RANNOCH FM

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• General information

  General information

  Attribute	Value
  Lithostrat. unit The lithostratigraphic unit's official name.	RANNOCH FM
  NPDID lithostrat. unit Norwegian Offshore Directorate's unique id for lithostratigraphic units.	126
  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.	BRENT GP

• Level below

  Level below

  Lithostrat. unit

• Description

  Rannoch Formation
  
  Name

  Named by Deegan and Scull (1977) who gave it "sub-unit" status.

  Well type section

  UK well 211/29-3 (Shell) from 2783 m to 2818m, coord N 61°08'06", E 01°43'36.5" (Fig 3.10) .

  Well reference section

  Norwegian well 33/9-1 (Mobil) from 2602 m to 2664 m, coord N 61°15'07.5", E 01°50'25.8" (Fig 3.11) .

  Thickness

  35 m in the type well and 62 m in 33/9-1 .

  Lithology

  In the type well the formation is a light brown, fine grained, well sorted, friable, very micaceous sandstone. In the Brent Field area the lower part is more argillaceous with siltstones and thin shales.
  Towards the top the formation tends to be coarser grained and less micaceous, often resulting in a distinctive gamma ray pattern suggesting a "coarsening upward" sequence. Some workers consider that the Rannoch Formation is occasionally represented on the Horda Platform by one or more such coarsening upward cycles. However, in the majority of cases these cannot be observed and the presence of the Rannoch Formation must be considered debatable.

  Boundaries

  The high mica content of the sandstone produces an anomalously high gamma ray log response and generally distinguishes the Rannoch Formation from the overlying and underlying sandstones. Where the Broom Formation is missing the lower boundary is gradational into the dark, silty shales of the Dunlin Group . The upper boundary is normally defined by the "blocky" gamma ray log of the overlying Etive Formation .

  Distribution

  The distribution of the Rannoch Formation is essentially the same as that of the Brent Group , except on the Horda Platform where the presence of the formation is under debate.

  Age

  Late Toarcian to Bajocian.

  Depositional environment

  The formation is generally interpreted as delta front sheet sands and/or prograding shoreface sands.

