34/10-33 C
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General information
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Wellbore history
GeneralWell 34/10-33 C is a sidetrack from appraisal well 34/10-33 B on the Gullfaks South Discovery. The B sidetrack was drilled to perform a long-period test from a horizontal well through the upper part of the Brent Group, as part of the development of the Gullfaks South discovery. As the test in the B sidetrack failed the C-sidetrack was drilled with the same main objectives, but this sidetrack was not to be drilled horizontally. The test should provide information about requirement for pressure support during oil production, pressure communication in the gas cap during production, treatment of oil with high wax content, and it should collect liquid samples from the reservoir. Secondary objectives for the C sidetrack was to penetrate a complete Rannoch formation down flanks from well 34/10-33 and to establish the oil/water contact in the lower part of the pressure regime (Etive/Rannoch formations).Operations and resultsThe well 34/10-33 B was abandoned and an EZSV set at 3280 metres. Appraisal well 34/10-33 C was kicked off on 10 July 1989 through the 9 5/8" casing from a Packstock tool set at 3279 metres in the Tarbert Formation. The well bore was drilled with the semi-submersible installation Deepsea Bergen to TD at 3752 m (3587 m TVD) in the Early Jurassic Drake Formation. No significant problems occurred while drilling this well. The well was drilled with Interdrill NT oil based mud from kick-off to TD.FMT pressure points defined a gas/oil contact at 3302 m (3242 m TVD MSL) +/- 5 m and an oil/water contact at 3604 m (3460 m TVD MSL) +/- 20 m. Logs and sidewall cores indicated oil down to 3617 m (3467 m TVD MSL). Further shows evaluation from cuttings is uncertain due to oil based mud. The FMT measurements proved a pressure barrier within the interval 3521 - 3550 m (3398 - 3418 TVD MSL) in the Ness Formation.Twenty-three sidewall cores were retrieved, but no conventional cores were cut in this well. An FMT wire line fluid sample was taken at 3641 m (3483 m TVD MSL) below OWC in the water zone.After long-term testing the well was suspended on 16 September 1989 as an oil and gas appraisal well.TestingA long-term test was conducted, producing a total of 60 000 Sm3 oil. During the test, from 1 August up to 16 September, the well was classified as test well under the name 34/10-T-33 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]3283.003751.00 -
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 availableDSTDST 1B0.000.0011.04.1990 - 00:00YES -
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 typeCONDUCTOR30219.036220.00.00LOTCONDUCTOR30225.036225.00.00LOTINTERM.20453.026461.01.43LOTINTERM.13 3/81828.017 1/21838.01.53LOTINTERM.9 5/83272.012 1/43493.01.70LOTLINER73751.08 1/23753.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.03448351720.6Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.023.00016.00042.000Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.016353055580.8590.680186 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL GR31603706DIFL ACL CDL CN GR32713755DIPS GR32853757FMT HP GR32813658FMT HP GR32903507MWD - GR DIR32813752SWC GR33503612 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit157963974102911391247151415621610182118211897204820482340300830083012301230453215321533453601361737223722 -
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]pdf0.60pdf31.75 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured33421.5533.010.0OIL BASED19.07.198933481.5521.03.5WATER BASED28.02.199033481.5518.02.5WATER BASED02.03.199033481.5515.03.5WATER BASED27.03.199033481.5516.03.0WATER BASED13.03.199033481.5516.03.0WATER BASED14.03.199033481.5517.02.5WATER BASED05.03.199034091.5533.010.0OIL BASED19.07.198934181.5515.03.5WATER BASED27.03.199034181.5515.03.5WATER BASED27.03.199034301.3734.010.0OIL BASED19.07.198934481.6517.03.0WATER BASED19.03.199034481.6517.03.0WATER BASED19.03.199034481.5515.03.0WATER BASED22.03.199034481.5515.03.0WATER BASED23.03.199034481.5515.02.5WATER BASED26.03.199034481.5516.03.0WATER BASED16.03.199034481.6517.03.0WATER BASED19.03.199034481.5515.03.0WATER BASED20.03.199034481.5514.03.0WATER BASED22.03.199034481.5517.03.0WATER BASED02.04.199034481.4519.03.0WATER BASED04.04.199034481.4517.03.0WATER BASED10.04.199034481.4820.03.5WATER BASED17.04.199034481.4820.02.5WATER BASED23.04.199034481.4925.06.0WATER BASED24.04.199034481.5515.03.0WATER BASED12.03.199034481.5526.04.0WATER BASED27.02.199034481.5518.02.5WATER BASED05.03.199034481.5517.02.5WATER BASED05.03.199034481.5518.02.5WATER BASED05.03.199034481.5517.02.0WATER BASED06.03.199034481.5515.03.5WATER BASED08.03.199034481.5513.03.0WATER BASED08.03.199034481.5514.03.0WATER BASED09.03.199034481.5516.03.0WATER BASED12.03.199034481.5515.03.0WATER BASED12.03.199034481.5515.03.5WATER BASED29.03.199034481.5515.03.0WATER BASED30.03.199034481.5520.05.0WATER BASED02.04.199034481.5517.03.0WATER BASED02.04.199034481.5516.03.0WATER BASED02.04.199034481.5520.03.0WATER BASED06.04.199034481.4517.03.0WATER BASED06.04.199034481.4517.03.0WATER BASED10.04.199034481.4518.03.0WATER BASED10.04.199034481.4818.03.5WATER BASED10.04.199034481.4818.03.0WATER BASED17.04.199034481.4820.03.5WATER BASED17.04.199034481.4820.03.5WATER BASED17.04.199034481.4820.03.5WATER BASED17.04.199034481.4821.03.5WATER BASED17.04.199034481.4821.03.5WATER BASED17.04.199034481.4820.03.0WATER BASED18.04.199034481.4820.03.5WATER BASED19.04.199034481.4818.02.5WATER BASED23.04.199034481.4823.04.5WATER BASED23.04.199034481.4723.04.5WATER BASED25.04.199035811.5535.010.0OIL BASED19.07.198937151.5517.05.5WATER BASED26.07.198937151.5516.09.5WATER BASED28.07.198937151.5515.05.5WATER BASED31.07.198937151.5512.04.0WATER BASED31.07.198937151.5515.05.0WATER BASED31.07.198937301.5535.010.5OIL BASED20.07.198937511.5747.014.0OIL BASED26.07.198937511.5538.09.5OIL BASED26.07.198937521.5538.010.0OIL BASED21.07.198937521.5537.010.5OIL BASED26.07.198937521.5537.010.5OIL BASED26.07.1989