Factpages Norwegian Offshore Directorate
Factpages Norwegian Offshore Directorate
Factpages Norwegian Offshore Directorate
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25/11-21 S

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  • General information
    General information
    Attribute Value
    Wellbore name
    Official name of wellbore based on Norwegian Offshore Directorate guidelines for designation of wells and wellbores.
    25/11-21 S
    Type
    Wellbore type. Legal values: EXPLORATION, DEVELOPMENT, OTHER (see 'Purpose' for more information)
    EXPLORATION
    Purpose
    Final classification of the wellbore.

    Legal values for exploration wellbores:
    WILDCAT, APPRAISAL, WILDCAT-CCS, APPRAISAL-CCS.

    Legal values for development wellbores:
    OBSERVATION, PRODUCTION, INJECTION, INJECTION-CCS, OBSERVATION-CCS.

    Legal values for other wellbores:
    SOIL DRILLING (drilling in connection with track surveys and other subsurface surveys to investigate the soil conditions prior to placement of facilities),
    SHALLOW GAS (drilling to investigate shallow gas before the first 'real' drilling on the location),
    PILOT (drilling to investigate the geology and fluid connectors for location of the main wellbore),
    SCIENTIFIC (drilling according to Law of Scientific research and exploration),
    STRATIGRAPHIC (driling according to Law of Petroleum activities §2-1).
    APPRAISAL
    Status
    Status for the wellbore. Legal values are:

    BLOWOUT: A blowout has occurred in the well.
    CLOSED: A development wellbore that has been closed in a shorter or longer periode. Also applies to development wellbores where drilling is completed, but production/injection has not yet been reported.
    DRILLING: The well is in the drilling phase - can be active drilling, logging, testing or plugging,
    JUNKED: The drilling operation has been terminated due to technical problems.
    P&A: Exploration: The well is plugged and abandoned, and can not be reentered for further use. Development wells: The production/injection from/to the well is stopped and the well is plugged. The wellhead is removed or else made unavailable for further well operations.
    PLUGGED: The wellbore has been plugged, but the upper parts of the wellbore can be re-used. A sidetrack might be drilled at a later stage.
    PRODUCING: It was produced from the wellbore at the time of the operators last monthly report to the Norwegian Offshore Directorate.
    INJECTING: It was injected to the wellbore at the time of the operators last monthly report to the Norwegian Offshore Directorate.
    PREDRILLED: The upper part of the well has been drilled, usually as part of a batch-drilling campaign covering several wellbores.
    RE-CLASS TO DEV: Exploration wellbore that is reclassified to a development wellbore.
    RE-CLASS TO TEST: Exploration wellbore that is reclassified to test production.
    SUSPENDED: The drilling operation in the wellbore has been temporarily stopped. The current plan is to continue drilling later on.
    P&A
    Factmaps in new window
    Main area
    Name of the area on the Norwegian Continental Shelf where the wellbore is located. Legal values: BARENTS SEA, NORWEGIAN SEA, NORTH SEA.
    NORTH SEA
    Field
    Name of the field the wellbore is related to.
    Discovery
    Name of the discovery the wellbore is related to.
    Well name
    Official name of the parent well for the wellbore based on Norwegian Offshore Directorate guidelines for designation of wells and wellbores.
    25/11-21
    Seismic location
    Position of spud location on seismic survey lines. SP: shotpoint.
    NH 9301- ROW 1405 & COLUMN 1750
    Production licence
    Official designation of the production licence the wellbore was drilled or planned to be drilled from ( well head posistion).
    Drilling operator
    Name of the licensee starting the drilling operation on behalf of the active production license (well head position). This will usually equal the operator of the production license.
    Norsk Hydro Produksjon AS
    Drill permit
    The drilling permit number together with the version of the drilling permit as stated in the drilling permit granted by the Norwegian Offshore Directorate.
    832-L
    Drilling facility
    Norwegian Offshore Directorate's name of the facility which the wellbore was drilled from.
    Drilling days
    Number of days from wellbore entry to wellbore completion.
    22
    Entered date
    The date when he wellbore was spudded. For sidetracks: The date when new formation was drilled by kicking off from the mother-wellbore,
    23.10.1995
    Completed date
    Exploration wellbores from moveable facilities:
    For floating facilities - date when anchor handling is started. For jackups - date the jacking-down started. Exploration wellbores from fixed facilities and all development wellbores:
    Date when the wellbore is at total depth, and last casing, liner or screen is set. In case of immediate plugging of the wellbore, completed date equals the date the last plug i set in the wellbore.
    Date when the wellbore is at total depth, and last casing, liner or screen is set. In case of immediate plugging of the wellbore, completed date equals the date the last plug i set in the wellbore.
    14.11.1995
    Release date
    Date when raw data which has been reported to the authorities from the wellbore is not confidential any longer. Normally 2 years after finishing the drilling. May be earlier if the area of the production license is relinquished.
    14.11.1997
    Publication date
    Date quality control of the wellbore information was completed, so it can be published on the internet as a 'Well Data Summary Sheet' wellbore with more information available than other wellbores.
    20.03.2003
    Purpose - planned
    Pre-drill purpose of the wellbore. Legal values for exploration wellbores: WILDCAT, APPRAISAL, WILDCAT-CCS, APPRAISAL-CCS. Example of legal values for development wellbores: OBSERVATION, PRODUCTION, INJECTION.
    APPRAISAL
    Reentry
    Status whether the wellbore has been re-entered (YES) or not (NO). Re-entered wellbores are not included in the count when wellbores are presented in statistical overviews.
    NO
    Content
    For exploration wellbores, status of discovery.

