Basin Modelling in Western Newfoundland Using Oil Seep Samples

Abstract

Recent drilling on the Port au Port Peninsula in western Newfoundland and the presence of oil and oil-seeps along the coast, have focused interest on the late Proterozoic Cow Head Group of the Humber Arm Allochthon as viable source rocks for petroleum. The Late Cambrian to Ordovician Green Point Formation and the more distal Northern Head Group in the Humber Arm Allochthon are type I/II source rocks with a TOC content of up to 10.35%. Hence, they are comparable to time-equivalent prolific source rock, e.g. Utica Shale, of the south Appalachians. Biomarkers from oil seeps are consistent with a Lower Paleozoic source rock. Western Newfoundland is situated at the eastern margin of the Gulf of St. Lawrence, preserving the tectonically-rich history of the northeast Canadian Appalachians, mainly represented by the Humber Arm Supergroup. Westward thrusting of the allochthon over a carbonate platform during the Taconian was overprinted by Acadian deformation shown in north northeast to south southwest trending moderately inclined folds. New Lithoprobe seismic profiles show promising inverted basins beneath the allochthon, reflecting the possibility of deeply buried high porosity carbonate successions of the St. George Group as potential oil reservoirs. The Watts Bight Formation of the St. George Group shows porosities up to 12.9%, however dolomite cement can decrease the pore space substantially. We are developing 1D and 2D models for hydrocarbon generation, expulsion and migration that are constrained by measured maturities from well and outcrops and that are consistent with structural models from seismic and field data. Modeling results will be compared to biomarker-based correlations between oils and potential source rocks.

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