16/1-21 A
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General information
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Wellbore history
GeneralWell 16/1-21 A is a geological sidetrack to well 16/1-21 S. It was drilled to appraise the 16/1-9 Ivar Aasen discovery on the Gungne Terrace in the North Sea. The objective was to obtain key depth and reservoir information for field development in the eastern part of the Ivar Aasen Discovery. The targets were reservoirs in the Hugin/Sleipner and Skagerrak Formations.Operations and resultsWildcat well 16/1-21 A was kicked off on 3 March 2015, from the main well 16/1-21 S with an open hole kick off below the 13 3/8" casing shoe at 1317 m. The well was drilled with the jack-up installation Mærsk Innovator to TD at 3313 m (2517 m TVD) in the Triassic Hegre Group. Due to severe losses when drilling the 12 1/4" section at 2951 m a cement plug was set and the 9 5/8" liner was run with shoe depth at 2796 m. The well was drilled with Versatec oil based mud from kick-off to TD.The well penetrated a 6.3 m net sand in the Sleipner Formation above the Skagerrak formation. The reservoir quality in the sand is very good with an average porosity in the net sand of 24 percent. The sand contains gas-condensate and oil. A gas oil contact is interpreted to be at 3192.0 m (2408.0 m TVD).The underlying Skagerrak reservoir is oil filled and the net sand interval above the Alluvial Fan is 20.3 meters. The average porosity in the net intervals is 23 percent in Skagerrak 2 and 21 percent in Skagerrak 1. The formation pressures in 16/1-21 A indicated a contact at 3273.9 m (2481.6 m TVD) in Skagerrak Alluvial Fan. However, the pressures in this very calcite cemented part of Skagerrak Formation is about 0.6 bar higher than in the oil-filled Skagerrak above, and the actual contact is not resolved. The deepest oil sample is from 3221.1 m.Oil shows were recorded on cores from 3183 m, in the Sleipner Formation. Shows were visible throughout the cored sections with a weakening trend towards the lowermost part of core 3 in the Skagerrak Formation. No shows are described below base of core 3 at 3234 m.Three cores were cut from 3174 m in the Heather Formation, through the Sleipner Formation and down to 3235.8 m in the Triassic Skagerrak Formation. The core recovery varied from 92.7% to 99.0 %. The core to log shift is reported to vary between +2.0 m to +3.0 m in different sections of the cores. MDT fluid samples were taken at 3191.03 m (gas-condensate), 3193.44 m (oil), 3195.53 m (oil), 3208.93 m (oil), and 3221.1 m (oil).The well was permanently abandoned on 20 April 2015 as a dry 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]1300.003312.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13174.03200.8[m ]23201.03218.6[m ]33218.83224.6[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]50.1Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit168168802848959959126418112094257625762634273628262828289029192919292629262972297231553187318731943194 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]LWD - DI168373LWD - GR RES DEN NEU SON DI PWD1681304LWD - GR RES DI PWD13172951LWD - GR RES DI PWD NEU DEN31333313MDT HC30243024MDT HC31193221MDT PPC28202820MRX XPT GR30703300PPC SS EMM GR UT33111656PPC SS GR EMM11002798VSI10813154ZAIT NMH IS AH NEXT PEX HNGS29653302 -
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 typeCONDUCTOR30223.136223.10.00SURF.COND.20368.026373.01.48LOTPILOT HOLE376.09 7/8376.00.00INTERM.13 3/81299.017 1/21304.01.67LOTLINER9 5/82796.012 1/42951.01.60FITLINER73015.00.00.00OPEN HOLE3315.08 1/23315.00.00 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured14401.5134.0Versatec OBM18501.5133.0Versatec OBM25501.5133.0Versatec OBM29501.2922.0Versatec OBM29501.5137.0Versatec OBM30091.2923.0Versatec OBM32191.3423.0Versatec OBM33130.99Sea water33131.3430.0Versatec OBM