30/9-6
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General information
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Wellbore history
GeneralWell 30/9-6 was drilled on the C-prospect on the southeast flank of the Oseberg Fault block. The structure is a rotated fault block with overall easterly dips towards the Horda Platform fault. The prospect is further bounded by faults to the west and to the northwest. The primary objective was to prove hydrocarbons in the Brent Group and verify possible pressure communication between the C-structure and the Oseberg Field Alpha structure to the North.Operations and resultsWildcat well 30/9-6 was spudded with the semi-submersible installation Polar Pioneer on 8 March 1987 and drilled to TD at 3034 m in the Early Jurassic Statfjord Group. Drilling proceeded without significant problems. The well was drilled with spud mud down to 970 m and with KCl/polymer mud from 970 m to TD.The Brent Group was encountered at 2591 m and had oil in three differently pressured sand bodies, one in the Tarbert Formation and two in the Ness Formation. The lowest seen oil was at 2645 m in the Ness Formation. Four different pressure regimes were found in the Brent group. The Tarbert Formation has 6 m gross with 4.5 m net pay. The average porosity is 19% and the average water saturation is 44%. The Ness Formation has 49 m gross (hydrocarbon-bearing interval) with 13.3 m net pay (combining the two oil bearing sand bodies). The average porosity is 23% and the average water saturation is 39%.Weak shows were described in limestones in the interval 2318 m to 2358 m in the top of the Shetland Group. Otherwise, no oil shows were described outside of the oil-bearing Brent reservoirs.Five conventional cores were cut in the Brent Group from 2593.5 - 2686 m. RFT fluid samples were taken at 2619 m in both runs 2A and 2B. Run 2B was performed in order to verify the previous run.The well was permanently abandoned on 21 April as an oil discovery.TestingTwo drill stem tests were performed.DST 1 tested the interval 2637.9 m to 2645.5 m in the lowermost oil bearing section in the Ness Formation. This test produced 185 Sm3 oil and 17175 Sm3 gas /day through a 20/64” choke. The GOR was 92.8 Sm3/Sm3, the oil density was 0.855 G/cm3, and the gas gravity was 0.698 (air = 1) with 1% CO2 and no detectable H2S. The bottom hole temperature was 100 °C.DST2 tested the interval 2591.5 m to 2596.5 m in the Tarbert Formation. This test produced 166 Sm3 oil and 16980 Sm3 gas /day through a 20/64” choke. The GOR was 102 Sm3/Sm3, the oil density was 0.856 g/cm3, and the gas gravity was 0.698 with 1% CO2 and no detectable H2S. The bottom hole temperature was 100 °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]970.003032.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12593.52603.3[m ]22608.02623.5[m ]32628.02636.0[m ]42649.02665.2[m ]52671.02676.8[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]55.2Cores 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 availableDSTDST12637.902645.50OIL08.04.1987 - 00:00YESDSTDST22591.502596.50OIL12.04.1987 - 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 typeCONDUCTOR30213.036214.00.00LOTINTERM.13 3/8954.017 1/2970.01.71LOTINTERM.9 5/82567.012 1/42587.01.81LOTLINER73031.08 1/23034.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0263826467.92.0259225977.9Drill 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]1.0185171750.8550.698932.0166169800.8560.698102 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL CET16002962CST21652570CST25832999DIL LSS LDT CNL GR SP CAL9503028DLL MSFL NGT25672800MWD GR SON NEU RES1262587RFT25913002RFT25922643RFT26190RLL GR EWR COND25652655SHDT9503033VSP6802950 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1266908282020202020802138230223172547254725912591259726932699272327232835284529072981 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]pdf0.19pdf0.24pdf1.32pdf1.08 -
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]pdf5.83pdf10.66 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1240.00WATER BASED21.04.19871310.00WATER BASED21.04.19871601.03WATER BASED09.03.19871650.00WATER BASED21.04.19872141.03WATER BASED10.03.19878631.03WATER BASED11.03.19879701.03WATER BASED12.03.19879701.3427.011.0WATER BASED13.03.198714381.3428.012.0WATER BASED16.03.198715271.4037.018.0WATER BASED16.03.198718881.4031.012.0WATER BASED16.03.198721361.4030.012.0WATER BASED17.03.198722671.4032.012.0WATER BASED18.03.198723501.2125.09.0WATER BASED21.04.198723991.4034.013.0WATER BASED19.03.198724651.2122.07.0WATER BASED21.04.198724721.4032.010.0WATER BASED20.03.198725281.4033.09.0WATER BASED25871.4031.09.0WATER BASED25871.2117.06.0WATER BASED24.03.198725931.2127.010.0WATER BASED25.03.198726241.2127.010.0WATER BASED26.03.198726341.2126.010.0WATER BASED13.04.198726341.2126.09.0WATER BASED14.04.198726341.2120.07.0WATER BASED21.04.198726511.2126.010.0WATER BASED30.03.198726861.2127.010.0WATER BASED30.03.198727591.2124.09.0WATER BASED30.03.198728581.2124.08.0WATER BASED30.03.198729651.2128.011.0WATER BASED06.04.198729651.2127.011.0WATER BASED06.04.198729651.2127.011.0WATER BASED07.04.198729651.2127.011.0WATER BASED08.04.198729651.2127.011.0WATER BASED13.04.198729651.2125.010.0WATER BASED13.04.198730341.2124.010.0WATER BASED31.03.198730341.2124.010.0WATER BASED01.04.198730341.2124.09.0WATER BASED02.04.198730341.2125.09.0WATER BASED03.04.1987