    Legal values:
    DRY, SHOWS (trace amounts of hydrocarbons), GAS, GAS/CONDENSATE, OIL or OIL/GAS.
    SHOWS (GAS SHOWS, OIL SHOWS or OIL/GAS SHOWS) are detected as fluorescent cut (organic extract), petroleum odour, or visual stain on cuttings or cores, or as increased gas reading on the mud-loggers gas detection equipment.
    Legal values for WILDCAT-CCS and APPRAISAL-CCS: WATER

    For development wellbores, type of produced/injected fluid.
    Legal values:
    WATER, CUTTINGS, NOT AVAILABLE, OIL, GAS/CONDENSATE, OIL/GAS, CO2, GAS, WATER/GAS, NOT APPLICABLE.
    OIL
    Discovery wellbore
    Indicator which tells if the wellbore made a new discovery. Legal values: YES, NO. Prior to press-release or other information regarding drilling results, the indicator will be “NO” as a default.
    NO
    1st level with HC, age
    Age of lithostratigraphic unit, 1st level, where hydrocarbons were encountered. Examples of legal values: CRETACEOUS, EARLY CRETACEOUS, LATE JURASSIC, EOCENE. See also Norwegian Offshore Directorate bulletins.
    PALEOCENE
    1st level with HC, formation
    Name of lithostartigraphic unit, 1st level, where hydrocarbons were encountered. Shown only for released wells. Examples of legal values: BASEMENT, COOK FM, EKOFISK FM, HEIMDAL FM, SANDNES FM, SOGNEFJORD FM, TARBERT FM, BRENT GP. See also Norwegian Offshore Directorate bulletins.
    HEIMDAL FM
    Kelly bushing elevation [m]
    Elevation of the rotary kelly bushing (RKB) above mean sea level.
    26.0
    Water depth [m]
    Depth in metres betweem mean sea level and sea floor.
    129.0
    Total depth (MD) [m RKB]
    Total measured length of wellbore from kelly bushing to total depth (driller's depth).
    1957.0
    Final vertical depth (TVD) [m RKB]
    Vertical elevation from total depth to kelly bushing. Shown only for released wells. Referred to as true vertical depth (TVD).
    1889.5
    Maximum inclination [°]
    Maximum deviation, in degrees, from a vertical well path.Shown only for released wells.
    27.9
    Bottom hole temperature [°C]
    Estimated temperature at final total depth of the wellbore. Shown only for released wells. See discription.
    72
    Oldest penetrated age
    Age (according to Geologic Time Scale 2004 by F. M. Gradstein, et al. (2004)) of the oldest penetrated formation. May differ from age at TD for example in deviated wellbores. Examples of legal values: CRETACEOUS, EARLY CRETACEOUS, LATE JURASSIC, EARLY PERMIAN, EARLY TRIASSIC, EOCENE.
    LATE CRETACEOUS
    Oldest penetrated formation
    Name of the oldest lithostratigraphic unit penetrated by the wellbore. Shown only for released wells. In most wellbores this is formation or group at total depth. May differ from formation or group at TD for example in wellbores drilled with high deviation or through faults. Examples of legal values: AMUNDSEN FM, BALDER FM, BASEMENT, BLODØKS FM, BRYNE FM, BURTON FM, COOK FM, DRAKE FM, DRAUPNE FM, EKOFISK FM, DUNLIN GP.
    HOD FM
    Geodetic datum
    Reference system for coordinates. Example of legal values: ED50.
    ED50
    NS degrees
    Geographic coordinate of the wellhead, north-south degrees.
    59° 9' 43.43'' N
    EW degrees
    Geographic coordinate of the wellhead, east-west degrees.
    2° 27' 53.07'' E
    NS UTM [m]
    Universal Transverse Mercator coordinate of the wellhead, north-south.
    6558372.45
    EW UTM [m]
    Universal Transverse Mercator coordinate of the wellhead, east-west.
    469391.49
    UTM zone
    Universal Transverse Mercator zone. Examples of legal values: 31, 32, 33, 34.
    31
    NPDID wellbore
    Norwegian Offshore Directorate's unique id for the wellbore.
    2701

