30/6-15
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General information
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Wellbore history
GeneralWell 30/6-15 was drilled on the Gamma North structure west of the Oseberg Alpha structure. Gamma North is a NNW-SSE trending fault block down-faulted to the adjacent Alpha structure. The primary objective was to find hydrocarbon accumulations in the Statfjord Group. The secondary objective was to test the hydrocarbon potential in the Cook Formation. The total depth of the well was planned ca 270 m into the Triassic at a depth of ca 3950 m, corresponding to ca 3200 m TVD.Operations and resultsWildcat well 30/6-15was spudded with the semi-submersible installation Treasure Seeker on 2 May 1984 and drilled deviated to TD at 3972 m (3200 m TVD) at a position ca 2180 meters west of the surface position. Operations suffered from comparatively much down time due to hole problems and equipment repairs. The 8 3/8" and 6" sections in particular suffered hole problems and difficult logging. The well was drilled with spud mud down to 195 m, with gel/sea water from 195 m to 617 m, with SafeMul oil based mud from 617 m to 3005 m, and with NaCl/polymer mud from 3005 m to TD.The Etive Formation (2884 - 2902 m, 2358 - 2372 m TVD) truncated by Cretaceous strata was found water bearing.No Cook Formation reservoir was encountered. The Statfjord Formation (3241 - 3548 m, 2641.5 -2878.5 m TVD) sandstones were found gas bearing down to 3313 m (2697 m TVD), and oil bearing down to 3348 m (2723.5 m TVD). An oil/water transition zone is seen down to 3359 m MD (2732 m TVD). The lithology of the hydrocarbon bearing interval was predominantly sandstones with some interbeds of claystones/shales. Net pay in the gas zone was calculated on logs to 67.4 m giving a net to gross ratio of 0.94. Net pay in the oil zone was 31.9 m giving a net to gross of 0.91.Hydrocarbon shows, rated as poor to locally fair, were reported from the Cretaceous limestones and on sandstone stringers in the Dunlin Group and in the Triassic.Eight conventional cores were cut in the Statfjord Formation from 3254 m (2652 m TVD) down to 3398.5 m (2762 m TVD). Five sets of segregated samples were taken. Sample 1 was taken at 3283.5 m in the gas zone, samples 2 and 3 at 3322 m in the oil zone, and samples 4 and 5 were taken in the transition zone at 3353 m and 3355.5 m respectively.The well was permanently abandoned on 5 September 1984 as an oil and gas discovery.TestingThree Drill stem tests (DST) were performed in the Statfjord Formation.DST no. 1 (3351.5 - 3354.5 m, 2726.2 - 2728.5 m TVD) tested the oil/water transition zone. The well produced 150 m3 water and 43 Sm3 oil /day through a 20/64" choke. The oil production rate increased through the test. The well also produced 1% CO2 and nil H2S. The wellhead pressure (WHP) was 46.3 bars and the bottom hole temperature (BHT) was 107 deg C.DST no. 2 (3323 -3330 m, 2704.4 - 2710 m TVD) tested the oil zone, and produced 536.6 Sm3 oil and 72200 Sm3 gas /day through a 28/64" choke. The GOR was 134.6 Sm3 /Sm3, the oil gravity was 37 deg API and the gas gravity was 0.66 (Air = 1). The WHP was 141.4 bars and the BHT was 104.8 deg C. 1% of C02 was produced and nil H2S. A second main flow produced 1033.5 Sm3 oil /day through a 44/64" choke. In this flow the gas rate was not measured due to malfunctioning measuring device.DST no. 3 (3250 -3265 m, 2649 - 2660.3 m TVD) was a gas test and produced 974100 Sm3 gas and 249.6 Sm3 condensate /day through a 64/64" choke. The gas/condensate ratio was 3902 Sm3/Sm3, the oil gravity was 54.7 deg API and the gas gravity was 0.68 (Air =1). The WHP was measured at 196.5 bars (2850 PSIA) and the BHT was 104.2 deg C. The test also produced 0.9 % CO2, but no measurable 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]200.003972.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13254.03272.1[m ]23272.03291.5[m ]33294.03321.0[m ]43321.03348.0[m ]53349.03363.6[m ]63365.03376.0[m ]73377.03388.1[m ]83390.03398.5[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]136.7Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory2884.0[m]SWCRRI3010.0[m]SWCRRI3156.0[m]SWCRRI3185.5[m]SWCRRI3200.0[m]SWCRRI3218.5[m]SWCRRI -
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 availableDSTDST23323.803330.4014.08.1984 - 00:00YESDSTDST33265.003250.0028.08.1984 - 00:00YES -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit13265897923602360247326232698271228842884290229023101310931743241324132723548 -
