34/6-3 S
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General information
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Wellbore history
GeneralWellbore 34/6-3 S was drilled to appraise the 34/6-2 S Garantiana discovery in the Visund area in the North Sea. The Primary objective was to prove hydrocarbon presence, determine fluid nature and evaluate reservoir characteristics in the Early Jurassic Cook Formation. The secondary objective was to prove petroleum in the Statfjord Group higher up on the structure than the 34/6-2 S well.Operations and resultsGarantiana appraisal well34/6-3 S was spudded with the semi-submersible installation Leiv Eiriksson on 30 May 2014 and drilled to 4462 m (3816 m TVD) in the Early Jurassic Statfjord Group. The well was drilled vertical down to ca 2500 m and deviated with a sail angle of ca 48 ° from there to TD. While RIH with cement stinger for plugging back the Statfjord reservoir prior to testing the Cook reservoir, severe losses leading to formation supercharging was observed. It resulted in ballooning effect. Several bleed off sequences was required to assess and regain normal situation. The well was drilled with seawater and hi-vis sweeps down to 1500 m, with Sildril Sodium Silicate WBM from 1500 m to 2058 m, with EMS-4600 NABM OBM from 2058 m to 3704 m, and with WARP-NABM mud from 3704 m to TD.Top Cook Formation was penetrated at 3850 m (3493 m TVD) and was oil filled all through (oil-down-to) to top Burton Formation at 4000 m (3593 m TVD). The NTG of the Cook formation was proven to be 86 %, with average effective porosity of 22 % and water saturation of 17.5 %. Formation pressure data and the PVT analysis of the acquired DST samples indicate that the formation fluid in the Cook reservoir of 34/6-3S is the same as the fluid encountered in the 34/6-2S exploration well. The Statfjord Group proved to be water bearing with a NTG of 45.7%, effective average porosity of 12.4% and water saturation of 98.4%. Oil shows were described only within the Cook Formation.A total of 77 metres of core was cut and 75.5 metres recovered (98.0% recovery) in two cores from the interval 3918 to 3995 m in the Cook Formation. No wire line fluid sample was taken.The wellbore was plugged back for sidetracking and abandoned on 24 September 2014. It is classified as an oil appraisal well.TestingA well test was performed within the Cook reservoir from 3911 to 3998 m (3533 to 3591 m TVD). The test produced 945 Sm3 oil and 16731 Sm3 gas through a 24/64" choke in the second main flow. The separator GOR was 42 Sm3/Sm3, the stock tank oil density was 0.8784 g/cm3 and the gas gravity was 0.927. The flowing bottom hole temperature was 132.2 °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]1500.004460.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13918.03959.9[m ]23959.93993.5[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]75.5Cores 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 typeCONDUCTOR30472.036472.50.00SURF.COND.201494.0261500.01.40FITINTERM.13 3/82049.017 1/22058.01.63LOTINTERM.9 7/83697.012 1/43704.01.66FITLINER74249.08 1/24462.00.00 -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0391139989.5Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.0132Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.0950167310.8200.92742 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]APS TLD HNGS AITC36303729CMR GR36973701GR RES SON DI20702086LWD - DI GR RES APWD4721500LWD - GR DI APWD RES GR SON39954662LWD - GR DI APWD RES NEU DEN FTW37534116LWD - GR DI APWD RES NEU DEN JPG11000LWD - GR RES SON DI APWD00LWD - GR RES SON DI APWD15003704LWD - GR RES SON DI APWD20532105LWD - RES DI GR APWD SON37043918OBMI PPC MSIP PPC GR32004153USIT CBL VDL GR30903692USIT CBL VDL GR35804163 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit40640611591246124618491849187618862008202220222249337736433759375937933793385140014013436043604407 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured4211.03Sea water4731.35Spud mud7341.03Sea water20611.6232.0NABM21121.6551.0NABM37091.8447.0NABM42511.8241.0NABM44621.8448.0NABM