Factpages Norwegian Offshore Directorate
Factpages Norwegian Offshore Directorate
Factpages Norwegian Offshore Directorate
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26.11.2024 - 01:27
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31/2-12

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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.
    31/2-12
    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
    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
    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.
    31/2-12
    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.
    373-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.
    93
    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,
    26.05.1983
    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.
    09.09.1983
    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.
    09.09.1985
    Plugged and abondon date
    Date when the P&A-operations of the wellbore was finished, as reported by the operator to the Norwegian Offshore Directorate throught DDRS (Daily Drilling Reporting System). Only applied once pr. wellhead/surface location.
    09.09.1983
    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
    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
    2nd level with HC, age
    Age of lithostratigraphic unit, 2nd level, where hydrocarbons were encountered. Examples of legal values: CRETACEOUS, EARLY CRETACEOUS, LATE JURASSIC, EOCENE.
    MIDDLE JURASSIC
    2nd level with HC, formation
    Name of lithostartigraphic unit, 2nd 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.
    FENSFJORD 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.
    334.0
    Total depth (MD) [m RKB]
    Total measured length of wellbore from kelly bushing to total depth (driller's depth).
    1615.0
    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).
    1615.0
    Maximum inclination [°]
    Maximum deviation, in degrees, from a vertical well path.Shown only for released wells.
    2
    Bottom hole temperature [°C]
    Estimated temperature at final total depth of the wellbore. Shown only for released wells. See discription.
    71
    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° 50' 5.4'' N
    EW degrees
    Geographic coordinate of the wellhead, east-west degrees.
    3° 30' 48.47'' E
    NS UTM [m]
    Universal Transverse Mercator coordinate of the wellhead, north-south.
    6744659.32
    EW UTM [m]
    Universal Transverse Mercator coordinate of the wellhead, east-west.
    527916.41
    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.
    14

  • Wellbore history
    General
    Well 31/2-12 was drilled as an appraisal well in the Troll West oil province in the Northern North Sea. The main objectives were to evaluate various techniques for gas production wells in the Troll field, to establish the reservoir quality in the central part of the Troll field gas accumulation, and to provide additional data point for the correlation and mapping of the depositional units.
    Operations and results
    Well 31/2-12 was spudded with the semi-submersible installation Borgny Dolphin on 26 May 1983 and drilled to TD at 1615 m in the Middle Jurassic Fensfjord Formation. On 4 June, after running the BOP-stack, operations were interrupted by a labour dispute. After the strike ended on 17 June problems with the BOP lead to a further 4 days delay before normal drilling operations were resumed. Some instability problems and well kicks were encountered while drilling and testing in the reservoir. The well was drilled with Seawater and gel down to 807 m, with KCl/polymer mud from 807 m to 1338 m, and with CaCl2/CaCO3/polymer mud from 1338 m to TD.
    Top reservoir in well 31/2-12 was encountered at 1365 m. The formations were interpreted to be gas bearing all through the Sognefjord Formation, the Heather Formation (1487 - 1541 m), and down to a clear GOC at 1570.5 m in the Fensfjord Formation. The upper part of the Sognefjord Formation consisted of generally clean sandstones. Below 1455 m the sands were micaceous and silty. Tight calcareous streaks occurred over the whole section. Oil was interpreted from 1570.5 m down to 1581.0 m, where an abrupt drop in resistivity was interpreted as the oil/water contact. The contact was somewhat obscured however by a change in lithology from clean, but rather tight, sandstone to micaceous sandstone. No movable oil was calculated below this depth, but shows (fluorescence and cut) was observed on sidewall cores down to 1608 m.
    Ten cores were cut in the Late Jurassic Sognefjord reservoir section. From a total of 89.5 m in the intervals 1366 - 1424 m and 1427 - 1458.5 m 86.7 m core (97%) was recovered. All cores were taken using fibreglass sleeve techniques to achieve better recovery in the poorly consolidated sands. Two gas samples were recovered from the uppermost reservoir section during RFT run 1. Recovery of an oil sample during RFT run 2 failed because of plugging by chalk particles in the mud cake. During a separate run with a modified "long nose" RFT probe an oil sample from the thin oil column at 1576 m was obtained.
    The well was permanently abandoned on 9 September 1983 as an oil and gas appraisal well.
    Testing
    Two intervals in the clean sands were tested. From 1428 to 1452 m the well bore was underreamed to 16 inch and completed with an external gravel pack (E6P). This test (PT1) produced 563700 Sm3 gas/day through a 17.5" choke. A second test (PT-2) used an internal gravel pack (IGP) over the interval from 1385 to 1405 m. During this test the well took a kick and had to be closed in. The production-string was cut and the well killed. After fishing out the production string a successful gravel pack test was performed. This test produced 684100 Sm3 gas/day through a 17.5" choke. The gas produced in the tests was dry (gas gravity = 0.61) with a gas/condensate ratio of 35622 Sm3/Sm3. The condensate produced had a gravity of 51  degAPI. The gas contained 1.5% N2, 0.6% C02 and 0.05 ppm H2S. The maximum down-hole temperatures measured in the two tests were 62.8 and 61.7 deg C in PT1 and PT2, respectively.

