34/10-38 S
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General information
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Wellbore history
GeneralWell 34/10-38 S was drilled to appraise the 34/10-17 Rimfaks Discovery south-west of the Gullfaks field in the North Sea. The primary objective was to test the hydrocarbon potential of the Middle Jurassic Brent Group in Segment 1 of the structure. Secondary objective was to test the hydrocarbon potential of the Early Jurassic Statfjord Group in Segment 2.Operations and resultsAppraisal well 34/10-38 S was spudded with the semi-submersible installation Deepsea Bergen on 5 April 1995 and drilled to TD at 3940 m (3393 m TVD) in the Late Triassic Lunde Formation. Drilling went forth without significant problem. Lost time was mostly related to logging problems in the 8 1/2" section. The well was drilled with bentonite and CMC/EHV down to 670 m, with ANCO 2000 mud from 670 m to 2075 m and with oil based Safemul PE/SE mud from 2075 m to TD.The results of the well differed from the geological prognosis. The Viking Group and most of the Brent Group in segment 2 was eroded and the remaining of the Brent Group was heavily faulted and fractured. Top Brent Group came in at 3021 m (2653.8 m TVD). Top Statfjord Group was penetrated at 3451 m (2995.2 m TVD), about 200 m shallower than prognosed. The Brent Group, the Cook Formation and the Statfjord Group proved to be hydrocarbon bearing. Pressure samples and log analysis proved an oil-water contact at 3585.6 m (3103.5 m TVD) in the Statfjord Group. Shows and log analysis indicated, however, oil with low saturation down to approx, 3658 m.Nine cores were cut in the well. The first core was cut from 3140 to 3159 m but recovered only a 10 cm piece. Cores 2 to 9 were cut in the Statfjord Group from 3465 m to 3631 m with generally good recovery. The core depths were from 0 to 3 m shallower than the log depths. FMT fluid samples were taken in the Brent Group at 3039.4 m (gas and condensate), and in the Statfjord Group at 3456.5 m (oil and gas), 3567.5 m (oil and gas), 3643 m (oil and water), and 3812 m (water). The oil in the sample from 3643 is believed to be residual oil mobilised by the oil base in the mud.The well was permanently abandoned on 29 May 1995 as an oil and gas appraisal well.TestingTwo intervals were tested in a comingled drill stem test from below and above the OWC in the Statfjord Group.The main objective for DST1 A from 3637 to 3646 m was to test the type of moveable fluid below the OWC where shows, a low hydrocarbon saturation and oil in an FMT sample indicated presence of oil. The result of the test was water at a rate of 23 Sm3/day through a 64/64" choke. Only traces of oil were produced. The flowing bottom hole temperature was 113.2 deg C.DST1 B tested the interval 3561 to 3570 m in the oil zone in addition to 3637 to 3646 m. DST1 B produced 858 Sm3 oil and 199056 Sm3 gas /day through a 36/64" choke. No water was produced. The GOR was 232 Sm3/Sm3, the oil density was 0.846 g/cm3, and the gas gravity was 0.807 (air = 1). The flowing bottom hole temperature was 115.4 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]680.003940.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13140.03140.1[m ]23465.03482.4[m ]33482.43484.1[m ]43485.03513.2[m ]53513.43535.4[m ]63537.03565.5[m ]73565.53595.8[m ]83598.03611.8[m ]93613.03631.3[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]160.2Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
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 availableDSTTEST1B0.000.0023.05.1995 - 02:35YES -
