STØ FM

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• General information

  General information

  Attribute	Value
  Lithostrat. unit The lithostratigraphic unit's official name.	STØ FM
  NPDID lithostrat. unit Norwegian Offshore Directorate's unique id for lithostratigraphic units.	159
  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.	REALGRUNNEN SUBGP

• Level below

  Level below

  Lithostrat. unit

• Description

  Stø Formation
  
  Name

  Stø is a farm on the northern coast of Langøya in Vesterålen. Our use of the term corresponds to the description by Olaussen et al. (1984) and to the informal term T2-5.

  Well type section

  Well 7121/5-1 (Statoil), coordinates 71°35'54.88"N, 21°24'21.78"E, from 2445 m to 2368 m. All but the uppermost 3 m of the formation are cored in this well (Fig 4.48) .

  Well reference section

  Well 7119/12-2 (Statoil), coordinates 71°00'51.81"N, 19°58'20.81"E, from 1517 m to 1372 m. Most of the lower and upper thirds of the formation are covered by cores, although base and top are not represented (Fig 4.49) .

  Thickness

  77 m in the type well and 145 m in the reference well.

  Lithology

  Moderately to well-sorted and mineralogically mature sandstones are dominant. Thin units of shale and siltstone are clear markers; phosphatic lag conglomerates occur in some wells, especially in upper parts of the unit.

  Basal Stratotype

  The base is defined by the sharp transition from regular and serrated gamma ray patterns of the underlying unit to the blocky to smooth cylindrical patterns of this sequence. Density readings decrease upwards over the boundary, but this change is more gradual.

  Lateral extent and variation

  The formation is thickest in southwestern wells, thinning generally eastwards. This pattern corresponds to that of the underlying Nordmela Formation . The entire unit may be divided into 3 depositional sequences, with bases defined by transgressive episodes. The basal sequence is only present in the western parts of the Hammerfest Basin. The middle (late Toarcian/Aalenian) sequence represents maximum transgression in the area. The uppermost Bajocian sequence is highly variable owing to syn-depositional uplift and winnowing and to later differential erosion.

  Age

  A late Pliensbachian to Bajocian age is indicated by present data. The base is apparently diachronous, younging from west to east in the Hammerfest Basin.

  Depositional environment

  The sands in the formation were deposited in prograding coastal regimes, and a variety of linear clastic coast lithofacies are represented. Marked shale/siltstone intervals represent regional transgressive pulses in the late Toarcian and late Aalenian.

  Source

  • Dalland, A., Worsley, D. and Ofstad, K. (eds.) 1988: A lithostratigraphic scheme for the Mesozoic and Cenozoic succession offshore mid- and northern Norway. NPD-Bulletin No. 4, 65 pp.

