Western Flank of the Central Graben
10 February 2015

The development of a system of Carboniferous rift basins and horst blocks within the Central North Sea area west of the Central Graben, analogous to that of northern and central England, has been known for many years. Well 27/3-1 (1967) and 27/10-1 (1970) proved the development of a basement horst block, the Devil’s Hole Horst, with subsequent drilling proving a thick Carboniferous section within the adjacent Forth Approaches Basin, including a coal-bearing Lower Carboniferous (Visean) in Well 26/7-1 (BP, 1985) and 26/8-1 (Mobil, 1992), whilst to the north-east, three Shell Well; 21/11-1 (1968), 21/12-2B (1982) and 21/13b-2 (1982) proven Visean sediments in a north-eastern extension of this graben system.