Factpages Norwegian Offshore Directorate
Factpages Norwegian Offshore Directorate
Factpages Norwegian Offshore Directorate
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01.11.2024 - 01:26
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31/4-2

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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.
    31/4-2
    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).
    WILDCAT
    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
    Multilateral
    Indicator telling if the parent well is multilateral, meaning it has more than one branch radiating from the main borehole. Example of legal values: YES, NO. See also Norwegian Offshore Directorate guidelines for designation of wells and wellbores.
    NO
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    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
    Well name
    Official name of the parent well for the wellbore based on Norwegian Offshore Directorate guidelines for designation of wells and wellbores.
    31/4-2
    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.
    226-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.
    51
    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,
    26.09.1979
    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.
    15.11.1979
    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.
    15.11.1981
    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.
    29.03.2014
    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.
    WILDCAT
    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
    Kelly bushing elevation [m]
    Elevation of the rotary kelly bushing (RKB) above mean sea level.
    25.0
    Water depth [m]
    Depth in metres betweem mean sea level and sea floor.
    142.0
    Total depth (MD) [m RKB]
    Total measured length of wellbore from kelly bushing to total depth (driller's depth).
    2900.0
    Bottom hole temperature [°C]
    Estimated temperature at final total depth of the wellbore. Shown only for released wells. See discription.
    82
    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.
    TRIASSIC
    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.
    HEGRE GP
    Geodetic datum
    Reference system for coordinates. Example of legal values: ED50.
    ED50
    NS degrees
    Geographic coordinate of the wellhead, north-south degrees.
    60° 36' 14.6'' N
    EW degrees
    Geographic coordinate of the wellhead, east-west degrees.
    3° 0' 26.7'' E
    NS UTM [m]
    Universal Transverse Mercator coordinate of the wellhead, north-south.
    6718845.00
    EW UTM [m]
    Universal Transverse Mercator coordinate of the wellhead, east-west.
    500406.14
    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.
    401

  • Wellbore history
    General
    Well 31/4-2 is a replacement for junk well 31/4-1. The well is located on the Brage Horst between the Oseberg and Troll Fields in the Northern North Sea. The primary objective was Middle Jurassic sandstones of the Brent Formation. A "flat-spot" was seen on the seismic sections and tentatively interpreted to represent a gas fluid contact in these sandstones. A secondary objective was sandstones in the Early Jurassic Statfjord Formation. Sandstone intervals of upper Early Jurassic age (Dunlin Formation) and of Triassic age (Hegre Group), were also expected to be penetrated, but were not considered to be prospective. The well was planned to be drilled to a depth of 2930 m RKB (+/- 90 m), ca 100 m into the Triassic.
    Operations and results
    Wildcat well 31/4-2 was spudded with the semi-submersible installation Norskald on 26 September 1979 and drilled to TD at 2900 m in the Triassic Lunde Formation. There were some problems with keeping position and anchor movements in rough weather, but otherwise operations went forth without significant problems. The well was drilled with Seawater and pre-hydrated bentonite down to 990 m, with Seawater/Drispac/pre-hydrated bentonite from 990 m to 1712 m, and with seawater/prehydrated bentonite/ligcon/Unical mud from 1712 m to TD.
    Good oil shows were recorded on sidewall cores from thin sandstone stringers at 2061 to 2069 m in the upper part of the Shetland Group. The well penetrated top Draupne Formation at 2146 m and top Heather Formation at 2171 m. The Heather Formation contained a 49 m thick very fine to silty water-bearing sandstone interval from 2190 to 2239 m. The well penetrated two hydrocarbon bearing sandstone intervals at 2325 to 2329 m and 2344.5 to 2354 m within a 29 m thick Middle Jurassic Brent Group. Both reservoirs consist of very fine to fine, occasional coarse grained sandstones. The upper reservoir has a net pay of 4m and an average calculated porosity and water saturation of 25.6 % and 39.2 %, respectively. Log interpretations suggest an OWC at 2328 m. The lower interval, which is separated from the interval above by a 15.5m thick claystone sequence, is hydrocarbon bearing down to 2349.5 m. At this level a tight limestone interval occurs, below which (2351.5 m) the sandstone is water-wet. The lower sandstone interval has a net pay of 5 m average calculated porosity and water saturation of 27.8 % and 57.5 %, respectively. Below this a 54 m thick "Intra-Dunlin Sand", Statfjord Group sands and Triassic sands were penetrated. These were all found to be water-bearing.
    Three cores were cut: core 1 from 2204.7 to 2222.7 m in the Heather Formation, core 2 from 2490 to 2495.1 m in the "Intra-Dunlin Sand", and core 3 from 2686 to 2693 m in the Statfjord Formation. The RFT was run for pressure recordings in the Cretaceous, Jurassic and Triassic intervals, and for formation fluid sampling in the hydrocarbon bearing Middle Jurassic sandstones. The pressures recorded showed a normal or close to normal pressure development through the whole well. The segregated samples were taken at 2326.5 m (gas-condensate) and at 2346 m (gas and thick oil).
    The well was permanently abandoned on 15 November 1979. It is a technical discovery, but it is classified as well with shows.
    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]
    1000.00
    2900.00

  • 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
    2205.7
    2222.7
    [m ]
    2
    2490.3
    2495.1
    [m ]
    3
    2688.9
    2693.0
    [m ]
    Cores at the Norwegian Offshore Directorate
    Total core sample length [m]
    26.0
    Cores at the Norwegian Offshore Directorate
    Cores available for sampling?
    YES