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 typeCONDUCTOR30219.036224.00.00LOTSURF.COND.20659.026670.01.57LOTINTERM.13 3/82064.017 1/22075.02.07LOTINTERM.73720.08 1/23940.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.03637364625.42.03561357014.3Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.02.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.010.8752.08581990560.8460.807232 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CIBL GR TTRM29893160DIPL MAC CN ZDL DSL TTRM20603847FMT QDYNE GR CHR30393039FMT QDYNE GR CHT30223864FMT QDYNE GR CHT31133465FMT QDYNE GR CHT35673567FMT QDYNE GR CHT36433643FMT QDYNE GR CHT38123812HRDIP GR29653940MWD - DPR20753940MWD - RGD2222075SWC GR30093720SWC GR38633927VSP18053930 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1608809631822182219072030302130213036304530523052311232113267345138443844 -
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]pdf16.94 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured2241.03water based12951.2620.0water based20751.25water based26731.6042.0oil based30211.6054.0oil based30301.6055.0oil based31591.6050.0oil based33741.6057.0oil based35651.4351.0oil based36131.6054.0oil based37261.6056.0oil based38861.6052.0oil based39401.6052.0oil based -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory960.0[m]DCGEOSTR980.0[m]DCGEOSTR1010.0[m]DCGEOSTR1040.0[m]DCGEOSTR1070.0[m]DCGEOSTR1100.0[m]DCGEOSTR1130.0[m]DCGEOSTR1160.0[m]DCGEOSTR1180.0[m]DCGEOSTR1220.0[m]DCGEOSTR1250.0[m]DCGEOSTR1280.0[m]DCGEOSTR1310.0[m]DCGEOSTR1340.0[m]DCGEOSTR1370.0[m]DCGEOSTR1400.0[m]DCGEOSTR1420.0[m]DCGEOSTR1470.0[m]DCGEOSTR1490.0[m]DCGEOSTR1520.0[m]DCGEOSTR1550.0[m]DCGEOSTR1580.0[m]DCGEOSTR1610.0[m]DCGEOSTR1640.0[m]DCGEOSTR1670.0[m]DCGEOSTR1700.0[m]DCGEOSTR1730.0[m]DCGEOSTR1760.0[m]DCGEOSTR1780.0[m]DCGEOSTR1790.0[m]DCGEOSTR1820.0[m]DCGEOSTR1850.0[m]DCGEOSTR1880.0[m]DCGEOSTR1910.0[m]DCGEOSTR1940.0[m]DCGEOSTR1970.0[m]DCGEOSTR1980.0[m]DCGEOSTR1990.0[m]DCGEOSTR2000.0[m]DCGEOSTR2030.0[m]DCGEOSTR2060.0[m]DCGEOSTR2090.0[m]DCGEOSTR2120.0[m]DCGEOSTR2150.0[m]DCGEOSTR2180.0[m]DCGEOSTR2210.0[m]DCGEOSTR2240.0[m]DCGEOSTR2270.0[m]DCGEOSTR2300.0[m]DCGEOSTR2330.0[m]DCGEOSTR2360.0[m]DCGEOSTR2390.0[m]DCGEOSTR2420.0[m]DCGEOSTR2450.0[m]DCGEOSTR2480.0[m]DCGEOSTR2500.0[m]DCGEOSTR2540.0[m]DCGEOSTR2570.0[m]DCGEOSTR2600.0[m]DCGEOSTR2630.0[m]DCGEOSTR2660.0[m]DCGEOSTR2696.0[m]DCGEOSTR2720.0[m]DCGEOSTR2750.0[m]DCGEOSTR2780.0[m]DCGEOSTR2810.0[m]DCGEOSTR2840.0[m]DCGEOSTR2870.0[m]DCGEOSTR2900.0[m]DCGEOSTR2930.0[m]DCGEOSTR2961.0[m]DCGEOSTR2991.0[m]DCGEOSTR3000.0[m]DCGEOSTR3010.0[m]SWCWESTL3012.0[m]DCGEOSTR3017.0[m]SWCWESTL3021.0[m]DCGEOSTR3022.0[m]SWCWESTL3030.0[m]SWCWESTL3045.0[m]SWCWESTL3048.0[m]SWCWESTL3053.0[m]SWCWESTL3062.0[m]SWCWESTL3072.0[m]DCGEOSTR3081.0[m]DCGEOSTR3090.0[m]DCGEOSTR3099.0[m]DCGEOSTR3107.0[m]SWCWESTL3113.0[m]SWCWESTL3121.0[m]SWCWESTL3129.0[m]DCGEOSTR3134.0[m]SWCWESTL3140.0[m]CWESTL3141.0[m]SWCWESTL3146.0[m]SWCWESTL3155.0[m]SWCWESTL3165.0[m]DCGEOSTR3173.0[m]SWCWESTL3186.0[m]DCGEOSTR3198.0[m]DCGEOSTR3212.0[m]SWCWESTL3222.0[m]DCGEOSTR3234.0[m]DCGEOSTR3249.0[m]DCGEOSTR3263.0[m]SWCWESTL3267.0[m]DCGEOSTR3270.0[m]SWCWESTL3285.0[m]DCGEOSTR3297.0[m]DCGEOSTR3312.0[m]DCGEOSTR3327.0[m]DCGEOSTR3342.0[m]DCGEOSTR3356.0[m]SWCWESTL3366.0[m]DCGEOSTR3381.0[m]DCGEOSTR3387.0[m]DCGEOSTR3396.0[m]DCGEOSTR3402.0[m]DCGEOSTR3408.0[m]DCGEOSTR3417.0[m]DCGEOSTR3423.0[m]DCGEOSTR3430.0[m]SWCWESTL3438.0[m]DCGEOSTR3444.0[m]DCGEOSTR3450.0[m]DCGEOSTR3450.0[m]SWCWESTL3483.0[m]CWESTL3489.0[m]CWESTL3494.0[m]CWESTL3499.0[m]CWESTL3501.0[m]CWESTL3513.0[m]CWESTL3517.0[m]CWESTL3521.0[m]CWESTL3526.0[m]CWESTL3537.0[m]CWESTL3543.0[m]CWESTL3549.0[m]CWESTL3557.0[m]CWESTL3569.0[m]CWESTL3573.0[m]CWESTL3579.0[m]CWESTL3583.0[m]CWESTL3588.0[m]CWESTL3594.0[m]CWESTL3600.0[m]CWESTL3609.0[m]CWESTL3613.0[m]CWESTL3620.0[m]CWESTL3646.0[m]DCGEOSTR3655.0[m]DCGEOSTR3676.0[m]DCGEOSTR3694.0[m]DCGEOSTR3715.0[m]DCGEOSTR3721.0[m]DCGEOSTR3733.0[m]DCGEOSTR3745.0[m]DCGEOSTR3757.0[m]DCGEOSTR3772.0[m]DCGEOSTR3784.0[m]DCGEOSTR3796.0[m]DCGEOSTR3808.0[m]DCGEOSTR3820.0[m]DCGEOSTR3832.0[m]DCGEOSTR3844.0[m]DCGEOSTR3850.0[m]DCGEOSTR3862.0[m]DCGEOSTR3874.0[m]DCGEOSTR3883.0[m]DCGEOSTR3904.0[m]DCGEOSTR3916.0[m]DCGEOSTR3928.0[m]DCGEOSTR3940.0[m]DCGEOSTR