34/8-11
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General information
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Wellbore history
GeneralWell 34/8-11 was drilled to appraise the 34/8-1 Visund discovery on Tampen Spur in the Northern North Sea. The main objective was to verify the extension of the Brent reservoir and fluid type encountered in Well 34/8-8.Operations and resultsAppraisal well 34/8-11 was spudded with the semi-submersible installation Polar Pioneer on 10 December 1993 and drilled to TD at 3140 m in the Early Jurassic Cook Formation. No significant problem was encountered in the operations. The well was drilled with seawater and hi-vis pills down to 1295 m, and with the ANCO 2000 glycol mud system from 1295 m to TD.A 1.5 m thick section of the Draupne Formation was encountered at 2852.5 m on top of a 15 m thick Heather Formation at 2854 m. The Brent Group was encountered at 2869 m. The Brent Group contained oil-bearing sandstones in the Tarbert, Ness, Etive and Rannoch Formations. A gross Brent reservoir thickness of 142 m was defined, giving a net pay of 69.4 m. From MDT pressures and logs an OWC was indicated between 2960 and 2965 m in the Rannoch Formation, however, moveable oil appears to be present all through the Rannoch. Reservoir geochemistry of core extracts indicate a shift from unaltered oil to slightly biodegraded residual oil somewhere between 2969 m and 2986 m. Good oil shows were recorded on the cores down to 3005 m otherwise no other oil shows were described in the well.Eight cores were cut in succession from 2859 to 3008 m, covering the lower half of the heather Formation and all of the Brent Formation. The core depth shifts relative to the logs were in the range -1.5 m to - 2.0 m; except for core no 4, which had a core-log shift of + 0.125 m. MDT fluid samples were taken at 2876.5 m. 2923 m, 2933 m, 2948 m, and at 2964 m.The well was permanently abandoned on 8 February 1994 as an oil appraisal well.TestingTwo drill stem tests were conducted in the Brent Group.DST 1A tested the interval 2942.2 - 2956.2 m. It produced 1142 Sm3 oil and 285300 Sm3 gas /day through a 40/64" choke. The GOR was 250 Sm3/Sm3, the oil density was 0.841 g/cm3, and the gas gravity was 0.755 (air = 1) with only a trace CO2. The bottom hole temperature measured at 2848.86 m was 111.6 deg C.DST 2B tested the intervals 2913.2 - 2939.0 m plus 2942.2 - 2956.2 m. It produced 1135 Sm3 oil and 291800 Sm3 gas /day through a 40/64" choke. The GOR was 257 Sm3/Sm3, the oil density was 0.839 g/cm3, and the gas gravity was 0.735 (air = 1) with 1.2 % CO2. The bottom hole temperature measured at 2848.86 m was 112.3 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]1295.003140.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12859.02871.0[m ]22871.02889.0[m ]32889.02896.2[m ]42915.02929.2[m ]52932.02960.0[m ]62960.02986.4[m ]72986.43000.2[m ]83002.03005.4[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]123.0Cores 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 availableDSTDST12950.102936.1013.01.1994 - 08:35YES -
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 typeCONDUCTOR30440.036440.00.00LOTSURF.COND.13 3/81280.017 1/21295.00.00LOTINTERM.9 5/82696.012 1/42711.00.00LOTLINER73138.08 1/23140.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.02942295615.82.02913295615.8Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.01112.0112Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.011422853000.8410.7552502.011352918000.8390.735257 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL23182977CBL VDL28002985DLL LSS GR AMS SP3552689DLL MSFL LSS GR SP AMS26983141EPT26983111FMI GR26983037LDL CNL GR3551291LDL CNL GR ACTS26983028MDT SGR AMS103020MDT SGR AMS28762876MDT SGR AMS29482964NGT RATIOS26983003VSP15003080 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit355107611021360137515151540182218221869200120012220285128532853285428692869288329082949301130113072 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]pdf0.60 -
