The movement of magma through the shallow crust and the impact of subsurface sill complexes on the hydrocarbon systems of prospective sedimentary basins has long been an area of interest and debate. Based on 3D seismic reflection and well data, we present a regional analysis of the emplacement and magmatic plumbing system of the Palaeogene Faroe-Shetland Sill Complex (FSSC), which is intruded into the Mesozoic and Cenozoic sequences of the Faroe-Shetland Basin (FSB). Identification of magma flow directions through detailed seismic interpretation of approximately 100 sills indicates that the main magma input zones into the FSB were controlled primarily by the NE-SW basin structure that compartmentalise the FSB into its constituent sub-basins.
An analysis of well data shows that potentially up to 88% of sills in the FSSC are <40 m in thickness, and thus below the vertical resolution limit of seismic data at depths at which most sills occur. This resolution limitation suggests that caution needs to be exercised when interpreting magmatic systems from seismic data alone, as a large amount of intrusive material could potentially be missed.
The interaction of the FSSC with the petroleum systems of the FSB is not well understood. Given the close association between the FSSC and potential petroleum migration routes into some of the oil/gas fields (e.g. Tormore), the role the intrusions may have played in compartmentalization of basin fill needs to be taken fully into account to further unlock the future petroleum potential of the FSB.
We extend our gratitude to the reviewers, Simon Kattenhorn and David Moy, whose careful reviews and comments greatly improved the paper. The editor is also thanked for clear guidance. This paper is dedicated to the memory of Dr Ken Thomson, who pioneered early work looking at intrusions within the Faroe-Shetland Basin. PGS are thanked for the generous donation of the FSB MegaSurveyPlus data set, which made this study possible, and for permission to publish this work. The Rosebank Joint Venture Project (Chevron North Sea Limited, OMV (U.K.)
Limited, and DONG EandP (UK) Limited) is thanked for making Fig. 12 available. Spectral decomposition was carried out using Foster Findlay Associates’ (FFA) GeoTeric software. Seismic Interpretation was undertaken using IHS Kingdom Software. NS would like to acknowledge support and generous research funding for “Regional Emplacement of the Faroe-Shetland Sill Complex” from STATOIL FÆRØYENE AS, Chevron North Sea limited, Hess Limited, DONG E&P (U.K.) and OMV (U.K.) Limited. Richard Lamb, Steve Morse, Mike Keavney and David Iacopini are thanked for discussions and suggestions.
- Faroe-Shetland Basin
- 3D seismic interpretation
- volcanic rifted margins