6306/10-1
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General information
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Wellbore history
GeneralWell 6306/10-1 was designed to drill the Skalmen prospect, a structural closure located at the northern apex of the Gossa High in block 6306/10. Amplitude anomalies was seen at 280-, 300-, 400-, 1200 to 1300-, and 2200- 2400 ms. The primary objective of the well was to test the hydrocarbon potential of Early Jurassic and Pre-Jurassic sequences, believed to be developed in a sandy facies of deltaic/fluvial origin. Secondary objective was to test potential reservoir developments in the Cretaceous and the Late Jurassic within dip-closure. A third objective was to test the hydrocarbon potential of Paleocene sands. The well should be drilled some 250-300 m into rocks of Pre-Jurassic age and would penetrate the primary objective some 300 m down-dip from the structural culmination.Operations and resultsWildcat well 6306/10-1 was spudded with the semi-submersible installation Dyvi Stena on 7 September 1990 and drilled to TD at 3187 m in basement rocks. Shallow gas was not observed. Overcompacted sediments and boulders caused some problems, and the well had to be re-spudded several times. Bad weather caused some delay in the drilling procedure, as the string was temporary hung off several times. The well was drilled with Bentonite and seawater down to 610 m and with PAC/gypsum mud from 610m to TD.The well encountered close to 150 m of Paleocene Egga sand at 1138 m. Some sand developments were seen also in an Intra-Kvitnos Unit at 1825 m and in a 7 m thick Lysing Formation at 1992 m. The well penetrated a hiatus from Aptian to Early Callovian at 2692 m. The Middle Jurassic section from 2692 m to 2980 m contained about 60 m net sand with relatively low porosities and poor permeabilities, based on petrophysical log evaluation. The logs also showed that this section was gas bearing. Shows were recorded in the Egga Informal unit from 1142 m to 1180 m, in sandstone stringers in the interval 1992 m to 2470 m in the Lysing and Lange Formation, in the Middle Jurassic Viking and Fangst Groups from 2700 m to 2980 m, and on sidewall cores taken in metamorphic basement. Production testing of the Jurassic interval and the basement produced small volumes of gas at very low rates from the Jurassic, while the basement produced no formation fluid to surface.Various laboratories conducted extensive organic geochemical analyses in this well. These could confirm migrant hydrocarbons (shows) in the Egga sand and in the Middle Jurassic. The Egga hydrocarbons were severely biodegraded, but appeared to originate from a very early mature source. The Middle Jurassic shows and the DST oil showed variable fingerprints, but a more or less waxy, terrestrial nature was interpreted in many samples. The Middle Jurassic contained silty shales in the upper part (Melke) and more coaly shales and coals in the lower part (Garn). Both constitute excellent source rocks for gas and oil. The well is mature for oil generation (%Ro = 0.5) from ca 2200 m depth to TD.FMT pressure surveys gave a clear water gradient in Egga sand. No gradient could be established over the Jurassic and basement sections. FMT Fluid sampling in the Jurassic gave only mud filtrate. A total of 5 conventional cores were cut in the well: two in the Egga sand, one in the Melke Formation, one in the Garn Formation, and one in basement rock.The well was permanently abandoned with shows on 17 December 1990.TestingTwo DST tests were carried out. No 1 perforated from 2995 - to 3187 m in basement. This test did not produce any formation fluid to surface. No 2 perforated from 2716 - to 2827 m in Jurassic rocks. It flowed gas at very low rates of some 1500 Sm3/d. Upon abandonment of the test the tubing content was circulated out. This indicated that condensate and some formation water had been produced (some 1 m3 of condensate and some 4 m3 of water, 13000 ppm C1-). -
