35/12-1
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General information
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Wellbore history
GeneralThe well 35/12-1 was drilled on the eastern border of the block 35/12 against a north-south oriented main fault, which is the eastern limit of the Uer Terrace. The primary purpose of the well was to test the hydrocarbon potential in sandstones of the Late Jurassic Sognefjord Formation. A secondary objective was to test the reservoirs of the Brent and Dunlin Groups.Operations and resultsWell 35/12-1 was spudded with the semi submersible rig Treasure saga on the 27 February 1992 and was drilled to TD at 3020 m in Early Jurassic (Early Pliensbachian - ?Sinemurian) rocks. The well was drilled with spud mud down to486m,with gel mud from 486 m to 1020 m,and with KCL mud from 1020 m to TD.The well penetrated mainly claystones with minor sandstone intervals in the Nordland and Rogaland Groups. Shetland and Cromer Knoll Groups consisted mainly of claystones with limestones and marls. The well encountered 37 m of Draupne. Top Heather Formation was penetrated at 2398 m. The reservoir quality in the Heather Formation was poor. The formation consists of siltstone and some thin beds of fine sandstones with low porosity.The sandstones in the Sognefjord Formation and the Fensfjord Formation sandstone had better reservoir quality with porosities around 20% in the Fensfjord Formation. Sandstones were also present in the Brent and Dunlin Groups. Some weak traces of hydrocarbons were observed in sandstone lamina on cores from the Upper parts of the Heather Formation. Weak traces of shows were recorded also in the Fensfjord Formation and into the Brent Group. Petrophysical evaluation showed that the sandstones of Jurassic age were water filled. The well was terminated 17 m into what was initially believed to be basement rocks, but which was shown by post-well analyses to be undifferentiated Early Jurassic sediments about 120 meters shallower than prognosis. Three cores were cut in the Heather Formation from 2415 m to 2458.5 m. One core was cut from 2598 m to 2606 m in the Sognefjord Formation. The well was permanently plugged on 24 April 1992 as a dry well.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]490.003018.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12415.02441.6[m ]22442.02456.7[m ]32457.02458.4[m ]42598.02605.2[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]49.9Cores 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 typeCONDUCTOR30474.036486.00.00LOTINTERM.20999.0261020.01.41LOTINTERM.13 3/82198.017 1/22215.01.60LOTOPEN HOLE3020.012 1/43020.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CST5201005CST10402208CST22803017DIL MSFL LSS VOL GR AMS21983023DLL MSFL LSS LDL GR AMS9982207DLL SFL LSS LDL CNL GR AMS21982700LDL CNL GR AMS26503023MWD - DIR479486MWD - GR RES DIR5201005MWD - GR RES DIR9982207MWD - GR RES DIR21983023RFT GR AMS24072660RFT GR AMS26602999SHDT GR AMS21983023VSP12852185VSP21103015 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit37755157357360099910541087140014341434151319242180218022472361236123982557266727902886288628902908290829213003 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.39 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]pdf3.24 -
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]pdf13.25 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3851.04WATER BASED4191.04WATER BASED4861.04WATER BASED8561.116.0WATER BASED10151.128.0WATER BASED10201.1710.0WATER BASED12801.3028.0WATER BASED14391.3029.0WATER BASED14871.3028.0WATER BASED16001.3027.0WATER BASED16931.3026.0WATER BASED17691.3028.0WATER BASED18271.3027.0WATER BASED18991.3028.0WATER BASED19591.3028.0WATER BASED20461.2827.0WATER BASED22151.2830.0WATER BASED23521.3230.0WATER BASED24181.3234.0WATER BASED24451.3234.0WATER BASED24581.3239.0WATER BASED25961.3229.0WATER BASED25981.3228.0WATER BASED26471.3227.0WATER BASED27001.3230.0WATER BASED27781.3032.0WATER BASED29231.2827.0WATER BASED29751.2527.0WATER BASED30011.2524.0WATER BASED30201.25WATER BASED -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory490.0[m]DCRRI500.0[m]DCRRI570.0[m]DCRRI610.0[m]DCRRI620.0[m]DCRRI640.0[m]DCRRI650.0[m]DCRRI660.0[m]DCRRI670.0[m]DCRRI680.0[m]DCRRI700.0[m]DCRRI710.0[m]DCRRI720.0[m]DCRRI750.0[m]DCRRI770.0[m]DCRRI890.0[m]DCRRI910.0[m]DCRRI930.0[m]DCRRI1020.0[m]DCRRI1040.0[m]DCRRI1060.0[m]DCRRI1080.0[m]DCRRI1100.0[m]DCRRI1120.0[m]DCRRI1130.0[m]DCRRI1170.0[m]DCRRI1190.0[m]DCRRI1210.0[m]DCRRI1230.0[m]DCRRI1250.0[m]DCRRI1270.0[m]DCRRI1290.0[m]DCRRI1310.0[m]DCRRI1330.0[m]DCRRI1350.0[m]DCRRI1370.0[m]DCRRI1380.0[m]DCRRI1400.0[m]DCRRI1420.0[m]DCRRI1440.0[m]DCRRI1450.0[m]DCRRI1465.0[m]DCRRI1480.0[m]DCRRI1495.0[m]DCRRI1510.0[m]DCRRI1535.0[m]DCRRI1550.0[m]DCRRI1580.0[m]DCRRI1615.0[m]DCRRI1630.0[m]DCRRI1645.0[m]DCRRI1660.0[m]DCRRI1675.0[m]DCRRI1690.0[m]DCRRI1705.0[m]DCRRI1720.0[m]DCRRI1735.0[m]DCRRI1750.0[m]DCRRI1765.0[m]DCRRI1780.0[m]DCRRI1795.0[m]DCRRI1810.0[m]DCRRI1820.0[m]DCRRI1850.0[m]DCRRI1865.0[m]DCRRI1880.0[m]DCRRI1895.0[m]DCRRI1910.0[m]DCRRI1925.0[m]DCRRI1955.0[m]DCRRI1970.0[m]DCRRI1985.0[m]DCRRI2060.0[m]DCRRI2075.0[m]DCRRI2090.0[m]DCRRI2165.0[m]DCRRI2180.0[m]DCRRI2195.0[m]DCRRI2210.0[m]DCRRI2370.0[m]DCRRI2398.0[m]DCRRI2423.0[m]CRRI2436.0[m]CRRI2448.0[m]CRRI2458.0[m]CRRI2475.0[m]DCRRI2490.0[m]DCRRI2505.0[m]DCRRI2520.0[m]DCRRI2532.0[m]DCRRI2538.0[m]DCRRI2544.0[m]DCRRI2550.0[m]DCRRI2574.0[m]DCRRI2580.0[m]DCRRI2601.0[m]CRRI2619.0[m]DCRRI2631.0[m]DCRRI2646.0[m]DCRRI2661.0[m]DCRRI2676.0[m]DCRRI2691.0[m]DCRRI2706.0[m]DCRRI2751.0[m]DCRRI2766.0[m]DCRRI2781.0[m]DCRRI2796.0[m]DCRRI2811.0[m]DCRRI2826.0[m]DCRRI2856.0[m]DCRRI2901.0[m]DCRRI2916.0[m]DCRRI2949.0[m]DCRRI2961.0[m]DCRRI2976.0[m]DCRRI2997.0[m]DCRRI3003.0[m]DCRRI3012.0[m]DCRRI3018.0[m]DCRRI -
Thin sections at the Norwegian Offshore Directorate
Thin sections at the Norwegian Offshore Directorate DepthUnit2602.65[m ]2598.13[m ]2439.47[m ]