m and 3727.5 m).The well was permanently abandoned on 21 June 1976 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]252.004612.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13736.03742.5[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]6.5Cores 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 typeLaboratory1290.0[m]DCRRI1308.0[m]DCRRI1356.0[m]DCRRI1380.0[m]DCRRI1398.0[m]DCRRI1416.0[m]DCRRI1446.0[m]DCRRI1464.0[m]DCRRI1506.0[m]DCRRI1536.0[m]DCRRI1554.0[m]DCRRI1584.0[m]DCRRI1614.0[m]DCRRI1644.0[m]DCRRI2373.0[m]DCRRI2403.0[m]DCRRI2433.0[m]DCRRI2463.0[m]DCRRI2493.0[m]DCRRI2523.0[m]DCRRI2553.0[m]DCRRI2583.0[m]DCRRI2610.0[m]DCRRI2643.0[m]DCRRI2664.0[m]DCRRI -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit164845900177517751827202826702670297329733035321632503285328533973440356537214030 -
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]pdf2.69pdf3.58 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CDM26243806CDM AP26243806DLL MSFL29404102FDC CNL18174616ISF SON2394615VELOCITY2394117 -
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 typeCONDUCTOR30241.036241.00.00SURF.COND.20470.026484.00.00INTERM.13 3/81824.017 1/21835.00.00INTERM.9 5/82625.012 1/42631.00.00OPEN HOLE4614.08 1/24614.00.00 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured4841.0140.0waterbased17641.1949.0waterbased20621.2447.0waterbased27951.4945.0waterbased39141.5045.0waterbased46121.4754.0waterbased