HEGRE GP

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• General information

  General information

  Attribute	Value
  Lithostrat. unit The lithostratigraphic unit's official name.	HEGRE GP
  NPDID lithostrat. unit Norwegian Offshore Directorate's unique id for lithostratigraphic units.	61
  Level Indicates the lithostratigraphic unit's level. Legal values: GROUP, FORMATION, MEMBER.	GROUP

• Level below

  Level below

  Lithostrat. unit
  ALKE FM
  LOMVI FM
  LUNDE FM
  SKAGERRAK FM
  SMITH BANK FM
  TEIST FM

• Description

  Hegre Group
  
  Name

  From the bird (English: heron) of the same name. The pre-Rhaetian Triassic rocks of the Northern North Sea were earlier designated the Cormorant Formation by Deegan and Scull (1977), having UK well 211/21-1A (Shell) as a type well section. In this report this Triassic Unit is given group status, while the Cormorant Formation is only applied to certain areas where a subdivision of the Triassic is impossible. We suggest that the Cormorant Formation should refer to attenuated sequences confined to structural highs in the UK sector.

  Type area

  The type area is the East Shetland Basin, west of the Viking Graben. The group is illustrated by UK well 211/29-5 (Shell), and Norwegian wells 33/5-1 (Norsk Hydro), 33/12-2 and 33/12-5 (Mobil).

  Thickness

  No well has penetrated a complete Triassic succession. The maximum drilled sequence is 1839 m in well 33/12-5 .

  Lithology

  The Hegre Group consists of intervals of interbedded sandstones, claystones and shales associated with sequences of dominantly sand or shale/claystone. Shales and claystones usually have reddish colours whereas the sandstones show a range in colour from white, light grey, orange to brick red. The grain size varies from very fine to very coarse and the sediments are in parts of a pebbly nature. The Hegre Group also has subordinate white limestone, anhydrite and brownishred marl.

  Boundaries

  The Hegre Group is directly overlain by Cretaceous strata on some of the structural highs. Where Jurassic is present, the top of the Hegre Group is normally placed at the change from interbedded sandstones and shales of the Hegre Group to the relatively massive clean sandstones of the Statfjord Formation . This is normally represented by a change from an irregular sonic log response in the Hegre Group to a more regular or blocky one in the Statfjord Formation . In addition the upper boundary of the Hegre Group is often close to the top of abundant red beds in the section - see also the description of the Statfjord Formation . The base of the Triassic rocks is only penetrated on structural highs and close to the margins of the sedimentary basin. In these sections only late Triassic seems to be present, and hence the nature of the lower boundary of the Hegre Group is not yet established. It is realized that the Hegre Group cannot be given full formal definition until its base has been adequately defined, but we nevertheless offer the term for interim use.

  Distribution

  The Hegre Group is apparently present in the whole Northern North Sea area. Its relationship to the Triassic units defined further south by Deegan and Scull (1977) is unclear. We therefore recommend that the term Hegre Group should only be used in the area north of 60°N. It is terminated to the west by major faults along the east flank of the East Shetland Platform and to the east by the Øygarden Fault Zone (Hamar et al., 1980). In the northeastern part of the North Sea area, where Precambrian/ Caledonian basement dips gently to the west, progressively younger Triassic sediments onlap basement in an easterly direction. In the east, on the Måløy Fault Blocks, Triassic strata are probably missing, but may have been preserved from erosion in N-S elongated basins to the east of the structural highs. Alternatively Triassic sediments might not have been deposited in this area. The thickness of the Hegre Group within the East Shetland Basin shows a general increase from the western flank toward the central part of the depositional basin. On the eastern flank thick Triassic deposits are found just west of the Øygarden Fault Zone, which may indicate that the Triassic sediments were deposited in an asymmetric basin.

  Age

  The Triassic sections penetrated in the Northern North Sea show ages from Late Triassic (early Rhaetian) to possibly Early Triassic (?Scythian).

  Subdivision

  The Hegre Group is divided into three formations: the (basal) Teist Formation, the Lomvi Formation and the Lunde Formation (top). The subdivision suggested here for the Triassic of the Northern North Sea is based on information from areas to the west of the Viking Graben. However, available data from the Horda Platform indicate that a subdivision is also possible in that area.

