CLASTIC SEDIMENT DISTRIBUTION AND DISPERSAL IN THE DEEPWATER SCOTIAN MARGIN:

The deep basin of the Scotian margin is an area of emergent industry focus and exploration activity. The deep basin, explored with a handful of wells, is an area that is yet to be fully understood. Deepwater wells are spread over a distance of 300 miles and provide sparse and incomplete information concerning the geologic potential of the basin. Recent drilling activity has focused on the deepwater potential outboard of the Sable Island area. Current and pending drilling activity may provide valuable information on the key concern of reservoir presence in the Shelburne sub-basin.

A key exploration risk in the Shelburne sub-basin of the deepwater Scotian basin is the uncertainty relating to the presence of significant clastic reservoirs. A lithologic examination of cores and cuttings from selected wells on the shelf and in the deepwater Shelburne sub-basin revealed a poorly understood distribution of arenaceous clastics. A study undertaken by Kerr McGee Oil and Gas and the Energy and Geoscience Institute at the University of Utah examined possible factors controlling sedimentation in the Scotian basin.

Oceanic fracture zones and pre-existing structural grains may play a key role in the distribution of coarse grained clastic sedimentation in the deepwater Scotian basin. Results of the study suggest that oceanic fracture zones accommodated inhomogenous seafloor spreading and became conduits or spillways for basinward transport of sediments across the uplifted rift margin. Sediment dispersal into the deep basin may therefore be more localized than previously indicated. Free Air Gravity data, recently acquired 3d seismic data and a study of wellbore lithic data are incorporated in the analysis of the basin and lend support to the current working hypothesis.