15/6-7
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General information
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Wellbore history
GeneralWell 15/6-7 was the first well in licence 166. The primary objective of the well was to test the hydrocarbon potential of the Middle Jurassic, Hugin Formation of Callovian age within a seismically defined structural trap. There were no secondary objectives for the well, however, other potential reservoir horizons, albeit outside closure, were anticipated within the early Tertiary succession. The well programme was designed to maximize the evaluation of these sections asrequired.Operations and resultsExploration well 15/6-7 was spudded on 24 April 1993 with the semi-submersible installation "Vildkat Explorer" and drilled to TD at 3540 m in the Triassic Smith Bank Formation. The well was drilled with gel and seawater down to 505 m, with PHPA/KCl mud from 505 m to 1173 m, with PHPA/KCl/Glycol mud from 1173 m to 2788 m, and with PHPA/KCl mud from 2788 m to TD.The Quaternary and Tertiary sequence represented by the Nordland, Hordaland and Rogaland Group is dominated by mudstone lithologies with occasional thick sandstone developments in the Utsira, Grid, and Heimdal Formations. Background gas values ranged from less than 0.1% to 0.5% with rare isolated gas peaks. The Late Cretaceous succession in the well, 493 m thick, is dominated by carbonate lithologies of the Shetland Group; below 3150 m these become increasingly and atypically sandy. A number of gas peaks were recorded over the interval 3025 m to 3157 m with a maximum gas peak of 5.42% recorded at 3154 m. The Early Cretaceous, 14.5 m thick, represented by the Cromer Knoll Group is substantially thinner than anticipated and consists of arenaceous limestones interbedded with thin calcareous sandstones. The Upper Jurassic Draupne Formation was penetrated at 3233 m, 36 m low to prognosis. Intra Draupne Formation Sandstone was encountered at 3292 m. A formation fluid influx of 3.9 m3 equivalent to a calculated pore pressure of 1.5 sg (RFT) occurred at 3327 m (3331 m loggers depth), a gas peak of 0.74% was associated with this influx. The mud weight was increased from 1.30 sg to 1.52 sg during well control operations. The top Heather Formation was penetrated at 3352.5 m, 75.5 m deeper than anticipated. Background gas values within the Draupne and Heather Formations gradually decreased with depth from 4% to 0.18% at the base of the Heather Formation. The primary objective, the Hugin Formation, was penetrated at 3390.5 m, 4.5 m shallower than anticipated. The Hugin Formation consists of interbedded mudstones and sandstones with the sandstone beds increasing in thickness with depth. The well failed to penetrate any hydrocarbon bearing horizons. The primary objective Hugin Formation was water bearing. This was confirmed by RFT and petrophysical evaluation of the logs.One conventional core was cut over the interval 3414 m to 3432 m (15.7 m recovered) in the Triassic Skagerrak Formation. Three RFT runs, 3/1,3/2 and 3/3, were performed in the 8.5" hole section in the Draupne, Hugin and Skagerrak Formations, over the interval 3433-3331 m. A segregated sample was taken on run 3/3. The sample recovered 5 l of muddy water in the 6-gallon chamber. The 1-gallon chamber was plugged.The well was permanently plugged and abandoned as a dry hole on 8 June 1993.TestingNo drill stem test was performed. -
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]510.003540.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13414.03429.7[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]15.7Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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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 typeCONDUCTOR30217.036220.00.00LOTINTERM.20492.026505.01.36LOTINTERM.13 3/81157.017 1/21173.01.84LOTINTERM.9 5/82773.012 1/42788.01.74LOTOPEN HOLE3540.08 1/23540.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL GR CCL22822765CST GR13502602CST GR13722732CST GR30193525CST GR31563524DLL MSFL SDT AS AMS27753540DLL MSFL SDT AS GR4921152DLL MSFL SDT AS GR SP11572768LDL CNL NGS AMS11572764LDL CNL NGS AMS27753543MWD - BGD132505MWD - BGD GR5051173MWD - DPR28003146MWD - DPR34093536MWD - RDG32463410MWD - RGD11732788RFT33313433SHDT FMS GR AMS30983544SHDT GR AMS17002715VSP AMS10853515 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1327729931117123313071406183621082258225823022369242726062645267626762740298431883196321932193230323332333292335333913391341134113476 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.66 -
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]pdf35.51 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1801.03WATER BASED2201.05WATER BASED5051.20WATER BASED11731.14190.0WATER BASED20671.30170.0WATER BASED21001.30180.0WATER BASED22131.30220.0WATER BASED24401.30180.0WATER BASED26141.30180.0WATER BASED26901.30190.0WATER BASED27001.30130.0WATER BASED27001.54230.0WATER BASED27881.30290.0WATER BASED31201.30180.0WATER BASED32261.50260.0WATER BASED34141.52200.0WATER BASED35401.52230.0WATER BASED -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1700.0[m]SWCRRI1715.0[m]DCRRI1725.0[m]DCRRI1735.0[m]SWCRRI1750.0[m]SWCRRI1766.0[m]SWCRRI1780.0[m]DCRRI1795.0[m]DCRRI1805.0[m]DCRRI1822.0[m]SWCRRI1832.0[m]SWCRRI1862.0[m]SWCRRI1870.0[m]SWCRRI1880.0[m]DCRRI1889.0[m]SWCRRI1950.0[m]DCRRI1957.0[m]SWCRRI1965.0[m]DCRRI2022.0[m]SWCRRI2030.0[m]DCRRI2050.0[m]DCRRI2069.0[m]SWCRRI2109.0[m]SWCRRI2125.0[m]DCRRI2140.0[m]DCRRI2155.0[m]DCRRI2167.0[m]SWCRRI2183.0[m]SWCRRI2197.0[m]SWCRRI2215.0[m]DCRRI2230.0[m]DCRRI2269.0[m]SWCRRI2277.0[m]SWCRRI2290.0[m]DCRRI2297.0[m]SWCRRI2310.0[m]DCRRI2325.0[m]DCRRI2336.0[m]SWCRRI2350.0[m]DCRRI2360.0[m]DCRRI2370.0[m]SWCRRI2385.0[m]DCRRI2394.0[m]SWCRRI2425.0[m]DCRRI2440.0[m]DCRRI2463.0[m]SWCRRI2473.0[m]SWCRRI2490.0[m]DCRRI2505.0[m]DCRRI2530.0[m]DCRRI2537.0[m]SWCRRI2555.0[m]DCRRI2570.0[m]DCRRI2585.0[m]DCRRI2597.0[m]SWCRRI2607.0[m]SWCRRI2613.0[m]SWCRRI2625.0[m]DCRRI2640.0[m]DCRRI2650.0[m]DCRRI2660.0[m]SWCRRI2675.0[m]DCRRI3163.0[m]SWCRRI3175.0[m]SWCRRI3195.0[m]SWCRRI3209.5[m]SWCRRI3215.5[m]SWCRRI3236.0[m]SWCRRI3244.5[m]SWCRRI3257.0[m]SWCRRI3261.0[m]DCRRI3281.0[m]SWCRRI3291.5[m]SWCRRI3306.0[m]DCRRI3318.0[m]DCRRI3336.0[m]SWCRRI3354.0[m]DCRRI3374.0[m]SWCRRI3408.0[m]DCRRI3411.0[m]DCRRI3414.0[m]DCRRI3418.0[m]CRRI3420.7[m]CRRI3423.1[m]CRRI3429.7[m]CRRI