Factpages Norwegian Offshore Directorate
Factpages Norwegian Offshore Directorate
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31.10.2024 - 01:27
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31/2-20 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.
    31/2-20 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).
    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
    Press release
    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.
    31/2-20
    Seismic location
    Position of spud location on seismic survey lines. SP: shotpoint.
    NH0102-Inline 1281 & crossline 898
    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.
    1045-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.
    9
    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,
    27.11.2002
    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.
    08.12.2002
    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.
    08.12.2004
    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.
    11.02.2005
    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
    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.
    LATE 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.
    SOGNEFJORD FM
    Kelly bushing elevation [m]
    Elevation of the rotary kelly bushing (RKB) above mean sea level.
    23.0
    Water depth [m]
    Depth in metres betweem mean sea level and sea floor.
    332.0
    Total depth (MD) [m RKB]
    Total measured length of wellbore from kelly bushing to total depth (driller's depth).
    3400.0
    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).
    1928.0
    Maximum inclination [°]
    Maximum deviation, in degrees, from a vertical well path.Shown only for released wells.
    66.5
    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.
    MIDDLE JURASSIC
    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.
    BRENT GP
    Geodetic datum
    Reference system for coordinates. Example of legal values: ED50.
    ED50
    NS degrees
    Geographic coordinate of the wellhead, north-south degrees.
    60° 47' 59.3'' N
    EW degrees
    Geographic coordinate of the wellhead, east-west degrees.
    3° 26' 57.7'' E
    NS UTM [m]
    Universal Transverse Mercator coordinate of the wellhead, north-south.
    6740732.20
    EW UTM [m]
    Universal Transverse Mercator coordinate of the wellhead, east-west.
    524457.97
    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.
    4636
  • Wellbore history

    General
    Well 31/2-20 S was drilled from the Troll B platform as a joint Pl054 and Pl191 activity. The objective was to investigate the Hydrocarbon-potential in the "P/Q"-prospect shortly west of the Troll West oil province. The main objective was the middle Jurassic Brent Group. A structural closure in the Late Jurassic Fensfjord formation was a secondary target.
    Operations and results
    Exploration well 31/2-20 S was kicked off on 27 November 2002 from the 13 3/8" casing at 2447/1468 m MD/TVD RKB in production well 31/2-E-3H/AY1H/AY2H/AY3H on the Troll B platform. It was drilled to TD at 3400/1928 m MD/TVD RKB in the Brent group without significant problems. It was drilled as an 8 1/2 " hole from kick-off to TD using a KCl/polymer mud. The main results were:
    The P/Q prospect was found to be dry. No hydrocarbon shows were observed in the Brent Group
    The Sognefjord Formation sandstones were encountered with oil and gas according to prognosis (GOC and OWC were met at 2695 m/1545.5 m MD/TVD MSL and 2759.2 m/1572 m MD/TVD MSL respectively). No other contacts were observed.
    Top Brent was penetrated 39 m deeper than expected ? basically due to higher than expected Jurassic interval velocities. A hydrocarbon fluid-inclusion study performed concludes: No fluorescent hydrocarbon fluid inclusions are observed, either in cemented fractures or in quartz overgrowth, which confirm low probability of any petroleum charging during geologic time.
    The well was drilled with return to seabed from seafloor 355m to setting depth of 15 5/8" casing at 1146m. MWD was run through the whole well. In the interval 2457-3400m MD RKB an LWD-suite comprising GR, resistivity, density, neutron, and sonic logs was run. No wire line survey was run. No cores were taken. No biostratigraphic evaluation has been performed. No fluid samples were taken.
    The well was permanently abandoned on 8 December. Oil and gas was encountered in the Sognefjord Formation as expected, but the exploration targets were dry.
    Testing
    No drill stem test was performed
  • Lithostratigraphy

    Lithostratigraphy
    Top depth [mMD RKB]
    Lithostrat. unit
    355
    765
    2200
    2669
    2673
    2673
    2887
    3148
    3252
    3365
  • 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
    1.17
    .PDF
    1.26
  • Logs

    Logs
    Log type
    Log top depth [m]
    Log bottom depth [m]
    LWD - GR DIR RES MPR-ECD
    417
    1137
    LWD - GR DIR RES MPR-ECD
    1096
    1981
    LWD - NBI GR RES DIR DEN NEU SON
    2447
    3203
    LWD - NBI GR RES DIR DEN NEU SON
    3203
    3395
    MWD - DIR
    355
    417
    MWD - DIR ECD
    1981
    2454
  • 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
    417.0
    36
    417.0
    0.00
    LOT
    SURF.COND.
    18 5/8
    1146.0
    26
    1146.0
    1.40
    LOT
    INTERM.
    13 3/8
    2447.0
    17 1/2
    2450.0
    1.43
    LOT
    OPEN HOLE
    3400.0
    8 1/2
    3400.0
    0.00
    LOT
  • Drilling mud

    Drilling mud
    Depth MD [m]
    Mud weight [g/cm3]
    Visc. [mPa.s]
    Yield point [Pa]
    Mud type
    Date measured
    2400
    1.25
    17.0
    WATER BASED
    2430
    1.25
    21.0
    WATER BASED
    2457
    1.25
    15.0
    WATER BASED
    2501
    1.25
    14.0
    WATER BASED
    2788
    1.25
    16.0
    WATER BASED
    3144
    1.25
    15.0
    WATER BASED
    3214
    1.25
    16.0
    WATER BASED
    3400
    1.25
    18.0
    WATER BASED