34/8-3
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General information
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Wellbore history
GeneralWell 34/8-3 was drilled on the A-structure on the Visund Field. This is a NNE-SSW oriented elongated fault block with the Pre-Cretaceous strata dipping towards WNW. The A-Central fault divides the A-structure into the A-North and A-South compartments. The primary objectives of the well were to test the hydrocarbon potential of the Brent Group on the A-North compartment. Planned TD was 50 m into the Statfjord Formation.Operations and resultsWildcat well 34/8-3 was spudded with the semi-submersible installation Polar Pioneer on 14 July 1988 and drilled to TD at 3328 m (3320 m TVD) in the Early Jurassic Statfjord Formation. There were no problems with shallow gas. 9 5/8" casing was set at 2597 m instead of 2800 m due to higher pressure than prognosed in formation of Cretaceous age. Below 2600 m the well started to build some angle, up to 9.6 deg at the most. This resulted in 8 meter discrepancy between measured depth and vertical depth towards TD. The well was drilled with seawater and hi-vis pills down to 1302 m and with KCl/polymer mud from 1302 m to TD.Oil shows were recorded in thin sandstone stringers in the Kyrre Formation between 2364 m and 2555 m. The Brent Group was encountered at 2837 m. It contained a 90 m gas column and a 13 m oil column. The gas/oil contact was at 2929 m. The oil/water contact could not be established, but DST 1 produced clean oil from the interval 2935 to 2947 m. Oil shows were recorded on sandstone on cores down to 2951 m.Seven cores were cut in the interval 2839.0 to 2957.5 m in the Brent Group. The core depths are 1 m shallow compared to logger's depth. One RFT wire line fluid sample was taken at 2936 m. The 2 3/4 gallon chamber contained 9 litres water and mud filtrate, 0.6 litres oil and 0.14 Sm3 gas.Since the oil/water contact was not found, it was decided to sidetrack. The well bore was plugged back to 845 m and permanently abandoned on 14 September 1988 as an oil and gas appraisal well.TestingThree drill stem tests were performed in the well.DST 1 tested the interval from 2935 to 2947 m in the oil zone in the Rannoch Formation. It produced 68 Sm3 oil and 18200 Sm3 gas /day through a 4.76 mm (12/64") choke. The GOR was 268 Sm3/Sm3, the oil density was 0.847 g/cm3, and the gas gravity was 0.635 (air = 1) with 1 % CO2 and 0 ppm H2S. The bottom hole temperature was 108.9 deg C, measured at 2895.8 m.DST 2 tested the interval from 2905 to 2921 m in the gas zone in the Rannoch Formation. It produced 613 Sm3 oil and 1540000 Sm3 gas /day through a 28.58 mm (72/64") choke. The GOR was 2520 Sm3/Sm3, the oil density was 0.0.775 g/cm3, and the gas gravity was 0.640 (air = 1) with 1.6 % CO2 and 1 ppm H2S. The bottom hole temperature was 110.8 deg C, measured at 2850.11 m.DST 3 tested the interval from 2868 to 2880 m in the gas zone in the Etive Formation. It produced 554 Sm3 oil and 1540000 Sm3 gas /day through a 25.4 mm (64/64") choke. The GOR was 2780 Sm3/Sm3, the oil density was 0.782 g/cm3, and the gas gravity was 0.648 (air = 1) with 1.5 % CO2 and 1 ppm H2S. The bottom hole temperature was 110.4 deg C, measured at 2825.56 m. -
