ABSTRACT
A variety of maturation indicators from 55 wells have been used to construct a maturation facies map for the base of the Cretaceous sediments on the Scotian Shelf. The Verrill Canyon Formation is largely mature in the Sable subbasin and contains terrestrially derived (Type III) organic matter. This organic matter is largely gas-prone except for an area in the northern part of the Sable subbasin where it has some oil potential. This oil potential is minor, however, because of the relatively low content of organic matter (C% = 1.20 ± 0.29%) in the Verrill Canyon sediments.
On the basis of analysis of gasoline-range and aromatic hydrocarbons from sediment and oil/condensate samples, the Verrill Canyon Formation is considered to be the source of hydrocarbon reservoirs in the Logan Canyon, Verrill Canyon, Mic Mac and Missisauga Formations. The composition of the hydrocarbon product is related to the degree of maturation of the source rock. Oils and condensates occurring in the Logan Canyon Formation in the West Sable and Cohasset structures are more mature than those in stratigraphically older and deeper reservoirs. This maturity reflects vertical migration of those hydrocarbons from the deep Verrill Canyon source. Variations in maturation of the source have been found to have a profound effect on the composition of gasoline-range and aromatic fractions of the generated hydrocarbons.
