15/12-4
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General information
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Wellbore history
Wildcat well 15/12-4 is located on the Maureen Terrace in the South Viking Graben in the North Sea. The primary objectives were the Palaeocene Heimdal Formation and sandstones of Jurassic and Triassic age. Secondary objectives were the Frigg Formation and fractured limestone in the Cretaceous.Operations and resultsWell 15/12-4 was spudded with the semi-submersible installation Deepsea Bergen on 13 September 1984 and drilled to TD at 3157 m, 17 m into the Triassic Group. Operations were completed within the time schedule and with very few problems. The well was drilled with seawater and gel down to 505 m, with gypsum polymer from 505 m to 2680 m, and with lignosulphonate from 2680 m to TD.No Heimdal or Frigg sands were encountered in the well. From logs and cores hydrocarbons were seen in the uppermost part of the Cretaceous chalk in the interval 2490 ? 2515 m. Core analysis and log analysis indicated very poor reservoir properties in this chalk. The water saturation was high (60 - 80 %) and the permeability was extremely low (0.01 - 0.5 mD). A 1.5 meter oil column was seen in the Jurassic sandstone, from 2911.5 to 2913 m with a transition zone down to 2915.5. Apart from these two intervals there were no shows or other hydrocarbon indications in the well.Four cores were cut, one in the Palaeocene, two in the Late Cretaceous and one in the Late Jurassic sequence. One FMT run was made in the Cretaceous. Here, no pressure points out of 19 attempts were successful due to seal failure and very low permeability in the formation. One attempt to get sample at 2439.5 m failed due to tight formation. In the Jurassic a segregated FMT sample was taken at 2912 m (5.8 l oil with a density of 0.847 g/cm3 in the 2 3/4 gallon chamber) and a second segregated sample at 2913.5 m (0.5 l oil and 9 l water/mud filtrate in the 2 3/4 gallon chamber).The well was permanently abandoned on 31 October 1984 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]180.003157.50 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12439.02449.0[m ]22494.52498.7[m ]32499.02513.6[m ]42902.02919.7[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]46.5Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory2285.0[m]DC2297.5[m]SWC2307.5[m]SWC2327.5[m]SWC2347.5[m]SWC2367.5[m]SWC2387.5[m]SWC2407.5[m]SWC2427.5[m]SWC2447.5[m]SWC2467.5[m]SWC2477.5[m]SWC2507.5[m]SWC2537.5[m]SWC2567.5[m]SWC2597.5[m]SWC2627.5[m]SWC2657.5[m]SWC2687.5[m]SWC2717.5[m]SWC2747.5[m]SWC2777.5[m]SWC2797.5[m]SWC -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit1101098127823202320233523932464247624762494262127122712273527592784278428922912291231343140 -
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]pdf21.19pdf12.35pdf2.32pdf0.16pdf1.44pdf0.26pdf0.95pdf0.41pdf0.63pdf1.45pdf1.25pdf2.88pdf1.40pdf1.88pdf1.87pdf1.49pdf2.01pdf1.18pdf3.04pdf2.12 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CDL CNL GR CAL15993157CDL GR CAL5041622DIFL BHC AC GR SP CAL1703157DLL MLL GR15993157FMT24382482FMT29013146FMT29112913HR DIP15993157VELOCITY6603150 -
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 typeCONDUCTOR30171.036173.00.00LOTSURF.COND.20505.026520.01.44LOTINTERM.13 3/81601.017 1/21620.01.84LOTINTERM.9 5/82666.012 1/42680.01.86LOTOPEN HOLE3179.08 1/23179.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1101.0355.05.3WATER BASED17.09.19841711.0749.04.5WATER BASED17.09.19842401.0749.04.5WATER BASED17.09.19845201.0846.020.0WATER BASED17.09.19845231.1140.09.6WATER BASED19.09.19847721.1442.010.0WATER BASED20.09.19849451.1447.012.0WATER BASED21.09.198412131.1445.012.0WATER BASED24.09.198414911.1449.013.0WATER BASED24.09.198416201.1444.012.0WATER BASED24.09.198418771.1445.09.0WATER BASED28.09.198422721.1446.09.0WATER BASED01.10.198423741.2044.08.6WATER BASED01.10.198424391.2545.09.1WATER BASED01.10.198424501.2542.08.6WATER BASED02.10.198424951.2545.010.0WATER BASED03.10.198425111.2543.09.1WATER BASED04.10.198425161.2546.09.6WATER BASED05.10.198425841.3042.09.0WATER BASED08.10.198426261.3045.010.0WATER BASED08.10.198426801.3047.010.0WATER BASED08.10.198426801.3044.05.8WATER BASED15.10.198427171.3054.05.8WATER BASED15.10.198427581.3055.05.8WATER BASED15.10.198428031.3555.06.0WATER BASED16.10.198428611.3552.06.0WATER BASED17.10.198429021.3559.05.6WATER BASED18.10.198429201.3560.05.6WATER BASED19.10.198430341.3556.07.0WATER BASED22.10.198431461.3562.06.7WATER BASED22.10.198431571.3576.06.7WATER BASED23.10.198431571.3576.06.7WATER BASED24.10.198431571.3561.06.2WATER BASED22.10.1984 -
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]pdf0.23