Insights Into the Influence of Rift Evolution on the Emplacement and Distribution of a Sill Complex, Faroe-Shetland Basin, Northeast Atlantic

Abstract

Large volumes 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 reduces this uncertainty and helps enhance our 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. Exactly how the characteristics and timing of 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 we place reservoir scale observations of sill morphology, size, distribution and sill-fault interactions within a wider basin context. We have identified three distinct sill facies through detailed 3D seismic interpretation and seismic attribute analysis, each show significant morphological variations and are emplaced within contrasting structural settings. Given the variations in sill size and frequency within each facies there are also implications for bulk regional intrusive magma distribution across the margin. We demonstrate 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.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015