Factpages Norwegian Offshore Directorate
Factpages Norwegian Offshore Directorate
Factpages Norwegian Offshore Directorate
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22.12.2024 - 01:25
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25/6-1

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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.
    25/6-1
    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
    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.
    25/6-1
    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.
    Saga Petroleum ASA
    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.
    493-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.
    48
    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,
    18.12.1985
    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.
    03.02.1986
    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.
    03.02.1988
    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.
    17.12.2003
    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.
    YES
    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.
    MIDDLE 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.
    HUGIN FM
    Kelly bushing elevation [m]
    Elevation of the rotary kelly bushing (RKB) above mean sea level.
    26.0
    Water depth [m]
    Depth in metres betweem mean sea level and sea floor.
    121.0
    Total depth (MD) [m RKB]
    Total measured length of wellbore from kelly bushing to total depth (driller's depth).
    2881.0
    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).
    2881.0
    Maximum inclination [°]
    Maximum deviation, in degrees, from a vertical well path.Shown only for released wells.
    1.3
    Bottom hole temperature [°C]
    Estimated temperature at final total depth of the wellbore. Shown only for released wells. See discription.
    120
    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.
    PRE-DEVONIAN
    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.
    BASEMENT
    Geodetic datum
    Reference system for coordinates. Example of legal values: ED50.
    ED50
    NS degrees
    Geographic coordinate of the wellhead, north-south degrees.
    59° 31' 32.04'' N
    EW degrees
    Geographic coordinate of the wellhead, east-west degrees.
    2° 48' 2.07'' E
    NS UTM [m]
    Universal Transverse Mercator coordinate of the wellhead, north-south.
    6598746.73
    EW UTM [m]
    Universal Transverse Mercator coordinate of the wellhead, east-west.
    488717.11
    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.
    524

  • Wellbore history
    General
    Well 25/6-1 was drilled on the northeastern part of the Utsira High. The main objective of the well was to test for hydrocarbons in a prospect west of the main fault in the southern part of the block. Primary targets were the Middle Jurassic reservoir sandstone belonging to the Vestland Group, which is partly eroded in this area, and the Early Jurassic Statfjord Formation sandstone. Secondary objective was the Early Tertiary sandstone. The total depth target was to drill through a strong seismic reflector between 2.5 and 2.6 second TWT. Shallow gas was expected at 282 to 344 m and 395 m.
    Operations and results
    Wildcat well 25/6-1 was spudded 18 December 1985 by Wilh. Wilhelmsen's Offshore Services semi-submersible installation Treasure Saga, and completed 3 February 1986 at a depth of 2881, 30 m into rocks of probably Early Palaeozoic/Pre-Cambrian age. The well was drilled with seawater and hi-vis pills down to 260 m, with bentonite gel mud from 260 m to 1028 m, with gypsum/polymer mud fro 1028 m to 2195 m, and with bentonite gel / polymer mud from 2195 m to TD. No shallow gas was encountered.
    The Quaternary/Tertiary sequence was 2017 m thick, and consisted of the Nordland, Hordaland, and Rogaland Groups. The Nordland Group was marine claystone with sands frequently developed, especially in the lower part, with 163 m of the sandy Utsira Formation. The Hordaland Group was clay/claystone with some thin sand units. Slightly tuffaceous claystone and a lower sand/marl/ claystone sequence were the main lithologies of the Rogaland Group. A 65.5 m thick Cretaceous sequence represented by Shetland and Cromer Knoll Groups was penetrated. The main lithology was chalky limestone, calcareous claystone grading to marl and minor sand.
    The Jurassic sediments represented by the Viking, Vestland, and Dunlin Groups and the Statfjord Formation were encountered at 2233.5 m.  Top Vestland Group was at 2277 m and top Statfjord Formation was at 2417 m. The Jurassic sequence was 269.5 m thick and consisted of Upper Jurassic shale, Middle Jurassic sandstones and alternating sandstones and silty claystone in the lower part. A 348 metres thick Triassic sequence represented by the Skagerrak and Smith Bank Formations was penetrated. The sequence consisted of shale/siltstone. The TD target seismic reflector was penetrated at the basement's upper surface.
    The upper part of the Vestland Group was found oil bearing with an OWC at 2282.5 m. The Statfjord Formation was found water bearing. Gas readings were mostly between 0% and 0.2% throughout the well. Between 2195 - 2289 m the average gas level increased to 0.4%, and the gas consisted of Cl, C2, C3, iC4 and nC4 from approx. 2236 m. A maximum of 4.27% at 2278 m was recorded, consisting of 12549 ppm C1, 1169 ppm C2, 1651 ppm C3, 267 ppm iC4 and 511 ppm nC4. From 2300 - 2450 m the average gas was 0.1% and consisted of C1-C3. From 2450 - 2881 m, gas values fell from 0.05% to 0.00% and only C1 was recorded. Oil show was observed within loose sandstones from 2278 - 2288.5 m. The show was characterized by a fair-good petroleum odour, with very light brown oil staining of the grains. The fluorescence was weak pale yellow, with a slightly streaming milky (crush) cut, occasionally leaving a white residue upon evaporation. Below 2289 m all oil shows disappeared.
    Three segregated samples were recovered with the FMT wire line tool, two of these (2279.8 m and 2283.2 m) from the oil zone and one from 2285 m below OWC. Two conventional cores were cut, core one from 2299 m to 2300 m, and core two from 2300 m and 2309.7 m.
    The well was permanently abandoned as an oil discovery.
    Testing
    One DST was performed in the interval 2276.7 m to 2279.7 m. The main flow period had duration of 22 hours.  The average production rate was 298 Sm3 /day with a wellhead pressure of 96 bar. The gas-oil ratio was 130 Sm3 /Sm3 at separator conditions of 43º C and 19.5 bar. The dead oil density was 725 kg/m3 and the specific gas gravity was 0.88 (air=l). Three stage flash to standard condition PVT analysis of reservoir fluid collected during the production test, gave an oil formation volume factor of 1.92 Rm3 /Sm3, a gas to oil ratio of 232.2 Sm3 /Sm3 and a stock tank oil density of 729 kg/m3. The bubble point pressure for the fluid was 106.9 bar. Sand production was not observed during the test, but 0.6 - 0.7 Sm3 water was produced.