  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]
  29/3-1	15.09.1986	3862	3912
  29/6-1	09.05.1982	4474	4489
  29/9-1	24.02.1984	4406	4415
  30/2-1	12.10.1982	3778	3793
  30/2-2	04.05.1985	4075	4098
  30/2-3	05.10.1992	3944	3974
  30/3-1 R	26.04.1982	3852	3866
  30/3-2 R	16.02.1981	2882	2891
  30/3-5 S	19.06.1992	4142	4155
  30/3-6 S	06.03.1994	5481	5503
  30/3-7 A	29.01.1998	6517	6526
  30/3-7 B	04.08.1998	5229	5259
  30/3-7 BR	17.11.2001	5229	5259
  30/3-7 S	12.12.1995	4910	4928
  30/3-7 S	12.12.1995	5063	5070
  30/3-8 A	23.05.2000	4250	4286
  30/3-8 A	23.05.2000	4821	4827
  30/3-8 S	04.05.2000	4243	4256
  30/3-8 S	04.05.2000	4791	4797
  30/3-11 S	09.09.2022	4535	4545
  30/4-1	14.05.1979	5340	5359
  30/4-2	16.05.1980	4036	4061
  30/4-3 S	09.10.2016	4556	4583
  30/6-7	24.08.1982	2737	2739
  30/6-19	21.06.1986	2915	2920
  30/6-19 R	25.05.1994	2914	2919
  30/6-22	13.07.1988	2938	2943
  30/6-22 R	02.06.1994	2937	2942
  30/6-23	01.07.1990	2836	2839
  30/6-25 S	06.01.1999	2704	2712
  30/6-25 S	06.01.1999	2904	2916
  30/6-30	18.11.2018	3350	3361
  30/7-6 R	03.06.1978	4035	4051
  30/7-8 R	29.01.1982	4283	4300
  30/9-4 S	30.03.1985	3551	3568
  30/9-6	21.04.1987	2693	2699
  30/9-7	23.12.1988	3110	3137
  30/9-8 R	25.09.1989	3135	3140
  30/9-9	06.11.1989	2408	2418
  30/9-10	21.09.1990	3096	3114
  30/9-11	19.11.1990	2507	2514
  30/9-11 A	29.12.1990	2667	2679
  30/9-16	08.08.1994	2989	3001
  30/9-23	21.08.2009	2812	2814
  30/9-28 S	26.02.2016	3301	3304
  30/9-B-18	25.09.1992	3825	3831
  30/9-B-18 A	23.10.1992	3694	3701
  30/9-B-18 A	23.10.1992	4751	4769
  30/11-7	03.02.2009	4017	4027
  30/11-8 A	03.07.2011	4425	4436
  30/11-8 S	20.05.2011	3993	3998
  30/11-10	26.12.2014	3997	4013
  30/11-14	06.07.2016	3405	3420
  30/11-14 B	23.07.2016	4129	4147
  31/1-1	15.02.2008	2564	2634
  31/1-2 A	29.01.2021	3694	3711
  31/1-2 S	12.01.2021	3301	3319
  31/2-21 S	04.06.2014	3013	3032
  31/4-9	07.03.1987	2398	2411
  31/4-A-13 C	26.07.2022	7068	7070
  31/11-1 S	28.06.2021	2758	2827
  33/5-2	18.11.1981	4079	4111
  33/6-1	06.07.1979	3603	3647
  33/6-5 S	16.10.2021	3358	3479
  33/9-1	04.06.1974	2596	2664
  33/9-3	14.11.1974	2540	2599
  33/9-6	31.08.1976	3103	3140
  33/9-12	03.08.1987	2517	2561
  33/9-13 S	24.12.1987	2727	2810
  33/9-14	09.04.1988	2836	2947
  33/9-19 A	09.08.1996	2939	3070
  33/9-19 S	23.07.1996	2742	2845
  33/12-6	21.06.1976	3250	3285
  33/12-7	27.04.1989	3248	3296
  33/12-8 A	16.05.2002	5075	5098
  33/12-8 S	26.04.2002	3098	3155
  33/12-9 S	08.01.2012	3727	3775
  34/3-4 A	13.02.2015	4089	4246
  34/3-5	16.04.2015	3877	4032
  34/4-14 S	19.05.2015	4350	4417
  34/4-15 A	12.08.2020	3704	3802
  34/4-15 S	15.07.2020	3426	3523
  34/4-16 S	31.03.2021	3468	3553
  34/5-2 S	04.07.2018	3481	3499
  34/6-1 S	28.08.2002	3583	3659
  34/6-2 A	12.12.2012	3478	3547
  34/6-2 S	05.11.2012	3536	3566
  34/6-3 S	24.09.2014	3759	3793
  34/6-4	02.03.2016	3786	3838
  34/7-5	16.03.1985	2564	2622
  34/7-12	17.12.1987	2269	2334
  34/7-13	13.04.1988	2523	2598
  34/7-14	02.12.1989	2343	2413
  34/7-15 S	03.09.1990	4513	4571
  34/7-16	13.08.1990	2434	2514
  34/7-16 R	15.10.1990	2435	2515
  34/7-16 R2	05.07.1994	2434	2514
  34/7-17	07.04.1991	2631	2697
  34/7-18	17.09.1991	2328	2399
  34/7-19	27.12.1991	2582	2658
  34/7-19 R	12.07.1994	2589	2665
  34/7-20	27.08.1992	2695	2785
  34/7-21	11.12.1992	2903	2966
  34/7-22	01.10.1993	2375	2456
  34/7-25 S	14.09.1996	3101	3178
  34/7-27	07.10.1998	2887	2930
  34/7-32	27.10.2001	2557	2636
  34/7-33	15.10.2008	2499	2561
  34/7-E-4 AH	13.07.2020	4366	4455
  34/8-1	08.03.1986	2900	2980
  34/8-3	14.09.1988	2897	2964
  34/8-3 A	31.10.1988	3131	3184
  34/8-4 S	09.06.1991	2903	2922
  34/8-5	01.04.1991	2983	3046
