34/8-10 S
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General information
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Wellbore history
GeneralWell 34/8-10 S was drilled to appraise the 34/8-1 Visund discovery on Tampen Spur in the Northern North Sea. The objectives were to confirm the presence of mobile hydrocarbons and the pressure regime in the SI segment (Statfjord Formation); to confirm the absence of free gas cap and also pressure regime and fluid composition in the NI segment (BrentGroup); to improve stratigraphic control of base Cretaceous, the A-Central Fault, top Statfjord and top Lunde; and to characterise the Lunde B/C aquifer and pressure regime.Operations and resultsAppraisal well 34/8-10 S was spudded with the semi-submersible installation Polar Pioneer on 28 September 1993 and drilled to TD at 3470 m (3316 m TVD) in the Late Triassic Lunde Formation. The well was drilled with an angle of 37 degrees through the reservoir to achieve the objectives. It was drilled with seawater and hi-vis pills down to 1358 m, and with Anco 2000 glycol mud from 1358 m to TD.The well penetrated oil-bearing sandstones in all the potential reservoirs: Brent-NI, Amundsen-SI, Statfjord-SI and Lunde-SI. The Brent Group was penetrated at 2879.5 m in a heavily faulted area. It was represented by the Rannoch Formation from 2879.5 to 2885 m and by Etive Formation from 2888 to 2896.5 m with a fault slice identified as Drake Formation in between (2885-2888 m). A gross reservoir thickness of 14 m was defined, giving a net pay of 10 m. The pressure in the Brent Group was found to be higher than previously documented, and in addition the oil was of a lighter composition. No free gas cap was found in the Brent sandstones.The Amundsen Sandstone was not expected to be penetrated as the well was planned to cut the A-Central fault very close to the Statfjord Formation. However, the well showed that top Statfjord was about 20 m deeper and the A-Central fault about 50 m further to the east than prognosed. The Amundsen Sandstone member was encountered from 2993 m to 3006 m. Core and wire line log data confirm this unit as oil-bearing with a gross reservoir thickness of 12.5m giving a net pay of 11.5m.Good oil shows were observed in the Rannoch and Etive Formations from 2877 to 2893m. Poor to moderate shows were seen from 2919 to 3018 m on sandstones of Dunlin Group. Good to very good shows were observed in the Statfjord Formation from 3036 - 3122 m. Poor to moderate shows were seen in the Lunde A and B/C sandstones from 3141 to 3256 m (ODT) and below 3255 m residual shows were observed. The Statfjord Formation was encountered at 3038.5 m, and was cored all through. Wire line logs and core data show the presence of oil in Statfjord sandstones with a net thickness of sand of 60 m and a net pay of 56.5 mLunde A Formation was penetrated from 3125 to 3243 m and Lunde B/C from 3243 m to TD. Core and wire line data proved Lunde to be oil-bearing down to 3256 m (ODT) in this well with a net sand thickness of 52.5 m and a net pay of 8.5 m.All in all, 203 m core was cut in 23 cores at different intervals throughout the well. MDT fluid samples were taken at 1951.8 m, 2891.5 