Factpages Norwegian Offshore Directorate
Factpages Norwegian Offshore Directorate
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04.11.2024 - 01:25
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ULA FM

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  • General information

    General information
    Attribute Value
    Lithostrat. unit
    The lithostratigraphic unit's official name.
    ULA FM
    NPDID lithostrat. unit
    Norwegian Offshore Directorate's unique id for lithostratigraphic units.
    179
    Level
    Indicates the lithostratigraphic unit's level. Legal values: GROUP, FORMATION, MEMBER.
    FORMATION
    Lithostrat. unit, parent
    The parent lithostratigraphic unit's official name. See also level. Will be empty if Level = GROUP.
  • Level below

    Level below
    Lithostrat. unit
  • Description

    Ula Formation

    Name
    From the Ula Field in Norwegian Block 7/12. The name was first proposed by Bailey et al., (1981) to describe a sequence of Oxfordian – Kimmeridgian marine sands overlying the non-marine Bryne Formation (then termed the Haldager Formation) in the Ula Field , but is extended here to a wider geographic area and stratigraphic range.
    Well type section
    Norwegian well 7/12-2 (BP) in the Ula Field , from 3378.5 to 3531.5 m, coord N 57°06'41.34", E 02°50'50.73" (Fig 3.32) .
    Well reference sections
    Norwegian well 2/1-2 (BP) from 3316 m to 3346.5 m, coord N 56°57' 30.76", E 03°12'23.07" (Fig 3.33) .
    Thickness
    152 m in the type well and 30.5 m in the reference well.
    Lithology
    In the type well the Ula Formation is a generally massive, fine to medium grained, grey sandstone. A thin, dark grey siltstone is present in the basal part of the formation. The sandstones are arkosic to subarkosic, glauconitic and micaceous. Sorting and angularity vary between individual units of the formation. Bivalve shells and belemnite debris occur, often concentrated in thin lag deposits. Thin, nodular calcite-cemented bands are common.
    Within the
    Ula Field the Ula Formation can be subdivided into a number of units on the basis of large scale coarsening upward and fining upward cycles (Bailey et al., op. cit.). The sandstones are extensively bioturbated throughout, and this usually obliterates smaller scale sedimentary features. However, in rare zones, parallel or low angle inclined lamination and planar cross bedding are preserved.
    Boundaries
    The base of the Ula Formation usually occurs where the marine sandstones pass downwards into the nonmarine sandstones/shale/coal sequence of the Bryne Formation . This boundary is often difficult to establish on log characteristics alone. In the region of the Ula Field there is a gamma ray break between the low values of the Ula Formation and the higher values of the more argillaceous Bryne Formation (e.g. in the type well 7/12-2 . Elsewhere, where the Bryne Formation contains cleaner, more massive sands, the base of the Ula Formation is picked at the top of the highest penetrated coal band. The top of the Ula Formation is easily recognized where the sands give way to the shales of the Tyne Group .
    Distribution
    The Ula Formation is developed around the eastern flanking "highs" of the Central Graben, in particular on the south-western flank of the Southern Vestland Arch. It passes basinwards into marine shales but is often recognizable as a very thin sandstone. It becomes thin or absent over the "highs". Tongues of similar sands occur locally in the Tyne Group mudstones (e.g. 3/5-2 from 3175 m to 3182.5 m). Comparable formations in lithofacies and partly in age occur both in the Sleipner Area (the Hugin Formation ) and in the Fiskebank and Egersund Sub-Basins (the Sandnes Formation ).
    Age
    Oxfordian to Ryazanian. In the region of the Ula Field the sands are Oxfordian to Early Volgian in age. Around the fringes of the Jæren and Mandal Highs and locally on the Southern Vestland Arch, developments of the formation may be as young as Middle/Late Volgian or possibly Ryazanian.
    Depositional environment
    The sands of the Ula Formation are generally shallow marine in origin although the type of marine environment probably varies from area to area. In the Ula Field the depositional environment of the sands is particularly difficult to establish due to the unusual thickness of the formation and the scarcity of sedimentary structures; the sands have at this location variously been called shoreface, offshore bar and tidal sand wave deposits (Bailey et al., 1981).
    Source
    • Vollset, J. and Doré, A. G. (eds.) 1984: A revised Triassic and Jurassic lithostratigraphic nomenclature for the Norwegian North Sea. NPD-Bulletin No. 3, 53 pp.
  • Wellbores penetrating

