31/4-11
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General information
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Wellbore history
GeneralWell 31/4-11 was drilled on the Bowmore structure in the northern part of the Brage Field as a combined appraisal/exploration well. The Bowmore structure is situated about 6-8 km NNE of the Brage platform. It is a NE-SW trending wedge shaped horst, rising and tapering towards the SW. The primary objective was to prove hydrocarbons in the Middle - Late Jurassic Fensfjord Formation. The secondary objectives were to prove hydrocarbons in sandstones of the Late Jurassic Sognefjord and Draupne formations and in the Middle Jurassic Brent Group. During drilling of the well, it was decided to extend the well and explore the hydrocarbon potential in the Statfjord Formation.Operations and resultsWildcat well 31/4-11 was spudded with the semi-submersible installation Scarabeo 6 on 27 July 2000 and drilled to TD at 3271 m (2765 m TVD) in the Early Jurassic Statfjord Group. This is a deviated well. It was drilled vertical down to 1410 m and deviated from there with up to 58.7 deg inclination. The well was drilled with sea water and hi-vis pills down to 283 m and with Glydril mud from 283 m to TD.Top Draupne Formation was encountered at 2130 m. Intra Draupne sandstones interbedded with claystones, shale and siltstone were penetrated from 2149 m to top Sognefjord Formation at 2201 m. The Draupne Formation sandstones were gas saturated while only water was sampled in the underlying Sognefjord Formation. However, geochemical analyses of cores indicated an oil column from 2189 m to 2217 m.The Fensfjord Formation was penetrated from 2351 m to 2426 m. Moveable oil was proven with an ODT at 2376 m.The Brent Group was encountered with top Tarbert Formation at 2644 m. Tarbert and Ness formations contained oil down to a shale sequence at 2682 m in the Ness Formation. Excellent pressure points indicated an OWC at exactly 2696 m.Top Statfjord Group was encountered at 3178 m. The Statfjord Group was water bearing with weak shows at the top.No oil shows were described above top Jurassic level.A total of 16 cores were cut from 2123 m to 2431 m in claystones, siltstones and sandstones of the Draupne, Sognefjord, Heather and Fensfjord formations. Core recovery varied from 6.3% to 100%. Wire line fluid samples were taken in the Draupne and Sognefjord formations at 2162 m (gas), 2182.5 m (gas), and 2205.8 m (water); in the Fensfjord Formation at 2357.5 m (oil) and 2372.3 m (oil); and in the Brent Group at 2678.5 m (oil), 2675.1 m (oil), 2699.2 m (water), and 2712.8 m (water)The well was permanently abandoned on 12 September as an oil and gas discovery.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]1110.003270.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12123.02133.6[m ]22134.02138.0[m ]32144.02149.0[m ]42149.02156.7[m ]52157.02161.0[m ]62179.02179.5[m ]72187.02204.5[m ]82204.52221.1[m ]92222.02240.0[m ]102316.02333.5[m ]112343.02354.2[m ]122361.02367.0[m ]132370.02376.7[m ]142376.72395.0[m ]152395.02412.9[m ]162413.02431.0[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]179.4Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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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 typeCONDUCTOR30283.036283.00.00LOTSURF.COND.13 3/81100.017 1/21100.01.68LOTINTERM.9 5/82166.012 1/42176.01.55LOTOPEN HOLE3271.08 1/23271.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CRFT21572162DSI VSP20002835HALS PEX11102005MDT21782784MDT21822362MDT21822372MDT23572701MWD - ARC VIS675 ADN19502176MWD - GST VIS675 ADN21603258MWD - PP CDR2092176 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit20978380217251725177718201980201920192098209821302130220122332351242625222538264426442654269727852785295729853178 -
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].pdf9.06.pdf3.64 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured11001.3213.0water based16001.5018.0water based21211.5023.0water based21391.5021.0water based23431.2014.0water based23701.2114.0water based28351.2115.0water based28351.2015.0water based32711.2314.0water based -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory2115.0[m]DCPETROSTR2117.0[m]DCPETROS2120.0[m]DCPETROS2122.0[m]DCPETROS2124.2[m]CPETROS2132.4[m]CPETROS2135.2[m]CPETROS2148.9[m]CPETROS2155.5[m]CPETROS2163.0[m]DCPETROS2167.0[m]DCPETROS2170.0[m]DCPETROS2172.0[m]DCPETROS2175.0[m]DCPETROS2177.0[m]DCPETROS2197.3[m]CPETROS2200.4[m]CPETROS2212.2[m]CPETROS