Factpages Norwegian Offshore Directorate
Factpages Norwegian Offshore Directorate
Factpages Norwegian Offshore Directorate
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31.12.2024 - 01:26
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31/4-8

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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.
    31/4-8
    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.
    31/4-8
    Seismic location
    Position of spud location on seismic survey lines. SP: shotpoint.
    NH 8501 - 077 SP. 172
    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.
    508-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.
    52
    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,
    21.03.1986
    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.
    11.05.1986
    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.
    11.05.1988
    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.
    01.04.2014
    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.
    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/GAS
    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.
    EARLY JURASSIC
    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.
    STATFJORD GP
    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.
    124.0
    Total depth (MD) [m RKB]
    Total measured length of wellbore from kelly bushing to total depth (driller's depth).
    2611.0
    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).
    2611.0
    Maximum inclination [°]
    Maximum deviation, in degrees, from a vertical well path.Shown only for released wells.
    1.9
    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 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.
    LUNDE FM
    Geodetic datum
    Reference system for coordinates. Example of legal values: ED50.
    ED50
    NS degrees
    Geographic coordinate of the wellhead, north-south degrees.
    60° 31' 22.82'' N
    EW degrees
    Geographic coordinate of the wellhead, east-west degrees.
    3° 0' 9.59'' E
    NS UTM [m]
    Universal Transverse Mercator coordinate of the wellhead, north-south.
    6709817.47
    EW UTM [m]
    Universal Transverse Mercator coordinate of the wellhead, east-west.
    500146.24
    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.
    312

  • Wellbore history
    General
    Well 31/4-8 was drilled on the Brage field in the North Sea to appraise the Statfjord Group oil discovery made in well 31/4-7. The Cook Formation of the Dunlin Group was the secondary target. This sandstone was found water bearing in well 31/4-7. Chances for finding hydrocarbons in well 31/4-9 were good since the formation would be penetrated in a structurally higher position. Prognosed TD was 2565 m or 50 m into Triassic rocks.
    Operations and results
    Appraisal well 31/4-8 was spudded with the semi-submersible installation Treasure Hunter on 11 May 1986 and drilled to TD at 2611 m in the Late Triassic Lunde Formation. The 13 3/8" casing got stuck at 1855 m. Diesel and spot fluid was pumped down the hole and the casing was worked free. The well was drilled with spud mud down to 900 m and with KCl/polymer mud from 900 m to TD. From 2030 m to ca 2400 m the KCl/polymer mud contained 1% diesel as a result of the problem with the stuck casing.
    The well 31/4-8 encountered hydrocarbon bearing sandstones and siltstones in the Viking Group, the Statfjord Group and the Lunde Formation. Of these, only the Statfjord reservoir is produceable. The Viking Group consisted of a thin Draupne Formation from 2085 m to 2088 m and a 29 m thick Fensfjord Formation with poorly developed, generally very fine-fine sandstones grading into and interbedded with siltstones and claystones. Some residual hydrocarbons were encountered in the best sands. Net pay in the Fensfjord Formation was 0.61 m, water saturation was 59.9% and the average porosity was 25.5%. The Cook Formation was found water bearing without traces of shows. Average porosity in the Cook sand was 17.7%. The Statfjord Group had a gross oil column of 60 m from 2346 to the OWC at 2406 m. This is practically the same as the OWC found in 31/4-7. The sandstones in the formation consisted of interbedded claystones/siltstones and very fine to very coarse quartz sands with an average porosity of 23.8%. The average porosity above OWC was 23.4%. The average permeability in the Statfjord formation was 1630 mD. The average water saturation of the oil zone in the Statfjord Group sands is 28.9%. The Lunde Formation consisted predominantly of claystones with occasional fine to coarse sandstone beds and limestone stringers. Traces of residual hydrocarbons were found locally in the Lunde sands. A net pay of 1.1 m was calculated, with average porosity of 20.7% and water saturation of 57.3% in the net pay zones. No oil shows were recorded above top Viking Group.
    Six cores were cut in the interval 2347 - 2451 m in the Dunlin and Statfjord groups, with recovery between 74 % and 100 %. A wire line SFT segregated sample at 2350.1 m recovered gas and oil.
    The well was permanently abandoned on 11 May 1986 as an oil and gas appraisal well.
    Testing
    Two DST tests were performed in this well:
    DST 1 tested the interval 2349.1 - 2397.6 m through a 1/2 inch choke. It flowed 502.7 Sm3 oil and 19900 Sm3 gas /day. The GOR was 40 Sm3/Sm3, the oil density was 0.83 g/cm3, and the gas gravity 0.82 (air = 1) with 2 % CO2 and no H2S.The test temperature was 95°C.
    DST 2 tested water from the interval 2421.7 - 2437.4 m through a 2 inch choke. The water flow rate was 1024 Sm3/day.
    The test temperature was 98°C.

