25/10-5
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General information
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Wellbore history
GeneralThe 25/10-5 well was drilled to establish the presence of an accumulation of Eocene oil sand in the western part of the Balder Field, and evaluate the geologic concept of sand-shale distribution and reservoir quality.Operations and resultsWildcat well 25/10-5 was spudded with the semi-submersible installation Glomar Biscay II on 15 June 1981 and drilled to TD at 2011 m in the Late Jurassic Viking Group. The well was drilled with sea water/gel/lignosulphonate.The top of the Early Eocene reservoir was encountered at 1733 m (1708 m sub sea), as prognosed. The reservoir consisted of thin sandstone beds interbedded with shale and was oil bearing. A 49.5 m gross oil column was found down to an OWC at 1782.5 m. The net oil sandstone thickness was 18.2 m. Late Eocene Grid Formation sandstone was penetrated at 1398 m to 1443 m and Paleocene Heimdal Formation sandstone from 1905 m to 1929 m. These were both water wet without shows.Four cores were cut in the Lower Eocene reservoir sequence. No wire line test or fluid sampling was carried out.The well was permanently abandoned on 17 July 1981 as an oil appraisal well.TestingTwo drill stem tests were performed in the Early Eocene reservoir. DST 1 perforated the interval 1756 m to 1753 m and produced 171 Sm3 oil/day. The oil gravity was 25.3 deg API and the gas/oil ratio was 59 m3/m3. DST2 perforated the intervals 1732 - 1740 m and 1756 - 1763 m. It produced 515 Sm3 oil/day. The oil gravity in DST2 was 25.5 deg API and the gas/oil ratio was 59 m3/m3. -
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]240.002011.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11739.01742.9[m ]21776.71777.7[m ]31781.01781.9[m ]41785.21792.8[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]13.3Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Oil samples at the Norwegian Offshore Directorate
Oil samples at the Norwegian Offshore Directorate Test typeBottle numberTop depth
MD [m]Bottom depth
MD [m]Fluid typeTest timeSamples availableDSTDST11740.001732.0011.07.1981 - 00:00YESDSTDST21763.001756.0012.07.1981 - 00:00YES -
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 typeCONDUCTOR30211.036211.00.00LOTINTERM.13 3/8484.517 1/2500.01.75LOTINTERM.9 5/81345.012 1/41370.01.90LOTLINER71991.08 1/22011.00.00LOT -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.01756176312.72.01732174025.4Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.02.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.0170100000.9000.640592.0515300000.9000.64059 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]CDL CNL13402008CDM AP13402008DLL MLL GR17002008IEL BHC ACL GR SP1452007SWC13972007VELOCITY1452007 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit150578943107711011399144317331733180418201831184818591906193919501955199119912001 -
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]pdf5.78pdf4.68pdf1.10pdf47.70pdf27.12pdf6.63pdf11.02pdf11.77pdf1.27 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured5001.07seawater12201.08seawater16561.17seawater20111.25seawater -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory1150.0[m]DC1180.0[m]DC1210.0[m]DC1240.0[m]DC1280.0[m]DC1310.0[m]DC1340.0[m]DC1380.0[m]DC1397.5[m]SWC1430.0[m]DC1443.5[m]SWC1470.0[m]DC1490.0[m]DC1520.0[m]DC1550.0[m]DC1580.0[m]DC1600.0[m]DC1630.0[m]DC1660.0[m]DC1690.0[m]DC1720.0[m]DC1735.4[m]SWC1741.4[m]C1742.5[m]C1746.0[m]SWC1749.5[m]SWC1750.0[m]DC1752.0[m]SWC1765.5[m]SWC1766.6[m]SWC1771.0[m]SWC1779.5[m]SWC1785.0[m]SWC1788.3[m]C1795.6[m]SWC1802.5[m]SWC1807.2[m]SWC1812.2[m]SWC1818.5[m]SWC1820.5[m]SWC1824.0[m]SWC1827.5[m]SWC1839.5[m]SWC1850.0[m]SWC1851.5[m]SWC1858.5[m]SWC1877.0[m]SWC1891.0[m]SWC1903.7[m]SWC1946.0[m]SWC1949.0[m]SWC1955.5[m]SWC1958.0[m]SWC1967.0[m]SWC1976.0[m]SWC