  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]
  2/1-15	05.09.2013	3523	3554
  2/4-23 S	05.09.2015	5310	5548
  2/6-6 S	18.01.2019	3521	3599
  3/4-1	26.02.1994	3013	3077
  3/7-9 S	28.04.2013	3680	3717
  3/7-10 S	14.09.2015	3467	3511
  3/7-11 S	27.05.2019	3611	3741
  7/4-3	03.06.2013	2733	3000
  7/7-2	25.04.1992	3347	3388
  7/8-4	20.02.1985	3826	4400
  7/11-9	09.03.1986	4183	4271
  7/11-10 S	10.09.1990	4395	4566
  7/11-12 A	31.12.2011	5587	5672
  7/11-12 S	16.07.2011	5213	5420
  7/11-13	03.11.2012	3697	3800
  7/12-8	23.12.1988	3814	3900
  8/5-1	28.03.2013	2371	2405
  8/10-5 A	24.05.2014	2470	2618
  8/10-5 S	04.03.2014	2760	2810
  8/10-7 S	04.01.2019	2954	3146
  9/1-1 S	21.11.2011	2484	2533
  15/5-1	08.04.1978	3729	3775
  15/5-2	16.12.1978	4113	4322
  15/6-4	16.08.1976	3268	3505
  15/6-5	29.11.1977	3723	3824
  15/6-12	09.02.2011	3876	3930
  15/6-13	15.05.2015	3499	3577
  15/6-13 A	03.06.2015	3860	3925
  15/6-13 B	29.06.2015	3670	3773
  15/6-15	02.06.2019	3645	3795
  15/6-16 S	28.06.2019	4130	4203
  15/9-2	17.06.1978	3699	3764
  15/9-8	25.05.1981	3625	3730
  15/9-9	14.07.1981	2642	2969
  15/9-15	01.08.1982	2821	3200
  15/12-5	04.05.1986	3077	3150
  15/12-9 S	08.10.1992	3688	3848
  15/12-12	09.02.2001	2977	3085
  15/12-24 S	20.05.2015	3097	3181
  15/12-26	13.05.2021	2771	2784
  16/1-13	21.01.2010	1960	2303
  16/1-16	07.12.2012	2429	2642
  16/1-16 A	01.01.2013	2729	2897
  16/1-17	20.03.2013	1870	1988
  16/1-18	14.05.2014	1894	1985
  16/1-20 A	21.10.2013	3060	3106
  16/1-21 A	20.04.2015	3194	3313
  16/1-21 S	03.03.2015	2491	2630
  16/1-22 A	04.06.2015	2769	2896
  16/1-22 B	14.06.2015	3066	3215
  16/1-22 S	27.05.2015	2506	2640
  16/1-23 S	25.08.2015	1953	2094
  16/1-26 S	14.04.2016	4896	5330
  16/1-31 S	10.05.2019	1938	2220
  16/1-33 S	05.08.2020	3068	3158
  16/1-35 S	28.02.2023	3177	3257
  16/2-7	01.09.2011	1986	2134
  16/2-7 A	29.09.2011	2041	2100
  16/2-8	19.08.2011	1951	2140
  16/2-9 S	24.09.2011	1949	1986
  16/2-10	28.10.2011	1968	2090
  16/2-11	29.03.2012	1946	2126
  16/2-11 A	04.05.2012	2239	2365
  16/2-13 A	29.09.2012	2626	2658
  16/2-13 S	30.08.2012	1949	1955
  16/2-14	17.11.2012	1887	1982
  16/2-15	13.01.2013	1969	2006
  16/2-16	12.12.2012	1999	2065
  16/2-16 A	07.02.2013	2385	2503
  16/2-17 S	20.05.2013	2020	2052
  16/2-19	03.04.2014	1952	1989
  16/2-19 A	03.05.2014	2283	2310
  16/2-20 A	16.02.2014	2125	2183
  16/2-20 S	21.11.2013	2038	2114
  16/2-21	07.06.2013	1965	2070
  16/2-U-18	28.11.2016	2057	2143
  16/3-5	07.03.2013	1931	1932
  16/3-8 A	01.04.2014	1979	1986
  16/3-8 S	16.03.2014	1978	1993
  16/4-6 S	03.05.2013	1955	2233
  16/4-7	21.08.2013	2529	2600
  16/4-8 S	26.08.2014	1934	2700
  16/4-9 S	16.08.2015	1984	2358
