Petroleum systems of the deep water Scotian salt province, offshore Nova Scotia, Canada

Hogg, J. R., D. A. Dolph, David Mackidd, and Karin Michel, PanCanadian Petroleum Ltd., Calgary, Alberta CANADA

Abstract

The Scotian basin, under Atlantic Canada’s continental shelf and slope, encompasses a corridor 100 to 150 km wide by 900 km long on the southeastern continental slope of the province of Nova Scotia, Canada. Since 1967, a total of 103 exploration wells have been drilled within the shelf portion of the basin within the setting of the Sable subbasin.

The Scotian basin is divided into a series of geologically distinct subbasins. Opening of the basin occurred during the Middle to Late Triassic, in response to separation of North America from Africa. During this time, synrift red beds, restricted marine dolomites and halites of the Eurydice, Iroquois, and Argo formations, respectively, were deposited. From the Early Jurassic to the end of the Cretaceous the basin continued to subside, infilling with significant quantities of fluviodeltaic and shelf sandstones. During lowstands, incision of the shelf carried sands down the paleoslope into deep marine environments, where they were deposited within a variety of subaqueous facies. The Tertiary-aged Banquereau Formation consists of fluvial, deltaic, and deepwater sandstone environments.

Although tectonically passive, deepwater portions of the Scotian basin contain the Scotian salt province. This subbasin is extensively deformed by halokinetic movement of Late Triassic Argo Formation halite which mobilized to form swells, walls, ridges and domes. Sedimentation and play types vary considerably along the 900 km of the salt province within water depths of 1,000 to 3,000 metres with the potential for a number of distinct petroleum systems throughout the subbasins and include potential subsalt exploration targets.