7/11-7
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Generell informasjon
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Brønnhistorie
GeneralThe primary objective of the wildcat 7/11-7 S was Late Jurassic sandstone surrounding a small salt piercement below the Paleocene Cod Field reservoir. Several discoveries had been made in the vicinity of Cod, in the Upper Jurassic Ula Formation. The Triassic and Permian constituted secondary targets. The well was drilled from the Cod platform with planned bottom hole location ca 0.9 km to the east.Operations and resultsWildcat well 7/11-7 S was spudded from the fixed installation Cod on 29 December 1982 and drilled deviated to TD at 4927 m (4661 m TVD) m in the Late Permian Zechstein Group. The well was scheduled as a 150-day project but a full drilling crew was still present on day 349 and it took until day 364 to set a plug above the last set of perforations. The length of this project was due to problems in drilling and extended testing to adequately evaluate the three zones of interest. There were delays in setting plugs, running casing, fishing, and installing necessary 10,000 psi surface equipment. The testing delays included problems with setting DHSV's, parted tubing, aborted stimulations, bad weather, and bailing operations. The well was drilled with seawater/lignite and Desco, an organic thinner.The well reached all three targets. Late Jurassic Ula Formation sandstone was encountered at 4527 m. The Ula Formation rested unconformable on Triassic Skagerrak Formation sandstone at 4566 m. The Permian Zechstein dolomites were encountered at 4856 m. Good shows were recorded in the Ula Formation, with weaker shows extending down to 4609 m in the Triassic Skagerrak Formation. A second Triassic zone with weak shows was observed at 4785 m to 4810 m. Source rock formations were found in the Tertiary interval from 1820 m to 2500 m, and in the Late Jurassic shales of the Mandal and Farsund Formations at 4405 m to 4527. The Tertiary interval had TOC in the range 2 - 4 %, Hydrogen Index from 100 to 120 mg HC/g rock, and was immature. The Late Jurassic had TOC in the range 4 - 8 %, HI in the range 80 - 200 mg/g and peak/late oil window maturity (% Ro around 0.8 and Tmax around 445 deg C). Six cores were cut in the Ula Formation and the upper part of the Skagerrak Formation. RFT results from the Triassic to Jurassic sandstones indicated mainly tight formation, but with some permeability in the upper part of the Ula Formation and possibly also in the top of the Skagerrak Formation. No fluid sample was taken on wire line.The well was suspended on 25 December 1983 as a minor Jurassic oil discovery. Later the well was re-entered and set in production on the Cod Field.TestingThree independent production tests were carried out. DST 1 from 4850 m to 4870 m in the Permian Zechstein Group did not produce. DST 2 test tested from three different zones (4779 m to 4789 m, 4670 m to 4684 m, and 4625 m to 4646 m) in the Triassic Skagerrak Formation. In this test the tubing failed. The fish was not recovered and a cement plug was set. DST 3 from the interval 4550 m to 4577 m in the Jurassic Ula Formation produced small amounts of oil and water. The flow was not stabilized and no reliable pressures were measured. Before acid stimulation the production was not sufficient to completely unload the well bore contents, though some oil (API 37-39) and gas samples were recovered. After acid stimulation the well produced a total of 116 bbls of oil. The gravity of the oil increased throughout this flow period to 41.1 deg API.It is probable that the mud program damaged the reservoir rock in the near well bore extensively, which in turn adversely affected the test flow rates. This was particularly important for DST 3 in the Ula Formation, the last of the three tests. This reservoir contained on average of 14% illite clay. When exposed to a low-KCl mud for an extended period of time this clay had probably swelled and severely reduced the permeability in the formation. -