• Wellbores penetrating

  Wellbores penetrating

  Wellbore name	Wellbore completion date	Top depth [m]	Bottom depth [m]
  7018/5-1	27.11.2020	910	1130
  7019/1-1	03.12.2000	2447	2610
  7119/9-1	25.09.1984	2748	2868
  7119/12-1	10.10.1980	2658	3088
  7119/12-2	26.06.1981	1372	1517
  7119/12-3	12.09.1983	3144	3299
  7119/12-4	17.02.2011	2296	2448
  7120/1-2	28.03.1989	2211	2365
  7120/2-2	23.03.1991	2692	2794
  7120/2-3 S	09.07.2011	2071	2221
  7120/5-1	06.06.1985	2285	2427
  7120/6-1	02.05.1985	2386	2470
  7120/6-2 S	22.07.2007	2564	2678
  7120/6-3 S	30.11.2012	2893	2979
  7120/7-1	08.10.1982	2408	2522
  7120/7-2	21.08.1983	2150	2256
  7120/7-3	09.06.1984	2889	2969
  7120/8-1	10.09.1981	2092	2190
  7120/8-2	29.07.1982	2081	2190
  7120/8-3	24.05.1983	2192	2277
  7120/8-4	10.12.2007	2264	2360
  7120/9-1	26.09.1982	1840	1896
  7120/9-2	20.10.1984	1971	2048
  7120/10-1	08.09.1984	1568	1655
  7120/12-1	12.10.1980	2047	2152
  7120/12-2	11.09.1981	1892	1978
  7120/12-3	05.05.1983	2158	2220
  7120/12-5	03.01.2011	2165	2230
  7121/1-2 S	02.03.2019	3343	3375
  7121/4-1	27.10.1984	2318	2396
  7121/4-2	14.04.1985	2480	2557
  7121/5-1	28.09.1985	2369	2445
  7121/5-2	06.07.1986	2323	2400
  7121/5-3	09.03.2001	1880	1928
  7121/7-1	05.08.1984	1849	1908
  7121/7-2	12.08.1986	1882	1938
  7121/8-1	15.07.2017	1911	1939
  7122/2-1	11.11.1992	2068	2120
  7122/4-1	13.01.1992	2326	2386
  7122/6-1	11.11.1987	2015	2038
  7122/6-2	19.09.2006	2048	2088
  7122/6-3 S	10.10.2021	1891	1905
  7123/4-1 A	14.05.2008	2091	2131
  7123/4-1 S	21.04.2008	2095	2111
  7124/4-1 S	12.10.2011	1259	1312
  7125/1-1	30.12.1988	1399	1521
  7130/4-1	08.01.2016	605	612
  7131/4-1	13.05.2005	878	883
  7132/2-1	09.02.2019	701	709
  7132/2-2	07.04.2019	752	759
  7219/8-1 S	26.12.1992	4521	4611
  7219/8-2	30.09.2013	2898	2985
  7219/9-1	25.02.1988	1951	2062
  7219/9-2	02.07.2017	2556	2568
  7219/12-2 A	30.11.2017	1618	1813
  7219/12-3 S	17.01.2018	2243	2348
  7220/2-1	10.10.2014	828	873
  7220/4-1	25.02.2014	2267	2293
  7220/5-1	24.03.2012	1337	1415
  7220/5-2	08.07.2013	1532	1606
  7220/5-3	26.10.2018	1413	1479
  7220/7-1	24.01.2012	1781	1857
  7220/7-3 S	05.05.2014	1448	1526
  7220/7-4	14.03.2021	1820	1890
  7220/8-1	02.05.2011	1276	1354
  7220/8-3	07.06.2022	936	1013
  7220/10-1	16.10.2012	1513	1645
  7223/5-1	14.01.2009	501	508
  7224/2-1	04.03.2016	682	703
  7224/7-1	19.06.1988	894	919
  7225/3-1	25.09.2011	727	770
  7225/3-2	07.08.2013	729	790
  7226/11-1	11.04.1988	1194	1202
  7227/10-1	10.11.2014	1539	1553
  7227/11-1 A	24.03.2006	1142	1166
  7227/11-1 S	22.02.2006	1142	1166
  7228/2-1 S	20.12.1989	1275	1300
  7228/7-1 A	02.02.2001	1361	1379
  7228/7-1 B	10.02.2001	1361	1379
  7228/7-1 S	08.01.2001	1362	1378
  7228/9-1 S	07.05.1990	1073	1083
  7229/11-1	15.12.1993	1270	1278
  7318/12-2	22.03.2017	3417	3448
  7321/4-1	01.10.2018	1341	1355
  7321/7-1	22.10.1988	1999	2022
  7321/8-1	03.09.1987	1437	1455
  7321/8-2 S	01.07.2020	1621	1657
  7321/9-1	28.11.1988	1379	1417
  7322/6-1 S	28.05.2021	707	719
  7324/2-1	18.06.2014	849	871
  7324/3-1	21.11.2018	877	909
  7324/6-1	31.07.2019	792	811
  7324/7-1 S	03.11.2013	780	796
  7324/7-2	06.07.2014	712	736
  7324/7-3 S	14.04.2016	1373	2354
  7324/7-3 S	14.04.2016	789	867
  7324/8-1	17.09.2013	662	679
  7324/8-2	16.05.2015	668	683
  7324/8-3	17.09.2017	665	688
  7324/9-1	07.08.2014	696	704
  7324/10-1	19.08.1989	569	577
  7325/1-1	21.07.2014	876	905
  7325/4-1	03.08.2017	772	792
  7335/3-1	15.06.2019	577	580
  7435/12-1	01.09.2017	577	583

• Wellbores with cores

  Wellbores with cores

  Wellbore name	Wellbore completion date	Core length [m]
  7019/1-1	03.12.2000	14
  7119/9-1	25.09.1984	33
  7119/12-1	10.10.1980	164
  7119/12-2	26.06.1981	90
  7119/12-3	12.09.1983	26
  7120/2-2	23.03.1991	4
  7120/2-3 S	09.07.2011	95
  7120/5-1	06.06.1985	138
  7120/6-1	02.05.1985	80
  7120/6-2 S	22.07.2007	110
  7120/7-1	08.10.1982	69
  7120/7-2	21.08.1983	78
  7120/7-3	09.06.1984	20
  7120/8-1	10.09.1981	28
  7120/8-2	29.07.1982	105
  7120/8-3	24.05.1983	36
  7120/9-1	26.09.1982	52
  7120/10-1	08.09.1984	14
  7120/12-1	12.10.1980	12
  7120/12-2	11.09.1981	30
  7120/12-3	05.05.1983	18
  7121/4-1	27.10.1984	75
  7121/4-2	14.04.1985	77
  7121/5-1	28.09.1985	76
  7121/5-2	06.07.1986	75
  7121/5-3	09.03.2001	28
  7121/7-1	05.08.1984	55
  7121/7-2	12.08.1986	33
  7121/8-1	15.07.2017	21
  7122/4-1	13.01.1992	65
  7122/6-1	11.11.1987	19
  7122/6-3 S	10.10.2021	7
  7125/1-1	30.12.1988	28
  7132/2-1	09.02.2019	4
  7219/8-1 S	26.12.1992	16
  7219/8-2	30.09.2013	81
  7219/9-1	25.02.1988	111
  7219/12-2 A	30.11.2017	53
  7220/2-1	10.10.2014	39
  7220/4-1	25.02.2014	19
  7220/5-1	24.03.2012	76
  7220/5-3	26.10.2018	55
  7220/7-1	24.01.2012	54
  7220/7-3 S	05.05.2014	69
  7220/7-4	14.03.2021	60
  7220/8-1	02.05.2011	60
  7220/8-3	07.06.2022	76
  7220/10-1	16.10.2012	58
  7224/7-1	19.06.1988	21
  7226/11-1	11.04.1988	0
  7228/2-1 S	20.12.1989	9
  7228/7-1 S	08.01.2001	11
  7321/7-1	22.10.1988	5
  7321/8-1	03.09.1987	12
  7321/9-1	28.11.1988	18
  7324/6-1	31.07.2019	16
  7324/7-2	06.07.2014	24
  7324/8-1	17.09.2013	16
  7324/8-3	17.09.2017	23
  7324/9-1	07.08.2014	8
  7325/4-1	03.08.2017	19