30/9-4 S
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General information
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Wellbore history
GeneralWell 30/9-4 S was drilled on the B-structure on the southeast flank of the Oseberg Field in the North Sea. The structure is an elongated rotated fault block bounded by faults in all directions. The Brent Group is truncated by the Base Cretaceous unconformity, and this well was expected to go directly from Cretaceous to the Ness formation. The objectives of the well were to find hydrocarbon accumulations in the Brent Group, secondary in the Statfjord Group. The well was designed to penetrate the Brent Group in a position where the sand in the Ness Formation is preserved. The well was deviated westwards at an angle of approximately 40°.Operations and resultsWildcat well 30/9-4 S was spudded with the semi-submersible installation Treasure Seeker on 22 November 1984 and drilled to TD at 4303 m (3577 m TVD) in the Early Jurassic Eiriksson Formation. No significant problems were encountered during operations. The well was drilled with spud mud down to 222 m, with seawater/gel from 222 m to 630 m, with oil based Safemul mud from 630 m to 3297 m, with NaCl/polymer mud from 3297 m to 3680 m, and with oil based Safemul mud from 3680 m to TD.The well 30/9-4 encountered two separate hydrocarbon reservoirs in the Middle Jurassic Brent Group. Pressure data indicated no communication between the two hydrocarbon columns. The Tarbert Formation and uppermost Ness Formation (3295-3379 m, 2773-2841 m TVD) sandstones were found to be gas bearing, but no definite gas/fluid contacts were evident. Net pay in the gas zone was calculated to be 27.6 m (22.1 m TVD), average porosity 18.6%, and the average water saturation 20.9%. The Ness Formation (3379-3551 m, 2841-2979 m TVD) proved to be oil bearing, but again no OWC could be discerned. Net pay in the oil zone was calculated to be 10.9 m (8.8 m TVD), average porosity to 22.2% and the average water saturation to 33.2%. The Statfjord Group was water bearing. No oil shows were reported above or below the hydrocarbon bearing Brent reservoir sands.Thirteen conventional cores were cut in the well. Cores no. 1-3 (3332 - 3381 m) and 4-11 (3432-3500 m) were cut in the gas bearing and oil bearing Brent Group sections, respectively. Core no. 12 (3580-3598.1 m) was cut in the Oseberg Formation and core no. 13 (4268-4277 m) was cut in the Eiriksson Formation. RFT fluid samples were taken in the Brent Group at 3319.5 m (oil and gas), 3421 m (condensate and gas), and in the top of the water bearing Statfjord Group at 4207.2 m.The well was permanently abandoned on 30 March 1985 as an oil and gas discovery.TestingTwo drill stem tests were performed in the Brent Group.DST 1 tested the interval 3416.9 to 3422.9 m (2871.4 m to 2876.1 m TVD) in the oil bearing part of the Ness Formation. The well produced 783.2 Sm3 oil and 158600 Sm3 gas/day through a 72/64" choke. The GOR was 202.5 