George’s Bank — A Turbidite Source for Cretaceous Deepwater Reservoirs in the Southwest Scotian Basin, Offshore Nova Scotia, Canada

Georges Bank is the most southwesterly bank on the Canadian Atlantic continental margin. It lies 125 km offshore Nova Scotia, Canada in water depths ranging from 60 metres to >8,000 metres. The west Georges Bank and east Georges Bank are separated by a physiographic high of intrusive basement rock called the Yarmouth Arch. The entire Georges Bank, including the U.S.A. portion, covers about 40,000 km2. A new project taken on by the Nova Scotia Department of Energy called the Play Fairway Analysis (PFA) has added valuable insight into the Scotian Basin stratigraphic architectures, tectonic evolution, petroleum systems and ultimate resource potential. George’s Bank has been determined as a key component to reservoir delivery and distribution into the southwest Scotian Basin for the productive Cretaceous sand reservoirs.

Approximately 6800 line kilometers 2-D seismic data was of reprocessed and interpreted across George’s Bank. Successful correlation of regional stratigraphic horizons from the PFA was made across the Scotian Shelf and Slope into the George’s Bank establishing a consistent stratigraphic control with biostratigraphic anchors across the Scotian Basin and George’s Bank. Regional correlation of stratigraphic markers produced intriguing results which independently substantiated 3D sediment modeling results in the southwest Scotian Basin.

Evident from interpretation is the building of a Late Jurassic to early Cretaceous (Missisauga Fm.) delta system on the outer shelf of George’s Bank, the Shelburne Delta. The middle Cretaceous interval (Logan Canyon Fm.) shows indications of a bypass system of paleo channels incising the outer edge of George’s Bank shelf and delivering sediment from the southwest into the present day deepwater of the southwest Scotian Basin. This observation serves well in corroborating the 3D sediment modeling results which indicate a reservoir (sediment) supply sourcing from George’s Bank. Previous to this interpretation the sediment supply into the SW Scotian Basin had been presumed a possible artifact of the modeling. Results of this George’s Bank study indicate an active sediment source shedding off the Yarmouth Arch and building on the outer shelf into the Shelburne Delta (Mississauga equivalents). During a sealevel regressive stage the Shelburne Delta system on George’s Bank was bypassed and sediment delivery continued from the Yarmouth Arch into present day oil prone deepwater of the southwestern Scotian Slope.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California