2/8-18 S
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General information
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Wellbore history
GeneralThe 2/8 ‐ 18 S well was drilled on the Clapton Prospect in the Feda Graben in the Norwegian North Sea. The main target was chalks of the Shetland Group, analogous to the nearby fields Eldfisk, Eldfisk East, Valhall and Ekofisk.Operations and resultsWildcat well 2/8-18 S was spudded with the jack-up installation Mærsk Guardian on 23 May 2012 and drilled to TD at 2852 m ((2662 m TVD) in the Late Cretaceous Hidra Formation. It was drilled deviated to avoid shallow gas over the crest of the structure and to penetrate the steeply dipping reservoir at the right angle. The well was vertical down to 1506 m and built up to a sailing angle of ca 36 deg at 1900 m. The well was drilled with KCL/GEM mud down to 568 m and with oil based XP-07 mud from 568 m to TD.Oil shows were encountered in the Utsira Formation at 870 m (869 m TVD), triggering a wire line acquisition programme to evaluate this reservoir. Pressure samples were acquired, proving a tight reservoir. Fluid sampling was not attempted. Petrophysical analysis concluded a low permeability siltstone reservoir with low oil saturation. Formation tops came in as prognosed down to top Rogaland Group. In the Rogaland Group, the Lista Formation turned out to be significantly thinner than expected, and the Våle Formation was not present. The deviation is interpreted to be caused by a fault, offsetting the lower part of the Lista Formation and the Våle Formation. The main target in the Shetland Group / Ekofisk Formation was encountered at 2742 m (2567.8 m TVD) with oil shows. Coring was initiated, and two cores containing a total of 36 m of core was recovered. All the formations of the Shetland Group were significantly thinner than prognosed. The matrix properties of the reservoir were within the expected range, but devoid of any open fracture system that could enhance the producability of the reservoir.The two cores were taken in the Ekofisk and Tor formations and the first one-meter of the Hod Formation over the interval 2746 m to 2782 m with 100% recovery. No wire line logs were run in the Shetland Group, only MWD. No fluid samples were taken in the well.The well was permanently abandoned on13 July as a dry well with 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]230.002852.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12746.02755.3[m ]22755.32782.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]36.0Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
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 typeCONDUCTOR30218.036226.00.00SURF.COND.20560.026568.00.00INTERM.13 3/81498.017 1/21498.00.00INTERM.9 5/82739.012 1/42743.00.00OPEN HOLE2852.08 1/22852.00.00 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]GR NEU DEN CAL5001450MWD LWD - DIR PWD112568MWD LWD - DIR PWD GR RES226568MWD LWD - DIR PWD GR RES27432746MWD LWD - DIR PWD GR RES DEN POR27462852MWD LWD - DIR PWD GR RES SON5682743RDT675965 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit11287016061606248026852685269527252735274227422771278128382841 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured2261.497.0Spud mud4551.199.0Spud mud5681.198.0KCL/GEM/Polymer5891.3523.0XP-07 OBM15061.4823.0OBM25101.7033.0OMB25391.4830.0OBM25601.7032.0OBM27461.6430.0OMB28351.6430.0XP-07