31/2-22 S
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General information
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Wellbore history
GeneralWell 31/2-22 was drilled to test the Blasto prospect located on the Lomre Terrace close to the Fram and Troll Fields in the North Sea. Blasto is in a rotated fault block setting up-dip of the dry 31/2-8 well located in the same structure. The primary objective is the Late Jurassic shallow marine Sognefjord Formation. Secondary objective was to evaluate the Fensfjord Formation.Operations and resultsWildcat well 31/2-22 S was drilled with the semi-submersible installation West Hercules. A pilot hole was drilled from seabed to 477 m. No shallow gas was observed. The main well was initiated on 13 November 2020 by opening to 26" hole, which was drilled to 730 m. Minor shallow water flow was observed but the flow died out. The 20" casing was set and cemented. Well 31/1-2 S (Røver Nord) was then drilled, before drilling the rest of the 31/2-22 S to TD at 2379 m (2313 m TVD) m in the Middle Jurassic, Heather Formation. Technical problems with the BOP caused close to 4 days down time, otherwise operations proceeded without significant problems. The well was drilled with seawater and hi-vis pills down to 730 m and with Glydril mud from 730 m to TD.Fractured carbonate in the Hardråde Formation proved to be gas bearing. The formation is difficult to evaluate hence the result are uncertain. Top Upper Sognefjord Formation was encountered at 1907 m (1859 m TVD) and proved to be oil bearing with a water leg. A second oil column was found in the Lower Sognefjord Formation also with a water leg. The reservoirs are pressure depleted ca 25 bars compared to virgin pressure due to production on the Troll Field. The Fensfjord Formation was water bearing. No shows were described above top Sognefjord. Oil shows (cut and direct fluorescence) were described down to the base of the cores at 2083 m.bearing.Three cores were cut in succession from 1927 to 2083 m in the Sognefjord and Heather formations with 98.5 to 100 % recovery. MDT fluid samples were taken in the Hardråde Formation at 1883.4 m (gas) and 1848.5 m (gas), and in the Sognefjord Formation at 1918.3 m (oil), 1942 m (water), 1999 m (oil) and 2048.8 m (water).The well was plugged back for side-tracking on 3 March 2021 as an oil discovery.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]740.002379.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11927.01963.5[m ]21963.52026.3[m ]32026.82082.2[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]154.7Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
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 typeCONDUCTOR30401.230401.20.00INTERM.20720.626730.01.42FITINTERM.13 3/81360.017 1/21366.01.52LOTINTERM.9 5/81839.012 1/41840.01.44LOTOPEN HOLE2379.08 1/22379.00.00 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]FMI MSIP13662377HRLA PEX HNGS18272380MDT18691999MDT DP18481883MWD - GR RES DEN NEU DIR13661773MWD - GR RES DIR4011366MWD - GR RES DIR17732379XLR18471923XPT CMR NEXT18482372ZOVSP5602380 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit3803807777771215142114211471154217751848184818811881190719801995206122312328 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured4771.3017.011.0KCl/Polymer7301.3017.011.0Glydril8111.3011.010.0Glydril9951.3116.012.0Glydril13661.3312.09.0Glydril18501.2010.010.0Glydril23791.2011.014.0Glydril23791.3115.013.5Glydril