2/7-28
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Generell informasjon
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Brønnhistorie
GeneralExploration well 2/7-28 was drilled on the Eldfisk Jurassic Prospect, on the flank of the Eldfisk Field on the western side of the Feda Graben in the North Sea. The well was positioned 1.8 kilometres west of the Eldfisk Alpha Platform. The primary objective was to prove hydrocarbons in sandstones in the Late Jurassic Eldfisk Formation. The Eldfisk Formation is interpreted as high density turbidite/debris flow deposits located on the eastern side of the major northwest-southeast trending Skrubbe Fault.Operations and resultsWell 2/7-28 was spudded with the jack-up installation Mærsk Guardian on March 8, 1992 and drilled to TD at 3893 m, 54 m into the Late Permian Zechstein Group. Drilling to the Upper Palaeocene Section proceeded without major difficulty, but the 11 3/4" liner was set higher than prognosed because of a combination of lost circulation in the Lower Palaeocene Våle Formation and instability in the Tertiary section above. A prognosed depleted chalk reservoir horizon, the flank of the Eldfisk Field, necessitated setting 9 7/8" casing at top of the Ekofisk Formation. Drilling proceeded to 3050.4 m in the Lower part of the Hod Formation, the proposed setting for the 8 3/4" casing. While under-reaming before running the linear, an under-reamer arm was lost in the hole. A successfully sidetrack hole was made below the liner. Drilling continued to 3061.1 m where the bottom hole assembly twisted off. The hole was sidetracked again and drilling continued to base of the Early Cretaceous where 7" liner was set. Further drilling to final TD went without significant difficulties. The well was drilled water based with spud mud down to 745 m, polymer mud from 745 m to 8313 m, sea water/Drispac/Soltex mud from 8313 m to 9304 m, polymer mud from 9304 m to 10008 m, and Thermadril mud from 10008 m to TD.Poor shows were recorded in intervals between 1510 m to 1950 m in Miocene to Late Oligocene claystones. At 1617 m in top Hordaland Group the shows were stronger with local strong smell of oil. A weak show was recorded also in the Balder Formation.The Våle Formation was encountered at 2827 m and top Ekofisk Formation at 2850 m. The Våle Formation proved to be in pressure communication with the depleted Ekofisk-Tor-Hod reservoir of the main Eldfisk Field. The reservoir was pressure depleted down to 2917 m in the Hod Formation due to production from the Eldfisk Field since 1979. Good oil shows were described throughout the chalk reservoir down to 2914 m in the Hod Formation. The shows became weaker below this depth and vanished below 3048 m.The base Cretaceous unconformity, top Farsund Formation, was encountered at 3339 m. The section from 3414 m to 3426 m in the Farsund Formation was extremely rich in organic carbon (TOC = 10 - 22%) and with log responses that confirmed an extremely rich source rock. The target Eldfisk Formation was encountered 20 m thick with top at 3498 m. The lower part from 3509 to 3518 m had sandstone with up to 20% porosity, but it was water bearing with only poor shows. There were poor oil shows on claystone throughout the Farsund and Haugesund formations.Two cores were cut. Core 1 was cut from 3414.4 m to 3433.3 m in the best source rock interval in the Farsund Formation. Core 2 was cut from 3514.1 m in the basal Eldfisk Formation to 3519.6 m in top Haugesund Formation. No wire line fluid samples were taken in the well.The well was permanently abandoned on 7 August 1992 as well with shows.TestingNo drill stem test was performed. -
