16/1-23 S
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General information
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Wellbore history
GeneralWell 16/1-23 S was drilled appraise the Edvard Grieg Field on the Utsira High in the North Sea. The primary objective was to investigate the hydrocarbon potential in the South Eastern part of the Field. It was also designed to allow installation of a CaTS pressure gauge for long term monitoring of reservoir pressure.Operations and resultsWildcat well 16/1-23 S was spudded with the jack-up installation Rowan Viking on 24 June 2015 and drilled to TD at 2130 m in basement rock. The well was drilled S-shaped with up to 24 ° deviation in the interval from 630 m to 1480 m. This was to avoid a fault at the reservoir level. Target location was approximately 43 m west of the spud location. No significant problem was encountered in the operations. The well was drilled with seawater and hi-vis sweeps down to 315 m, with KCl/polymer mud from 634 m to 1888 m, and with Aquadril mud from 188 m to TD.Well 16/1-23 S proved a 66 metres gross oil column in conglomerates and sandstones with medium to good reservoir quality. The top of the reservoir, from 1953 to 1953.5 m, is a marine sandstone unit with a basal conglomeratic transgression lag belonging to the Åsgard Formation, the remaining reservoir is conglomerates and thin sandstone units belonging to the Triassic Skagerrak Formation. A Free Water Level was established from pressure gradients at ca 2020.4 m (1985.5 m TVD). The pressure points further proved an oil gradient with the same density as in the rest of the Edvard Grieg field. Fair to poor oil shows were recorded on cores below the FWL down to 2054 m.Eight cores were cut. Core 1 was cut from 1681 to 1690 m in Hordaland Group claystone for hole instability studies. Core recovery was 104.1%. Cores 2 to 8 were cut from 1945.5 m in the Åsgard Formation to 2064.4 m in the Skagerrak Formation. Recovery varied from 92.5 to 100%. MDT fluid samples were taken at 1958.2 m (oil), 1990.0 m (oil), 1990.6 m (oil), 2015.21 m (oil), 2024.7 m (water), 2061.4 m (water), 2061.72 m (water), and 2030.85 m (water). Single stage separation of the oil samples gave oil densities in the range 0.857 to 0.886 g/cm3 and GORs in the range 149 to 111 Sm3/Sm3.The CaTS reservoir pressure monitoring system was installed before the well was permanently abandoned on 25 August 2015 as an oil appraisal well.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]320.002129.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11681.01690.4[m ]21945.51954.8[m ]31955.51974.2[m ]41975.51979.4[m ]51979.51992.2[m ]61993.02021.5[m ]72012.92040.0[m ]82040.02064.5[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]134.0Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit160780103510401621175017501761180918791901190119161934194319431946195319532094 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]DSL CN ZDL XMAC RTEX MLL2002129DSL FLEX MREX18502128DSL SBT15001992DSL STAR HD UXPL18802122DSL SWC18942103DSL SWC20652080DSL VSP2002128FST GR18912018FTWT GR19552067GR MDT STURN19572061MWD - ECD DIR315633MWD - ECD GR DIR160303MWD - GR ECD RES DIR18821944MWD - GR ECD RES DIR AC315634MWD - GR ECD RES DIR DEN CAL NEU18822129MWD - GR RES ECD DIR CAL NEU NEU6331888 -
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 typeCONDUCTOR30308.136315.00.00SURF.COND.20626.026633.01.60FITPILOT HOLE634.09 7/8634.00.00INTERM.9 5/81882.012 1/41888.01.68LOTOPEN HOLE2130.08 1/22130.00.00 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1601.4016.0Water Based3241.1311.0Water Based5651.3917.0Water Based6331.1911.0Water Based6341.1311.0Water Based6381.2113.0Water Based11461.3014.0Water Based16191.1827.0Oil Based16421.3519.0Water Based18881.4023.0Water Based19461.1514.0Water Based19931.1816.0Water Based21301.1624.0Oil Based21301.1515.0Water Based