31/4-4
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General information
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Wellbore history
GeneralWildcat well 31/4-4 is located on the Lomre Terrace north of the Brage Field and east of the Oseberg Field. The primary objective of the well was to test possible sandstone reservoirs of Cretaceous age. The secondary objective was to test sandstone reservoirs of Late Jurassic age, anticipated to be Intra Heather Formation sands.The well is Reference Well for the Etive, Ness, and Tarbert Formations of the Brent Group.Operations and resultsWell 31/4-4 was spudded with the semi-submersible installation Nortrym on 17 December 1980 and drilled to TD at 3150 m in Early Jurassic sediments of the Statfjord Formation. The well was drilled with seawater and viscous gel down to 900 m and with KCl / polymer mud from 900 m to TD.No reservoir sands of Cretaceous age were encountered in the well. Poor shows were reported from two limestone stringers and a thin, tight sandstone stringer of Late Cretaceous (Maastrichtian and Late Campanian) age. A Late Jurassic "Intra Heather Sand I" (Sognefjord Formation) was encountered at 2363 m with a gross thickness of 39 m. The net sand interval was 24 m and consisted of fine-grained to very fine-grained argillaceous, micaceous sandstone. Average porosity was calculated to 16 %. Eighty-nine percent water saturation was calculated for this sand indicating that poor oil shows encountered while drilling the interval, were residual. A second "Intra Heather Sand II" (Fensfjord Formation) was penetrated at 2482 m with a gross thickness of 45 m. The sand was water bearing without shows. The lithology was similar to the upper sand. The other reservoir sequences encountered in the well, sandstones in the Middle Jurassic Brent Formation, the Early Jurassic Cook Formation, and the Statfjord Formation, were also water bearing. The gross sand thicknesses of these were 118 m, 21m and 67m, respectively.A single conventional core was cut between 2490m and 250 8m, near the top of the lower Intra Heather Sand interval. It was dated to Oxfordian in age and consisted of 18 m (100%) of very fine-grained sandstone with good porosity, except in some heavily cemented horizons. No fluid sample was taken.The well was permanently abandoned on 17 February 1981 as a dry hole.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]350.003150.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12490.02508.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]18.0Cores 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 typeLaboratory740.0[m]DC760.0[m]DC790.0[m]DC820.0[m]DC850.0[m]DC880.0[m]DC910.0[m]DC940.0[m]DC970.0[m]DC1000.0[m]DC1030.0[m]DC1060.0[m]DC1090.0[m]DC1120.0[m]DC1150.0[m]DC1180.0[m]DC1210.0[m]DC1240.0[m]DC1270.0[m]DC1300.0[m]DC1330.0[m]DC1360.0[m]DC1390.0[m]DC1420.0[m]DC1450.0[m]DC1480.0[m]DC1510.0[m]DC1540.0[m]DC1570.0[m]DC1600.0[m]DC1630.0[m]DC1660.0[m]DC1690.0[m]DC1720.0[m]DC1720.0[m]DC1750.0[m]DC1780.0[m]DC1810.0[m]DC1840.0[m]DC1870.0[m]DC1900.0[m]DC1910.0[m]DC1930.0[m]DC1945.0[m]DC1960.0[m]DC1970.0[m]DC1980.0[m]DC1990.0[m]DC2000.0[m]DC2020.0[m]DC2040.0[m]DC2050.0[m]DC2080.0[m]DC2100.0[m]DC2115.0[m]DC2130.0[m]DC2150.0[m]DC2160.0[m]DC2175.0[m]DC2190.0[m]DC2200.0[m]DC2213.0[m]SWCIKU2216.0[m]SWCIKU2220.0[m]DC2227.0[m]DC2250.0[m]DC2255.0[m]DC2280.0[m]DC2280.0[m]CIKU2285.0[m]DCPETROSTR2287.0[m]DCPETROS2290.0[m]DCPETROS2295.0[m]DCPETROS2300.0[m]DC2302.0[m]DCPETROS2305.0[m]CIKU2312.0[m]DCPETROSTR2317.0[m]DCPETROS2325.0[m]DCPETROS2330.0[m]DCPETROS2330.0[m]CIKU2335.0[m]DCPETROSTR2352.0[m]DCPETROSTR2357.0[m]DCPETROS2362.0[m]DCPETROS2364.0[m]SWCIKU2365.0[m]DCPETROSTR2367.0[m]DCPETROS2382.0[m]DCPETROS2382.0[m]SWCIKU2385.0[m]DCPETROSTR2387.0[m]DCPETROS2410.0[m]SWCIKU2480.0[m]SWCIKU2484.9[m]SWCIKU2489.6[m]CIKU2493.5[m]CIKU2498.0[m]CIKU2502.5[m]CIKU2506.8[m]CIKU2507.7[m]CIKU2522.9[m]SWCIKU2528.9[m]SWCIKU2577.0[m]SWCIKU2628.0[m]SWCIKU2667.0[m]SWCIKU2697.0[m]SWCIKU2716.0[m]SWCIKU2767.0[m]SWCIKU2785.9[m]SWCIKU2788.6[m]SWCIKU2830.0[m]SWCIKU2851.0[m]SWCIKU2855.0[m]SWCIKU2959.0[m]SWCIKU2986.0[m]SWCIKU3022.0[m]SWCIKU3040.0[m]SWCIKU3060.0[m]SWCIKU3080.0[m]SWCIKU3136.0[m]SWCIKU3152.0[m]SWCIKU -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit239733810890179617961853189320502067219523002300236524022482252726802680269527212798293529563087 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.49 -
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]pdf12.43pdf2.24 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CST20602410CST20662735CST24803152FDC CNL GR CAL19093153FDC GR CAL8861908HDT20003153ISF BHC GR SP3243152RFT23663147VELOCITY8003140 -
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 typeCONDUCTOR30324.036325.00.00LOTSURF.COND.20886.026900.01.60LOTINTERM.13 3/81481.017 1/21918.01.60LOTOPEN HOLE3152.012 1/43152.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3251.04100.0seawater9001.1139.0seawater19181.4053.018.0seawater24901.3057.017.0seawater31501.3061.022.0seawater -
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]pdf0.22