    Wellbores penetrating
    Wellbore name
    Wellbore completion date
    Top depth [m]
    Bottom depth [m]
    24.03.1983
    4178
    4324
    24.03.1983
    4435
    4542
    27.05.1997
    5005
    5086
    31.07.1998
    4266
    4414
    31.07.1998
    4431
    4516
    16.09.2016
    5831
    5911
    26.02.1978
    3316
    3347
    29.03.1980
    3820
    3991
    03.08.1982
    4251
    4261
    05.04.1983
    4193
    4199
    12.08.1984
    4560
    4566
    06.03.1985
    4024
    4061
    23.11.1985
    4037
    4063
    06.07.1991
    4048
    4257
    08.03.1992
    4099
    4379
    14.01.1992
    4189
    4322
    10.02.1999
    3251
    3341
    10.02.1999
    3513
    3548
    28.02.2009
    6022
    6036
    13.07.2013
    3490
    3659
    13.07.2013
    3701
    3891
    03.07.1982
    3357
    3752
    11.05.1983
    3880
    3930
    07.06.1988
    3324
    3902
    19.02.1992
    3538
    3989
    24.07.1984
    3006
    3215
    29.02.1992
    4340
    4389
    14.03.2008
    5176
    5225
    22.02.2015
    4567
    4622
    05.09.2015
    5205
    5310
    30.05.1969
    3217
    3233
    02.02.1981
    4693
    4810
    14.03.1990
    4690
    4807
    09.06.1999
    4469
    4634
    04.09.1979
    4292
    4316
    14.12.1989
    4525
    4543
    12.03.1987
    4597
    4672
    26.02.1994
    2736
    2920
    08.05.2008
    2945
    3122
    21.08.1993
    3065
    3083
    13.03.2008
    3382
    3400
    25.04.1992
    3327
    3347
    04.07.1993
    3491
    3507
    12.12.1983
    3724
    3767
    03.06.2006
    3950
    4021
    29.05.1971
    2487
    2495
    10.06.1982
    4155
    4241
    20.10.1982
    4098
    4145
    25.12.1983
    4527
    4566
    08.10.1984
    4527
    4566
    09.03.1986
    4169
    4183
    10.09.1990
    4341
    4395
    10.06.2007
    4470
    4618
    31.12.2011
    5493
    5587
    16.07.2011
    5197
    5213
    31.10.2021
    4075
    4104
    23.09.1976
    3379
    3532
    06.09.1977
    3638
    3827
    12.12.1977
    3445
    3529
    07.06.1981
    3831
    3901
    24.07.1981
    3406
    3521
    26.07.1988
    3772
    3855
    23.12.1988
    3718
    3814
    14.05.1990
    3701
    3760
    29.08.1991
    3627
    3642
    06.11.1991
    3788
    3800
    17.03.1996
    6018
    6079
    18.05.2012
    4255
    4481
    18.12.2011
    3432
    3602
    27.10.2011
    2948
    3004
    24.05.2014
    2403
    2470
    04.03.2014
    2708
    2760
    16.07.2014
    2051
    2110
    04.01.2019
    2938
    2954
    20.05.2015
    2903
    2985
    13.05.2021
    2709
    2764
    21.08.2013
    2489
    2529
    27.11.2012
    2929
    3016
  • Wellbores with cores

    Wellbores with cores
    Wellbore name
    Wellbore completion date
    Core length [m]
    24.03.1983
    67
    27.05.1997
    15
    31.07.1998
    105
    26.02.1978
    18
    29.03.1980
    51
    06.07.1991
    104
    08.03.1992
    178
    14.01.1992
    95
    03.07.1982
    32
    11.05.1983
    17
    19.02.1992
    45
    29.02.1992
    16
    30.05.1969
    9
    14.12.1989
    18
    12.03.1987
    37
    26.02.1994
    18
    21.08.1993
    7
    13.03.2008
    18
    25.04.1992
    9
    04.07.1993
    16
    12.12.1983
    36
    10.06.1982
    70
    20.10.1982
    45
    25.12.1983
    17
    09.03.1986
    14
    10.09.1990
    38
    10.06.2007
    109
    23.09.1976
    88
    06.09.1977
    86
    12.12.1977
    81
    07.06.1981
    56
    24.07.1981
    114
    26.07.1988
    41
    23.12.1988
    26
    14.05.1990
    21
    29.08.1991
    15
    27.10.2011
    45
    04.03.2014
    52
    16.07.2014
    53