35/10-1
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General information
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Wellbore history
GeneralWildcat well is located on the Marflo Spur, ca 15 km west of the Fram and Vega discoveries. The main objective was to test the hydrocarbon potential of the Middle Jurassic Brent Group sandstones located in a rotated fault block. A secondary target was the Early Jurassic Cook Formation.Operations and resultsWell 35/10-1 was spudded with the semi-submersible installation Deepsea Bergen on 1 August 1991 and drilled to TD at 3986 m in the Early Jurassic Statfjord Formation. A 9 7/8" pilot hole was drilled to 760 m where MWD indicated potential sand with shallow gas at 753 m. Pilot hole was therefore plugged back to 740 m before opening up to 26" and running 20" casing. Electric logs did not confirm gas in the sand layer. The 17 1/2" hole was drilled to 1895 m. The well started flowing (oil kick from 2 m thick Lista sand at 1892 m). The well was shut in and the drill pipe became stuck. The well was plugged back and sidetracked from kick-off point at 735 m. At 3326 m in the 8 1/2" hole the well started flowing (salt water kick from the Brent Group). The hole was plugged back and 7" liner was run with shoe at 3288 m. Further problems with lost circulation and gain caused by coal beds occurred at 3986 m. The well was plugged back and abandoned at this depth. Before logging, the well was plugged back to 3920 m; hence no electric logs were run beyond 3860 m. The well was drilled with seawater/hi-vis pills /CMC EHV down to 736 m and with Gyp/PAC mud from 736 m to 1895 m. At this point an IMCOSPOT/PIPELAX pill was added to free the stuck pipe, without success. From sidetrack at 735 m the well was drilled to 3040 m using Gyp/PAC mud, and from 3040 m to TD the well was drilled with AncoTemp/bentonite/causticised lignite.A 2 meter thick sand layer from 1891 m to 1893 m in the Lista Formation, proved to be oil bearing (well kick, FMT sample at 1892 m). Both the Primary and secondary objectives proved to be water bearing, although low saturation of hydrocarbons were observed throughout the Brent Group. Log evaluation indicated water saturation of 50-100% in the Brent and Dunlin Groups. A well kick at 3325 m confirmed water in the top of the Brent Group (Tarbert Formation). In the Cook Formation, there was low saturation of hydrocarbons, but FMT pressure points indicated a possible gas-cap in the top, from 3525 m to 3543 m.Oils shows were recorded in the sand from 1891 - 1893 m in the Lista Formation and in the Shetland Formation from 2011 m to 2140 m. Poor shows were observed in the sandy sequences