  • Wellbore history
    General
    Well 25/11-21 S was drilled on the Grane Field. The primary objectives of well 25/11-21 S were to calibrate the depth conversion model with reference to top and base of the Grane reservoir and the oil-water contact, and to investigate horizontal and vertical reservoir barriers and reservoir heterogeneities. The secondary objectives of well 25/11-21 S were to obtain reservoir and fluid data and to investigate uncontaminated initial water saturation values in the oil zone. The well location was selected to allow building up hole angle for later drilling of a horizontal section (25/11-21 A) at the required depth and coordinates and at the same time to provide an accurate seismic tie, i.e. an area with minimal compaction effects and away from faults, in an area where there are indications of a thick sand on the seismic data.
    Sidetrack well 25/11 -21 A was drilled to obtain 600 m to 900 m of horizontal reservoir information. The objectives were to appraise the reservoir in terms of reservoir quality and to confirm the structural top and base reservoir maps; to obtain lateral velocity information for calibration of the depth conversion model; to identify possible reservoir heterogeneities indicated on seismic; and finally to perform an extended test production in the horizontal section of the well.
    Operations and results
    Appraisal well 25/11-21 S was spudded with the semi-submersible installation "Treasure Saga" on 23 October 1995 and drilled to TD at 1957 m (1863.5 m TVD MSL) in Late Cretaceous Hod Formation. The well was drilled with seawater and hi-vis bentonite sweeps down to 1270 m and with KCl / Polymer mud from 1270 m to TD.
    Heimdal Formation sand was penetrated at 1788 m (1711.5 m TVD MSL). A reservoir thickness of 88 m (79.5 m TVD) was defined, giving a net pay of 57.9 m. The pressure data from the Heimdal Formation indicates a 0.4 bar pressure difference to well 25/11-18 T2 and 1.7 bar difference to well 25/11-15 based on HP gauge measurements. The oil-water contact (FWL) in the well was found at 1765 m TVD MSL, i.e. more or less the same as in well 25/11-18-T2 and 2.5 meters deeper than in well 25/11-15. No free gas cap was found.& Both the top and base reservoir seismic reflectors and the depth conversion model were proven to be correct in the area, and the reservoir characteristics as found in wells 25/11-15 and 25/11-18 T2 were confirmed. A walk away VSP and walk away AVO VSP were acquired in well 25/11-21 S yielding good qualify high resolution data. The entire reservoir section was cored from 1778 m to 1880.5 m. The wire line logging programme was followed successfully except for an operational failure of the GHMT-tool. MDT Oil samples were taken at 1790 m (1713.09 m TVD MSL), 1796 m (1718.6 m TVD MSL), 1813 m (1734 m TVD MSL), 1828 m (1747.4 m TVD MSL), 1830 m (1749.4 m TVD MSL), 1837.5 m (1756.2 m TVD MSL), and 1845 m (1763 m TVD MSL). MDT water samples were taken at 1850 m (1767.5 m TVD MSL), 1855 m (1772.1 m TVD MSL), 1861.5 m (1777.9 m TVD MSL), and 1874 m (1789.2 m TVD MSL). Well 25/11-21 S was plugged back to the 13 3/8" casing shoe and suspended as an oil appraisal on 14 November 1995.
    The well was re-entered with the semi-submersible installation "Treasure Saga" on 15 May 1996. Well 25/11-21 A was kicked of at 1262 m and drilled down to 1973 m in the Heimdal Formation. The hole was drilled with a too low angle to reach the 10 3/4" casing point within acceptable tolerances. Thus the hole was plugged back from 1973 m, and a technical sidetrack, 25/11-21 A T2, was drilled from 1783 m, continued inclined to horizontal, and drilled to TD at 3006 m (1801.4 m TVD MSL) in the Late Paleocene Lista Formation. The sidetrack was drilled water based with KCl / Polymer mud from kick off to 2448 m and with CaCO3 / NaCl mud from 2448 m to TD.& In well 25/11-21 A T2, the top of the Heimdal Formation sand was penetrated at 1837.5 m (1705.7 m TVD MSL). At a depth of 1749 m TVD MSL a 820 m horizontal section was drilled. Here a 3 m thick calcite cemented layer, corresponding to an intra reservoir reflector, was penetrated at 2514.5 m. A deformed shaly zone, penetrated at 2627.5 - 2652 was probably due to drilling very close to top reservoir in this area. The Base of the Heimdal Formation was reached at 1765.7 m TVD MSL. The reservoir quality of the Heimdal sand is good, showing average porosities of 33%, and a general porosity increase from the SW towards the NE along the well path. The net to gross ratio of the Heimdal Formation is 0.98, due to the penetrated cemented and shaly zones. The oil-water contact (FWL) was found at 1765.6 m TVD MSL, confirming the results from the wells 25/11-21 S and 25/11-18 T2. The average oil saturation within the oil zone is 90%. Only MWD logs were obtained in the sidetrack. No wire line logs were run; consequently no fluid samples were taken on wire line. No conventional or sidewall cores were cut in the sidetrack. Well 25/11-21 A was suspended as an oil appraisal on 1 October 1996
    Testing
    No drill stem test was performed.