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]pdf14.20 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured4401.20WATER BASED15.12.19937941.06WATER BASED15.12.199312041.5522.05.5WATER BASED04.02.199412041.5521.07.0WATER BASED07.02.199412951.20WATER BASED15.12.199312951.20WATER BASED15.12.199312951.20WATER BASED15.12.199312951.20WATER BASED20.12.199312951.20WATER BASED20.12.199316681.5034.011.0WATER BASED22.12.199320251.5030.09.5WATER BASED22.12.199324001.5033.010.0WATER BASED22.12.199327111.5125.07.5WATER BASED22.12.199327111.5124.07.0WATER BASED23.12.199327111.5124.08.0WATER BASED22.12.199327331.6832.08.5WATER BASED28.12.199327861.6834.08.5WATER BASED28.12.199328561.6835.08.0WATER BASED28.12.199328841.6834.07.0WATER BASED28.12.199328891.6623.06.5WATER BASED03.02.199429141.6831.06.0WATER BASED28.12.199329321.6836.07.5WATER BASED29.12.199329861.6836.07.0WATER BASED30.12.199329941.6833.07.0WATER BASED31.12.199330081.6838.07.5WATER BASED03.01.199430901.6633.010.0WATER BASED20.01.199430901.6634.010.0WATER BASED25.01.199430901.6634.010.0WATER BASED25.01.199430901.6634.010.0WATER BASED25.01.199431401.6625.07.0WATER BASED27.01.199431401.6837.08.0WATER BASED06.01.199431401.6638.010.0WATER BASED11.01.199431401.6638.010.0WATER BASED12.01.199431401.6633.010.0WATER BASED18.01.199431401.6633.010.0WATER BASED18.01.199431401.6839.09.5WATER BASED03.01.199431401.6839.09.5WATER BASED03.01.199431401.6839.09.5WATER BASED04.01.199431401.6837.08.0WATER BASED06.01.199431401.6638.010.0WATER BASED07.01.199431401.6638.010.0WATER BASED10.01.199431401.6638.010.0WATER BASED10.01.199431401.6638.010.0WATER BASED10.01.199431401.6636.08.5WATER BASED13.01.199431401.6636.08.5WATER BASED17.01.199431401.6635.09.0WATER BASED18.01.199431401.6633.010.0WATER BASED18.01.1994 -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1310.0[m]DCGEOST1340.0[m]DCGEOST1355.0[m]DCGEOST1385.0[m]DCGEOST1400.0[m]DCGEOST1430.0[m]DCGEOST1445.0[m]DCGEOST1475.0[m]DCGEOST1490.0[m]DCGEOST1520.0[m]DCGEOST1535.0[m]DCGEOST1565.0[m]DCGEOST1580.0[m]DCGEOST1610.0[m]DCGEOST1625.0[m]DCGEOST1655.0[m]DCGEOST1670.0[m]DCGEOST1700.0[m]DCGEOST1715.0[m]DCGEOST1745.0[m]DCGEOST1760.0[m]DCGEOST1790.0[m]DCGEOST1805.0[m]DCGEOST1820.0[m]DCGEOST1835.0[m]DCGEOST1850.0[m]DCGEOST1880.0[m]DCGEOST1895.0[m]DCGEOST1925.0[m]DCGEOST1935.0[m]DCGEOST1945.0[m]DCGEOST1965.0[m]DCGEOST1970.0[m]DCGEOST1980.0[m]DCGEOST2010.0[m]DCGEOST2025.0[m]DCGEOST2040.0[m]DCGEOST2070.0[m]DCGEOST2085.0[m]DCGEOST2100.0[m]DCGEOST2130.0[m]DCGEOST2145.0[m]DCGEOST2175.0[m]DCGEOST2190.0[m]DCGEOST2205.0[m]DCGEOST2220.0[m]DCGEOST2235.0[m]DCGEOST2265.0[m]DCGEOST2280.0[m]DCGEOST2310.0[m]DCGEOST2325.0[m]DCGEOST2355.0[m]DCGEOST2370.0[m]DCGEOST2385.0[m]DCGEOST2400.0[m]DCGEOST2415.0[m]DCGEOST2445.0[m]DCGEOST2460.0[m]DCGEOST2490.0[m]DCGEOST2505.0[m]DCGEOST2535.0[m]DCGEOST2550.0[m]DCGEOST2580.0[m]DCGEOST2595.0[m]DCGEOST2620.0[m]DCGEOST2640.0[m]DCGEOST2660.0[m]DCGEOST2680.0[m]DCGEOST2700.0[m]DCGEOST2720.0[m]DCGEOST2740.0[m]DCGEOST2760.0[m]DCGEOST2780.0[m]DCGEOST2800.0[m]DCGEOST2820.0[m]DCGEOST2840.0[m]DCGEOST2850.0[m]DCGEOST2852.0[m]DCGEOST2855.0[m]DCGEOST2857.0[m]DCGEOST2859.0[m]CGEOST2862.8[m]CGEOST2863.8[m]CGEOST2864.4[m]CGEOST2864.9[m]CGEOST2866.0[m]CGEOST2870.1[m]CGEOST2881.0[m]CGEOST2889.0[m]CGEOST2895.6[m]CGEOST2910.0[m]DCGEOST2926.0[m]CGEOST2935.9[m]CGEOST2944.0[m]CGEOST2956.5[m]CGEOST2962.4[m]CGEOST2974.0[m]CGEOST2978.5[m]CGEOST2985.0[m]CGEOST2990.0[m]CGEOST2995.5[m]CGEOST2999.0[m]CGEOST3005.4[m]CGEOST