Factpages Norwegian Offshore Directorate
Factpages Norwegian Offshore Directorate
Factpages Norwegian Offshore Directorate
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23.11.2024 - 01:30
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25/8-12 A

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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.
    25/8-12 A
    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
    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.
    25/8-12
    Seismic location
    Position of spud location on seismic survey lines. SP: shotpoint.
    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.
    Esso Exploration and Production Norway A/S
    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.
    955-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.
    6
    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,
    09.06.1999
    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.
    19.06.1999
    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.
    19.06.2001
    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.
    18.12.2002
    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.
    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.
    23.0
    Water depth [m]
    Depth in metres betweem mean sea level and sea floor.
    127.0
    Total depth (MD) [m RKB]
    Total measured length of wellbore from kelly bushing to total depth (driller's depth).
    2156.0
    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).
    2083.0
    Maximum inclination [°]
    Maximum deviation, in degrees, from a vertical well path.Shown only for released wells.
    24.9
    Bottom hole temperature [°C]
    Estimated temperature at final total depth of the wellbore. Shown only for released wells. See discription.
    85
    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.
    SMITH BANK FM
    Geodetic datum
    Reference system for coordinates. Example of legal values: ED50.
    ED50
    NS degrees
    Geographic coordinate of the wellhead, north-south degrees.
    59° 17' 22.57'' N
    EW degrees
    Geographic coordinate of the wellhead, east-west degrees.
    2° 26' 39.45'' E
    NS UTM [m]
    Universal Transverse Mercator coordinate of the wellhead, north-south.
    6572584.32
    EW UTM [m]
    Universal Transverse Mercator coordinate of the wellhead, east-west.
    468340.44
    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.
    3772

  • Wellbore history
    General
    Well 25/8-12 A is a sidetrack from well 25/8-12 S, which encountered oil in Lower Jurassic, Upper Statfjord Formation sandstones. It was drilled to appraise the southern extension of the 25/8-11 Ringhorn discovery. In the Ringhorn structure, the BCU is also the base of the chalk and represents the overall top of the Lower Jurassic reservoir interval. The primary objective for well 25/8-12 A was Lower Statfjord Formation sandstones, in an eroded horst, fault block.
    Operations and results
    Appraisal well 25/8-12 A was drilled with the semi-submersible installation "Mærsk Jutlander". It was kicked of from 1014 m in the 8 1/2" section of 25/8-12 S on June 9, 1999 and drilled to TD at 2156 m in the Triassic Smith Bank Formation. The wellbore was drilled with oil based "Environment" mud. Top Statfjord Formation was found at 1945.7 m (1863.1 m TVD SS). Oil was encountered in Lower Statfjord Formation sandstones, as prognosed. Pressures and fluid sampling was undertaken with Schlumberger's Modular Dynamic Tester (MDT). Pressure measurements gave an oil gradient of 0.0719 bars/m (0.318 psi/ft), consistent with the oil gradient in the original 25/8-12 S wellbore (0.0749 bars/m) and in the 25/8-11 well (0.0741 bars/m). The oil and water gradients intersect to give an OWC at 1917.5 m TVD SS (2005 m MD RKB), in agreement with the Free Water Level defined in the 25/8-11. The deepest sands in the wellbore, the water bearing sands below 1970 m TVD SS, appear to record a separate, higher reservoir gradient. Four oil samples were collected in 450 cc MDT chambers at 1975 m, within the main Jurassic sand reservoir. No draw down was seen during the sampling. Temperature (measured, not static) ranged from 78.4 deg C to 79.3 deg C during the sampling. In addition to the 450 cc chambers, a single one-gallon chamber was filled with oil at the same depth. A one-gallon water sample was obtained at 2008.2 m. One core was cut in the interval 1951 - 1988.5 in the Statfjord Formation. Well 25/8-12 A was permanently abandoned on June 19 1999 as an oil appraisal well.
    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]
    1600.00
    2156.00

  • 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
    1951.0
    1988.5
    [m ]
    Cores at the Norwegian Offshore Directorate
    Total core sample length [m]
    37.5
    Cores at the Norwegian Offshore Directorate
    Cores available for sampling?
    YES

  • Core photos
    Core photos
    Core photo at depth: 1951-1956m
    Core photo at depth: 1956-1961m
    Core photo at depth: 1961-1966m
    Core photo at depth: 1966-1971m
    Core photo at depth: 1971-1976m
    1951-1956m
    1956-1961m
    1961-1966m
    1966-1971m
    1971-1976m
    Core photo at depth: 1976-1981m
    Core photo at depth: 1981-1986m
    Core photo at depth: 1986-1989m
    Core photo at depth:  
    Core photo at depth:  
    1976-1981m
    1981-1986m
    1986-1989m

  • Palynological slides at the Norwegian Offshore Directorate
    Palynological slides at the Norwegian Offshore Directorate
    Sample depth
    Depth unit
    Sample type
    Laboratory
    1948.0
    [m]
    DC
    RRI
    1951.0
    [m]
    DC
    RRI
    1958.0
    [m]
    DC
    RRI
    2002.0
    [m]
    DC
    RRI
    2014.0
    [m]
    DC
    RRI
    2020.0
    [m]
    DC
    RRI
    2032.0
    [m]
    DC
    RRI

  • Lithostratigraphy

  • Composite logs
    Composite logs
    Document name
    Document format
    Document size [MB]
    pdf
    0.39

  • 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
    2.04
    .pdf
    76.15

  • Logs
    Logs
    Log type
    Log top depth [m]
    Log bottom depth [m]
    AIT-H DSI IPLT GR
    986
    2160
    MDT GR
    1948
    2064
    MWD - DIR
    153
    213
    MWD - EWR4 DGR
    213
    2156
    VSP
    300
    2150

  • 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
    211.0
    36
    213.0
    0.00
    LOT
    INTERM.
    9 5/8
    990.0
    12 1/4
    990.0
    0.00
    LOT
    OPEN HOLE
    2156.0
    8 1/2
    2156.0
    1.62
    LOT

  • Drilling mud
    Drilling mud
    Depth MD [m]
    Mud weight [g/cm3]
    Visc. [mPa.s]
    Yield point [Pa]
    Mud type
    Date measured
    825
    1.32
    30.0
    OIL (ENVIRON)
    860
    1.33
    30.0
    OIL (ENVIRON)
    1340
    1.32
    30.0
    OIL (ENVIRON)
    2156
    1.32
    27.0
    OIL (ENVIRON)

  • 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
    0.20