2/5-10 A
Eksport: PDF
-
Generell informasjon
-
Brønnhistorie
GeneralExploration well 2/5-10 is located in the Central Graben on the Steinbit Terrace. The well was drilled with Late Jurassic sandstone of Oxfordian age, in a combination trap with structural and dip closing elements, as the primary target. Secondary targets were the Middle Jurassic Bryne Formation in the same combination trapping configuration, while the Late Cretaceous Chalk and the Lower Cretaceous Cromer Knoll Group were stratigraphic trap targets. After reaching TD evaluation of the cores and electric logs concluded that a fault had been intercepted within the main Jurassic target, justifying a sidetrack in search of a better pay zone. Well 2/5-10 was therefore plugged back in and well 2/5-10 A sidetracked.Operations and resultsWell 2/5-10 was spudded with the semi-submersible installation "Polar Pioneer" on 23 May 1993 and drilled to TD at 4701 m in rocks of the Triassic Smith Bank Formation. The well was drilled with sea water and hi-vis sweeps down to 865 m, with KCl/Polymer mud from 865 m to 4235 m, and with HPHT/Polymer mud from 4235 m to TD. Shallow gas was encountered after drilling the 8 1/2" pilot hole, prior to opening up the hole to 26" and running 20" casing. In order to ensure a good 20" casing cement job without compromising rig safety it was decided to plug back the gas bearing zone and set 20" casing at 509m, 291m shallower than originally planned 800m. To avoid gas migration the cement slurries for the 20" and 13 3/8" were redesigned with gas tight cement (microblock added).Top reservoir was encountered at 4582 m, 174 m deeper than prognosis due to complex geology and higher than expected shale interval velocities in the Late Jurassic. The main part of the Late Jurassic sandstone target was removed by faulting, and Triassic strata were encountered 5 m below top reservoir through a fault plane. The Late Jurassic sandstone was highly affected by the faulting, and the reservoir quality was poor. The secondary target Middle Jurassic Bryne Formation was not present. The Smith Bank Formation was encountered 5 m below top reservoir through a fault plane. A small hydrocarbon accumulation was found in the main target Late Jurassic Oxfordian age sandstone. Weak shows were encountered also in the Chalk and in the Vestland Group.Two conventional cores were cut from 4575 m in the Late Jurassic sandstone and down to 4591 m in the Smith Bank Formation. Two samples collected at 4594.3 m and 4583.1 m in the Vestland Group during the MDT run contained weak hydrocarbon shows, a discontinuous film of oil in sample #1 and gas traces in sample #2. Because of a failure of the MDT tool's equalization valve, a leakage between the two chambers was considered likely and therefore the location of these hydrocarbon shows is doubtful. However they should more likely be attributed to the top part of the Late Jurassic SST as confirmed by the sample #3 collected in the following RFT run which contained at 4594.3 m (same depth as sample #1) formation water. Only mud filtrate was finally recovered in the sample #4 taken at 4614 m. Well bore 2/5-10 was subsequently plugged back and permanently abandoned on 26 August 1993 as a well with shows.Sidestep 2/5-10 A was kicked off from 4306 m in 2/5-10 on 27 August 1993 and was drilled to a total depth of 4715 m in the Triassic Smith Bank Formation. The well was drilled with HPHT/polymer mud from kick-off to TD. The expected reservoir was encountered at 4616 m with a thickness of 57 m and with poor to medium reservoir characteristics. The shows encountered were poor, and no hydrocarbons could be extracted using downhole testing tools. Three conventional cores were cut in the Late Jurassic sandstone from 4612 m to 4640.1 m. Four RFT samples collected at 4619 m, 4624.1 m, 4630 m and 4657 m contained formation water and mud filtrate with only traces of oil. Sidetrack 2/5-10 A was permanently plugged and abandoned on 25 September 1993 as a 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]4295.004715.00 -
Borekjerner i Sokkeldirektoratet
Borekjerner i Sokkeldirektoratet Kjerneprøve nummerKjerneprøve - topp dybdeKjerneprøve - bunn dybdeKjerneprøve dybde - enhet14612.04620.8[m ]24621.54631.4[m ]34631.44640.2[m ]Borekjerner i Sokkeldirektoratet Total kjerneprøve lengde [m]27.5Borekjerner i Sokkeldirektoratet Kjerner tilgjengelig for prøvetaking?YES -
Kjernebilder
-
Litostratigrafi
Litostratigrafi Topp Dyb [mMD RKB]Litostrat. enhet881733305230523062307231813214321433423735429542984298461646734673 -
Spleisede logger
Spleisede logger Dokument navnDokument formatDokumentstørrelse [MB]pdf0.09 -
Geokjemisk informasjon
-
Dokumenter – rapportert av utvinningstillatelsen (frigitt ihht til regelverk)
Dokumenter – rapportert av utvinningstillatelsen (frigitt ihht til regelverk) Dokument navnDokument formatDokumentstørrelse [MB]pdf1.05pdf50.05 -
Logger
Logger Type loggTopp dyp for logg [m]Bunn dyp for logg [m]AIT BHC MSFL GR AMS42194715CBL VDL GR21004219CST GR42304704LDL CNL NGS FMS AMS42194711MDT-PO GR46174688MWD - DIR42924318MWD - GR DIR43184631MWD - GR RAR RPD DIR46404715VSP30004715 -
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 formasjonstestINTERM.9 5/84217.012 1/44217.00.00LOTOPEN HOLE4715.08 3/84715.00.00LOT -
Boreslam
Boreslam Dybde MD [m]Egenvekt, slam [g/cm3]Viskositet, slam [mPa.s]Flytegrense [Pa]Type slamDato, måling42152.0639.0WATER BASED43012.0233.0WATER BASED43122.0236.0WATER BASED43182.0436.0WATER BASED43942.0235.0WATER BASED44302.0237.0WATER BASED44602.0237.0WATER BASED45002.0239.0WATER BASED45982.0240.0WATER BASED46122.0239.0WATER BASED46312.0438.0WATER BASED46402.0236.0WATER BASED46792.0635.0WATER BASED47152.0635.0WATER BASED -
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]pdf0.22