Abstract

Petroleum exploration has been carried out in four major Mesozoic-Cenozoic tectonic provinces off the east coast of Canada. Numerous structural and stratigraphic traps occur in the Scotian Basin continental margin clastic and carbonate wedge, which overlies a thick, mobile evaporite sequence. Maximum thickness of sedimentary rocks exceeds 11 km. The subsurface of the Grand Banks is characterized by a series of fault-bounded sub-basins with most of the trap types related to salt and basement tectonics. Sedimentary thicknesses are generally less than 7 km. The East Newfoundland Basin contains a clastic wedge superimposed on fault-bounded sub-basins with a total sedimentary thickness exceeding 12 km. Similarly, on the Labrador Shelf the thick Cretaceous-Tertiary clastic wedge covers faulted basement structures, with basal beds draped over these features.

The hydrocarbon occurrences on the Scotian Shelf are predominantly gas, with some condensate and oil. Generally poor source rocks have been encountered, due partly to a preponderance of terrestrial-type organic matter and partly to thermal immaturity. There is an indication of good marine Jurassic source rocks at greater depths, which enhances the oil potential for deeper, undrilled prospects. Three good gas shows have been encountered on the Labrador Shelf. The coincidental improvement in source rocks, reservoir and seal makes the hydrocarbon potential of this area more attractive.