Factpages Norwegian Offshore Directorate
Factpages Norwegian Offshore Directorate
Factpages Norwegian Offshore Directorate
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25.11.2024 - 01:30
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31/2-11

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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.
    31/2-11
    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
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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
    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.
    31/2-11
    Seismic location
    Position of spud location on seismic survey lines. SP: shotpoint.
    79 - 406 SP 778
    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.
    A/S Norske Shell
    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.
    365-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.
    70
    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,
    17.03.1983
    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.
    25.05.1983
    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.
    25.05.1985
    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.
    19.12.2007
    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.
    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.
    25.0
    Water depth [m]
    Depth in metres betweem mean sea level and sea floor.
    336.0
    Total depth (MD) [m RKB]
    Total measured length of wellbore from kelly bushing to total depth (driller's depth).
    1744.0
    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).
    1744.0
    Maximum inclination [°]
    Maximum deviation, in degrees, from a vertical well path.Shown only for released wells.
    1.25
    Bottom hole temperature [°C]
    Estimated temperature at final total depth of the wellbore. Shown only for released wells. See discription.
    76
    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.
    FENSFJORD FM
    Geodetic datum
    Reference system for coordinates. Example of legal values: ED50.
    ED50
    NS degrees
    Geographic coordinate of the wellhead, north-south degrees.
    60° 49' 27.76'' N
    EW degrees
    Geographic coordinate of the wellhead, east-west degrees.
    3° 25' 30.16'' E
    NS UTM [m]
    Universal Transverse Mercator coordinate of the wellhead, north-south.
    6743460.35
    EW UTM [m]
    Universal Transverse Mercator coordinate of the wellhead, east-west.
    523116.74
    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.
    6

  • Wellbore history
    General
    Well 31/2-11 was drilled as an appraisal well in the Troll West oil province in the Northern North Sea. The main objectives were to appraise the reservoir quality and the extension of the 28-m oil column in the southern part of the 31/2-7 accumulation in the Viking Group reservoir sequence. The well would assist in the mapping of the permeability distribution in the oil province, provide an additional data point for the correlation and mapping of the depositional units, and obtain additional oil production test data for input to the field development.
    Operations and results
    Well 31/2-11 was spudded with the semi-submersible installation Borgny Dolphin on 17 March 1983 and drilled to TD at 1744 m in the Middle Jurassic Fensfjord Formation. No major problems occurred during drilling. The well was drilled with Seawater and gel down to 810 m, with KCl/polymer mud from 810 m to 1535 m, and with CaCl2/CaCO3/polymer mud from 1535 m to TD.
    Top Jurassic, Sognefjord Formation, was encountered at 1558 m. The reservoir sands were found to be hydrocarbon bearing with GOC at 1566 m (1541 m sub-sea) and OWC (50% saturation) at 1593 m (1567 m sub-sea), in-line with the regional contacts in this area of the Troll West Oil Province. Below OWC residual oil was interpreted down to some 1640 m.
    A total of eight cores were cut. To enable investigation of the shallow sediments, 2 cores were cut in the interval 380 m to 399 m and one from 475 to 476 m. Five cores were cut in the Late Jurassic reservoir sands from 1555 to 1629 m using fibre glass sleeve techniques to achieve better recovery in the poorly consolidated sands. Attempts to obtain RFT fluid samples were unsuccessful due to plugging of the tool with chalk particles from the mud.
    The well was permanently abandoned on 25 May 1983 as an oil and gas appraisal.
    Testing
    Two DST's were performed, one in the water zone and one in the oil zone. DST 1 tested the interval 1681 to 1685 m in the water zone with the objective of obtaining representative formation water samples. The test produced 20 m3 water before the well died. Representative Formation water samples were obtained. DST 2 in the oil zone was carried out in a clean sand interval between 1571 and 1582 m. It produced at maximum rate on 2x128/64" choke 1248 Sm3 oil with a GOR of 315 Sm3/Sm3. The oil produced had a gravity of 28.6 deg API and the separator gas gravity was 0.66 (air = 1). The gas contained about 2% CO2 and no measurable H2S. No water or gas breakthrough was observed, probably due to tight calcareous streaks above and below the tested interval. The maximum temperature recorded in DST 2 was 68.6 deg 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]
    480.00
    1734.00