Borekaks i Sokkeldirektoratet
Borekaks i Sokkeldirektoratet Borekaks tilgjengelig for prøvetaking?YESBorekaks i Sokkeldirektoratet Borekaksprøve, topp dybde [m]Borekaksprøve, bunn dybde [m]551.803879.90 -
Borekjerner i Sokkeldirektoratet
Borekjerner i Sokkeldirektoratet Kjerneprøve nummerKjerneprøve - topp dybdeKjerneprøve - bunn dybdeKjerneprøve dybde - enhet111202.011262.2[ft ]211529.011547.0[ft ]Borekjerner i Sokkeldirektoratet Total kjerneprøve lengde [m]23.8Borekjerner i Sokkeldirektoratet Kjerner tilgjengelig for prøvetaking?YES -
Kjernebilder
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Litostratigrafi
Litostratigrafi Topp Dyb [mMD RKB]Litostrat. enhet11216162729272927422784282728502850289829023091309631763176319032633281333933393498351837963839 -
Dokumenter – eldre Sokkeldirektoratets WDSS rapporter og andre relaterte dokumenter
Dokumenter – eldre Sokkeldirektoratets WDSS rapporter og andre relaterte dokumenter Dokument navnDokument formatDokumentstørrelse [MB]pdf0.66pdf0.23 -
Dokumenter – rapportert av utvinningstillatelsen (frigitt ihht til regelverk)
Dokumenter – rapportert av utvinningstillatelsen (frigitt ihht til regelverk) Dokument navnDokument formatDokumentstørrelse [MB]pdf2.37pdf5.35pdf3.49 -
Logger
Logger Type loggTopp dyp for logg [m]Bunn dyp for logg [m]BGT GR14942829BHC GR26512830DLL MSFL GR14942828DLL MSFL GR33343850DLL MSFL SDT GR30223339FMS GR28443038FMS GR33343839LDL CNL GR30223328LDL CNL NGL33343847MWD - GR RES2181494SDT GR27553021SDT GR33343842VSP15243840VSP15243307 -
Foringsrør og formasjonsstyrketester
Foringsrør og formasjonsstyrketester Type utforingUtforing diam.
[tommer]Utforing dybde
[m]Brønnbane diam.
[tommer]Brønnbane dyp
[m]LOT/FIT slam eqv.
[g/cm3]Type formasjonstestCONDUCTOR30218.836220.00.00LOTINTERM.20534.626540.01.40LOTINTERM.13 3/81494.817 1/21500.02.00LOTINTERM.11 3/42810.317 1/22815.00.00LOTINTERM.9 7/82836.212 1/42840.00.00LOTINTERM.8 3/83019.212 1/43022.00.00LOTLINER73331.58 1/23893.00.00LOT -
Boreslam
Boreslam Dybde MD [m]Egenvekt, slam [g/cm3]Viskositet, slam [mPa.s]Flytegrense [Pa]Type slamDato, måling1371.03WATER BASED1631.03WATER BASED2021.03WATER BASED2271.20WATER BASED4761.1523.0WATER BASED5091.2024.0WATER BASED5431.1328.0WATER BASED8141.3230.0WATER BASED10031.8727.0WATER BASED12961.5334.0WATER BASED13722.0420.0WATER BASED14631.8026.0WATER BASED15011.5628.0WATER BASED16821.7324.0WATER BASED18171.7439.0WATER BASED21251.7443.0WATER BASED23491.7445.0WATER BASED23971.7418.0WATER BASED24081.8735.0WATER BASED24201.7436.0WATER BASED24691.7325.0WATER BASED25341.7436.0WATER BASED25911.8023.0WATER BASED26211.7415.0OIL BASED27211.7435.0WATER BASED27431.4315.0WATER BASED27431.7323.0WATER BASED27811.7433.0WATER BASED28001.7431.0WATER BASED28101.8737.0WATER BASED28221.7318.0WATER BASED28301.7422.0WATER BASED28341.6722.0WATER BASED28361.7317.0WATER BASED28361.0423.0WATER BASED28361.4031.0WATER BASED28361.5830.0WATER BASED30021.0315.0WATER BASED30201.4016.0WATER BASED30231.5715.0WATER BASED30341.5616.0WATER BASED30461.3218.0WATER BASED30482.0422.0WATER BASED30481.2613.0WATER BASED30501.4016.0WATER BASED30501.4017.0WATER BASED30511.5615.0WATER BASED30601.5616.0WATER BASED30611.5715.0WATER BASED32221.6714.0WATER BASED32771.6712.0WATER BASED33381.6715.0WATER BASED35132.0219.0WATER BASED35202.0217.0WATER BASED36562.0221.0WATER BASED37192.0219.0WATER BASED37192.0219.0WATER BASED38932.0419.0WATER BASED