  16/4-11	01.04.2018	1950	2069
  16/4-12	08.10.2021	2129	2144
  16/5-2 S	28.01.2012	1967	2042
  16/5-3	20.03.2013	1912	1990
  16/5-4	28.09.2013	1936	2100
  16/5-5	29.12.2013	1936	2085
  16/5-6	10.07.2016	2241	2350
  16/7-4	06.12.1982	2521	2781
  16/7-11	04.09.2015	2546	2650
  16/8-3 S	01.05.2013	2656	2734
  17/8-1	23.10.2021	2466	2658
  25/5-7	23.10.2010	2995	3045
  25/6-6 S	22.04.2019	3170	3546
  25/7-8 S	09.01.2020	3120	3250
  25/8-19 A	19.03.2020	2483	2806
  25/8-19 S	30.12.2019	2434	2716
  25/8-20 B	28.05.2021	2438	2698
  25/8-20 S	10.05.2021	2504	2733
  25/8-21 S	20.06.2021	2391	2633
  25/8-22 S	20.07.2021	2325	2589
  25/10-12 S	18.01.2015	2439	2597
  25/10-13 S	19.06.2015	2555	2925
  25/10-14 S	17.01.2016	2410	2474
  25/10-15 S	02.08.2016	2564	2628
  25/10-16 A	09.08.2018	3653	3704
  25/10-16 B	18.08.2018	4832	4893
  25/10-16 C	26.08.2018	4305	4405
  25/10-16 S	30.07.2018	2655	2765
  25/10-17 S	10.02.2023	3978	4150
  25/11-28	25.09.2015	2147	2229
  25/11-29 S	13.05.2019	2147	2230
  29/6-1	09.05.1982	4786	4832
  30/3-7 S	12.12.1995	5322	5581
  30/4-2	16.05.1980	4670	4775
  30/5-3 S	12.04.2009	3396	4335
  30/6-1	22.09.1979	3003	3175
  30/6-2	11.12.1979	2808	2890
  30/6-9	16.12.1982	3389	3476
  30/6-9 R	12.05.1990	3387	3476
  30/6-15	05.09.1984	3548	3972
  30/6-16	21.01.1985	3224	3300
  30/6-18	23.11.1985	3670	3690
  30/6-24 S	06.12.1991	3940	3986
  30/6-28 S	29.03.2012	2754	4064
  30/7-8 R	29.01.1982	4687	4813
  30/9-3 A	20.05.1984	4249	4300
  30/9-5 S	19.07.1985	2872	2980
  30/9-24	17.10.2009	3718	3767
  30/10-5	01.05.1975	5127	5186
  31/2-1	09.11.1979	2381	2433
  31/2-1 R	09.11.1981	2382	2434
  31/2-2 R	06.10.1980	2500	2600
  31/2-3	20.07.1980	2358	2601
  31/2-4 R	06.04.1981	2422	5035
  31/2-4 R2	12.11.1982	2422	5035
  31/2-5	21.12.1980	2471	2532
  31/2-5 R	20.07.1981	2464	2525
  31/2-5 R2	22.04.1984	2464	2525
  31/2-8	18.08.1982	3274	3375
  31/3-1	13.10.1983	2160	2374
  31/4-2	15.11.1979	2786	2900
  31/4-3	11.05.1980	2879	4981
  31/4-5	29.07.1981	2849	2930
  31/4-8	11.05.1986	2438	2611
  31/5-2	11.11.1983	2393	2500
  31/5-2 R	30.08.1984	2393	2500
  31/6-1	28.10.1983	2156	3978
  31/6-2 R	08.09.1984	2198	2235
  31/6-3	26.12.1983	2195	2250
  31/6-6	29.07.1984	2277	2293
  31/11-1 S	28.06.2021	3120	3284
  32/2-1	01.07.2008	1247	1300
  32/4-1	04.12.1996	1832	3132
  32/4-3 S	26.10.2019	1847	2017
  33/2-2 S	10.06.2015	2946	3530
  33/5-1	18.10.1979	2692	3829
  33/5-2	18.11.1981	4455	4520
  33/6-1	06.07.1979	3862	3900
  33/6-3 S	24.07.2012	4377	4444
  33/9-3	14.11.1974	2973	2992
  33/9-4	17.09.1975	2974	3076
  33/9-12	03.08.1987	2936	2959
  33/12-2	23.08.1974	2951	4354
  33/12-5	21.02.1976	2735	4574
  33/12-6	21.06.1976	4030	4612