of the Brent Group. Fair shows were recorded on the cores from 3602 m to 3658 m in the Dunlin Group and very poor shows were seen from 3658 m down to top Statfjord Formation at 3826 m.A total of 257.2 m core was recovered in 19 conventional cores from 3329 m to 3657.7 m in the Brent and Dunlin Groups. FMT fluid sampling was performed after sidetracking. Samples were taken in the Lista Formation at 1892 m (ca 2 litre with 37 deg. API oil), and in the Cook Formation at 3536.5 m (leakage in sample chamber: only mud filtrate and formation water was recovered) and at 3598 m (mud filtrate and ca 13 l gas).The well was permanently abandoned on 16 January 1992 as a minor oil 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]750.003984.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom13329.03340.8[m ]23342.03360.5[m ]33360.03388.0[m ]43388.23396.5[m ]53396.53400.6[m ]63401.03414.8[m ]73415.03416.8[m ]83416.83419.4[m ]93419.43422.7[m ]103422.83432.0[m ]113432.03437.0[m ]123438.03450.7[m ]133450.83469.1[m ]143469.03486.1[m ]153489.03511.5[m ]163511.13517.9[m ]173575.03602.5[m ]183602.03630.0[m ]193630.03657.7[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]267.0Cores 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 typeCONDUCTOR30445.036446.00.00LOTINTERM.20730.026732.01.49LOTINTERM.13 3/81789.017 1/21790.01.55LOTINTERM.9 5/83020.012 1/43022.01.69LOTLINER73288.08 1/23986.02.15LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CBL VDL3822860CBL VDL28553284CBL VDL GR3841786CBL VDL GR28203025CN GR17863029CN GR30163290CN GR32853652CN GR32863856CORGUN GR9051790CORGUN GR17923027CORGUN GR30313260CORGUN GR33043850DIFL ACL ZDL GR445735DIFL ACL ZDL GR7301808DIFL ACL ZDL GR17863032DIFL ACL ZDL GR30163290DIFL ACL ZDL GR32863652DIFL ACL ZDL MLL GR32863856DIPLOG GR30163290DIPLOG GR32863425DIPLOG GR33753857FMT GR9131222FMT GR18262011FMT GR33243841FMT GR33283330FMT GR35363564FMT GR35943841MWD - GR RES DIR4543326SWAL GR7301781SWAL GR17292980TEMP SONAN3501740VSP8753848 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit38491294812031252175517551824184119942005200522273007304330583066306630813085309830983146332433243344344934603507350735093649366538063826 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.76 -
Geochemical information
Geochemical information Document nameDocument formatDocument size [MB]pdf4.13 -
