34/10-21
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General information
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Wellbore history
GeneralWell 34/10-21 was the third well drilled on the Gullfaks South structure in the Tampen Spur area in the northern North Sea. The objective was to test for possible hydrocarbon accumulations and for a possible extension of reserves in the Gullfaks South field. Targets included the Brent, Cook and Statfjord Sandstones and possible sand accumulations in the Early Cretaceous.Operations and resultsAppraisal well 34/10-21 was spudded with the semi-submersible installation Dyvi Delta on 26 July 1984 and drilled to TD at 4005 m in Late Triassic sediments of the Raude Formation. The well was drilled with gel/seawater down to 615 m, with gypsum/CMC/lignosulphonate from 615 m 3196 m, and with gel/lignosulphonate from 3196 m to TD.No sandstones were encountered in the Early Cretaceous. Hydrocarbon bearing Brent sandstone was encountered at 3287 m, with the hydrocarbon/water contact established at 3333 m+/-3 m. No hydrocarbons were identified in the Cook sandstones. The logs indicated hydrocarbons in the Statfjord Group, but drill stem test gave no flow from these sandstones. No shows were described above the Tarbert reservoir. Below the OWC, shows on sandstone were described down to 3359 m.Six cores were cut; four from 3289 m to 3383 in the Brent Group and two from 3970 m to 3985.5 in the Raude Formation. Core recoveries were from 90 % to 100 %. RFT fluid samples were taken in the Brent Group oil zone at 3298.5 m, 3317.3 m, and 3325.0 m.The well was permanently abandoned on 22 October 1984 as a gas appraisal well.TestingTwo drill stem tests were performed.DST 1 tested the interval 3905.2 m to 3922.2 m in the Statfjord Group. This test gave no flow.DST 2 tested the interval 3290.7 - 3312.7 m in the Tarbert Formation. This test produced 130 Sm3 condensate and 837800 Sm3 gas /day through a 14.29 mm choke. The GOR was 6424 SM3/Sm3, the condensate density was 0.80 g/cm3, the gas gravity was 0.65 (air=1). The downhole temperature reading in the test was 119.3 °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]228.004002.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13289.03306.3[m ]23307.03331.4[m ]33333.93359.0[m ]43361.53383.2[m ]53970.03973.6[m ]63973.53985.4[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]104.0Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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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 availableDSTTEST23290.003312.00CONDENSATE13.10.1984 - 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 typeCONDUCTOR30226.036228.00.00LOTSURF.COND.20600.026745.01.81LOTINTERM.13 3/81896.017 1/21990.01.56LOTINTERM.9 5/83181.012 1/43196.01.99LOTLINER74000.08 1/24005.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0390539220.02.03290331325.42.13290331225.42.23290331225.4Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.02.021.0002.113.00045.0002.227.00014.00045.000Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.02.019411320000.80458402.119711310000.80457322.211300000.8005700 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL GR7503954CEQL30353954CET GR30353966CST GR28553103DLL MSFL GR31814006ISF LSS MSFL GR6004005LDL CNL GR6004006MWD226600NGS31933611RFT GR32903512RFT GR32933498SHDT GR18963961WSS VSP2404005 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1659091053179917991870191520142014231329002900290429112920292030473287328733463497350335503550363237633906390639143930 -
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]pdf2.54pdf28.56pdf0.22pdf13.03pdf7.60pdf1.65pdf29.87pdf0.22pdf4.41 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured2281.03WATER BASED30.07.19844951.068.020.0WATER BASED30.07.19846291.227.020.0WATER BASED31.07.19847451.105.08.0WATER BASED03.08.198412371.115.07.1WATER BASED07.08.198417551.106.86.8WATER BASED07.08.198417601.176.87.7WATER BASED07.08.198419151.178.04.8WATER BASED07.08.198419151.2010.05.7WATER BASED07.08.198419151.2210.07.7WATER BASED07.08.198419151.2010.05.7WATER BASED07.08.198419151.2210.07.7WATER BASED07.08.198419181.299.04.2WATER BASED10.08.198419901.2913.04.8WATER BASED14.08.198421341.2814.04.9WATER BASED14.08.198428511.2615.05.8WATER BASED20.08.198429481.2715.05.0WATER BASED20.08.198429491.3314.07.7WATER BASED20.08.198430271.3317.06.6WATER BASED20.08.198430461.33WATER BASED21.08.198430471.3916.07.3WATER BASED21.08.198431351.3918.07.3WATER BASED22.08.198431851.4419.08.0WATER BASED23.08.198431961.4418.08.0WATER BASED24.08.198432201.4417.07.7WATER BASED28.08.198433611.4414.06.0WATER BASED03.09.198435861.4416.07.9WATER BASED06.09.198436121.4415.06.9WATER BASED10.09.198437001.4415.06.0WATER BASED11.09.198437601.4417.05.2WATER BASED13.09.198438461.4417.05.0WATER BASED17.09.198439621.4416.05.0WATER BASED19.09.1984 -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory3045.0[m]SWCGEOCH3063.0[m]SWCGEOCH3077.0[m]SWCGEOCH3089.0[m]SWCGEOCH3102.0[m]DCGEOCH3103.0[m]SWCGEOCH3111.0[m]DCGEOCH3120.0[m]DCGEOCH3132.0[m]DCGEOCH3141.0[m]DCGEOCH3153.0[m]DCGEOCH3162.0[m]DCGEOCH3171.0[m]DCGEOCH3180.0[m]DCGEOCH3195.0[m]DCGEOCH3210.0[m]DCGEOCH3219.0[m]DCGEOCH3231.0[m]DCGEOCH3243.0[m]DCGEOCH3258.0[m]DCGEOCH3270.0[m]DCGEOCH3282.0[m]DCGEOCH3288.0[m]DCGEOCH