UK Rockall prospectivity: re-awakening exploration in a frontier basin

Abstract

The UK Rockall, located to the west of Scotland and the Hebrides, is a frontier petroleum-bearing basin. Exploratory drilling in the basin took place over a quarter of a century (1980–2006), during which time a total of 12 wells were drilled, leading to the discovery of a single, subcommercial gas accumulation. We argue that the basin, which has seen no drilling activity for more than a decade, has not been sufficiently tested by the existing well stock. We examine the reasons for the absence of key Jurassic source rocks in the UK Rockall wells, which are widely distributed elsewhere on the UK Continental Shelf (UKCS), and argue that their absence in the wells does not preclude their existence in the basin at large. An evaluation of the Permian–Early Eocene successions, based upon the seismic interpretation of new 2D seismic data, has been integrated with legacy data and regional evidence to establish the potential for source, reservoir and sealing elements within each interval. Finally, we look at the future for exploration in the UK Rockall and suggest a way forward in the drilling of a new joint governmental–industry test well that may help to unlock the exploration potential of this under-explored, yet prospective, basin. Thematic collection: This article is part of the Under-explored plays and frontier basins of the UK continental shelf collection available at: https://www.lyellcollection.org/cc/under-explored-plays-and-frontier-basins-of-the-uk-continental-shelf

Stratigraphy of volcanic rock successions of the North Atlantic rifted margin: the offshore record of the Faroe–Shetland and Rockall basins

“…Eruptive cyclicity was recorded within the Beinisvørð Formation of the FIBG (Jolley et al 2012), with a total cessation of Beinisvørð Formation eruption at ∼55.85 Ma. This cessation of volcanic activity is recorded basin-wide from Kangerlussuaq (Ellis & Stoker 2014) in the W, the Faroe Islands , around the Erlend Volcanic complex in the N (Jolley & Bell 2002) to the eastern margin of the Rockall Basin in the S (Schofield et al 2018;Broadley et al 2020).…”

“…2018; Broadley et al . 2020) has identified basin flank lava fields within both Sequence T40 and Sequence T36 along the eastern Rockall margin (Fig. 1).…”

“…The Rockall Basin has fewer well penetrations and a lower density of seismic data coverage than the FSB. Recent re-appraisal of hydrocarbon prospectivity in the Rockall Basin to the S of the FSB (Schofield et al 2018;Broadley et al 2020) has identified basin flank lava fields within both Sequence T40 and Sequence T36 along the eastern Rockall margin (Fig. 1).…”

Geology and petroleum prospectivity of the Sea of Hebrides Basin and Minch Basin, offshore NW Scotland

“…They provide an invaluable resource for direct insight into the characteristics and temporal and geographical distribution of Mesozoic aged petroleum system components (source, reservoir, seal), which play key roles in many active petroleum systems in other UK Atlantic margin basins (Scotchman et al 1998;Ritchie et al 2011;Schofield et al 2018;Scotchman et al 2018;Broadley et al 2020).…”

“…Late Palaeozoic-Mesozoic rift basins such as the Rockall Trough and the Faroe-Shetland Basin were formed under the same tectonic regime (Arctic Rift System) as the Sea of Hebrides and Minch basins, but were subsequently buried by thick sequences (>km) of Cretaceous and Cenozoic strata (Ritchie et al 2011;Schofield et al 2018;Broadley et al 2020). Understanding constraints on the early and middle Mesozoic geology are hampered along the Atlantic Margin by limited well penetrations and issues with seismic imaging of Jurassic and deeper stratigraphy, due to overlying igneous sill complexes within the Cretaceous and Paleocene sequences.…”