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]pdf32.74 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured4931.25WATER BASED7401.25WATER BASED7591.25WATER BASED7701.2020.0WATER BASED10211.2024.0WATER BASED11361.2022.0WATER BASED12661.2022.0WATER BASED13701.2018.0WATER BASED15001.2018.0WATER BASED15701.2317.0WATER BASED16851.2316.0WATER BASED17961.2021.0WATER BASED18201.2717.0WATER BASED18551.2719.0WATER BASED20241.3523.0WATER BASED21151.3921.0WATER BASED23151.3924.0WATER BASED24591.3931.0WATER BASED26251.3927.0WATER BASED27511.3929.0WATER BASED27691.3927.0WATER BASED28211.3928.0WATER BASED29181.3925.0WATER BASED29691.3925.0WATER BASED30281.3921.0WATER BASED30391.3921.0WATER BASED31651.5521.0WATER BASED32751.5519.0WATER BASED32791.5817.0WATER BASED33251.8631.0WATER BASED33291.8442.0WATER BASED33601.8442.0WATER BASED33881.8527.0WATER BASED33961.8639.0WATER BASED34101.8635.0WATER BASED34171.8639.0WATER BASED34311.8640.0WATER BASED34381.8638.0WATER BASED34501.8636.0WATER BASED34891.8635.0WATER BASED35121.8636.0WATER BASED35181.8630.0WATER BASED35751.8631.0WATER BASED36021.8628.0WATER BASED36301.8627.0WATER BASED36571.8623.0WATER BASED37061.8522.0WATER BASED38240.0023.0WATER BASED39320.0028.0WATER BASED39651.8431.0WATER BASED39861.8320.0WATER BASED39871.8325.0WATER BASED -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory930.0[m]DCPALEO940.0[m]DCPALEO950.0[m]SWCSTATO970.0[m]DCPALEO980.0[m]DCPALEO999.0[m]SWCSTATO1010.0[m]DCPALEO1030.0[m]DCPALEO1040.0[m]DCPALEO1060.0[m]DCPALEO1070.0[m]DCPALEO1090.0[m]DCPALEO1110.0[m]SWCSTATO1120.0[m]DCPALEO1140.0[m]DCPALEO1150.0[m]DCPALEO1170.0[m]DCPALEO1190.0[m]SWCSTATO1200.0[m]DCPALEO1220.0[m]DCPALEO1230.0[m]DCPALEO1250.0[m]DCPALEO1264.0[m]SWCSTATO1280.0[m]DCPALEO1290.0[m]DCPALEO1305.0[m]SWCSTATO1320.0[m]DCPALEO1340.0[m]DCPALEO1350.0[m]DCPALEO1370.0[m]DCPALEO1380.0[m]SWCSTATO1400.0[m]DCPALEO1410.0[m]DCPALEO1425.0[m]SWCSTATO1460.0[m]DCPALEO1470.0[m]DCPALEO1493.0[m]SWCSTATO1510.0[m]DCPALEO1520.0[m]DCPALEO1540.0[m]DCPALEO1550.0[m]DCPALEO1570.0[m]DCPALEO1580.0[m]DCPALEO1610.0[m]DCPALEO1630.0[m]DCPALEO1640.0[m]DCPALEO1660.0[m]DCPALEO1670.0[m]DCPALEO1690.0[m]DCPALEO1700.0[m]SWCSTATO1720.0[m]DCPALEO1750.0[m]SWCSTATO1760.0[m]SWCSTATO1775.0[m]SWCSTATO1791.5[m]SWCSTATO1811.5[m]SWCSTATO1821.5[m]SWCSTATO1826.5[m]SWCSTATO1916.5[m]SWCSTATO1922.5[m]SWCSTATO1926.5[m]SWCSTATO1961.5[m]SWCSTATO1981.5[m]SWCSTATO2001.5[m]SWCSTATO2006.5[m]SWCSTATO2019.7[m]SWCSTATO2036.0[m]DCPALEO2050.0[m]DCPALEO2070.0[m]DCPALEO2090.0[m]DCPALEO2101.5[m]SWCSTATO2120.0[m]DCPALEO2130.0[m]DCPALEO2150.0[m]DCPALEO2160.0[m]DCPALEO2180.0[m]DCPALEO2190.0[m]DCPALEO2210.0[m]DCPALEO2220.0[m]DCPALEO2240.0[m]DCPALEO2250.0[m]DCPALEO2270.0[m]DCPALEO2280.0[m]DCPALEO2300.0[m]DCPALEO2310.0[m]DCPALEO2330.0[m]DCPALEO2340.0[m]DCPALEO2360.0[m]DCPALEO2370.0[m]DCPALEO2390.0[m]DCPALEO2400.0[m]DCPALEO2420.0[m]DCPALEO2430.0[m]DCPALEO2440.0[m]DCPALEO2460.0[m]DCPALEO2480.0[m]DCPALEO2501.5[m]SWCSTATO2510.0[m]DCPALEO2530.0[m]DCPALEO2540.0[m]DCPALEO2560.0[m]DCPALEO2570.0[m]DCPALEO