  34/2-3	13.08.1981	3344	3742
  34/2-5 S	31.03.2018	3568	3680
  34/4-1	16.12.1979	2508	2916
  34/4-2	24.05.1980	2697	3599
  34/4-3	30.03.1982	4410	4460
  34/4-4	03.02.1983	2425	3800
  34/4-5	06.04.1984	3599	3917
  34/4-6	27.03.1986	2577	3282
  34/4-7	12.05.1987	2502	2950
  34/4-8	21.06.1994	2913	3110
  34/4-9 S	15.02.1997	2513	3440
  34/4-11	10.01.2010	4224	4327
  34/4-12 A	18.02.2010	2563	2761
  34/4-12 S	25.01.2010	2738	3066
  34/4-13 S	02.01.2011	4905	5010
  34/4-14 S	19.05.2015	4754	4822
  34/6-1 S	28.08.2002	4313	4360
  34/6-2 S	05.11.2012	4252	4335
  34/7-1	24.07.1984	2392	2905
  34/7-2	10.10.1984	2271	2475
  34/7-3	02.01.1985	2513	3414
  34/7-4	16.01.1985	2628	3115
  34/7-5	16.03.1985	3010	3146
  34/7-6	30.05.1985	2654	3685
  34/7-7	16.12.1985	2678	3526
  34/7-8	11.04.1986	2373	2766
  34/7-9	12.06.1986	2443	3240
  34/7-10	29.10.1986	2683	3000
  34/7-12	17.12.1987	2763	2784
  34/7-13	13.04.1988	2962	2994
  34/7-16 R	15.10.1990	2945	2980
  34/7-16 R2	05.07.1994	2944	2979
  34/7-17	07.04.1991	3085	3115
  34/7-20	27.08.1992	3128	3177
  34/7-34	10.03.2009	2584	2701
  34/7-34 A	20.03.2009	2972	3022
  34/8-1	08.03.1986	3417	3610
  34/8-2	17.11.1986	3051	3240
  34/8-4 A	27.05.1992	3143	3567
  34/8-4 AR	07.03.2003	3151	3574
  34/8-4 S	09.06.1991	2950	4150
  34/8-5	01.04.1991	3484	3540
  34/8-7	16.07.1992	5208	5460
  34/8-7 R	10.02.1993	5208	5460
  34/8-8	24.08.1992	3474	3625
  34/8-8 R	09.03.1993	3474	3624
  34/8-9 S	28.12.1992	3245	3530
  34/8-10 S	09.12.1993	3125	3470
  34/8-12 S	09.12.2001	3253	3347
  34/8-13 S	26.06.2009	4282	4442
  34/8-16 S	15.11.2015	3116	3875
  34/8-17 S	14.03.2014	4485	4587
  34/8-18 S	22.02.2019	6001	6068
  34/10-1	08.09.1978	2367	2460
  34/10-2	08.12.1978	3540	3729
  34/10-3	07.06.1979	2715	2802
  34/10-3 R	10.10.1987	2712	2799
  34/10-4	15.10.1979	2481	2600
  34/10-5	02.01.1980	2764	2780
  34/10-7	23.03.1980	2180	2250
  34/10-7 R	14.07.1983	2177	2247
  34/10-11	05.03.1981	2089	2155
  34/10-13	05.01.1982	2052	3392
  34/10-14	19.03.1982	2596	2647
  34/10-16	11.04.1983	4010	4042
  34/10-16 R	27.09.1983	4007	4039
  34/10-19	06.12.1983	2188	2218
  34/10-30	12.05.1986	3375	3785
  34/10-32	13.07.1987	3538	3753
  34/10-32 R	10.08.1987	3538	3742
  34/10-38 S	29.05.1995	3844	3940
  34/10-43 S	11.04.2001	4370	4950
  34/10-44 S	08.07.2001	4200	4865
  34/10-48 A	15.02.2005	3657	4645
  34/10-48 S	22.12.2004	3657	4645
  34/10-55 S	26.03.2017	7390	7811
  35/1-1	18.07.2002	4476	4540
  35/4-1	24.05.1997	4918	4936
  35/9-6 S	07.12.2010	3710	3740
  35/11-1	06.08.1984	3265	3361
  6201/11-1	06.11.1987	2678	3850
  6201/11-2	11.03.1991	3697	3726
  6201/11-3 R	20.10.2012	2703	2940
  6407/8-2	25.11.1994	1847	1950