  • 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
    1615.00

  • 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
    1366.0
    1375.5
    [m ]
    2
    1375.0
    1378.7
    [m ]
    3
    1380.0
    1386.0
    [m ]
    4
    1389.0
    1398.2
    [m ]
    5
    1398.0
    1407.2
    [m ]
    6
    1407.0
    1416.0
    [m ]
    7
    1416.0
    1424.2
    [m ]
    8
    1427.0
    1436.0
    [m ]
    9
    1436.0
    1449.0
    [m ]
    10
    1449.0
    1458.5
    [m ]
    Cores at the Norwegian Offshore Directorate
    Total core sample length [m]
    86.3
    Cores at the Norwegian Offshore Directorate
    Cores available for sampling?
    YES

  • Core photos
    Core photos
    Core photo at depth: 1366-1372m
    Core photo at depth: 1372-1375m
    Core photo at depth: 1375-1378m
    Core photo at depth: 1380-1386m
    Core photo at depth: 1386-1387m
    1366-1372m
    1372-1375m
    1375-1378m
    1380-1386m
    1386-1387m
    Core photo at depth: 1389-1395m
    Core photo at depth: 1395-1397m
    Core photo at depth: 1398-1403m
    Core photo at depth: 1404-1407m
    Core photo at depth: 1407-1413m
    1389-1395m
    1395-1397m
    1398-1403m
    1404-1407m
    1407-1413m
    Core photo at depth: 1413-1416m
    Core photo at depth: 1416-1422m
    Core photo at depth: 1422-1424m
    Core photo at depth: 1427-1433m
    Core photo at depth: 1433-1436m
    1413-1416m
    1416-1422m
    1422-1424m
    1427-1433m
    1433-1436m
    Core photo at depth: 1436-1442m
    Core photo at depth: 1442-1447m
    Core photo at depth: 1448-1449m
    Core photo at depth: 1449-1455m
    Core photo at depth: 1455-1458m
    1436-1442m
    1442-1447m
    1448-1449m
    1449-1455m
    1455-1458m

  • 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
    1428.00
    1452.00
    CONDENSATE
    30.07.1983 - 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
    458.0
    36
    468.0
    0.00
    LOT
    SURF.COND.
    20
    802.0
    26
    810.0
    1.54
    LOT
    INTERM.
    13 3/8
    1338.0
    17 1/2
    1348.0
    1.63
    LOT
    INTERM.
    9 5/8
    1424.0
    12 1/4
    1427.0
    0.00
    LOT
    OPEN HOLE
    1600.0
    8 1/2
    1615.0
    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
    1428
    1452
    17.5
    2.0
    1385
    1405
    17.5
    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
    564000
    2.0
    684000

  • Logs
    Logs
    Log type
    Log top depth [m]
    Log bottom depth [m]
    BGT GR
    1423
    1453
    CBL
    797
    1428
    CNL
    1365
    1419
    CNL GP
    1335
    1405
    CNL NGT
    1337
    1423
    CST
    1337
    1423
    CST
    1424
    1507
    CST
    1509
    1604
    DLL MSFL CAL GR
    1424
    1615
    DLL MSFL GR
    1337
    1423
    DLL MSFL GR
    1424
    1460
    GR
    1240
    1424
    GR CCL SH
    1300
    1340
    GR CCL SH
    1300
    1350
    GR ISF
    1337
    1423
    HDT
    1424
    1614
    ISF BHC GR
    458
    551
    ISF BHC GR
    551
    806
    ISF BHC GR
    801
    1336
    ISF BHC GR
    1424
    1613
    LDT CNL CAL NGT
    1424
    1614
    LDT CNL GR CAL
    458
    552
    LDT CNL GR CAL
    551
    807
    LDT CNL GR CAL
    801
    1338
    LDT GR CAL
    1337
    1423
    LDT GR CAL
    1424
    1460
    RFT HP
    1368
    1408
    RFT HP
    1472
    1600
    SHDT GR
    1424
    1614
    SONIC GR CBL VDL
    1337
    1423
    WST
    608
    1610

  • Lithostratigraphy
    Lithostratigraphy
    Top depth [mMD RKB]
    Lithostrat. unit
    359
    730
    1181
    1181
    1234
    1258
    1354
    1365
    1365
    1487
    1541

  • 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
    11.38
    pdf
    0.11
    pdf
    1.50
    pdf
    0.68
    pdf
    1.18
    pdf
    4.07
    pdf
    5.81
    pdf
    1.13
    pdf
    1.55
    pdf
    0.65
    pdf
    1.18
    pdf
    2.85
    pdf
    13.78
    pdf
    23.30

  • Drilling mud
    Drilling mud
    Depth MD [m]
    Mud weight [g/cm3]
    Visc. [mPa.s]
    Yield point [Pa]
    Mud type
    Date measured
    360
    1.04
    100.0
    water based
    600
    1.04
    84.0
    water based
    850
    1.25
    54.0
    water based
    1000
    1.28
    54.0
    water based
    1100
    1.31
    54.0
    water based
    1500
    1.28
    63.0
    water based