  • Cuttings at the Norwegian Offshore Directorate
    Cuttings at the Norwegian Offshore Directorate
    Cuttings available for sampling?
    NO
    Cuttings at the Norwegian Offshore Directorate
    Cutting sample, top depth [m]
    Cutting samples, bottom depth [m]
    270.00
    2881.00

  • 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
    2289.0
    2300.0
    [m ]
    2
    2300.0
    2310.1
    [m ]
    Cores at the Norwegian Offshore Directorate
    Total core sample length [m]
    21.1
    Cores at the Norwegian Offshore Directorate
    Cores available for sampling?
    YES

  • 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
    DST1
    2277.00
    2280.00
    OIL
    30.01.1986 - 00:00
    YES

  • 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
    255.0
    36
    260.0
    0.00
    LOT
    SURF.COND.
    20
    1013.0
    26
    1028.0
    1.42
    LOT
    INTERM.
    13 3/8
    2180.0
    17 1/2
    2195.0
    1.74
    LOT
    INTERM.
    9 5/8
    2881.0
    12 1/4
    2881.0
    0.00
    LOT

  • Drill stem tests (DST)
    Drill stem tests (DST)
    Test number
    From depth MD
    [m]
    To depth MD
    [m]
    Choke size
    [mm]
    1.0
    2277
    2280
    7.9
    Drill stem tests (DST)
    Test number
    Final shut-in pressure
    [MPa]
    Final flow pressure
    [MPa]
    Bottom hole pressure
    [MPa]
    Downhole temperature
    [°C]
    1.0
    9.600
    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
    298
    0.725
    130

  • Logs
    Logs
    Log type
    Log top depth [m]
    Log bottom depth [m]
    ACBL VDL GR
    750
    2178
    CDL CNL GR
    2178
    2560
    CDL CNL GR
    2480
    2875
    CDL GR
    256
    1006
    CDL GR
    1013
    2173
    COREGUN-45SWC
    0
    0
    COREGUN-93SWC
    0
    0
    DIFL LSBHC GR
    256
    1026
    DIFL LSBHC GR
    1013
    2193
    DIFL LSBHC GR
    2178
    2560
    DIFL LSBHC GR
    2530
    2875
    DIPLOG
    2178
    2558
    DIPLOG
    2370
    2855
    DLL ML
    2178
    2560
    DLL MLL
    2178
    2559
    FMT
    0
    0
    GR
    121
    256
    MWD
    255
    2881
    SPECTRALOG
    2178
    2560
    VSP
    1700
    2975