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]1320.003327.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12839.02849.0[m ]22849.02871.0[m ]32871.02895.0[m ]42895.02898.5[m ]52899.02927.0[m ]62927.02946.0[m ]72946.02957.1[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]117.6Cores 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 availableDST0.000.00YESDSTTEST12935.002947.0018.08.1988 - 00:00YESDSTDST22905.002921.0030.08.1988 - 00:00YESDSTDST32868.002880.00CONDENSATE08.09.1988 - 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 typeCONDUCTOR30491.036970.00.00LOTINTERM.13 3/81302.017 1/21317.01.63LOTINTERM.9 5/82598.012 1/42622.01.86LOTLINER73312.08 1/23328.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0293529474.82.02905292128.63.02868288025.4Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.01092.01103.0110Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.068182000.8470.6352682.061315400000.7750.64025203.055415400000.7820.6482776 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]AMS25973328CBL VDL12003232CST GR27333306DIL LSS GR SP10903328DLL MSFL25973328LDL CNL10903328MWD4022838NGS25973328RFT28423302SHDT25973312VSP8003230 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit4051119117518201820186220122012230027952827282728372837286728972964296529653007311831553278 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]pdf0.58 -
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]pdf5.06pdf15.67 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured4191.03WATER BASED15.07.19884821.03WATER BASED19.07.19884911.03WATER BASED19.07.19889701.03WATER BASED19.07.198813171.03WATER BASED19.07.198813171.03WATER BASED21.07.198813171.2015.08.0WATER BASED27.07.198818641.3622.013.0WATER BASED27.07.198823121.4126.016.0WATER BASED27.07.198823901.5219.06.0WATER BASED13.09.198823901.5220.08.0WATER BASED14.09.198823901.5220.08.0WATER BASED15.09.198824691.4624.09.0WATER BASED27.07.198826221.5226.08.0WATER BASED27.07.198826221.5225.08.0WATER BASED27.07.198826221.5225.08.0WATER BASED28.07.198826271.5220.06.0WATER BASED01.08.198827491.5224.08.0WATER BASED01.08.198828391.6025.08.0WATER BASED01.08.198828701.6023.06.0WATER BASED01.08.198828971.7024.08.0WATER BASED09.09.198828971.7025.08.0WATER BASED08.09.198829331.7024.09.0WATER BASED02.09.198829331.7024.09.0WATER BASED05.09.198829331.7025.09.0WATER BASED06.09.198829331.7024.08.0WATER BASED07.09.198829571.6024.06.0WATER BASED04.08.198829921.6023.07.0WATER BASED08.08.198830661.6021.07.0WATER BASED08.08.198831691.6024.07.0WATER BASED08.08.198832161.6024.08.0WATER BASED08.08.198832641.6022.010.0WATER BASED09.08.198833161.6625.09.0WATER BASED23.08.198833161.6621.010.0WATER BASED23.08.198833161.7025.09.0WATER BASED30.08.198833161.7024.09.0WATER BASED31.08.198833161.6625.010.0WATER BASED19.08.198833161.6624.010.0WATER BASED19.08.198833161.6924.09.0WATER BASED25.08.198833161.6924.09.0WATER BASED26.08.198833161.6924.09.0WATER BASED29.08.198833161.7024.09.0WATER BASED30.08.198833281.6023.09.0WATER BASED15.08.198833281.6023.09.0WATER BASED10.08.198833281.6023.09.0WATER BASED11.08.198833281.6024.09.0WATER BASED12.08.198833281.6629.06.0WATER BASED15.08.198833281.6629.07.0WATER BASED15.08.198833281.6629.010.0WATER BASED16.08.1988 -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory2641.0[m]SWCHYDRO2690.0[m]SWCHYDRO2733.0[m]SWCHYDRO2770.0[m]SWCHYDRO2810.0[m]DCHYDRO2820.0[m]DCHYDRO2824.0[m]SWCHYDRO2827.5[m]SWCHYDRO2828.0[m]SWCHYDRO2835.0[m]SWCHYDRO2837.0[m]SWCHYDRO2839.0[m]CHYDRO2839.9[m]CHYDRO2840.0[m]DCHYDRO2842.0[m]CHYDRO2852.0[m]CHYDRO2852.5[m]CHYDRO2855.0[m]DCHYDRO2855.1[m]CHYDRO2860.9[m]CHYDRO2861.0[m]CHYDRO2866.0[m]CHYDRO2876.2[m]CHYDRO2880.3[m]CHYDRO2931.0[m]CHYDRO2931.0[m]CHYDRO2933.4[m]CHYDRO2934.0[m]CHYDRO2935.2[m]CHYDRO2942.1[m]CHYDRO2947.0[m]CHYDRO2952.4[m]CHYDRO2955.0[m]DCHYDRO2956.8[m]CHYDRO2957.2[m]CHYDRO2962.0[m]DCHYDRO2970.0[m]DCHYDRO2985.0[m]DCHYDRO2995.7[m]SWCHYDRO2997.5[m]SWCHYDRO3000.0[m]DCHYDRO3015.0[m]DCHYDRO3030.0[m]SWCHYDRO3034.0[m]SWCHYDRO3045.5[m]SWCHYDRO3075.0[m]SWCHYDRO3128.0[m]SWCHYDRO3155.0[m]SWCHYDRO3165.0[m]SWCHYDRO3180.0[m]SWCHYDRO3220.0[m]SWCHYDRO3273.0[m]SWCHYDRO3277.0[m]SWCHYDRO