2590.0[m]DCPALEO2601.5[m]SWCSTATO2620.0[m]DCPALEO2630.0[m]DCPALEO2650.0[m]DCPALEO2660.0[m]DCPALEO2680.0[m]DCPALEO2690.0[m]DCPALEO2710.0[m]DCPALEO2720.0[m]DCPALEO2740.0[m]DCPALEO2750.0[m]DCPALEO2770.0[m]DCPALEO2780.0[m]DCPALEO2801.5[m]SWCSTATO2810.0[m]DCPALEO2830.0[m]DCPALEO2840.0[m]DCPALEO2860.0[m]DCPALEO2870.0[m]DCPALEO2890.0[m]DCPALEO2901.5[m]SWCSTATO2920.0[m]DCPALEO2930.0[m]DCPALEO2950.0[m]DCPALEO2960.0[m]DCPALEO2980.0[m]DCPALEO2990.0[m]DCPALEO2996.5[m]SWCSTATO3016.5[m]SWCSTATO3031.5[m]SWCSTATO3045.0[m]SWCSTATO3057.5[m]SWCSTATO3069.0[m]SWCSTATO3083.0[m]SWCSTATO3085.0[m]SWCSTATO3090.0[m]SWCSTATO3100.0[m]SWCSTATO3110.0[m]SWCSTATO3118.0[m]SWCSTATO3130.0[m]SWCSTATO3140.0[m]SWCSTATO3146.0[m]SWCSTATO3153.5[m]SWCSTATO3167.0[m]SWCSTATO3177.0[m]SWCSTATO3186.0[m]DCPALEO3193.0[m]SWCSTATO3201.0[m]DCPALEO3210.5[m]SWCSTATO3219.0[m]DCPALEO3226.0[m]SWCSTATO3234.0[m]DCPALEO3240.0[m]SWCSTATO3251.0[m]SWCSTATO3260.0[m]DCSTATO3260.0[m]SWCSTATO3270.0[m]DCPALEO3279.0[m]DCPALEO3288.0[m]DCPALEO3297.0[m]DCPALEO3304.0[m]SWCSTATO3306.0[m]DCPALEO3315.0[m]DCPALEO3324.0[m]DCPALEO3332.3[m]CSTATO3332.7[m]CSTATO3340.7[m]CSTATO3343.3[m]CSTATO3343.9[m]CSTATO3346.8[m]CSTATO3350.8[m]CSTATO3361.5[m]CSTATO3366.8[m]CSTATO3375.5[m]CSTATO3378.8[m]CSTATO3387.5[m]CSTATO3391.3[m]CSTATO3395.6[m]CSTATO3399.6[m]CSTATO3408.5[m]CSTATO3418.7[m]CSTATO3426.0[m]CSTATO3435.0[m]CSTATO3442.0[m]CSTATO3448.0[m]CSTATO3450.2[m]CSTATO3457.0[m]CSTATO3460.1[m]CSTATO3461.6[m]CSTATO3473.1[m]CSTATO3482.5[m]CSTATO3490.9[m]CSTATO3492.0[m]CSTATO3500.0[m]CSTATO3510.0[m]CSTATO3517.9[m]CSTATO3529.0[m]SWCSTATO3537.0[m]DCPALEO3548.0[m]SWCSTATO3555.0[m]DCPALEO3575.9[m]CSTATO3584.0[m]CSTATO3592.0[m]CSTATO3597.1[m]CSTATO3610.0[m]CSTATO3618.4[m]CSTATO3626.9[m]CSTATO3630.8[m]CSTATO3639.4[m]CSTATO3642.7[m]CSTATO3650.4[m]CSTATO3656.7[m]CSTATO3666.0[m]DCPALEO3672.0[m]DCPALEO3690.0[m]DCPALEO3697.0[m]SWCSTATO3708.0[m]DCPALEO3718.5[m]SWCSTATO3729.0[m]DCPALEO3741.5[m]SWCSTATO3747.0[m]DCPALEO3754.0[m]SWCSTATO3759.0[m]DCPALEO3773.0[m]SWCSTATO3783.5[m]SWCSTATO3792.0[m]DCPALEO3801.0[m]DCPALEO3810.0[m]DCPALEO3822.0[m]DCPALEO3827.0[m]SWCSTATO3843.0[m]DCPALEO3850.0[m]SWCSTATO3861.0[m]DCPALEO3870.0[m]DCPALEO3885.0[m]DCPALEO3900.0[m]DCPALEO3912.0[m]DCPALEO3930.0[m]DCPALEO3942.0[m]DCPALEO3960.0[m]DCPALEO3972.0[m]DCPALEO3984.0[m]DCPALEO -
Thin sections at the Norwegian Offshore Directorate
Thin sections at the Norwegian Offshore Directorate DepthUnit1550.00[m ]1340.00[m ]1430.00[m ]1310.00[m ]1280.00[m ]1370.00[m ]1400.00[m ]1460.00[m ]1250.00[m ]1050.00[m ]3597.30[m ]3600.00[m ]3600.25[m ]3600.70[m ]3601.73[m ]3604.25[m ]3614.95[m ]3616.50[m ]3619.75[m ]3620.88[m ]3622.68[m ]3641.15[m ]3643.07[m ]3645.45[m ]3649.19[m ]3649.71[m ]