  • 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]
    910.00
    2610.00

  • 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
    2347.0
    2355.9
    [m ]
    2
    2359.0
    2375.0
    [m ]
    3
    2377.0
    2395.6
    [m ]
    4
    2395.0
    2413.6
    [m ]
    5
    2413.6
    2432.3
    [m ]
    6
    2432.3
    2451.1
    [m ]
    Cores at the Norwegian Offshore Directorate
    Total core sample length [m]
    99.6
    Cores at the Norwegian Offshore Directorate
    Cores available for sampling?
    YES

  • Core photos
    Core photos
    Core photo at depth: 2347-2352m
    Core photo at depth: 2352-2355m
    Core photo at depth: 2359-2364m
    Core photo at depth: 2364-2369m
    Core photo at depth: 2369-2374m
    2347-2352m
    2352-2355m
    2359-2364m
    2364-2369m
    2369-2374m
    Core photo at depth: 2374-2375m
    Core photo at depth: 2377-2382m
    Core photo at depth: 2382-2387m
    Core photo at depth: 2387-2392m
    Core photo at depth: 2392-2395m
    2374-2375m
    2377-2382m
    2382-2387m
    2387-2392m
    2392-2395m
    Core photo at depth: 2395-2400m
    Core photo at depth: 2400-2405m
    Core photo at depth: 2405-2410m
    Core photo at depth: 2410-2413m
    Core photo at depth: 2413-2418m
    2395-2400m
    2400-2405m
    2405-2410m
    2410-2413m
    2413-2418m
    Core photo at depth: 2418-2423m
    Core photo at depth: 2423-2428m
    Core photo at depth: 2428-2432m
    Core photo at depth: 2432-2437m
    Core photo at depth: 2437-2442m
    2418-2423m
    2423-2428m
    2428-2432m
    2432-2437m
    2437-2442m
    Core photo at depth: 2442-2447m
    Core photo at depth: 2447-2451m
    Core photo at depth:  
    Core photo at depth:  
    Core photo at depth:  
    2442-2447m
    2447-2451m

  • Lithostratigraphy

  • Geochemical information
    Geochemical information
    Document name
    Document format
    Document size [MB]
    pdf
    0.26
    pdf
    0.46

  • 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
    12.00

  • Drill stem tests (DST)
    Drill stem tests (DST)
    Test number
    From depth MD
    [m]
    To depth MD
    [m]
    Choke size
    [mm]
    1.0
    2349
    2398
    12.7
    2.0
    2422
    2437
    50.8
    Drill stem tests (DST)
    Test number
    Final shut-in pressure
    [MPa]
    Final flow pressure
    [MPa]
    Bottom hole pressure
    [MPa]
    Downhole temperature
    [°C]
    1.0
    95
    2.0
    98
    Drill stem tests (DST)
    Test number
    Oil
    [Sm3/day]
    Gas
    [Sm3/day]
    Oil density
    [g/cm3]
    Gas grav. rel.air
    GOR
    [m3/m3]
    1.0
    503
    19900
    0.830
    0.820
    40
    2.0

  • Logs
    Logs
    Log type
    Log top depth [m]
    Log bottom depth [m]
    CBL
    652
    2011
    CBL
    1916
    2546
    CDL CAL GR
    876
    1989
    CDL SGR CAL
    1868
    2571
    CST
    2036
    2562
    DIL LSS GR SP
    876
    2571
    DLL MSFL GR SP CAL
    2011
    2572
    DWLD
    242
    900
    FED GR
    2011
    2570
    SFT
    2075
    2406
    SFT
    2350
    2350
    SFT
    2386
    2386
    SFT
    2406
    2552
    VSP
    833
    2570