  • Cuttings at the Norwegian Offshore Directorate
    Cuttings at the Norwegian Offshore Directorate
    Cuttings available for sampling?
    YES
    Cuttings at the Norwegian Offshore Directorate
    Cutting sample, top depth [m]
    Cutting samples, bottom depth [m]
    1280.00
    1957.00

  • Cores at the Norwegian Offshore Directorate
    Cores at the Norwegian Offshore Directorate
    Core sample number
    Core sample - top depth
    Core sample - bottom depth
    Core sample depth - uom
    1
    1778.0
    1785.2
    [m ]
    2
    1789.0
    1807.7
    [m ]
    3
    1808.0
    1826.8
    [m ]
    4
    1827.0
    1846.0
    [m ]
    5
    1846.0
    1865.7
    [m ]
    6
    1865.0
    1874.9
    [m ]
    7
    1876.0
    1880.5
    [m ]
    Cores at the Norwegian Offshore Directorate
    Total core sample length [m]
    97.8
    Cores at the Norwegian Offshore Directorate
    Cores available for sampling?
    YES

  • Core photos
    Core photos
    Core photo at depth: 1778-1783m
    Core photo at depth: 1783-1785m
    Core photo at depth: 1789-1794m
    Core photo at depth: 1794-1799m
    Core photo at depth: 1799-1804m
    1778-1783m
    1783-1785m
    1789-1794m
    1794-1799m
    1799-1804m
    Core photo at depth: 1804-1807m
    Core photo at depth: 1808-1813m
    Core photo at depth: 1813-1818m
    Core photo at depth: 1818-1823m
    Core photo at depth: 1823-1826m
    1804-1807m
    1808-1813m
    1813-1818m
    1818-1823m
    1823-1826m
    Core photo at depth: 1827-1832m
    Core photo at depth: 1832-1837m
    Core photo at depth: 1837-1842m
    Core photo at depth: 1842-1846m
    Core photo at depth: 1846-1851m
    1827-1832m
    1832-1837m
    1837-1842m
    1842-1846m
    1846-1851m
    Core photo at depth: 1851-1856m
    Core photo at depth: 1856-1861m
    Core photo at depth: 1861-1865m
    Core photo at depth: 1865-1870m
    Core photo at depth: 1870-1874m
    1851-1856m
    1856-1861m
    1861-1865m
    1865-1870m
    1870-1874m
    Core photo at depth: 1876-1880m
    Core photo at depth:  
    Core photo at depth:  
    Core photo at depth:  
    Core photo at depth:  
    1876-1880m

