The
APT-Chemostrat Faroe-Shetland Basin basement characterisation and thermal
calibration database and report was published by the NSTA in May 2021 under the
NSTA user agreement. The project comprises a PDF report and 5 excel files.
The
study has generated a multi-disciplinary dataset that constrains the thermal
evolution of the Faroe-Shetland Basin.
The basement composition work
reveals a clear variation in basement composition which results in a
marked trend in heat flow and geothermal gradient from cool in the SW of
the AOI to hot in the NE of the AOI.
The thermal calibration data
demonstrates that the basinal areas investigated are at or close to their
maximum temperatures present day. Evidence for higher paleo-temperatures
is sporadic and is indicated to occur in the Late Tertiary rather than the
Early Tertiary when the intrusive igneous activity occurred. Models
testing the impact of thermal erosion of the lithosphere suggest that the
impact on the temperature histories caused by this are very modest.
Heating associated with direct intrusive activity is of much greater
magnitude but is thought to be relatively localised.
Results obtained from 1D
modelling, combined with appropriate expulsion modelling suggest that the
charge timing ‘issue’ in the Faroe-Shetland Basin has been over-emphasised
in previous studies.
The
study has implication for both exploration teams engaged in the modelling and
prediction of the petroleum system in the Faroe-Shetland basins, and for
geoscientific researchers working on the processes involved in the basin
evolution. While previously considered complex, it is believed that where the
complexity is either misplaced or misunderstood in terms of the petroleum
system then this can lead to poorer risking and a less clarity on the framework
in which to assess new exploration opportunities.