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]620.003169.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11144.01170.0[m ]21172.01198.7[m ]32747.02758.3[m ]42880.02888.0[m ]53156.03159.7[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]75.7Cores 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 availableDSTDST22716.002827.0011.12.1990 - 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 typeCONDUCTOR30169.036171.00.00LOTINTERM.20603.026605.01.87LOTINTERM.13 3/81499.017 1/21501.01.80LOTINTERM.9 5/82644.012 1/42647.02.20LOTLINER73187.08 1/23187.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0296731580.0Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.0 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBIL GR29953184CBL VDL01498CBL VDL GR24802978CND CNL GR CAL6031495CND CNL GR CAL14982631CND CNL GR SPL29953184CND CNL SPL CAL26423141DIFL AC SP GR6031495DIFL AC SP GR14982631DIFL AC SP GR26423141DIFL AC SP GR29953184DIPMETER26473137DLL MLL GR26423042DLL MLL GR29953184DLL MSFL GR10751325FMT GR11381280FMT GR18281849FMT GR18281849FMT GR27213115MWD - GR RES DIR1003074RSCT GR31013139SWC GR6141477SWC GR15242610SWC GR26603107VELOCITY6143175VSP GR8703140 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit108275275610610113812851285152517501825188519921992199926922692278127812980 -
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]pdf45.22 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1210.00100.0WATER BASED10.09.19901750.00100.0WATER BASED10.09.19906100.00100.0WATER BASED13.09.19906100.00100.0WATER BASED17.09.19906100.00100.0WATER BASED17.09.19906100.00100.0WATER BASED17.09.19906100.00100.0WATER BASED17.09.19906101.3060.015.0WATER BASED20.09.19906100.00100.0WATER BASED14.09.199010311.3052.017.0WATER BASED20.09.199011441.3051.018.0WATER BASED24.09.199011441.3051.018.0WATER BASED24.09.199011721.3053.012.0WATER BASED24.09.199012001.3051.012.0WATER BASED25.09.199013281.3048.013.0WATER BASED26.09.199014781.3050.07.0WATER BASED26.09.199015101.3068.010.0WATER BASED28.09.199015101.3068.010.0WATER BASED01.10.199015101.3068.010.0WATER BASED01.10.199015101.3098.017.0WATER BASED01.10.199015101.3092.05.0WATER BASED02.10.199015541.2041.05.0WATER BASED03.10.199018501.2044.06.0WATER BASED04.10.199019141.2142.05.0WATER BASED04.10.199019901.2142.017.0WATER BASED05.10.199020451.2145.06.0WATER BASED08.10.199021321.2545.06.0WATER BASED08.10.199021331.2545.06.0WATER BASED08.10.199021331.2544.06.0WATER BASED09.10.199021331.2544.06.0WATER BASED10.10.199021331.2542.05.0WATER BASED11.10.199021331.2542.05.0WATER BASED12.10.199021331.2542.06.0WATER BASED15.10.199021331.2546.06.0WATER BASED15.10.199023161.2553.07.0WATER BASED15.10.199024141.2549.07.0WATER BASED16.10.199024971.2548.06.0WATER BASED17.10.199025951.2549.08.0WATER BASED18.10.199026441.3563.012.0WATER BASED29.10.199026441.3563.012.0WATER BASED25.10.199026551.2547.07.0WATER BASED22.10.199026551.2547.07.0WATER BASED22.10.199026551.2547.07.0WATER BASED22.10.199026551.3546.08.0WATER BASED23.10.199026551.3563.011.0WATER BASED23.10.199026831.3550.06.0WATER BASED29.10.199027071.3550.06.0WATER BASED29.10.199027471.5549.06.0WATER BASED29.10.199027831.6053.08.0WATER BASED30.10.199028591.6052.08.0WATER BASED31.10.199028761.6053.08.0WATER BASED31.10.199028891.6059.09.0WATER BASED01.11.199029081.6061.010.0WATER BASED02.11.199029501.5866.010.0WATER BASED10.12.199029501.5866.010.0WATER BASED10.12.199029501.5866.010.0WATER BASED10.12.199029501.5866.010.0WATER BASED12.12.199029501.5865.010.0WATER BASED13.12.199029501.5865.09.0WATER BASED14.12.199029501.5865.09.0WATER BASED17.12.199029501.5866.011.0WATER BASED10.12.199029501.5866.010.0WATER BASED11.12.199029501.5862.09.0WATER BASED17.12.199029651.6052.06.0WATER BASED05.11.199029761.6054.07.0WATER BASED05.11.199030191.6053.07.0WATER BASED05.11.199030611.6054.07.0WATER BASED07.11.199030741.6056.07.0WATER BASED08.11.199031241.6056.07.0WATER BASED09.11.199031411.6062.09.0WATER BASED19.11.199031411.6057.08.0WATER BASED12.11.199031411.6057.08.0WATER BASED12.11.199031411.6057.08.0WATER BASED12.11.199031411.6060.09.0WATER BASED13.11.199031411.6060.09.0WATER BASED14.11.199031411.6060.09.0WATER BASED15.11.199031411.6060.09.0WATER BASED16.11.199031411.6063.09.0WATER BASED19.11.199031411.6063.09.0WATER BASED19.11.199031411.6053.07.0WATER BASED20.11.199031411.6060.08.0WATER BASED21.11.199031411.6060.08.0WATER BASED22.11.199031411.5560.09.0WATER BASED26.11.199031581.5568.08.0WATER BASED26.11.199031671.5582.07.0WATER BASED26.11.199031821.5582.06.0WATER BASED26.11.199031871.5582.07.0WATER BASED27.11.199031871.5584.013.0WATER BASED28.11.199031871.5584.013.0WATER BASED30.11.199031871.5597.012.0WATER BASED04.12.199031871.5594.012.0WATER BASED04.12.199031871.5588.011.0WATER BASED04.12.199031871.5584.010.0WATER BASED04.12.199031871.5583.09.0WATER BASED04.12.199031871.5568.013.0WATER BASED05.12.199031871.5584.013.0WATER BASED30.11.1990 -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1145.0[m]CRRI1145.8[m]CRRI1147.0[m]CRRI1148.4[m]CRRI1150.0[m]CRRI1157.9[m]CRRI1159.1[m]CRRI1165.2[m]CRRI1172.1[m]CRRI1177.2[m]CRRI1184.8[m]CRRI