New insights into the stratigraphic evolution of southwest Britain: Implications for Triassic salt and hydrocarbon prospectivity
File(s)
Published version
Author(s)
Husein, SS
Fraser, A
Roberts, GG
Bell, R
Type
Journal Article
Abstract
The discovery of Wytch Farm field in the Wessex Basin, and Kinsale Head field in the North Celtic Sea Basin in the early 1970s, led to exploration interest offshore in the Western Approaches Trough. Despite this activity, little evidence for prospective hydrocarbon resources has been found. To better understand the failures and analyse remaining hydrocarbon potential in this region, we make use of a large collection of new seismic reflection and well data to map Carboniferous to Neogene stratigraphy. The improved seismic imaging has allowed a better interpretation of the hitherto poorly understood, salt-related structures in the South Melville and the Plymouth Bay basins. The implications of the new interpretations for Carnian (Late Triassic), and Carboniferous stratigraphic and geodynamic evolution are assessed and contextualised with regional salt deposition in the Wessex, Bristol, and South Celtic Sea basins. From a petroleum system perspective, the Lias and Carboniferous source rocks are evaluated and modelled to analyse the maturity and evolution of the petroleum systems. We conclude that the Lias is an ineffective petroleum system due to timing and source maturation risk. However, the Triassic salt and associated subcropping faults have produced several possible pre-salt hydrocarbon traps. The traps may be charged from sporadic Mid-Late Carboniferous coal-bearing post-orogenic basins, a petroleum system previously overlooked.
Date Issued
2023-05-25
Date Acceptance
2023-03-26
Citation
Petroleum Geoscience, 2023, 29 (2), pp.1-19
ISSN
1354-0793
Publisher
Geological Society of London
Start Page
1
End Page
19
Journal / Book Title
Petroleum Geoscience
Volume
29
Issue
2
Copyright Statement
© 2023 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License (http://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
http://dx.doi.org/10.1144/petgeo2022-051
Subjects
0403 Geology
0914 Resources Engineering and Extractive Metallurgy
Energy
Publication Status
Published online
Date Publish Online
2023-03-29