  • 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
    4
    1555.0
    1562.4
    [m ]
    5
    1564.0
    1568.9
    [m ]
    6
    1578.0
    1587.5
    [m ]
    7
    1592.0
    1610.5
    [m ]
    8
    1610.5
    1628.8
    [m ]
    Cores at the Norwegian Offshore Directorate
    Total core sample length [m]
    58.7
    Cores at the Norwegian Offshore Directorate
    Cores available for sampling?
    YES

  • Core photos
    Core photos
    Core photo at depth: 1555-1561m
    Core photo at depth: 1561-1562m
    Core photo at depth: 1564-1568m
    Core photo at depth: 1578-1584m
    Core photo at depth: 1584-1587m
    1555-1561m
    1561-1562m
    1564-1568m
    1578-1584m
    1584-1587m
    Core photo at depth: 1592-1598m
    Core photo at depth: 1598-1604m
    Core photo at depth: 1604-1610m
    Core photo at depth: 1610-1611m
    Core photo at depth: 1610-1615m
    1592-1598m
    1598-1604m
    1604-1610m
    1610-1611m
    1610-1615m
    Core photo at depth: 1616-1622m
    Core photo at depth: 1622-1627m
    Core photo at depth: 1628-1629m
    Core photo at depth:  
    Core photo at depth:  
    1616-1622m
    1622-1627m
    1628-1629m

  • Oil samples at the Norwegian Offshore Directorate
    Oil samples at the Norwegian Offshore Directorate
    Test type
    Bottle number
    Top depth
    MD [m]
    Bottom depth
    MD [m]
    Fluid type
    Test time
    Samples available
    DST
    1576.00
    1582.00
    08.05.1983 - 00:00
    YES

  • Lithostratigraphy
    Lithostratigraphy
    Top depth [mMD RKB]
    Lithostrat. unit
    361
    788
    1342
    1342
    1408
    1443
    1537
    1550
    1558
    1558
    1611
    1678

  • 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
    9.09
    pdf
    0.36
    pdf
    1.33
    pdf
    0.31
    pdf
    0.14
    pdf
    1.86
    pdf
    28.94
    pdf
    19.25
    pdf
    1.87
    pdf
    1.07
    pdf
    0.29
    pdf
    0.85
    pdf
    18.45
    pdf
    0.29
    pdf
    1.59
    pdf
    12.13
    pdf
    8.89
    pdf
    1.25
    pdf
    2.04
    pdf
    0.99

  • Drill stem tests (DST)
    Drill stem tests (DST)
    Test number
    From depth MD
    [m]
    To depth MD
    [m]
    Choke size
    [mm]
    1.0
    1681
    1685
    50.8
    2.0
    1576
    1582
    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
    2.0
    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
    2.0
    1240
    69000
    0.883
    0.667
    56

  • Logs
    Logs
    Log type
    Log top depth [m]
    Log bottom depth [m]
    CBL VDL
    500
    1523
    CBL VDL
    1150
    1686
    CST
    1537
    1725
    DLL MSFL
    1523
    1728
    HDT
    1523
    1730
    ISF BHC GR
    460
    814
    ISF BHC GR
    799
    1534
    ISF BHC GR
    1523
    1731
    LDL CNL GR CAL
    460
    810
    LDL CNL GR CAL
    799
    1535
    LDL CNL NGT CAL
    1523
    1732
    RFT
    0
    0
    WST
    1110
    1725

  • 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
    460.0
    36
    470.0
    0.00
    LOT
    SURF.COND.
    20
    799.0
    26
    810.0
    1.49
    LOT
    INTERM.
    13 3/8
    1525.0
    17 1/2
    1535.0
    1.50
    LOT
    INTERM.
    9 5/8
    1720.0
    12 1/4
    1744.0
    0.00
    LOT

  • Drilling mud
    Drilling mud
    Depth MD [m]
    Mud weight [g/cm3]
    Visc. [mPa.s]
    Yield point [Pa]
    Mud type
    Date measured
    500
    1.05
    waterbased
    650
    1.09
    waterbased
    950
    1.32
    53.0
    waterbased
    1200
    1.33
    53.0
    waterbased
    1350
    1.35
    53.0
    waterbased
    1600
    1.15
    77.0
    waterbased
    1744
    1.18
    60.0
    waterbased

  • 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
    0.17