  • 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
    237.0
    36
    242.0
    0.00
    LOT
    SURF.COND.
    20
    875.0
    26
    903.0
    0.00
    LOT
    INTERM.
    13 3/8
    2012.0
    17 1/2
    2030.0
    1.60
    LOT
    INTERM.
    9 5/8
    2596.0
    12 1/4
    2611.0
    0.00
    LOT

  • Drilling mud
    Drilling mud
    Depth MD [m]
    Mud weight [g/cm3]
    Visc. [mPa.s]
    Yield point [Pa]
    Mud type
    Date measured
    190
    1.03
    SEAWATER
    11.05.1986
    236
    1.03
    WATER
    23.03.1986
    240
    1.10
    WATER
    23.03.1986
    242
    1.03
    WATER
    24.03.1986
    242
    0.00
    WATER
    25.03.1986
    507
    1.03
    WATER
    31.03.1986
    609
    1.03
    WATER
    31.03.1986
    900
    1.03
    WATER
    31.03.1986
    900
    0.00
    WATER
    01.04.1986
    903
    1.20
    18.0
    10.0
    WATERBASED
    02.04.1986
    1231
    1.26
    21.0
    11.0
    WATERBASED
    03.04.1986
    1506
    1.35
    25.0
    14.0
    WATERBASED
    07.04.1986
    1828
    1.35
    24.0
    13.0
    WATERBASED
    07.04.1986
    2015
    1.35
    24.0
    12.0
    WATERBASED
    07.04.1986
    2030
    1.40
    20.0
    13.0
    WATER BASED
    10.04.1986
    2030
    0.00
    16.0
    9.0
    WATERBASED
    09.04.1986
    2030
    0.00
    16.0
    10.0
    WATERBASED
    10.04.1986
    2044
    1.21
    11.0
    8.0
    WATERBASED
    13.04.1986
    2222
    1.21
    11.0
    7.0
    WATERBASED
    13.04.1986
    2340
    1.21
    14.0
    10.0
    WATERBASED
    11.05.1986
    2347
    1.20
    13.0
    8.0
    WATERBASED
    13.04.1986
    2359
    1.20
    13.0
    8.0
    WATERBASED
    14.04.1986
    2391
    1.20
    13.0
    8.0
    WATERBASED
    15.04.1986
    2414
    1.21
    14.0
    10.0
    WATERBASED
    16.04.1986
    2444
    1.20
    13.0
    9.0
    WATERBASED
    20.04.1986
    2487
    1.20
    13.0
    7.0
    WATERBASED
    20.04.1986
    2553
    0.00
    14.0
    10.0
    WATERBASED
    30.04.1986
    2553
    0.00
    14.0
    10.0
    WATERBASED
    05.05.1986
    2553
    1.20
    14.0
    10.0
    WATERBASED
    25.04.1986
    2553
    0.00
    14.0
    10.0
    WATERBASED
    28.04.1986
    2553
    0.00
    14.0
    10.0
    WATERBASED
    01.05.1986
    2553
    0.00
    14.0
    10.0
    WATERBASED
    04.05.1986
    2553
    0.00
    13.0
    10.0
    WATERBASED
    06.05.1986
    2553
    0.00
    13.0
    9.0
    WATERBASED
    08.05.1986
    2556
    1.20
    13.0
    6.0
    WATERBASED
    25.04.1986
    2570
    1.20
    16.0
    7.0
    WATERBASED
    20.04.1986
    2570
    0.00
    17.0
    7.0
    WATERBASED
    20.04.1986
    2570
    0.00
    12.0
    7.0
    WATERBASED
    21.04.1986
    2570
    0.00
    12.0
    7.0
    WATERBASED
    22.04.1986
    2572
    1.20
    12.0
    7.0
    WATERBASED
    23.04.1986
    2611
    1.20
    13.0
    6.0
    WATERBASED
    24.04.1986

  • 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
    0.21