The potential role of igneous intrusions on hydrocarbon migration, West of Shetland

Abstract

Numerous challenges for petroleum exploration exist within basins containing sequences of intrusive and extrusive rocks, ranging from seismic imaging to drilling. One poorly understood element in dealing with volcanic-affected basins is assessing the impact magmatism has on the elements of the petroleum system. Within this study we attempt to evaluate the potential impact that the extensive sequence of igneous intrusions of the Faroe–Shetland Basin may have on hydrocarbon migration. Using available well data combined with regional 3D seismic surveys, we show that geometrical relationships between sills location and overlying hydrocarbons shows, together with several cases of gas-charged open fractures in the sills, point toward the recognition of igneous intrusions as a factor in hydrocarbon migration through sill intrusions acting as both barriers or conduits to hydrocarbon migration. We also provide a series of general conceptual models dealing with hydrocarbon migration and igneous compartmentalization within sedimentary basins, which can be applied not just to the Faroe–Shetland Basin, but to other sedimentary basins world-wide if it is found (via well data or other methods) that the intrusions are interacting with a petroleum system.