25/11-14 S
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General information
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Wellbore history
GeneralWell 25/11-14 S was drilled centrally on the Balder Field on the Utsira High in the North Sea. This field was discovered in 1967 by the 25/11-1 well, and was the first well on the Norwegian shelf that proved oil. Well 25/11-14 S was planned to be completed for a long term test by the FPV Petrojarl 1. The well was planned deviated in order to avoid possible shallow gas at 235 m, 254 m, and 515 m. The main objective of this well was to test two Paleocene Heimdal Formation sands; the IB4 sand at 1863 m and the IB3 sand at 1897 m. The Heimdal Formation had previously proved oil-bearing in the three neighbouring wells 25/11-6, -7, and -8. Eocene sands constituted a secondary objective for testing. Based on data from surrounding wells, no abnormal pressure was expected. The surface location and well trajectory for this well, was designed so that a later plug-back and sidetrack to a horizontal completion could be accomplished.Operations and resultsAppraisal well 25/11-14 S was spudded with the semi-submersible installation Byford Dolphin on 13 September 1990. During setting of the 30" casing a fatal accident occurred as one of the roughnecks was hit by the rig tongs and perished on the drilling floor. A 9 7/8" pilot was drilled with MWD from 189 m to check possible shallow gas. Sands were detected, but they contained salt water only. The planned deviation was initiated at 950 m. While POOH for coring the Heimdal Formation sand, the pipe became stuck (packed off by sloughing shales) and the well bore abandoned at a TD of 1908 m (1749 m TVD), 5 m into the target Heimdal Formation. The well was drilled with seawater down to 452 m and with KCl/polymer/gel mud from 452 m to TD.The secondary target Eocene sands were not present. The IB3 sand came in at 1903 m (1746 m TVD RKB), but no wire line logs were run and no test performed due to stuck pipe. Strong shows in mud and cuttings were observed when entering the formation.Five cores were cut in the prognosed IB4 sand in the interval 1859 to 1886 m. The cores recovered predominantly claystone with only thin stringers of sandstone, proving that the IB4 sand was in fact not present in the well. The sandstone stringers had good oil shows.Since the well did not fulfil its main objective it was decided to make a sidetrack. The well bore below the 13 3/8" casing shoe was thus plugged back and abandoned on 13 October 1990 and a sidetrack (classified as a re-entry) was prepared.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]480.002080.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11862.01864.0[m ]21864.01868.0[m ]31868.01876.5[m ]41876.51883.0[m ]51883.31883.8[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]21.6Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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Oil samples at the Norwegian Offshore Directorate
Oil samples at the Norwegian Offshore Directorate Test typeBottle numberTop depth
MD [m]Bottom depth
MD [m]Fluid typeTest timeSamples availableDSTTEST11992.202015.2023.11.1990 - 21:45YES -
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 typeCONDUCTOR30187.036190.00.00LOTINTERM.20452.026454.01.72LOTINTERM.13 3/81564.017 1/21570.01.73LOTINTERM.9 5/82068.012 1/42070.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]MWD1871908 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1526007297487489181059111217621762183418591903 -
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]pdf1.14pdf25.91pdf39.30 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured7441.1618.08.6WATER BASED27.09.19909501.1818.07.2WATER BASED28.09.199011961.1615.06.7WATER BASED01.10.199012541.1818.010.5WATER BASED01.10.199014331.1619.08.1WATER BASED01.10.199015721.5020.09.6WATER BASED22.10.199015761.1817.08.1WATER BASED03.10.199015761.1818.09.1WATER BASED04.10.199015761.1618.09.6WATER BASED02.10.199015761.1618.09.6WATER BASED02.01.199116401.2016.09.6WATER BASED05.10.199017951.5025.014.4WATER BASED22.10.199018591.2624.013.9WATER BASED08.10.199018691.2620.013.4WATER BASED08.10.199018811.2623.014.4WATER BASED08.10.199018861.2621.013.9WATER BASED09.10.199019081.2623.014.8WATER BASED10.10.199019081.2621.013.8WATER BASED11.10.199019081.2617.011.9WATER BASED12.10.199019081.2620.012.0WATER BASED15.10.199019081.2620.012.0WATER BASED15.10.199019081.2617.09.6WATER BASED15.10.199019081.2619.010.5WATER BASED18.10.199019081.2619.010.5WATER BASED18.10.199019081.2619.010.5WATER BASED16.10.199019081.2619.010.5WATER BASED22.10.199019131.5026.013.0WATER BASED22.10.199020021.5028.013.9WATER BASED23.10.199020101.5025.013.4WATER BASED24.10.199020101.5027.014.4WATER BASED25.10.199020271.5026.013.4WATER BASED26.10.199020351.5027.014.8WATER BASED29.10.199020651.07WATER BASED12.11.199020651.08WATER BASED12.11.199020661.07WATER BASED12.11.199020661.14WATER BASED13.11.199020661.12WATER BASED14.11.199020661.12WATER BASED19.11.199020661.12WATER BASED19.11.199020661.12WATER BASED20.11.199020661.12WATER BASED22.11.199020661.12WATER BASED23.11.199020661.12WATER BASED26.11.199020661.12WATER BASED26.11.199020661.12WATER BASED26.11.199020661.12WATER BASED27.11.199020661.06WATER BASED28.11.199020661.06WATER BASED29.11.199020661.06WATER BASED03.12.199020661.06WATER BASED03.12.199020661.06WATER BASED04.12.199020661.06WATER BASED10.12.199020661.04WATER BASED10.12.199020661.04WATER BASED10.12.199020661.04WATER BASED12.12.199020661.04WATER BASED14.12.199020661.05WATER BASED17.12.199020661.05WATER BASED17.12.199020661.05WATER BASED18.12.199020661.05WATER BASED19.12.199020661.05WATER BASED21.12.199020661.04WATER BASED27.12.199020661.04WATER BASED27.12.199020661.04WATER BASED27.12.199020661.04WATER BASED28.12.199020661.04WATER BASED28.12.199020661.04WATER BASED28.12.199020661.04WATER BASED31.12.199020661.04WATER BASED31.12.199020661.12WATER BASED15.11.199020661.12WATER BASED16.11.199020661.12WATER BASED19.11.199020661.12WATER BASED21.11.199020661.06WATER BASED30.11.199020661.06WATER BASED03.12.199020661.06WATER BASED05.12.199020661.04WATER BASED10.12.199020661.04WATER BASED12.12.199020661.04WATER BASED14.12.199020661.05WATER BASED17.12.199020661.05WATER BASED20.12.199020661.04WATER BASED27.12.199020661.04WATER BASED31.12.199020661.04WATER BASED02.01.199120661.04WATER BASED03.01.199120661.04WATER BASED04.01.199120661.04WATER BASED07.01.199120661.04WATER BASED07.01.199120661.04WATER BASED07.01.199120701.5027.014.8WATER BASED29.10.199020701.5027.014.4WATER BASED30.10.199020701.5026.013.4WATER BASED31.10.199020701.5026.012.0WATER BASED01.11.199020811.5026.014.8WATER BASED02.11.199020811.5023.014.4WATER BASED05.11.199020811.5023.011.0WATER BASED05.11.199020811.5021.013.4WATER BASED07.11.199020811.5019.013.0WATER BASED08.11.199020811.5022.013.0WATER BASED09.11.199020811.5021.012.9WATER BASED05.11.199020811.5024.016.7WATER BASED07.11.1990