31/5-4 S
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General information
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Wellbore history
GeneralWell 31/5-4 S was drilled in a southern, down flank compartment of the Troll West Gas province, 1000 m north west of well 31/5-2. The Troll West Province is an easterly rotated fault block where the southern part is approximately 10 x 15 km with a general dip of 1 to 2 degrees at reservoir level. The primary objective was to provide a penetration hole for a later test production in a horizontal side track hole in the 13 m oil layer in the Sognefjord Formation. The test production should confirm the oil production potential from the Troll West Gas Province; obtain dynamic data from a potential development type well and obtain static reservoir and geological data to provide proper understanding of well behaviour.Operations and resultsWell 31/5-4 S was spudded with the semi-submersible installation Transocean 8 on 13 September 1990 and drilled to TD at 1909 m in the Middle Jurassic Fensfjord Formation. No shallow gas was encountered, as prognosed. The well was drilled vertical down to 1040 m from where angle was built up to 53 deg at 1571 m. Tight hole problems were experienced at several depths, and at 1360 m the hole packed off and mud return was temporary lost. The well was drilled with seawater and hi-vis pills down to 940 m and with KCl/polymer polyacrylamide mud from 940 m to TD.The Sognefjord Formation was penetrated from 1619 m (1535.4 m TVD RKB) to 1830 m (1660 m TVD RB). The formation was gas filled down to 1670 m (1535.4 m TVD RKB) and oil filled from there down to 1692.3 m (1567.2 m TVD RKB).The well bore was plugged back to 1496 m for sidetracking. It was permanently abandoned on 10 October 1990 as a gas and oil appraisal 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]950.001905.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11647.51647.8[m ]21649.51649.7[m ]31650.01667.5[m ]41667.01672.4[m ]51674.91685.0[m ]61685.01703.0[m ]71703.01708.6[m ]81716.41731.2[m ]91731.21747.3[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]88.0Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit340654120512051292139314491449146114701470150715151515161918301879 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.17 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL GR CCL12481565DLL MSFL SDT GR15671904GCT CCL3391557LDL CNL GR CAL15671879MWD - CDR CDN GR DIR15671900MWD - CDR GR RES4321900SHDT15671881VSP12501870 -
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 typeCONDUCTOR30424.036425.00.00LOTINTERM.18 5/8924.024926.01.45LOTINTERM.13 3/81567.017 1/21570.01.40LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3761.0520.019.0WATER BASED14.09.19904251.0520.019.0WATER BASED17.09.19904251.0520.019.0WATER BASED17.09.19907101.0520.019.0WATER BASED17.09.19909431.0520.019.0WATER BASED18.09.19909431.30WATER BASED19.09.19909431.05WATER BASED20.09.19909431.05WATER BASED21.09.19909431.3518.013.0WATER BASED24.09.19909431.3119.013.0WATER BASED24.09.199010051.3114.012.0WATER BASED24.09.199012611.3217.011.0WATER BASED25.09.199014401.3219.012.0WATER BASED26.09.199015081.2517.012.0WATER BASED02.10.199015291.3220.014.0WATER BASED27.09.199015691.2431.014.0OIL BASED12.10.199015711.3220.014.0WATER BASED28.09.199015711.2617.012.0WATER BASED02.10.199015751.2629.012.0OIL BASED15.10.199016481.2520.014.0WATER BASED02.10.199016591.2529.011.0OIL BASED15.10.199017281.2528.012.0OIL BASED15.10.199018031.2531.012.0OIL BASED22.10.199018031.2532.015.0OIL BASED16.10.199018031.2531.012.0OIL BASED18.10.199018031.2531.012.0OIL BASED18.10.199018031.2532.010.0OIL BASED22.10.199018031.2634.010.0OIL BASED22.10.199018031.159.08.0WATER BASED22.10.199018051.2511.011.0WATER BASED23.10.199018051.259.010.0WATER BASED24.10.199018051.2510.010.0WATER BASED25.10.199018091.2510.011.0WATER BASED29.10.199018111.2510.011.0WATER BASED26.10.199018651.2520.013.0WATER BASED09.10.199018791.2520.015.0WATER BASED09.10.199019081.2419.015.0WATER BASED09.10.199019081.2520.015.0WATER BASED10.10.199019591.2511.013.0WATER BASED29.10.199020251.2511.013.0WATER BASED29.10.199020891.2513.014.0WATER BASED30.10.199021331.2513.013.0WATER BASED31.10.199022271.2514.015.0WATER BASED01.11.199023661.2513.015.0WATER BASED02.11.199025181.2514.015.0WATER BASED05.11.199025851.202.0WATER BASED22.11.199026011.2511.011.0WATER BASED13.11.199026011.202.0WATER BASED19.11.199026011.202.0WATER BASED20.11.199026011.2513.013.0WATER BASED08.11.199026011.2511.011.0WATER BASED09.11.199026011.20WATER BASED13.11.199026011.202.0WATER BASED13.11.199026011.192.0WATER BASED16.11.199026011.202.0WATER BASED19.11.199026011.202.0WATER BASED19.11.199026011.202.0WATER BASED21.11.199026031.2514.015.0WATER BASED05.11.199026031.2513.015.0WATER BASED05.11.199026031.2513.014.0WATER BASED06.11.199026031.2513.014.0WATER BASED08.11.199026031.2510.06.0WATER BASED10.07.199126031.2510.08.0WATER BASED15.07.199126031.2510.08.0WATER BASED16.07.199126031.2510.08.0WATER BASED16.07.199126031.2510.08.0WATER BASED16.07.199126031.2510.08.0WATER BASED17.07.199126031.2510.08.0WATER BASED18.07.1991