2/8-13
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General information
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Wellbore history
GeneralExploration well 2/8-13 was designed to test the Tertiary and Upper Cretaceous chalks overlying a salt induced domal feature, unofficially named Mode, in the western part of block 2/8. The objectives were to test the possible hydrocarbon accumulation contained within the Tertiary and Upper Cretaceous chalks of the Ekofisk, Tor and Hod Formations; to determine the reservoir quality of the Shetland Group over the structure; to determine the chalk stratigraphy over the Mode salt dome; and to acquire a VSP to help to image the chalk distribution and thickness over the Mode feature.The well was planned to penetrate the Shetland Group on a structurally high at the northern flank of the Mode salt feature. Shallow gas was expected at 507- 590- and 730 m.OperationsWildcat well 2/8-13 was spudded with the semi-submersible installation Dyvi Stena on 28 April 1989 and drilled to TD at 1940 m in the Permian Zechstein Group. The well was drilled with seawater / gel / polymer down to 380 m, with PHPA/PAC mud from 380 m to 1253 m, with PHPA/PAC/ANCOMEL mud from 1253 m to 1457 m, with PHPA/PAC/NaCl mud from 1457 to 1758 m, and with NaCl/PAC mud from 1758 m to TD. Shallow gas was encountered at the prognosed depths, and controlled with heavy mud. Shallow gas encountered in sands at 828 m, caused the well to flow. The flow was killed with heavy mud, and caused no injuries or damages. The drill pipe got stuck, and had to be shot of above the BHA, which than was cemented in. The well was kicked off for the 2/8-13 sidetrack at 412 m.The Paleocene section was thinner than expected, with Balder Sele and part of the Lista Formations missing. The gas cloud above the structure caused some difficulties as to predicting formation depths and velocity correlations across the structure. The well drilled directly from Upper Cretaceous to Permian rocks. The Shetland Group came in 220 m higher than prognosed and was 9.5 m thick, compared to prognosed 270 m. No biostratigraphic evidence for the Hod, Blodøks, or Hidra Formations was found, nor of the Lower Cretaceous, Jurassic, or Triassic rocks. Shows were observed on cuttings and sidewall cores throughout the well below 700 m. An unexpected section of Celestite (strontium sulphate) was on top of the Anhydrite section. One core was cut from 1780 m to 1782 m in the Celestite section with poor reservoir quality. Good shows were recorded on the core. After having cut the core, the well became unstable and was killed and cemented back to 1415 m and an unintentional sidetrack was made. The Paleocene section came in 10 m deeper in the redrilled hole. No fluid sample was taken in. Well 2/8-13 was permanently abandoned 22 June 1989 as a dry hole with oil and gas shows.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]380.001921.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11780.01782.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]2.0Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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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 typeCONDUCTOR30178.036183.00.00LOTINTERM.20374.026380.01.60LOTINTERM.13 3/81238.817 1/21255.01.85LOTINTERM.9 5/81449.012 1/41457.01.98LOTLINER71757.08 1/21783.02.18LOTOPEN HOLE1940.05 7/81940.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL GR9251300CST17601924DIL BHC GR SP12371455DLL BHC GR SP14491753DLL SDT GR SP17571936LDL CNL GR CAL12371457LDL CNL GR CAL14491757LDL CNL GR CAL17571939LDL LSS GR CAL178380MWD - GR RES DIR94824MWD - GR RES DIR4121780SHDT GR14491758SHDT GR17571934VSP2601800 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit9473012151760176017631766176617731775 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.22 -
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]pdf24.20 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1571.8233.04.8WATER BASED30.05.19892761.20WATER BASED03.05.19893231.20WATER BASED03.05.19893231.20WATER BASED03.05.19893321.20WATER BASED03.05.19893801.20WATER BASED03.05.19893801.20WATER BASED08.05.19893801.207.03.8WATER BASED08.05.19896101.3816.02.9WATER BASED16.05.19896421.2014.05.3WATER BASED09.05.19898281.3313.04.8WATER BASED09.05.19898281.3312.04.3WATER BASED09.05.19898281.3311.04.8WATER BASED09.05.19898281.3315.08.1WATER BASED10.05.19898281.3311.03.4WATER BASED11.05.19898321.5017.05.7WATER BASED16.05.19899061.5417.05.7WATER BASED18.05.19899931.5422.04.3WATER BASED18.05.198912041.5618.09.1WATER BASED18.05.198912041.5821.03.8WATER BASED19.05.198912551.6127.07.7WATER BASED19.05.198912551.6224.05.7WATER BASED19.05.198912551.6121.05.7WATER BASED23.05.198912551.6123.06.7WATER BASED23.05.198912551.6121.05.7WATER BASED23.05.198912571.6818.08.6WATER BASED23.05.198912601.8023.02.4WATER BASED25.05.198914571.8233.09.6WATER BASED25.05.198914571.8234.09.6WATER BASED26.05.198914571.8534.05.3WATER BASED30.05.198915241.8931.06.2WATER BASED30.05.198916821.8934.08.6WATER BASED30.05.198917801.8727.03.8WATER BASED31.05.198917831.8527.02.9WATER BASED02.06.198917831.8524.02.9WATER BASED05.06.198917831.8722.02.9WATER BASED05.06.198917831.8727.03.8WATER BASED05.06.198917831.8633.06.7WATER BASED06.06.198917831.8839.09.1WATER BASED07.06.198917831.8836.07.2WATER BASED08.06.198917831.8832.07.2WATER BASED09.06.198917831.8737.08.1WATER BASED13.06.198917831.8737.08.1WATER BASED13.06.198917831.6821.03.3WATER BASED13.06.198917831.8728.04.8WATER BASED01.06.198917901.7834.03.8WATER BASED14.06.198918001.7838.04.8WATER BASED14.06.198918171.7839.05.3WATER BASED15.06.198919081.7836.05.3WATER BASED16.06.198919401.7838.05.8WATER BASED19.06.198919401.7836.05.8WATER BASED19.06.198919401.7833.05.8WATER BASED19.06.198919401.7833.06.3WATER BASED20.06.198919400.00WATER BASED21.06.198919400.00WATER BASED23.06.198919400.00WATER BASED23.06.1989