Sm3/Sm3. The oil gravity was 41.8 °API and the gas gravity was 0.8 (air=l). The bottom hole temperature was 111.1°C. The test produced 2.2% C02 and no H2S.DST 2 tested the interval 3311.3 to 3324.3 m (2787 to 2797.7 m TVD) in the gas bearing Tarbert Formation. It produced 1130000 Sm3 gas and 333.9 Sm3 condensate/day through a 64/64" choke. The GOR was 3384.3 Sm3/Sm3. The oil gravity was 55.7 °API and the gas gravity was 0.7 (air=l). The bottom hole temperature was 108.3°C. The test produced 1.5% C02 and 0.8 ppm H2S. -
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]230.004300.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13332.03350.3[m ]23350.63368.0[m ]33368.63379.0[m ]43432.43436.0[m ]53437.03444.5[m ]63445.03466.2[m ]73457.03462.7[m ]83467.03469.6[m ]93472.03474.7[m ]103475.03483.8[m ]113484.03498.1[m ]123580.03598.0[m ]134268.04276.3[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]138.6Cores 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 availableDSTDST13422.003416.00OIL11.03.1985 - 00:00YESDSTDST23324.003311.00CONDENSATE20.03.1985 - 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 typeCONDUCTOR30221.036222.00.00LOTSURF.COND.20619.026630.01.40LOTINTERM.13 3/81648.017 1/21667.01.66LOTINTERM.9 5/83275.012 1/43297.01.75LOTLINER73553.08 1/24303.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.03417342328.62.03311332425.0Drill 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]1.07831580000.8000.80020252.033411000000.8000.7003384 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL GR CCL2721648CBL VDL GR CCL12003261CBL VDL GR CCL31673475CET GR12003261CET GR31673475CST27393285CST33074080CST40884307DIL LSS GR6184304DLL MSFL GR CAL32813677HDT32814305ISF LSS GR MSFL2213679LDL GR CAL CNL6184305NGT SDT32724305RFT32963626RFT33190RFT35954259RFT42070SHDT32813681VSP16244307 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit135595845845236623662486254927542769276930413295329533563551356836333633392439914054417341734209 -
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]pdf6.42pdf30.68 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured341.2719.05.0WATER BASED22.01.19852220.00WATERBASED26.11.19846171.0944.07.0WATERBASED26.11.19846171.0944.07.0WATER BASED26.11.19846251.106.015.0WATERBASED26.11.19846251.106.015.0WATER BASED26.11.19846301.116.016.0WATER BASED27.11.19846301.106.016.0WATER BASED28.11.19846301.0713.04.0WATER BASED04.12.19846301.1514.04.0WATER BASED04.12.19846300.00WATERBASED29.11.19846301.116.016.0WATERBASED27.11.19846300.006.016.0WATERBASED28.11.19846300.0013.04.0WATERBASED04.12.19846300.0014.04.0WATERBASED04.12.19847001.1514.04.5WATERBASED04.12.19847001.1514.04.5WATER BASED04.12.19848851.1517.09.0WATER BASED05.12.19848851.1517.09.0WATERBASED05.12.198410761.1520.08.5WATERBASED06.12.198410761.1520.08.5WATER BASED06.12.198412271.1520.010.5WATER BASED07.12.198412271.1520.010.5WATERBASED07.12.198413541.1523.012.0WATERBASED11.12.198413541.1523.012.0WATER BASED11.12.198414441.1522.011.0WATER