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]pdf20.95 -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0335533527.92.03324333017.53.03251326625.4Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.032.00030.00032.0002.031.00031.0003.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.0430.8502.010340.8411353.02509755000.7600.6803902 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL CCL4901880CBL VDL CET12862980CBL VDL CET28323500DIL LSS GR5902992DLL MSFL GR29893390HDT23002981ISF LSS GR193614ISF LSS GR29893394ISF LSS GR32073507ISF LSS GR34973966LDL CNL GR5903686NGL32073508RFT28862899RFT32433392RFT32833283RFT33133439RFT33223322RFT33223322RFT33533353SHDT29893509VSP3563625 -
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 typeCONDUCTOR30194.036195.00.00LOTSURF.COND.20592.026617.01.43LOTINTERM.13 3/81883.017 1/21900.01.62LOTINTERM.9 5/82989.512 1/43034.01.73LOTLINER73500.08 1/23512.01.73LOTOPEN HOLE3972.063972.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1951.04WATER BASED04.05.19841951.04WATER BASED04.05.19841951.04WATER BASED03.05.19842401.03WATER BASED06.05.19843861.07WATER BASED07.05.19845291.10WATER BASED10.05.19845691.12OIL BASED17.05.19846171.10WATER BASED10.05.19846171.11WATER BASED13.05.19846171.10WATER BASED13.05.19846171.10WATER BASED14.05.19846171.06WATER BASED15.05.19846171.11WATER BASED13.05.19846171.10WATER BASED14.05.19846171.06WATER BASED15.05.19846171.10WATER BASED13.05.19846201.05WATER BASED17.05.19847791.15OIL BASED20.05.19848721.15OIL BASED20.05.198411201.18OIL BASED22.05.198412891.20OIL BASED23.05.198413241.20OIL BASED24.05.198414331.20OIL BASED25.05.198415581.20OIL BASED28.05.198417191.21OIL BASED28.05.198419001.25OIL BASED29.05.198419001.37OIL BASED01.06.198419001.25OIL BASED29.05.198419001.37OIL BASED01.06.198419001.25OIL BASED28.05.198421281.45OIL BASED04.06.198425921.48OIL BASED04.06.198429041.48OIL BASED05.06.198430051.50OIL BASED05.06.198430341.30WATER BASED14.06.198430851.35WATER BASED14.06.198432011.30WATER BASED15.06.198432541.30WATER BASED17.06.198432941.31WATER BASED17.06.198432961.28WATER BASED13.08.198432961.28WATER BASED15.08.198432961.28WATER BASED16.08.198432961.28WATER BASED21.08.198432961.28WATER BASED14.08.198432961.28WATER BASED16.08.198432961.28WATER BASED21.08.198432961.28WATER BASED23.08.198432961.28WATER BASED14.08.198432961.28WATER BASED23.08.198432961.28WATER BASED15.08.198433181.28WATER BASED24.08.198433181.28WATER BASED27.08.198433181.28WATER BASED27.08.198433491.31WATER BASED17.06.198433691.34WATER BASED18.06.198433901.31WATER BASED20.06.198434011.31WATER BASED22.06.198434181.28WATER BASED06.08.198434181.28WATER BASED08.08.198434181.28WATER BASED09.08.198434181.28WATER BASED13.08.198434181.28WATER BASED07.08.198434181.28WATER BASED08.08.198434181.28WATER BASED09.08.198434181.28WATER BASED13.08.198434181.28WATER BASED07.08.198434341.31WATER BASED26.06.198435121.28WATER BASED26.06.198435121.2812.06.0WATER BASED26.06.198435121.2810.07.0WATER BASED28.06.198435121.2812.06.0WATER BASED29.06.198435121.2814.05.0WATER BASED03.07.198435121.29WATER BASED06.07.198435121.28WATER BASED06.07.198435121.28WATER BASED10.07.198435121.28WATER BASED11.07.198435121.28WATER BASED12.07.198435121.2812.06.0WATER BASED26.06.198435121.2810.07.0WATER BASED28.06.198435121.2812.06.0WATER BASED29.06.198435121.3015.05.0WATER BASED03.07.198435121.2814.05.0WATER BASED03.07.198435121.29WATER BASED06.07.198435121.28WATER BASED06.07.198435121.28WATER BASED10.07.198435121.28WATER BASED11.07.198435121.28WATER BASED12.07.198435121.28WATER BASED16.07.198435121.3015.05.0WATER BASED03.07.198435121.28WATER BASED16.07.198435471.28WATER BASED18.07.198435641.28WATER BASED20.07.198436051.28WATER BASED20.07.198437101.28WATER BASED23.07.198437701.28WATER BASED23.07.198438541.2817.07.0WATER BASED24.07.198439721.28WATER BASED30.07.198439721.2819.09.0WATER BASED01.08.198439721.28WATER BASED01.08.198439721.28WATER BASED06.08.198439721.2819.09.0WATER BASED01.08.198439721.28WATER BASED01.08.198439721.28WATER BASED26.07.198439721.28WATER BASED06.08.1984 -
Pressure plots
Pressure plots The pore pressure data is sourced from well logs if no other source is specified. In some wells where pore pressure logs do not exist, information from Drill stem tests and kicks have been used. The data has been reported to the NPD, and further processed and quality controlled by IHS Markit.Pressure plots Document nameDocument formatDocument size [MB]pdf0.23