31/5-5
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General information
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Wellbore history
GeneralThe well was drilled as part of the appraisal programme initiated for the southern part of the Troll West Gas province (TWGP-S). The objectives of the well were to provide geological, geophysical and petrophysical data for evaluation of the potential for a group of oil producers in TWGP-S; and to provide data on the Fensfjord and Krossfjord Formations to improve aquifer modelling. The well was further planned for later re-entry, either for sidetracking and completion as a horizontal producer, or for vertical recompletion for Sognefjord Formation reservoir monitoring.Operations and resultsWell 31/5-5 was spudded with the semi-submersible installation West Delta on 30 December 1992 and drilled to a total depth at 1930 m in the Middle Jurassic Krossfjord Formation. The well was drilled with spud mud to 940 m and with KCl/brine from 940 m to TD.The Sognefjord Formation was encountered from 1572 m to 1725 m, and was hydrocarbon bearing. Strong oil shows were recorded from 1573 m to1587.5 m, weaker oil shows were recorded below this depth down to 1650 m. The gas-oil contact was identified at 1573.5, and the oil-water contact was identified at 1585.5 m. From FMT pressure tests a gas gradient of 0.152 g/cc, an oil gradient of 0.825 g/cc, and a water gradient of 1.02 g/cc was defined. Twelve conventional cores were cut. The first ten were from 1555 m in the top of the Sognefjord Formation to1726 m, one meter into the Fensfjord Formation. Cores 11 and 12 were cut from 1835 m in the Fensfjord Formation to 1888 m in the Krossfjord Formation. FMT fluid samples were taken at 1583 m (two samples, both contained oil and gas), 1576.5 m (oil and gas), and at 1571 m (gas).The well was temporarily plugged at 1450 m and 450 m using two 9 5/8" Baker type N1 bridge plugs and suspended as an oil and gas appraisal well on 11 February 1993.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]950.001930.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11555.01571.5[m ]21571.51583.0[m ]31585.51601.0[m ]41603.51622.0[m ]51622.71640.0[m ]61640.01658.0[m ]71658.01674.7[m ]81675.01693.0[m ]91693.01710.5[m ]101710.51736.0[m ]111835.01860.0[m ]121861.01888.9[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]227.9Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit34874112951295137514041529155415721572166017251855 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.26 -
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]pdf16.77 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]ACL SDL GR347910ACL SDL GR8701412ACL SDL GR13501500CST GR15831925DCBIL HDIP GR15371923DLL MLL AC ZDL CN SP GR14611927FMT VPC FQPG GR15371923FMT VPC FQPG GR15721572FMT VPC FQPG GR15771577FMT VPC FQPG GR15831583MAC SL14741928MWD - GR DPR DIR15601930MWD - GR RES DIR3471555VSP9601920 -
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 typeCONDUCTOR30432.036432.00.00LOTINTERM.18 5/8926.024940.01.58LOTINTERM.9 5/81515.012 1/41530.01.54LOTOPEN HOLE1930.08 1/21930.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured4001.347.0WATER BASED4561.349.0WATER BASED9401.20WATER BASED12551.347.0WATER BASED14661.3411.0WATER BASED15301.3422.0WATER BASED15711.1723.0WATER BASED16401.1719.0WATER BASED17371.1719.0WATER BASED19301.17WATER BASED -
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]pdf0.17