31/2-4
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General information
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Wellbore history
GeneralWell 31/2-4 is located some 10 km NNW of the discovery well 31/2-1 in a separate fault compartment near the crest of the Jurassic gas accumulation. This crestal area appeared also to coincide with the culminations of all deeper horizons that could be mapped. The well had two main objectives. The first was to appraise the Jurassic gas accumulation in the 31/2-1 Troll Discovery in a location with nearly maximum gross hydrocarbon column. The well should test lateral variations in this reservoir. The second major objective was to explore deeper Triassic/Palaeozoic Formations. The well would test possible hydrocarbon accumulations under the Late Jurassic Troll reservoir, explore possible pre-Jurassic source rocks, and provide geological ages for deep horizons and thus improve the regional geological setting.TD of the well was proposed to be 5000 m below sea level or in Palaeozoic formations whatever came first.Operations and resultsWell 31/2-4 was spudded with the semi-submersible installation Borgny Dolphin on 1 September 1980 and drilled to TD at 815 m in the Hordaland Group. The well was drilled with seawater and hi-vis pills. After having set the 20" casing, the well was secured and suspended on September 13 due to a farm out of the rig to Statoil. Statoil had requested the Borgny Dolphin to be released to secure their well 34/10-10, which was blowing gas from a shallow gas zone.The well was classified as a dry well.TestingNo drill stem test was performed in the well. -
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]460.005025.00 -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1371.2[m]CSHELL1375.9[m]CSHELL1376.6[m]CSHELL1380.8[m]CSHELL1398.3[m]CSHELL1398.8[m]CSHELL1403.6[m]CSHELL1412.0[m]CSHELL1413.6[m]CSHELL1460.8[m]CSHELL1460.9[m]CSHELL1463.5[m]CSHELL1516.6[m]CSHELL1518.3[m]CSHELL1521.6[m]CSHELL1521.7[m]CSHELL1521.7[m]CSHELL1521.9[m]CSHELL1522.1[m]CSHELL1522.2[m]CSHELL1523.1[m]CSHELL1524.0[m]CSHELL1524.0[m]CSHELL1526.1[m]CSHELL1530.5[m]CSHELL1530.6[m]CSHELL1530.7[m]CSHELL1531.6[m]CSHELL1531.9[m]CSHELL1532.5[m]CSHELL1532.6[m]CSHELL1537.7[m]CSHELL1542.4[m]CSHELL1544.0[m]CSHELL1545.9[m]CSHELL1546.4[m]CSHELL1546.8[m]CSHELL1546.9[m]CSHELL1548.2[m]CSHELL1549.0[m]CSHELL1557.6[m]CSHELL1562.0[m]CSHELL1562.9[m]CSHELL1596.6[m]CSHELL1625.1[m]CSHELL1661.9[m]CSHELL1662.4[m]CSHELL -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit361494528724 -
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]pdf28.56pdf2.47pdf10.67pdf1.75pdf4.07pdf1.39pdf0.61pdf0.58pdf0.69pdf1.63pdf1.61pdf1.65pdf1.81pdf2.23pdf0.50pdf3.07pdf2.68pdf8.31pdf5.07pdf1.09pdf0.97pdf0.87pdf0.07pdf0.34pdf0.35pdf0.35pdf0.13pdf0.14pdf0.53pdf26.75pdf1.38pdf7.83pdf1.41pdf0.81pdf0.40pdf0.38pdf1.12pdf0.57pdf0.58pdf7.26pdf2.77pdf4.74 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]BGT GR8071274BGT GR12701933BGT GR12701938BGT GR12701939BGT GR12711940CBL VDL GR6001804CBL VDL GR7191271CBL VDL GR7191276CBL VDL GR CCL3521913CBL VDL GR CCL18003985DDBHC GR12711940DLL MSFL GR12711936FDC CNL GR CAL450818FDC CNL GR CAL8071270FDC CNL GR CAL12711938FDC CNL GR CAL19263990FDC CNL GR CAL39855032HDT12711938HDT19263990HDT39855032ISF BHC GR SP450818ISF BHC GR SP8071269ISF BHC GR SP12711938ISF BHC GR SP19263988ISF BHC GR SP39855031ISF BHC GR SP39855031LDT CNL GR12711936LDT CNL GR13501635NGT12711938RFT13961845RFT GR21423585RFT GR41044955 -
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 typeCONDUCTOR30420.036425.00.00LOTCONDUCTOR30446.036450.00.00LOTSURF.COND.20782.026790.00.00LOTSURF.COND.20807.026815.01.71LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3531.05100.0seawater7901.2852.0seawater -
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]PDF0.18