BASED11.12.198414441.1522.011.0WATERBASED11.12.198415811.1523.015.0WATERBASED11.12.198415811.1523.015.0WATER BASED11.12.198416671.1825.015.0WATER BASED11.12.198416671.2531.011.0OIL BASED13.12.198416671.2737.013.5OIL BASED16.12.198416671.0546.015.0OIL BASED16.12.198416671.5042.016.0OIL BASED16.12.198416671.2531.011.0OIL BASED13.12.198416670.0046.015.0OIL BASED15.12.198416671.1825.015.0WATERBASED11.12.198416671.2026.012.5OIL BASED11.12.198416670.0037.013.5OIL BASED15.12.198416670.0042.016.0OIL BASED15.12.198418371.5033.011.5OIL BASED19.12.198418371.5033.011.5OIL BASED18.12.198420671.5038.014.0OIL BASED20.12.198422111.5039.011.0OIL BASED20.12.198424021.5031.010.0OIL BASED26.12.198424601.5034.010.5OIL BASED26.12.198424771.5036.012.0OIL BASED26.12.198425761.5039.014.0OIL BASED26.12.198426931.5042.017.0OIL BASED26.12.198427381.5045.018.0OIL BASED26.12.198427801.5142.016.0OIL BASED27.12.198429211.5045.018.0OIL BASED01.01.198530871.5043.015.0OIL BASED01.01.198531171.3132.05.0OIL BASED24.03.198531511.5039.016.0OIL BASED01.01.198532531.5042.016.0OIL BASED01.01.198532971.2720.06.5WATER BASED06.01.198532971.5040.017.0OIL BASED02.01.198532971.5040.017.0OIL BASED03.01.198532971.5040.017.0OIL BASED06.01.198532971.2720.06.5WATER BASED06.01.198532971.5039.016.0OIL BASED01.01.198532971.5040.017.0OIL BASED02.01.198532971.5040.017.0OIL BASED03.01.198532971.5040.017.0OIL BASED06.01.198533011.2719.07.5WATER BASED06.01.198533241.2723.04.0OIL BASED21.03.198533401.2720.08.0WATER BASED07.01.198533481.2729.05.0OIL BASED24.03.198533481.2931.04.5OIL BASED24.03.198533481.2725.05.0OIL BASED18.03.198533481.2724.05.0OIL BASED19.03.198533481.2725.04.0OIL BASED20.03.198533481.2724.05.0OIL BASED19.03.198533481.2725.04.0OIL BASED20.03.198533481.2729.05.0OIL BASED24.03.198533481.2931.04.5OIL BASED24.03.198533501.2847.08.0OIL BASED17.03.198533501.2734.06.0OIL BASED17.03.198533501.2833.07.0OIL BASED17.03.198533501.2833.07.0OIL BASED17.03.198533501.2847.08.0OIL BASED17.03.198533681.2723.09.0WATER BASED07.01.198533871.2721.08.0WATER BASED07.01.198534321.2725.011.0WATER BASED10.01.198534451.2724.010.0WATER BASED14.01.198534571.2722.05.5WATER BASED21.01.198534571.2717.05.5WATER BASED14.01.198534571.2718.06.0WATER BASED15.01.198534571.2720.07.0WATER BASED16.01.198534571.2719.08.0WATER BASED18.01.198534571.2719.07.0WATER BASED21.01.198534571.2722.05.5WATER BASED21.01.198534571.2720.07.5WATER BASED14.01.198534571.2717.05.5WATER BASED14.01.198534571.2718.06.0WATER BASED15.01.198534571.2720.07.0WATER BASED16.01.198534571.2719.07.5WATER BASED17.01.198534571.2719.08.0WATER BASED18.01.198534571.2719.07.0WATER BASED21.01.198534571.2719.07.5WATER BASED17.01.198534671.2821.06.0WATER BASED21.01.198534721.2721.05.0WATER BASED21.01.198535001.2718.05.0WATER BASED23.01.198535451.3139.012.0OIL BASED25.02.198535451.2729.065.0OIL BASED25.02.198535451.2731.06.0OIL BASED26.02.198535451.2720.05.0OIL BASED27.02.198535451.2723.05.0OIL BASED01.03.198535451.2724.05.0OIL BASED03.03.198535451.2725.05.0OIL