  34/8-6	03.11.1991	3757	3880
  34/8-7	16.07.1992	4714	4764
  34/8-7 R	10.02.1993	4714	4764
  34/8-8	24.08.1992	3008	3077
  34/8-8 R	09.03.1993	3007	3077
  34/8-9 S	28.12.1992	2963	2984
  34/8-10 S	09.12.1993	2879	2885
  34/8-11	08.02.1994	2949	3011
  34/8-14 A	01.12.2008	3617	3720
  34/8-14 B	25.01.2009	3809	4079
  34/8-14 C	08.12.2008	3722	3820
  34/8-14 D	10.02.2009	3752	3797
  34/8-14 S	21.10.2008	3337	3411
  34/8-15 S	19.02.2013	3546	3649
  34/8-17 S	14.03.2014	4009	4069
  34/10-1	08.09.1978	1871	1935
  34/10-2	08.12.1978	3083	3124
  34/10-3	07.06.1979	2002	2084
  34/10-3 R	10.10.1987	1999	2081
  34/10-4	15.10.1979	1816	1905
  34/10-5	02.01.1980	2070	2134
  34/10-6	22.01.1980	2197	2273
  34/10-8	25.05.1980	2005	2040
  34/10-9	09.05.1980	1867	1945
  34/10-9 R	03.07.1980	1867	1945
  34/10-12	12.09.1981	2198	2250
  34/10-14	19.03.1982	2003	2069
  34/10-16	11.04.1983	3412	3475
  34/10-16 R	27.09.1983	3409	3472
  34/10-17	08.07.1983	2937	3000
  34/10-18	30.08.1983	2524	2595
  34/10-21	22.10.1984	3503	3550
  34/10-23	13.10.1985	4287	4335
  34/10-33	15.12.1988	3374	3424
  34/10-33 A	03.02.1989	3758	3851
  34/10-33 C	01.08.1989	3617	3722
  34/10-33 CR	27.04.1990	3617	3722
  34/10-34	31.05.1991	2188	2268
  34/10-36	13.07.1992	3524	3555
  34/10-37	22.02.1995	2750	2796
  34/10-38 S	29.05.1995	3036	3045
  34/10-39 S	20.06.1995	2727	2800
  34/10-40 S	13.10.1995	5712	5820
  34/10-41 S	28.08.1997	2792	2863
  34/10-42 S	19.09.1999	4369	4403
  34/10-43 S	11.04.2001	3326	3345
  34/10-47 S	02.11.2002	2910	3000
  34/10-47 S	02.11.2002	3000	3285
  34/10-48 S	22.12.2004	5500	5843
  34/10-49 B	21.05.2006	2557	2627
  34/10-49 S	08.05.2006	2557	2627
  34/10-52 A	06.08.2011	3445	3470
  34/10-52 B	22.08.2011	3874	3998
  34/10-53 A	01.06.2011	4760	4822
  34/10-53 S	24.03.2011	3890	3956
  34/10-54 A	18.04.2014	4191	4203
  34/10-54 S	11.02.2014	4076	4117
  34/11-1	25.10.1994	4177	4221
  34/11-2 S	17.05.1996	4261	4320
  34/11-3	16.01.1997	4155	4197
  34/11-4	14.04.1999	4292	4339
  34/11-5 S	03.07.2006	7307	7370
  34/11-6 S	26.01.2017	7057	7105
  34/12-1	30.04.2008	4457	4499
  35/4-3	17.05.2022	4277	4427
  35/7-1 S	15.08.2011	4454	4515
  35/8-1	24.01.1981	3680	3743
  35/8-2	21.05.1982	3814	3868
  35/8-3	15.10.1988	3896	3944
  35/8-5 S	20.07.2003	3975	4000
  35/9-1	07.05.1989	2250	2267
  35/9-1 R	27.07.1989	2250	2267
  35/9-2	03.04.1991	2646	2680
  35/9-6 S	07.12.2010	3515	3552
  35/9-7	14.04.2012	2974	3006
  35/9-8	11.04.2013	3215	3256
  35/9-9	18.11.2013	3092	3118
  35/9-10 A	16.01.2014	3172	3203
  35/9-10 S	26.11.2013	3580	3619
  35/9-11 A	21.05.2014	3523	3557
  35/9-11 S	15.04.2014	3522	3558
  35/9-12 S	26.12.2014	3537	3556
  35/10-1	16.01.1992	3460	3507
  35/10-2	22.08.1996	4280	4319
  35/10-4 S	10.10.2018	3761	3801
  35/10-7 A	27.12.2021	3468	3492
  35/10-7 S	11.12.2021	3374	3398
  35/11-1	06.08.1984	2557	2583
  35/11-2	04.12.1987	3487	3524
  35/11-3 S	09.09.1989	3538	3573
  35/11-4	29.12.1990	2686	2707
  35/11-4 R	27.01.1992	2696	2717
  35/11-5	03.11.1991	3312	3342
  35/11-6	20.04.1992	3635	3678
  35/11-7	29.09.1992	2511	2528
  35/11-8 S	11.05.1996	3480	3505
  35/11-10	23.06.1997	2728	2746
  35/11-10 A	14.07.1997	3190	3212
  35/11-11	22.05.1998	3085	3119
  35/11-17	01.05.2014	2744	2773
  35/11-18	27.09.2015	3617	3657
  35/11-18 A	16.12.2015	3665	3705
  35/11-20 B	15.09.2016	4725	4789
  35/11-21 A	17.10.2018	2809	2847
  35/11-21 S	05.09.2018	2686	2724
  35/11-22 S	02.02.2019	3353	3377
  35/11-23	06.11.2019	2816	2835
  35/11-25 A	04.06.2021	3692	3723
  35/12-4 A	17.07.2011	3373	3413
  35/12-4 S	26.06.2011	3205	3250
  35/12-5 S	19.06.2015	3535	3554
  35/12-7	25.07.2018	2683	2708
  36/1-4 S	30.01.2022	3182	3228
  36/7-1	07.05.1996	2727	2770