Borekaks i Sokkeldirektoratet
Borekaks i Sokkeldirektoratet Borekaks tilgjengelig for prøvetaking?YESBorekaks i Sokkeldirektoratet Borekaksprøve, topp dybde [m]Borekaksprøve, bunn dybde [m]1383.794922.52 -
Borekjerner i Sokkeldirektoratet
Borekjerner i Sokkeldirektoratet Kjerneprøve nummerKjerneprøve - topp dybdeKjerneprøve - bunn dybdeKjerneprøve dybde - enhet114923.014959.0[ft ]214961.014966.0[ft ]314966.014995.0[ft ]415012.015051.0[ft ]515052.015103.0[ft ]615105.015152.0[ft ]Borekjerner i Sokkeldirektoratet Total kjerneprøve lengde [m]63.1Borekjerner i Sokkeldirektoratet Kjerner tilgjengelig for prøvetaking?YES -
Kjernebilder
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Palynologiske preparater i Sokkeldirektoratet
Palynologiske preparater i Sokkeldirektoratet Prøve dybdeDybde enhetPrøve typeLaboratorie14979.0[ft]COD15052.3[ft]COD15077.0[ft]COD15086.0[ft]COD -
Litostratigrafi
Litostratigrafi Topp Dyb [mMD RKB]Litostrat. enhet1121615313331333146318533773390339034683874420843184318436044054405444845274527456645664856 -
Geokjemisk informasjon
Geokjemisk informasjon Dokument navnDokument formatDokumentstørrelse [MB]pdf4.84 -
Dokumenter – eldre Sokkeldirektoratets WDSS rapporter og andre relaterte dokumenter
Dokumenter – eldre Sokkeldirektoratets WDSS rapporter og andre relaterte dokumenter Dokument navnDokument formatDokumentstørrelse [MB]pdf0.20pdf0.42 -
Dokumenter – rapportert av utvinningstillatelsen (frigitt ihht til regelverk)
Dokumenter – rapportert av utvinningstillatelsen (frigitt ihht til regelverk) Dokument navnDokument formatDokumentstørrelse [MB]pdf95.22pdf2.81pdf0.06pdf13.13pdf1.11pdf0.43pdf0.27pdf1.17pdf1.96pdf0.65pdf0.27pdf0.28pdf1.98pdf1.17pdf0.27pdf0.34pdf2.08pdf0.26pdf2.64pdf3.56 -
Borestrengtester (DST)
Borestrengtester (DST) Test nummerFra dybde MD
[m]Til dybde MD
[m]Reduksjonsventil størrelse
[mm]1.0485048700.02.0462547890.03.0455045771.6Borestrengtester (DST) Test nummerEndelig avstengningstrykk
[MPa]Endelig strømningstrykk
[MPa]Bunnhullstrykk
[MPa]Borehullstemperatur
[°C]1.02.03.0Borestrengtester (DST) Test nummerOlje produksjon
[Sm3/dag]Gass produksjon
[Sm3/dag]Oljetetthet
[g/cm3]Gasstyngde rel. luftGOR
[m3/m3]1.02.03.0230.820 -
Logger
Logger Type loggTopp dyp for logg [m]Bunn dyp for logg [m]CBL VDL GR CCL1211376CBL VDL GR CCL26093461CBL VDL GR CCL27723148CBL VDL GR CCL34254908CCL061CNL GR CCL43434867DI MSFL GR LSS33703491DI MSFL LSS NGS34874931DIL GR SLS CALI31553491DISF BHCS NGL34264620DISFL SP CALI31553406GR CALI31553331ISF GR LSS CALI13773157ISF LSS GR4791383ISF LSS GR31553405LDL CNL GR34264676LDL CNL GR34874621LDL CNL GR CALI31553406NGRS34874931NGS34264615NGT34254612NGT SPECT31553404RFT34874931RFT45494854RFT GR31873309RFT GR33503405SHDT34874932SONIC WAVEFORM44804891VSP7314877 -
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 formasjonstestCONDUCTOR30183.8360.00.00LOTSURF.COND.20498.0260.00.00LOTINTERM.161379.218 3/41390.01.70LOTINTERM.13 3/83156.017 1/23158.01.80LOTINTERM.9 5/83492.812 1/43489.01.83LOTLINER74912.88 1/24913.00.00LOT -
Boreslam
Boreslam Dybde MD [m]Egenvekt, slam [g/cm3]Viskositet, slam [mPa.s]Flytegrense [Pa]Type slamDato, måling14001.5148.0waterbased15401.6866.0waterbased16451.6566.0waterbased31001.6566.0waterbased32901.0352.0waterbased33401.4454.0waterbased39301.4460.0waterbased42501.4553.0waterbased45401.6458.0waterbased47801.7754.0waterbased