BASED03.03.198535451.2723.06.0OIL BASED04.03.198535451.2723.06.0OIL BASED05.03.198535451.2723.06.0OIL BASED06.03.198535451.2729.06.5OIL BASED08.03.198535451.2725.06.0OIL BASED10.03.198535451.2733.08.0OIL BASED10.03.198535451.2724.05.5OIL BASED10.03.198535451.2724.06.0OIL BASED12.03.198535451.2724.06.0OIL BASED13.03.198535451.2736.06.0OIL BASED14.03.198535451.2731.06.0OIL BASED26.02.198535451.2720.05.0OIL BASED27.02.198535451.2723.05.0OIL BASED01.03.198535451.2724.05.0OIL BASED03.03.198535451.2725.05.0OIL BASED03.03.198535451.2723.06.0OIL BASED04.03.198535451.2723.06.0OIL BASED05.03.198535451.2723.06.0OIL BASED06.03.198535451.2729.06.5OIL BASED08.03.198535451.2725.06.0OIL BASED10.03.198535451.2733.08.0OIL BASED10.03.198535451.2724.05.5OIL BASED10.03.198535451.2724.055.0OIL BASED11.03.198535451.2724.06.0OIL BASED12.03.198535451.2736.06.0OIL BASED14.03.198535451.2729.065.0OIL BASED25.02.198535451.2724.06.0OIL BASED13.03.198535451.2724.055.0OIL BASED11.03.198535581.2720.06.0WATER BASED24.01.198535801.2721.06.5WATER BASED29.01.198536801.2733.012.5OIL BASED04.02.198536801.2733.012.5OIL BASED04.02.198536801.2722.06.5WATER BASED04.02.198538711.2727.013.0OIL BASED04.02.198539721.2728.012.0OIL BASED05.02.198540461.2726.011.0OIL BASED06.02.198541201.2731.011.0OIL BASED07.02.198541201.2735.011.0OIL BASED08.02.198541201.2735.011.0OIL BASED08.02.198541661.2730.010.0OIL BASED10.02.198541891.2731.011.0OIL BASED10.02.198541891.2731.010.5OIL BASED10.02.198541891.2731.010.5OIL BASED10.02.198542281.2737.010.0OIL BASED12.02.198542681.2732.010.0OIL BASED12.02.198542771.2730.09.0OIL BASED13.02.198543031.2735.09.0OIL BASED18.02.198543031.2735.010.0OIL BASED17.02.198543031.2736.010.0OIL BASED17.02.198543031.2735.09.0OIL BASED17.02.198543031.2735.09.0OIL BASED18.02.198543031.2736.010.0OIL BASED19.02.198543031.2737.011.0OIL BASED21.02.198543031.2938.011.0OIL BASED21.02.198543031.2731.010.0OIL BASED14.02.198543031.2735.010.0OIL BASED17.02.198543031.2736.010.0OIL BASED17.02.198543031.2735.09.0OIL BASED17.02.198543031.2736.010.0OIL BASED19.02.198543031.2737.011.0OIL BASED21.02.198543031.2938.011.0OIL BASED21.02.1985 -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory2550.0[m]DCRRI2565.0[m]DCRRI3232.0[m]DCRRI3252.0[m]DCRRI3315.0[m]DCRRI3330.0[m]DCRRI3345.0[m]DCRRI3364.2[m]CRRI3395.0[m]DCRRI3412.0[m]DCRRI3417.0[m]DCRRI3432.0[m]DCRRI3432.6[m]CRRI3443.1[m]CRRI3452.8[m]CRRI3458.6[m]CRRI3467.8[m]CRRI3480.8[m]CRRI3498.1[m]CRRI3510.0[m]DCRRI3525.0[m]DCRRI3540.0[m]DCRRI3555.0[m]DCRRI3570.0[m]DCRRI3634.0[m]SWCRRI3665.0[m]DCRRI3680.0[m]DCRRI3935.0[m]DCRRI3950.0[m]DCRRI3960.0[m]DCRRI3974.0[m]SWCRRI3977.0[m]DCRRI3990.0[m]DCRRI4003.0[m]SWCRRI4005.0[m]DCRRI4020.0[m]DCRRI4025.0[m]SWCRRI4035.0[m]DCRRI4045.0[m]SWCRRI4050.0[m]SWCRRI4050.0[m]DCRRI4064.0[m]SWCRRI4065.0[m]DCRRI4080.0[m]SWCRRI4080.0[m]DCRRI4082.0[m]DCRRI4088.0[m]SWCRRI4097.0[m]DCRRI4115.0[m]SWCRRI4130.0[m]SWCRRI4139.0[m]SWCRRI4149.0[m]SWCRRI4162.0[m]SWCRRI4174.5[m]SWCRRI4268.3[m]CRRI4276.5[m]CRRI4287.0[m]DCRRI4292.0[m]SWCRRI4302.0[m]SWCRRI