2/1-5
Eksport: PDF
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Generell informasjon
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Brønnhistorie
GeneralWell 2/1-5 was drilled on the Cod Terrace of the Central Graben in the southern North Sea. The primary objective was test a Late Jurassic sandstone prospect on the south side of a large, central salt culmination in block 2/1. The prospect was developed by analogy with the 2/1-3 oil discovery (Gyda) on the north-western slope of the same salt high. There, the reservoir is a 60 to 90 m thick sand within the Farsund formation, with closure formed primarily by pinch out/truncation beneath the Mandal Formation on lapping on the central salt high. Secondary objectives were possible deeper reservoirs such as the Ula and Bryne Formations and the Triassic down to top salt.Operations and resultsWildcat well 2/1-5 was spudded with the semi-submersible installation Sedco 707 on 13 November 1982 and drilled to TD at 4454 m. In the Cretaceous sequence the string got stuck and the well had to be sidetracked from 2882 m. After a drilling break at 4186 m an oil kick occurred with 21.5 m influx and oil appearing in the mud. RFT measurements in sandstone units below the oil kick showed pore pressures on a gradient equivalent to a mud weight of 2.10 g/cm. This gave little margin for safe onward drilling to Top Salt and the well was terminated in dark, carbonaceous mudstone of uncertain, possibly Early Jurassic age. The well was drilled with seawater/gel down to 635 m, with gypsum/lignosulfonate mud from 635 m to 3830 m, and with Lignosulphonate/lignite mud from 3830 m to TD.Well 2/1-5 reached the Base Cretaceous Unconformity and the "Hot shale" at 3882 m as predicted. Coring was initiated when traces of sand were observed near the predicted "top reservoir", but only dark, carbonaceous mudstone/siltstone was recovered. In total, 300 metres of mudstone/siltstone were then drilled without any clear trace of the expected equivalent of the 2/1-3 reservoir sandstone. Then, at 4193 m a porous, highly over pressured sandstone unit was penetrated, causing an oil kick and creating new hope for the prospect. However, the thickness of this oil sand was only 6 m, rendering it uneconomic as a single productive reservoir zone. The sand is classified as Ula formation. Several thin bands of sandstones occur within the mudstone sequence below the "kick sand", but these were all well cemented and thus unproductive. Oil shows were seen in sidewall cores in these bands of cemented sandstone down to as deep as 4300 m.One core was cut from 3929.0 to 3946.3 m in the Farsund Formation. The RFT tool was run on wire line for pressure sampling, but no fluid samples were taken.The well was permanently abandoned on 5 April 1983 as a minor oil discovery.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]180.004454.00 -
Borekjerner i Sokkeldirektoratet
Borekjerner i Sokkeldirektoratet Kjerneprøve nummerKjerneprøve - topp dybdeKjerneprøve - bunn dybdeKjerneprøve dybde - enhet13928.93947.3[m ]Borekjerner i Sokkeldirektoratet Total kjerneprøve lengde [m]18.4Borekjerner i Sokkeldirektoratet Kjerner tilgjengelig for prøvetaking?YES -
Kjernebilder
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Palynologiske preparater i Sokkeldirektoratet
Palynologiske preparater i Sokkeldirektoratet Prøve dybdeDybde enhetPrøve typeLaboratorie4202.0[m]DCSAGA4226.0[m]DCSAGA4253.0[m]DCSAGA4280.0[m]DCSAGA4316.0[m]DCSAGA4337.0[m]DCSAGA4370.0[m]DCSAGA4391.0[m]DCSAGA4415.0[m]DCSAGA4439.0[m]DCSAGA4454.0[m]DCSAGA -
Litostratigrafi
Litostratigrafi Topp Dyb [mMD RKB]Litostrat. enhet9017852886288629072929296130023101313631363237359737413758376837683790379738333882388239144053419341934199 -
Spleisede logger
Spleisede logger Dokument navnDokument formatDokumentstørrelse [MB]pdf0.77 -
Geokjemisk informasjon
Geokjemisk informasjon Dokument navnDokument formatDokumentstørrelse [MB]pdf1.20 -
Dokumenter – eldre Sokkeldirektoratets WDSS rapporter og andre relaterte dokumenter
Dokumenter – eldre Sokkeldirektoratets WDSS rapporter og andre relaterte dokumenter Dokument navnDokument formatDokumentstørrelse [MB]pdf0.17pdf0.42 -
Dokumenter – rapportert av utvinningstillatelsen (frigitt ihht til regelverk)
Dokumenter – rapportert av utvinningstillatelsen (frigitt ihht til regelverk) Dokument navnDokument formatDokumentstørrelse [MB]pdf17.09 -
Logger
Logger Type loggTopp dyp for logg [m]Bunn dyp for logg [m]CBL VDL550800CBL VDL17502050CST GR39004100CST GR40904300CST GR41304210CST GR42104458DLL MSFL GR SP CAL41504453HDT38214217HDT38214180HDT38214458ISF BHC GR SP162635ISF BHC GR SP38304217ISF BHC MSFL GR SP CAL6263830ISF BHC MSFL GR SP CAL42184457LDL CNL NGS GR CAL38214457RFT GR41944374RFT GR41954214RFT GR42004200 -
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 formasjonstestCONDUCTOR30161.036167.00.00LOTSURF.COND.18 5/8625.024635.01.58LOTINTERM.13 3/82001.017 1/22008.01.86LOTINTERM.9 5/83817.012 1/43830.02.13LOTOPEN HOLE4454.08 3/84454.00.00LOT -
Boreslam
Boreslam Dybde MD [m]Egenvekt, slam [g/cm3]Viskositet, slam [mPa.s]Flytegrense [Pa]Type slamDato, måling6501.2035.0WATERBASED10101.2845.0WATERBASED13801.4572.0WATERBASED20301.5156.0WATERBASED29401.6854.0WATERBASED44502.1367.0WATERBASED -
Trykkplott
Trykkplott Porertrykksdataene kommer fra logging i brønnen hvis ingen annen kilde er oppgitt. I noen brønner der trykk ikke er logget, er det brukt informasjon fra formasjonstester eller brønnspark. Trykkdataene er rapportert inn til Oljedirektoratet og videre prosessert og kvalitetssikret av IHS Markit.Trykkplott Dokument navnDokument formatDokumentstørrelse [MB]PDF0.21