  • Palynological slides at the Norwegian Offshore Directorate
    Palynological slides at the Norwegian Offshore Directorate
    Sample depth
    Depth unit
    Sample type
    Laboratory
    1280.0
    [m]
    DC
    RRI
    1300.0
    [m]
    DC
    RRI
    1310.0
    [m]
    DC
    RRI
    1330.0
    [m]
    DC
    RRI
    1340.0
    [m]
    DC
    RRI
    1360.0
    [m]
    DC
    RRI
    1370.0
    [m]
    DC
    RRI
    1390.0
    [m]
    DC
    RRI
    1400.0
    [m]
    DC
    RRI
    1420.0
    [m]
    DC
    RRI
    1430.0
    [m]
    DC
    RRI
    1450.0
    [m]
    DC
    RRI
    1460.0
    [m]
    DC
    RRI
    1480.0
    [m]
    DC
    RRI
    1490.0
    [m]
    DC
    RRI
    1510.0
    [m]
    DC
    RRI
    1520.0
    [m]
    DC
    RRI
    1560.0
    [m]
    DC
    RRI
    1570.0
    [m]
    DC
    RRI
    1590.0
    [m]
    DC
    RRI
    1600.0
    [m]
    DC
    RRI
    1620.0
    [m]
    DC
    RRI
    1630.0
    [m]
    DC
    RRI
    1650.0
    [m]
    DC
    RRI
    1660.0
    [m]
    DC
    RRI
    1680.0
    [m]
    DC
    RRI
    1690.0
    [m]
    DC
    RRI
    1700.0
    [m]
    DC
    RRI
    1705.0
    [m]
    DC
    RRI
    1710.0
    [m]
    DC
    RRI
    1715.0
    [m]
    DC
    RRI
    1722.0
    [m]
    DC
    RRI
    1725.0
    [m]
    DC
    RRI
    1732.0
    [m]
    DC
    RRI
    1737.0
    [m]
    DC
    RRI
    1740.0
    [m]
    DC
    RRI
    1745.0
    [m]
    DC
    RRI
    1750.0
    [m]
    DC
    RRI
    1757.0
    [m]
    DC
    RRI
    1762.0
    [m]
    DC
    RRI
    1770.0
    [m]
    DC
    RRI
    1775.0
    [m]
    DC
    RRI
    1783.0
    [m]
    C
    RRI
    1877.0
    [m]
    C
    RRI
    1878.0
    [m]
    C
    RRI
    1879.0
    [m]
    C
    RRI
    1880.0
    [m]
    C
    RRI
    1887.0
    [m]
    DC
    RRI
    1890.0
    [m]
    DC
    RRI
    1895.0
    [m]
    DC
    RRI
    1900.0
    [m]
    DC
    RRI
    1905.0
    [m]
    DC
    RRI
    1910.0
    [m]
    DC
    RRI
    1915.0
    [m]
    DC
    RRI
    1920.0
    [m]
    DC
    RRI
    1925.0
    [m]
    DC
    RRI

  • Lithostratigraphy

  • Composite logs
    Composite logs
    Document name
    Document format
    Document size [MB]
    pdf
    0.30

  • 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 name
    Document format
    Document size [MB]
    pdf
    22.72

  • Logs
    Logs
    Log type
    Log top depth [m]
    Log bottom depth [m]
    CMR MSFL GR ACTS
    1257
    1955
    DLL MSFL DSI GR SP AMS
    1257
    1956
    LDL CNL FMS GR AMS
    1256
    1956
    MDT GR ACTS
    1769
    1874
    MDT GR ACTS
    1790
    1790
    MDT GR ACTS
    1830
    1855
    MWD - GR RES DIR
    155
    1957
    VSP
    308
    1940

  • Casing and leak–off tests
    Casing and leak–off tests
    Casing type
    Casing diam.
    [inch]
    Casing depth
    [m]
    Hole diam.
    [inch]
    Hole depth
    [m]
    LOT/FIT mud eqv.
    [g/cm3]
    Formation test type
    SURF.COND.
    30
    218.0
    30
    218.0
    0.00
    LOT
    INTERM.
    13 3/8
    1270.0
    17 1/2
    1270.0
    0.00
    LOT
    OPEN HOLE
    1957.0
    8 1/2
    1957.0
    0.00
    LOT

  • Drilling mud
    Drilling mud
    Depth MD [m]
    Mud weight [g/cm3]
    Visc. [mPa.s]
    Yield point [Pa]
    Mud type
    Date measured
    173
    1.25
    WATER BASED
    216
    1.02
    WATER BASED
    217
    1.25
    WATER BASED
    1051
    1.02
    WATER BASED
    1150
    1.36
    22.0
    WATER BASED
    1270
    1.25
    WATER BASED
    1275
    1.36
    16.0
    WATER BASED
    1748
    1.36
    15.0
    WATER BASED
    1827
    1.36
    15.0
    WATER BASED
    1876
    1.36
    19.0
    WATER BASED
    1911
    1.36
    21.0
    WATER BASED
    1957
    1.36
    21.0
    WATER BASED

  • Pressure plots
    Pressure plots
    The pore pressure data is sourced from well logs if no other source is specified. In some wells where pore pressure logs do not exist, information from Drill stem tests and kicks have been used. The data has been reported to the NPD, and further processed and quality controlled by IHS Markit.
    Pressure plots
    Document name
    Document format
    Document size [MB]
    pdf
    0.19