34/3-3 S
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General information
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Wellbore history
GeneralWell 34/3-3 S was drilled on the Jordbær Vest west of the Knarr field (formerly called Jordbær) in the northern part of the North Sea. The objective was to prove hydrocarbons in the Early Jurassic Cook formation.Operations and resultsWildcat well 34/3-3 S was spudded with the semi-submersible installation West Alpha on 10 September 2011 and drilled to TD at 4063 m (4012 m TVD) in the Early Jurassic Burton Formation. A 9 7/8" pilot hole was drilled to 983 m to check for shallow gas. No shallow gas was encountered. The well was drilled vertical down to 2220 m and deviated with up to 15 dg inclination from there to TD. No significant problem was reported. The well was drilled with sea water and hi-vis sweeps down to 984 m, with Glydril/KCl mud from 984 m to 2240 m, with Versatec oil based mud from 2240 m to 3780 m, and with Versatherm oil based mud from 3780 m to TD.Cook Formation sandstones were penetrated at 3907.5 m (3859.8 m TVD), which was 42.8 m deeper than prognosed. Light oil was encountered in the upper Cook Formation down to 3932 m (3884 m TVD). A definite OWC was not resolved from the data. Convincing oil shows were recorded on cores from the reservoir down to 3938 m, otherwise no oil shows above the oil based mud were reported from the well.A total of 80.42 m core was cut in the Cook Formation from 3910.85 m to 3992 m. The upper 9 m of core 1 was fragmented due to problems with the inner core liner. Core depth shifts were from 0.14 to 0.94 m relative to logger's depth. MDT fluid samples were taken at 3915.9 m (oil) and 3946.7 m (water). The temperature at sea bed was measured by ROV and at survey stations in the Jordbær area wells at different times during the year. These measurements gave an average of 6.5 deg C at sea bed.The well was plugged back for sidetracking on 19 November 2011. It is classified as an oil discovery.TestingA successful DST was performed over the interval in 3912.5 to 3928.5 m in the Upper Cook Formation. The reservoir produced at a rate of 1220 Sm3 oil and 75700 Sm3 gas/day through a 32/64" fixed choke during the main flow. The first stage separator GOR was 62 Sm3/Sm3, oil density was 0.778 - 0.805 g/cm3, H2S = 5 - 10 ppm, CO2 = 4 - 9%, and gas gravity was 0.832 - 0.864 (air = 1). The maximum bottom hole temperature measured during the main flow was 137.8 deg 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]990.004063.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13910.93938.4[m ]23938.43965.8[m ]33965.83991.3[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]80.4Cores 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 availableMDT3928.503912.50OILYES -
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 typeCONDUCTOR36496.042498.00.00LOTSURF.COND.20980.026984.01.66LOTINTERM.13 3/82235.017 1/22240.01.92LOTINTERM.9 5/83774.012 1/43781.02.06LOTLINER74053.08 1/24063.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.03912392812.7Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.0137Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.01200757000.7780.83262 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]GR DI418498GR DI498984GR RES DEN NEU DI APWD39924063GR RES DI APWD SON418983GVR GR RES DI APWD37813911MDT39073965MSCT GR37744047PDGR GR RES DI APWD SON9842240PDGR GR RES DI APWD SON DEN22403781PEX CMR ECS HNGS38964008VSI4 GR20004040ZAIT PPC MSIP PPC GPIT GR37264066 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit41841813881483148319641964198820052090209022673433373937393748374839083996 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured25701.6037.0Versamud39101.8041.0Versamud39381.8040.0Versamud39921.8041.0Versamud40631.7836.0Versamud40630.0053.0Versamud40631.7836.0Versamud40631.031.0Versamud