  • Core photos
    Core photos
    Core photo at depth: 2205-2208m
    Core photo at depth: 2208-2211m
    Core photo at depth: 2211-2213m
    Core photo at depth: 2213-2216m
    Core photo at depth: 2216-2219m
    2205-2208m
    2208-2211m
    2211-2213m
    2213-2216m
    2216-2219m
    Core photo at depth: 2219-2221m
    Core photo at depth: 2221-2222m
    Core photo at depth: 2490-2493m
    Core photo at depth: 2493-2494m
    Core photo at depth: 2688-2691m
    2219-2221m
    2221-2222m
    2490-2493m
    2493-2494m
    2688-2691m
    Core photo at depth: 2691-2693m
    Core photo at depth:  
    Core photo at depth:  
    Core photo at depth:  
    Core photo at depth:  
    2691-2693m

  • 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
    CONDUCTOR
    30
    254.0
    36
    255.0
    0.00
    LOT
    SURF.COND.
    20
    972.0
    26
    990.0
    1.79
    LOT
    INTERM.
    13 3/8
    1697.0
    17 1/2
    1712.0
    1.90
    LOT
    OPEN HOLE
    2900.0
    12 1/4
    2900.0
    0.00
    LOT

  • Logs
    Logs
    Log type
    Log top depth [m]
    Log bottom depth [m]
    CPI
    2155
    2887
    CST
    2035
    2598
    CST
    2050
    2884
    CST
    2230
    2630
    CST
    2300
    2598
    CST
    2633
    2897
    DLL MSFL
    2190
    2550
    FDC CNL
    971
    2895
    HDT
    1698
    2897
    HRT
    180
    1671
    ISF SON
    971
    2896
    RFT
    1850
    2858
    RFT
    2047
    2171
    RFT
    2297
    2523
    VELOCITY
    549
    2890

  • Lithostratigraphy

  • Geochemical information
    Geochemical information
    Document name
    Document format
    Document size [MB]
    pdf
    0.40
    pdf
    0.25
    pdf
    2.52
    pdf
    1.49
    pdf
    4.36
    pdf
    1.05

  • 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
    12.59

  • Drilling mud
    Drilling mud
    Depth MD [m]
    Mud weight [g/cm3]
    Visc. [mPa.s]
    Yield point [Pa]
    Mud type
    Date measured
    995
    1.29
    58.0
    waterbased
    1500
    1.40
    70.0
    waterbased
    1735
    1.56
    50.0
    waterbased
    1970
    1.56
    80.0
    waterbased
    2040
    1.50
    50.0
    waterbased
    2645
    1.30
    44.0
    waterbased

  • Palynological slides at the Norwegian Offshore Directorate
    Palynological slides at the Norwegian Offshore Directorate
    Sample depth
    Depth unit
    Sample type
    Laboratory
    1410.0
    [m]
    DC
    GEOCH
    1440.0
    [m]
    DC
    GEOCH
    1470.0
    [m]
    DC
    GEOCH
    1500.0
    [m]
    DC
    GEOCH
    1530.0
    [m]
    DC
    GEOCH
    1560.0
    [m]
    DC
    GEOCH
    1590.0
    [m]
    DC
    GEOCH
    1620.0
    [m]
    DC
    GEOCH
    1650.0
    [m]
    DC
    GEOCH
    1680.0
    [m]
    DC
    GEOCH
    1710.0
    [m]
    DC
    GEOCH
    1740.0
    [m]
    DC
    GEOCH
    1770.0
    [m]
    DC
    GEOCH
    1800.0
    [m]
    DC
    GEOCH
    1830.0
    [m]
    DC
    GEOCH
    1860.0
    [m]
    DC
    GEOCH
    1890.0
    [m]
    DC
    GEOCH
    1920.0
    [m]
    DC
    GEOCH
    1950.0
    [m]
    DC
    GEOCH
    1980.0
    [m]
    DC
    GEOCH
    2010.0
    [m]
    DC
    GEOCH
    2040.0
    [m]
    DC
    GEOCH
    2050.0
    [m]
    DC
    GEOCH
    2060.0
    [m]
    DC
    GEOCH
    2090.0
    [m]
    DC
    GEOCH
    2120.0
    [m]
    DC
    OD
    2140.0
    [m]
    DC
    OD
    2140.0
    [m]
    SWC
    2148.0
    [m]
    SWC
    2150.0
    [m]
    DC
    OD
    2160.0
    [m]
    DC
    OD
    2170.0
    [m]
    DC
    OD
    2170.0
    [m]
    SWC
    2180.0
    [m]
    DC
    OD
    2190.0
    [m]
    DC
    OD
    2200.0
    [m]
    DC
    2200.0
    [m]
    DC
    2205.7
    [m]
    C
    2216.0
    [m]
    C
    2220.0
    [m]
    DC
    2221.6
    [m]
    C
    2240.0
    [m]
    SWC
    2242.0
    [m]
    DC
    2262.0
    [m]
    DC
    2265.0
    [m]
    SWC
    2280.0
    [m]
    DC
    2300.0
    [m]
    DC
    2315.0
    [m]
    SWC
    2320.0
    [m]
    DC
    2322.0
    [m]
    SWC
    2332.0
    [m]
    SWC
    2340.0
    [m]
    DC
    2357.0
    [m]
    SWC
    2360.0
    [m]
    DC
    2385.0
    [m]
    SWC
    2435.0
    [m]
    SWC
    2477.0
    [m]
    SWC
    2550.0
    [m]
    SWC
    2598.0
    [m]
    SWC
    2630.0
    [m]
    SWC
    2657.0
    [m]
    SWC
    2685.0
    [m]
    SWC
    2688.9
    [m]
    C
    2690.5
    [m]
    C
    2691.5
    [m]
    C
    2745.0
    [m]
    SWC
    2779.0
    [m]
    SWC
    2795.0
    [m]
    SWC
    2825.0
    [m]
    SWC
    2880.0
    [m]
    SWC