Thermal history modelling in the southern Faroe-Shetland Basin

Hydrocarbon generation is a temperature-dependent process and the prediction of hydrocarbon generation in basin modelling requires the crustal heat flow history to be predicted. Tectonically, the Faroe-Shetland Basin (FSB) has been subjected to a number of Cretaceous rifting events, followed in the Tertiary by Balder volcanism and, finally, by Oligo-Miocene inversion. In this study the thermal history of the FSB is derived using two independent methods (rifting-volcanic-subsidence history and maturation). The methodology is described using two wells (204/19-1 and 205/22-1) in the southern FSB. The vitrinite reflectance results predicted by the PresRo(R) model, which was devised for modelling maturation in overpressured basins such as the FSB, produced predicted vitrinite reflectances that matched the measured values. The method was then applied to a pseudowell within the Foinaven sub-basin, and the predicted vitrinite reflectance values for the Kimmeridge Clay Formation source at 8 km depth indicate that the source is still mature for oil generation due to the extensive retardation induced by the highly overpressured, argillaceous Mesozoic sediments.