Thermal Modelling of the Central Scotian Slope, Offshore Nova Scotia ...

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The passive continental Scotian Margin located offshore Nova Scotia formed as the result of Late. Triassic ... location of the Shubenacadie H-100 well. Plotted ...
Thermal Modelling of the Central Scotian Slope, Offshore Nova Scotia: The Effects of Salt on Heat Flow and Implications for Hydrocarbon Maturation E. Negulic Department of Earth Sciences, Dalhousie University Halifax, Nova Scotia B3H 4J1, Canada [email protected] K.E. Louden Department of Oceanography, Dalhousie University Halifax, Nova Scotia B3H 4J1, Canada [email protected] P.K. Mukhopadhyay Global Geoenergy Research Ltd. Halifax, Nova Scotia B3J 2A1, Canada muki@global -geoenergy.com H.Wielens Geological Survey of Canada (Atlantic) Dartmouth, Nova Scotia B2Y 4A2, Canada [email protected] and M.R. Nedimović Department of Earth Sciences, Dalhousie University Halifax, Nova Scotia B3H 4J1, Canada [email protected]

Summary Seafloor heat flow measurements were acquired in the summer of 2008 across the central Scotian Slope along three existing deep MCS profiles (Fig. 1). In this area the Scotian Slope is cut by numerous highly thermally conductive salt bodies which significantly distort local geothermal gradients. Seafloor heat flow measurements were acquired both across salt structures and in regions not underlain by salt to measure the effects of salt on seafloor heat flow and to determine variations in regional heat flux across the margin respectively. Two phases of 2D petroleum systems models were developed to determine the hydrocarbon maturation potential of the region. Comparison of model seafloor heat flow predictions with the observed seafloor heat flow data indicate that early models can explain much of the variation across the salt structures, although some misfit suggests possible effects due to 3D variations in salt geometry or the presence of convective fluid flow through the overlying sediments. In addition, the regional heat flow values indicate much lower temperatures than previously suggested, which alters the predicted maturation of the expected deeply buried Jurassic and Early Cretaceous source rocks. New 3D petroleum systems models are being developed which include additional constraints of salt geometries from crossing seismic profiles and thermal constraints from seafloor heat flow measurements with regional basement heat flux histories calculated from standard lithospheric rift models. These 3D models will better predict the maturation potential of the margin than previous 2D models. Introduction The passive continental Scotian Margin located offshore Nova Scotia formed as the result of Late Triassic rifting of the North American and African plates. The associated Scotian Basin underlies both the shallow water Scotian Shelf (