• Wellbores with cores

  Wellbores with cores

  Wellbore name	Wellbore completion date	Core length [m]
  7/7-2	25.04.1992	21
  7/8-4	20.02.1985	33
  7/11-9	09.03.1986	26
  7/11-10 S	10.09.1990	8
  8/10-5 S	04.03.2014	10
  15/6-4	16.08.1976	37
  15/9-9	14.07.1981	107
  15/9-15	01.08.1982	57
  15/12-12	09.02.2001	19
  16/1-13	21.01.2010	41
  16/1-16	07.12.2012	13
  16/1-17	20.03.2013	118
  16/1-18	14.05.2014	83
  16/1-21 A	20.04.2015	30
  16/1-21 S	03.03.2015	96
  16/1-22 S	27.05.2015	44
  16/1-23 S	25.08.2015	117
  16/1-31 S	10.05.2019	93
  16/2-7 A	29.09.2011	12
  16/2-8	19.08.2011	56
  16/2-9 S	24.09.2011	33
  16/2-11	29.03.2012	7
  16/2-11 A	04.05.2012	4
  16/2-13 A	29.09.2012	32
  16/2-13 S	30.08.2012	6
  16/2-14	17.11.2012	18
  16/2-15	13.01.2013	22
  16/2-16 A	07.02.2013	35
  16/2-17 S	20.05.2013	21
  16/2-19	03.04.2014	37
  16/2-19 A	03.05.2014	22
  16/2-20 A	16.02.2014	14
  16/2-20 S	21.11.2013	16
  16/2-21	07.06.2013	11
  16/3-5	07.03.2013	1
  16/3-8 S	16.03.2014	15
  16/4-6 S	03.05.2013	69
  16/4-8 S	26.08.2014	74
  16/4-9 S	16.08.2015	80
  16/4-11	01.04.2018	52
  16/5-2 S	28.01.2012	7
  16/5-3	20.03.2013	11
  16/5-4	28.09.2013	27
  16/5-5	29.12.2013	45
  16/7-4	06.12.1982	94
  25/7-8 S	09.01.2020	14
  25/8-19 A	19.03.2020	8
  25/8-19 S	30.12.2019	88
  25/8-20 S	10.05.2021	52
  25/8-21 S	20.06.2021	110
  30/5-3 S	12.04.2009	84
  31/2-4 R	06.04.1981	8
  31/4-3	11.05.1980	3
  31/4-8	11.05.1986	13
  33/2-2 S	10.06.2015	30
  33/5-1	18.10.1979	10
  34/2-3	13.08.1981	39
  34/4-1	16.12.1979	90
  34/4-4	03.02.1983	182
  34/4-5	06.04.1984	48
  34/4-6	27.03.1986	54
  34/4-7	12.05.1987	183
  34/4-9 S	15.02.1997	208
  34/4-12 A	18.02.2010	54
  34/4-12 S	25.01.2010	52
  34/4-13 S	02.01.2011	11
  34/7-1	24.07.1984	223
  34/7-3	02.01.1985	52
  34/7-6	30.05.1985	57
  34/7-7	16.12.1985	103
  34/7-8	11.04.1986	5
  34/7-9	12.06.1986	243
  34/8-1	08.03.1986	9
  34/8-4 A	27.05.1992	79
  34/8-4 S	09.06.1991	355
  34/8-7	16.07.1992	8
  34/8-8	24.08.1992	22
  34/8-10 S	09.12.1993	32
  34/8-16 S	15.11.2015	107
  34/10-13	05.01.1982	45
  34/10-30	12.05.1986	189
  34/10-32	13.07.1987	16
  6201/11-1	06.11.1987	151
  6201/11-2	11.03.1991	14
  6201/11-3 R	20.10.2012	21