30/4-2
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General information
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Wellbore history
GeneralWell 30/4-2 was drilled test an easterly dipping fault block on the western margin of the Viking Graben. The primary target was the Brent Group, which had already been proven to contain gas condensate by well 30/7-6 located 3 km to the South on the same structure. Secondary objectives were to test Palaeocene and Lower Eocene sandstones, and the Statfjord Formation. Well 30/7-2 had earlier encountered a hydrocarbon column with dry gas overlying heavy oil in the uppermost part of the Eocene Frigg Formation.Operations and resultsWell 30/4-2 was spudded with the semi-submersible installation SEDCO 707 on 16 November 1979 and drilled to TD at 4775 m in the Triassic Hegre Group. Bad weather caused some delay, and on 12 March, the drill string was hung-off due to adverse weather conditions. Whilst retrieving the running assembly an influx from the well was observed. The influx was bull-headed and it took five days before the well was in stable conditions again. Otherwise, no significant incident happened in the operations. The well was drilled with seawater and gel down to 1096 m, with lignosulphonate/Drispac/Gypsum mud from 1096 m to 2530 m, and with lignosulphonate/Poly-rx from 2530 to TD.The Frigg Formation was encountered water-wet without shows at 1820 m, 36.5 m below the OWC defined in the 30/7-2 Frigg discovery. The Brent Group was encountered at 3779 m. Brent contained gas/condensate and had excellent poroperm characteristics. The gas-water contact established between 3876.5 m and 3893.5 m in the Ness Formation. The Statfjord Formation was encountered water-wet at 4337 m with only some poor shows in the top. Pressure analysis showed that it was not communicating with the Brent Group.Thirteen full-hole cores were cut in well 30/4-2: two in the Tertiary, ten in the Jurassic Brent Group and one in the Dunlin formation. A total of 143.7 m core was recovered. A segregated RFT sample was take at 3827.5 mThe well was permanently abandoned on 16 May 1980 as a gas/condensate appraisal well.TestingOne drill stem test was performed from the interval 3832 to 3838.1 m. The test produced 811300 Sm3 gas and 174 Sm3 condensate /day through two downhole 1/2" chokes and a 38/64" surface choke. The GOR was 4663 Sm3/Sm3, the oil gravity was 45 °API, and the gas gravity was 0.64 (air = 1). The maximum gauge temperature in the test was 134.4 °C. -
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]288.004774.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom22043.02047.4[m ]33784.03784.9[m ]43788.83805.4[m ]53805.43822.3[m ]63823.53829.9[m ]73829.93834.7[m ]83834.73852.8[m ]93853.13871.3[m ]103871.53873.0[m ]113873.03891.4[m ]123891.43909.7[m ]134239.54257.8[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]142.7Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
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 typeCONDUCTOR30261.036264.00.00LOTSURF.COND.201105.0261111.01.53LOTINTERM.13 3/82499.017 1/22506.01.79LOTINTERM.9 5/83694.012 1/43692.02.09LOTLINER74170.08 1/24172.02.27LOTOPEN HOLE4751.064751.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.03807381315.0Drill 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]1.068188120000.8020.640199 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL21002716CBL35054153CBL35154174CST00DLL37173964FDC CNL11202115FDC CNL39254196FDC CNL41844772HDT37174196HDT41854501HRT20002897ISF SON2841137ISF SON11002525ISF SON17452117ISF SON24903723ISF SON36953716ISF SON39254197ISF SON41903393ISF SON44054775RDC CNL37173966RFT31613701RFT37823782RFT37853947RFT43494476VS2843725VS37254532 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit147975182019591959197319962313370537053726378037803862402440364061406141274208424343374670 -
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]pdf78.46 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured9461.06waterbased15321.19waterbased20911.28waterbased29771.65waterbased34551.70waterbased39422.04waterbased47512.09waterbased -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1070.0[m]DCGEOCH1100.0[m]DCGEOCH1110.0[m]DCGEOCH1160.0[m]DCGEOCH1190.0[m]DCGEOCH1220.0[m]DCGEOCH1250.0[m]DCGEOCH1280.0[m]DCGEOCH1310.0[m]DCGEOCH1340.0[m]DCGEOCH1370.0[m]DCGEOCH1400.0[m]DCGEOCH1430.0[m]DCGEOCH1460.0[m]DCGEOCH1490.0[m]DCGEOCH1520.0[m]DCGEOCH1550.0[m]DCGEOCH1580.0[m]DCGEOCH1610.0[m]DCGEOCH1640.0[m]DCGEOCH1670.0[m]DCGEOCH1710.0[m]DCGEOCH1740.0[m]DCGEOCH1769.0[m]DCGEOCH1796.0[m]DCGEOCH1823.0[m]DCGEOCH1850.0[m]DCGEOCH1877.0[m]DCGEOCH1904.0[m]DCGEOCH1931.0[m]DCGEOCH1958.0[m]DCGEOCH1994.0[m]DCGEOCH2021.0[m]DCGEOCH2045.0[m]DCGEOCH2075.0[m]DCGEOCH2102.0[m]DCGEOCH2130.0[m]DCGEOCH2160.0[m]DCGEOCH2190.0[m]DCGEOCH2220.0[m]DCGEOCH2250.0[m]DCGEOCH2280.0[m]DCGEOCH2310.0[m]DCGEOCH2340.0[m]DCGEOCH