  • Lithostratigraphy

  • Composite logs
    Composite logs
    Document name
    Document format
    Document size [MB]
    pdf
    0.44

  • Geochemical information
    Geochemical information
    Document name
    Document format
    Document size [MB]
    pdf
    1.78
    pdf
    1.85
    pdf
    1.27

  • 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
    13.56

  • Drilling mud
    Drilling mud
    Depth MD [m]
    Mud weight [g/cm3]
    Visc. [mPa.s]
    Yield point [Pa]
    Mud type
    Date measured
    185
    1.04
    WATER BASED
    19.12.1985
    190
    1.10
    9.0
    4.4
    WATER BASED
    05.02.1986
    260
    1.04
    WATER BASED
    23.12.1985
    627
    1.16
    7.0
    20.6
    WATER BASED
    23.12.1985
    827
    1.17
    6.0
    18.7
    WATER BASED
    22.12.1985
    1028
    1.17
    5.0
    16.8
    WATER BASED
    23.12.1985
    1028
    1.17
    6.0
    20.6
    WATER BASED
    23.12.1985
    1028
    1.03
    WATER BASED
    26.12.1985
    1028
    1.10
    15.0
    9.6
    WATER BASED
    26.12.1985
    1028
    1.19
    6.0
    18.2
    WATER BASED
    26.12.1985
    1200
    1.10
    14.0
    7.7
    WATER BASED
    26.12.1985
    1434
    1.15
    13.0
    8.2
    WATER BASED
    29.12.1985
    1653
    1.25
    15.0
    8.7
    WATER BASED
    30.12.1985
    1820
    1.25
    13.0
    9.6
    WATER BASED
    03.01.1986
    1820
    1.30
    13.0
    9.6
    WATER BASED
    06.01.1986
    2090
    1.25
    12.0
    9.6
    WATER BASED
    03.01.1986
    2195
    1.30
    14.0
    9.6
    WATER BASED
    06.01.1986
    2195
    1.31
    12.0
    7.2
    WATER BASED
    06.01.1986
    2195
    1.33
    13.0
    7.2
    WATER BASED
    08.01.1986
    2195
    1.33
    12.0
    7.2
    WATER BASED
    13.01.1986
    2225
    1.33
    14.0
    10.1
    WATER BASED
    13.01.1986
    2270
    1.10
    9.0
    4.4
    WATER BASED
    05.02.1986
    2289
    1.25
    14.0
    7.2
    WATER BASED
    13.01.1986
    2289
    1.25
    17.0
    7.7
    WATER BASED
    13.01.1986
    2289
    1.25
    16.0
    7.2
    WATER BASED
    13.01.1986
    2313
    1.25
    17.0
    7.7
    WATER BASED
    14.01.1986
    2325
    1.10
    9.0
    4.4
    WATER BASED
    05.02.1986
    2325
    1.10
    10.0
    4.8
    WATER BASED
    05.02.1986
    2325
    1.10
    11.0
    4.8
    WATER BASED
    05.02.1986
    2360
    1.10
    11.0
    20.6
    WATER BASED
    05.02.1986
    2360
    1.10
    12.0
    6.3
    WATER BASED
    05.02.1986
    2438
    1.25
    17.0
    7.7
    WATER BASED
    13.01.1986
    2493
    1.25
    17.0
    7.2
    WATER BASED
    13.01.1986
    2561
    1.10
    13.0
    5.8
    WATER BASED
    19.01.1986
    2561
    1.25
    18.0
    7.2
    WATER BASED
    19.01.1986
    2561
    1.10
    16.0
    6.8
    WATER BASED
    19.01.1986
    2590
    1.11
    12.0
    6.8
    WATER BASED
    19.01.1986
    2745
    1.11
    12.0
    6.8
    WATER BASED
    19.01.1986
    2852
    1.10
    12.0
    6.8
    WATER BASED
    05.02.1986
    2881
    1.10
    12.0
    6.8
    WATER BASED
    05.02.1986
    2881
    1.10
    11.0
    5.8
    WATER BASED
    05.02.1986