18/11-1
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General information
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Wellbore history
GeneralWell 18/11-1 is located on the Stavanger Platform, ca 25 km north of the Yme Field in the North Sea. The primary objective was to test possible hydrocarbon accumulation in Middle Jurassic sandstones in a seismic structure interpreted on the same trend as the 17/12-1R Bream Discovery. Secondary objectives were possible Triassic or Rotliegendes sandstones in a faulted triangular block tilted southwest. Planned TD was 150 -200 m below the primary target, prognosed at 2365 m.The well is Reference Well for the Sandnes Formation.Operations and resultsWildcat well 18/11-1 was spudded with the semi-submersible installation Deepsea Driller on 17 February 1974 and drilled to TD at 2086 m in Pre-Devonian Basement rocks.Late Cretaceous limestones from 498 m to 985 m had excellent reservoir properties. Limestones below this level became harder; more compacted, and had poor reservoir properties. The well penetrated top Sandnes Formation at 1878 m with fine, argillaceous cemented, well sorted sandstone down to 1919 m, and a Bryne Formation sequence with fine to coarse, angular grained, sandstones with variegated shale from 1964 m to 2060 m. The Jurassic sands rested directly on basement at 2060 m. No noticeable shows were recorded in the well. Organic geochemical analysis proved a thermally immature well all through down to basement (%Ro < 0.36). Good source potential (TOC in the range 1.3 % to 6 % and Hydrogen Index from 30 to 230 mg HC/g rock was seen in a ca 80 m thick Kimmeridgian shale sequence from 1735 m. High TOC in the range 1.3 % up to 6.9 % was seen also below 1919 m in Callovian claystones, but Hydrogen Index in the range 30 - 180 mg HC/g rock suggested a more inertinitic, gas prone kerogen in this sequence.One conventional core was cut at TD from 2082 m to 2086 m. No fluid samples were taken.The well was permanently abandoned on 31 March 1974 as dry hole.TestingNo drill stem test was performed. -
Cuttings at the Norwegian Offshore Directorate
Cuttings at the Norwegian Offshore Directorate Cuttings available for sampling?NOCuttings at the Norwegian Offshore Directorate Cutting sample, top depth [m]Cutting samples, bottom depth [m]400.002080.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12082.02086.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]4.0Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory420.0[m]DCRRI440.0[m]DCRRI460.0[m]DCRRI480.0[m]DCRRI500.0[m]DCRRI520.0[m]DCRRI540.0[m]DCRRI560.0[m]DCRRI580.0[m]DCRRI600.0[m]DCRRI1895.0[m]DC1950.0[m]DC2000.0[m]DC2050.0[m]DC -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit14137346346348649249649849857286098598511351325160916091650174718001878187819642060 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.17 -
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]pdf3.08pdf0.59pdf2.91 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]BHC GR376819BHC GR8041706BHC GR15501814BHC GR18022082CBL300800CBL4001801FDC GR18022081GR141376HDT18022082IES376820IES8041814IES18022082VELOCITY3762081 -
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 typeCONDUCTOR30177.036177.00.00LOTSURF.COND.20373.026386.00.00LOTINTERM.13 3/8805.017 1/2823.00.00LOTINTERM.9 5/81805.012 1/41815.00.00LOTOPEN HOLE2086.08 1/22086.00.00LOT -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured8231.2343.04.0waterbased15031.2852.08.0waterbased18151.3045.06.0waterbased20821.3245.06.0waterbased