The Volcanic Development and Petroleum System Evolution of the Faroe-Shetland Basin.

The large volume of intrusive igneous material associated with volcanic rift margins introduces significant uncertainty to both hydrocarbon exploration and subsequent prospectivity. Understanding the habit, emplacement and distribution of such material in the context of rift evolution is essential to understanding the evolution of volcanic rift margins. The recent availability of high-quality 3D seismic data from the rift basins of the NE Atlantic Margin has enhanced our understanding of the 3D geometry and emplacement mechanisms of sill intrusions. Although how these intrusions fit within the wider margin context is often overlooked. The West of Shetland area provides an insight into the process of volcanic rift interaction in a petroleum prospective area.

Using multi-client 2D and 3D seismic data this study places reservoir scale observations of sill morphology, distribution and sill-fault interactions within a wider basin context. The study demonstrates that the style and volume of sill intrusion is heavily influenced by the large scale basin structure, the position along the volcanic margin and small scale structural heterogeneities. Given the variations in sill size and frequency there are also implications for the bulk intrusive magma distribution across the margin. Predicting hydrocarbon prospectivity in frontier, or under-explored basins, is inherently uncertain. In order to reduce this uncertainty, sensitivity analysis is performed on key modeling input parameters to define a best practice workflow for undertaking basin modeling in the Faroe-Shetland Basin and similar passive continental margin settings. As the emplacement of igneous intrusions into sedimentary successions has been shown to locally elevate heat flow, the sill complex is incorporated into the regional 2D modeling to investigate the effect sill emplacement has on hydrocarbon prospectivity.

The results highlight the importance of determining the timing of emplacement and the volume of igneous material when assessing the potential impact on maturation and generation of hydrocarbons. The modelling suggests that through an appraisal of sensitivity in areas of poor, limited or even absent data, such as frontier basins we can derive a more constrained basin modeling approach that reduces exploration uncertainty.