m, 3002.8 m, and at 3255.0 mThe well was permanently abandoned on 9.December 1993 as an oil appraisal well.TestingA production test (Test no 1) was performed in the intervals 3039 - 3052 m and 3062-3087.5 m (2983 - 3021 m TVD all across) in the Statfjord Formation sandstones. A 5 day main flow period produced 1180 Sm3 oil and 414000 Sm3 gas/day with a FWHP of 210.4 bar and a GOR of 350 Sm3/Sm3 through a 44/64" fixed choke with an average permeability of 1370 mD. The density of oil was recorded as 0.82 g/cc, while the gas gravity was 0.755 (air = 1) 1.4% CO2 and 2.6 ppm H2S. The temperature measured in the flow was114 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]1370.003470.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11924.01925.8[m ]21926.01941.5[m ]32874.02878.1[m ]42880.02884.7[m ]52884.72894.9[m ]62894.92897.4[m ]72913.52917.4[m ]82917.42919.4[m ]92922.02924.8[m ]102996.03002.2[m ]113002.23029.9[m ]123029.93042.0[m ]133042.03053.6[m ]143053.63058.6[m ]153058.63083.4[m ]163084.53085.6[m ]173086.53097.2[m ]183097.53111.4[m ]193114.63122.8[m ]203122.83123.8[m ]213124.03129.3[m ]223130.53147.0[m ]233270.03281.6[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]203.2Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1370.0[m]DCSPT1390.0[m]DCSPT1410.0[m]DCSPT1430.0[m]DCSPT1450.0[m]DCSPT1500.0[m]DCSPT1520.0[m]DCSPT1540.0[m]DCSPT1580.0[m]DCSPT1600.0[m]DCSPT1620.0[m]DCSPT1640.0[m]DCSPT1660.0[m]DCSPT1670.0[m]DCSPT1726.0[m]SWCSPT1740.0[m]DCSPT1760.0[m]DCSPT1780.0[m]DCSPT1800.0[m]DCSPT1820.0[m]DCSPT1840.0[m]DCSPT1880.0[m]DCSPT1900.0[m]DCSPT1920.0[m]DCSPT1924.0[m]CSPT1936.0[m]CSPT1941.5[m]CSPT1953.0[m]SWCSPT1957.3[m]SWCSPT1966.0[m]SWCSPT2030.0[m]DCSPT2060.0[m]DCSPT2080.0[m]DCSPT2100.0[m]DCSPT2120.0[m]DCSPT2140.0[m]DCSPT2160.0[m]DCSPT2180.0[m]DCSPT2220.0[m]DCSPT2260.0[m]DCSPT2280.0[m]DCSPT2300.0[m]DCSPT2560.0[m]DCSPT2628.0[m]SWCSPT2650.0[m]SWCSPT2669.0[m]SWCSPT2700.0[m]SWCSPT2724.0[m]SWCSPT2750.0[m]SWCSPT2870.0[m]SWCSPT2872.0[m]DCSPT2875.3[m]CSPT2875.5[m]CSPT2876.2[m]CSPT2876.7[m]CSPT2877.3[m]CSPT2882.0[m]DCSPT2883.0[m]CSPT2894.9[m]CSPT2896.0[m]CSPT2896.6[m]CSPT2897.4[m]CSPT2914.0[m]CSPT2916.0[m]CSPT2923.0[m]CSPT2930.0[m]SWCSPT2940.0[m]SWCSPT2944.0[m]SWCSPT2952.0[m]SWCSPT2954.0[m]SWCSPT2959.0[m]SWCSPT2964.0[m]SWCSPT2971.0[m]SWCSPT2978.0[m]SWCSPT3033.0[m]CSPT3050.0[m]CSPT3056.0[m]CSPT3058.0[m]CSPT3122.8[m]CSPT3312.0[m]DCSPT3460.0[m]DCSPT3470.0[m]DCSPT -
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 availableDSTDST10.000.0024.11.1993 - 05:20YES -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit3491081110911451552158016361655181518151854195019711994199422202838284328502871287128792879288528852888288828972932293229392972303931253125 -
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]pdf24.49 -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.03039305217.4Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.0114Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.011804140000.8230.755350 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL15003385CST GR14192240CST GR26283254DLL MSFL EPT LSS NGT SP AMS25543472DLL MSFL LDL CNL LSS GR SP AMS4341360DLL MSFL LDL CNL LSS NGT SP AMS13482560FMI GR ACTS25543472LDL CNL GR25543472MDT GR AMS19521968MDT GR AMS29953082MDT GR AMS32553255MWD - GR RES DIR3611353MWD DPR - GR RES DIR13533470VSP7402550VSP22803410 -
