2/7-1
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General information
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Wellbore history
an lang=EN-GB>GeneralWell 2/7-1 was drilled on the Eldfisk structure on the Lindesnes Ridge in the North Sea. The primary objective was to test the Late Cretaceous to Paleocene chalk sequence that had proved oil in the Ekofisk structure north of Eldfisk. A secondary objective was to test older Mesozoic sedimentsOperations and resultsWildcat well 2/7-1 was spudded with the semi-submersible installation Ocean Viking on 3 August 1970 and drilled to TD at 4573 m in the Vestland Group. The well was drilled with seawater and hi-vis sweeps down to 588 m, with seawater/Drill Aid mud from 588 m to 3102 m, and with seawater/lignosulphonate mud from3102 m to TD.Top of the Danian chalk sequence, Ekofisk Formation, is at 2934 m, while top of the Cretaceous chalk, Tor Formation, is at 3014 m. In this first well on the structure, only small amounts of live hydrocarbons were found in the Ekofisk carbonates.Three cores were cut from 2956.6 to 2987.3 m in the Ekofisk Formation. A fourth core was cut from 3032.8 to 3041.9 m. No fluid sample was taken.The well was permanently abandoned on 11 December 1970 as an oil discoveryTestingA drill stem test was performed in the interval 2942 to 2954 m plus 2957 to 2975 m in the Danian chalk (Ekofisk Formation). The flow rate after acidizing was too small to measure. The recovered fluid was composed of 65% oil and 35% water. The oil density was 32.2 °API. -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom19700.09721.0[ft ]29721.09751.0[ft ]39751.09797.6[ft ]49950.09981.0[ft ]Cores at the Norwegian Offshore Directorate Total core sample length [m]39.2Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit98168128202820283128732918293429343014304732923303342334233707370737304258 -
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]pdf2.48pdf18.42 -
Documents – Norwegian Offshore Directorate papers
Documents – Norwegian Offshore Directorate papers Document nameDocument formatDocument size [MB]pdf72.88pdf0.74pdf0.82 -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.0294229750.0Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.0 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]BHC GR5794499CBL1374253DLL30884264FDC24394502GR137579GRN28964268HDT30884268IES5794502LL724393102ML MLL C27444502SNP24394502SRS5794499 -
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 typeCONDUCTOR30136.036136.00.00SURF.COND.20579.026588.00.00INTERM.13 3/81592.017 1/21601.00.00INTERM.9 5/83088.012 1/43106.00.00LINER74267.08 1/24268.00.00 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3651.10seawater6091.5647.0waterbased27431.7146.0waterbased32001.7146.0waterbased36571.7648.0waterbased38201.8845.0waterbased41851.9046.0waterbased45721.9345.0waterbased