• Wellbores with cores

  Wellbores with cores

  Wellbore name	Wellbore completion date	Core length [m]
  29/9-1	24.02.1984	10
  30/2-1	12.10.1982	15
  30/2-2	04.05.1985	22
  30/2-3	05.10.1992	20
  30/3-1 R	26.04.1982	3
  30/3-2 R	16.02.1981	9
  30/3-5 S	19.06.1992	13
  30/3-11 S	09.09.2022	10
  30/6-7	24.08.1982	2
  30/6-19	21.06.1986	5
  30/6-22	13.07.1988	5
  30/6-23	01.07.1990	3
  30/6-30	18.11.2018	11
  30/9-9	06.11.1989	9
  30/9-11	19.11.1990	4
  30/11-10	26.12.2014	16
  31/1-2 S	12.01.2021	18
  33/5-2	18.11.1981	17
  33/6-1	06.07.1979	9
  33/9-3	14.11.1974	46
  33/9-12	03.08.1987	42
  33/9-13 S	24.12.1987	75
  33/9-14	09.04.1988	40
  34/4-15 S	15.07.2020	81
  34/4-16 S	31.03.2021	85
  34/7-5	16.03.1985	55
  34/7-12	17.12.1987	64
  34/7-13	13.04.1988	64
  34/7-14	02.12.1989	65
  34/7-16	13.08.1990	76
  34/7-19	27.12.1991	75
  34/8-1	08.03.1986	74
  34/8-3	14.09.1988	59
  34/8-3 A	31.10.1988	17
  34/8-5	01.04.1991	27
  34/8-8	24.08.1992	67
  34/8-10 S	09.12.1993	5
  34/8-11	08.02.1994	55
  34/10-1	08.09.1978	58
  34/10-2	08.12.1978	11
  34/10-3	07.06.1979	23
  34/10-4	15.10.1979	74
  34/10-14	19.03.1982	43
  34/10-16	11.04.1983	51
  34/10-17	08.07.1983	30
  34/10-23	13.10.1985	21
  34/10-33	15.12.1988	49
  34/10-34	31.05.1991	80
  34/10-54 S	11.02.2014	41
  34/11-1	25.10.1994	40
  34/11-2 S	17.05.1996	32
  34/11-3	16.01.1997	28
  35/8-1	24.01.1981	30
  35/9-1	07.05.1989	18
  35/9-2	03.04.1991	33
  35/9-6 S	07.12.2010	35
  35/9-11 A	21.05.2014	4
  35/10-1	16.01.1992	44
  35/10-7 S	11.12.2021	24
  35/11-1	06.08.1984	6
  35/11-2	04.12.1987	29
  35/11-5	03.11.1991	24
  35/11-6	20.04.1992	43
  35/11-7	29.09.1992	16
  35/11-10	23.06.1997	18
  35/11-11	22.05.1998	17
  35/11-17	01.05.2014	27
  35/11-21 A	17.10.2018	30
  35/11-21 S	05.09.2018	38
  35/11-25 A	04.06.2021	0