34/5-1 S
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General information
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Wellbore history
GeneralWell 34/5-1 S was drilled on the Blåbær prospect in Tampen North in the northern North Sea, ca 10 km to the southwest the 34/3-1 S Jordbær discovery. The objective was to prove hydrocarbons in the Cook and Statfjord formations.Operations and resultsWildcat well 34/5-1 S was spudded with the semi-submersible installation Bredford Dolphin on 7 January 2010 and drilled to TD at 3900 m (3737 m TVD) in the Early Jurassic Statfjord Formation. The spud location was selected to avoid an area with risk of possible shallow gas. It was drilled vertical down to the end of the 17 1/2" section at 2135 m, deviated to maximum 35 degrees through the 12 1/4" section and back to vertical in the deepest 100 m of the final 8 1/2" section. Some hole problems were encountered in the 17 1/2" section, believed to be caused by the hole being left open too long due to WOW, otherwise operations went forth without significant problems. The well was drilled with seawater and hi-vis sweeps down to 467 m, with KCl/Glycol Enhanced Mud (GEM) from 467 m to 2135 m, and with XP-07 oil based mud from 2135 m to TD.Top Cook (Late Pliensbachian) reservoir came in at 3629 m, 57 m shallower than the pre-drill prediction. The Cook Formation sandstones had an average porosity of 18.3% and 20 m of net sand based on a 50% Vsh cut-off and 10% porosity. The secondary target Statfjord Formation was penetrated at 3834 m, 55 m shallower than prognosed. Statfjord was inferred to be water bearing from the LWD data. An extensive wire line programme was carried out after reaching TD. After analysing the acquired data it was concluded that the Cook reservoir was oil bearing. The lower Cook interval showed the best reservoir quality with average porosity of 20% and average Sw of 40%. The oil/water contact was interpreted to be below the lowest sand in the Cook Fm. Oil shows were recorded only in the Cook Formation reservoir, with weak shows in the upper part, and the strongest shows below 3684 m.Two cores were cut in the reservoir. Core 1 was in the interval 3640.5 m to 3667.5 m with 100% recovery. Core 2 was cut from 3667.5 m to 3702 m, with a 62% recovery from the top of the interval. Oil samples were collected by MDT at 3647.5 m, 3688 m, 3690.2 m and 3694.1 m.The well plugged back on 13 March 2010 for sidetrack 34/5-1 A to test a neighbouring Blåbær fault block. It is classified 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]480.003900.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13640.53667.5[m ]23667.53688.9[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]48.4Cores 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 availableMDT3690.200.00OILYESMDT3694.100.00OILYESMDT3688.000.00OILYES -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit412133314351450156115681890189019222010201022353355354435443553355336293696376138343834 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CMR XPT EDTC GR ATCS LEH QT35943780HNGS EDTC LEH QT35813902LWD - ALD CTN BAT FTWD35913900LWD - BAT PWD EWR AGR ABGT21353591LWD - BAT PWD EWR DGR GABI PCDC9622135LWD - DGR EWR PWD466964LWD - DWD412470LWD - GABI DIR RES GR PWD -35913900LWD - PCDC ALD21353591MDT35813694MSCT35953694MSCT36213640MSCT36953719OBMI DS35813775OBMI GPIT DSI PPC EDTC GR LEH QT35813895VSI4693890ZAIT GPIT TLD CNL ECS -35813902ZAIT GPIT TLD CNL ECS HNGS35813800 -
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 typeCONDUCTOR30466.036470.00.00LOTSURF.COND.20957.026964.00.00LOTINTERM.13 3/82125.017 1/22135.00.00LOTINTERM.9 5/83583.012 1/43591.00.00LOTOPEN HOLE3900.08 1/23900.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured4551.04HiVis sweeps4601.3921.0KCL/GEM4631.04Hi-vis sweeps4921.3928.0KCL/GEM5601.04KCL GEM6271.3923.0KCL/GEM9641.3925.0KCL/GEM10541.3519.0KCL/GEM17691.3512.0KCL GEM21351.4022.0XP-0721351.4124.0XP-0721351.3525.0KCL/GEM22721.6029.0XP-0731381.5729.0XP-0734831.6028.0XP-0736411.8535.0XP-0737021.8536.0XP-0739001.8538.0XP-0740981.6023.0XP-07