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 typeCONDUCTOR30434.036434.00.00LOTINTERM.13 3/81348.017 1/21358.01.69LOTINTERM.9 5/82552.012 1/42560.01.88LOTLINER73468.08 1/23470.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3901.6022.09.5WATER BASED09.12.19934341.05WATER BASED30.09.199311101.6223.09.5WATER BASED08.12.199313581.20WATER BASED30.09.199313581.20WATER BASED01.10.199313581.20WATER BASED04.10.199313581.20WATER BASED04.10.199316331.4017.013.5WATER BASED04.10.199319001.4216.016.0WATER BASED06.10.199322021.5024.017.5WATER BASED07.10.199325601.5025.016.0WATER BASED11.10.199325601.5023.012.0WATER BASED11.10.199325601.5120.011.0WATER BASED12.10.199325601.5023.016.0WATER BASED08.10.199325601.5222.017.0WATER BASED11.10.199325711.5018.011.0WATER BASED13.10.199326531.5026.015.0WATER BASED14.10.199327411.6127.015.0WATER BASED18.10.199328181.6538.016.0WATER BASED18.10.199328741.7033.013.0WATER BASED18.10.199328851.7034.012.0WATER BASED19.10.199329001.7031.014.0WATER BASED20.10.199329231.6932.013.0WATER BASED22.10.199329401.6933.014.0WATER BASED25.10.199329901.6929.013.0WATER BASED25.10.199330101.6928.013.0WATER BASED26.10.199330151.6928.013.0WATER BASED25.10.199330421.6931.014.0WATER BASED27.10.199330591.6835.015.0WATER BASED28.10.199330851.6835.015.0WATER BASED01.11.199330901.6937.015.0WATER BASED01.11.199331231.6935.016.0WATER BASED01.11.199331301.6935.015.0WATER BASED01.11.199331471.7033.014.0WATER BASED02.11.199332701.6837.016.0WATER BASED03.11.199332811.6838.016.0WATER BASED04.11.199332811.6838.016.0WATER BASED08.11.199334091.6632.07.5WATER BASED01.12.199334701.6625.07.0WATER BASED06.12.199334701.6625.07.0WATER BASED06.12.199334701.6625.07.0WATER BASED06.12.199334701.6019.07.0WATER BASED07.12.199334701.6833.013.0WATER BASED08.11.199334701.6629.07.5WATER BASED22.11.199334701.6627.05.5WATER BASED02.12.199334701.6626.06.0WATER BASED06.12.199334701.6625.06.5WATER BASED06.12.199334701.6834.014.0WATER BASED08.11.199334701.6833.014.0WATER BASED08.11.199334701.6833.013.0WATER BASED09.11.199334701.6838.013.0WATER BASED11.11.199334701.6835.013.0WATER BASED12.11.199334701.6837.014.0WATER BASED12.11.199334701.68367.017.0WATER BASED16.11.199334701.68367.017.0WATER BASED16.11.199334701.6627.08.0WATER BASED16.11.199334701.6628.08.5WATER BASED16.11.199334701.6628.08.5WATER BASED17.11.199334701.6628.07.5WATER BASED18.11.199334701.6628.07.5WATER BASED19.11.199334701.6529.07.0WATER BASED22.11.199334701.6629.07.0WATER BASED22.11.199334701.6630.06.0WATER BASED23.11.199334701.6629.07.0WATER BASED24.11.199334701.6629.07.0WATER BASED25.11.199334701.6629.07.0WATER BASED26.11.199334701.6629.07.0WATER BASED30.11.199334701.6625.07.5WATER BASED30.11.1993 -
Pressure plots
Pressure plots The pore pressure data is sourced from well logs if no other source is specified. In some wells where pore pressure logs do not exist, information from Drill stem tests and kicks have been used. The data has been reported to the NPD, and further processed and quality controlled by IHS Markit.Pressure plots Document nameDocument formatDocument size [MB]pdf0.22