Depositional Architecture of Slope-Apron and Basin- Floor Turbidite Systems from the North Slope of Alaska to the Mackenzie Delta of Canada: Examples from Outcrops and Oilfields

By

M. Myers (Alaska Division of Oil and Gas)

As oil exploration on Alaska’s North Slope enters maturity, more emphasis is being placed on the search for subtle stratigraphically trapped oil accumulations. Oil discoveries at Badami, Stump Island, Flaxman Island and Tarn reveal that a significant amount of oil is present within deep-water sandstone reservoirs deposited within foreland basin settings during the middle Cretaceous to Paleocene. Well, seismic, and production data from these discoveries reveal a wide variety of submarine fan geometries, lithofacies, turbidite elements and reservoir properties. Submarine fans which crop out on the basin margin in Alaska and the Mackenzie Delta provide detailed information on bedforms, depositional processes, internal geometries, turbidite elements and lateral and vertical continuity of both slope-apron and basin-floor fan systems.

Outcrops of the Torok Formation along the Chandler River in Alaska illustrate the characteristics of large basin-floor fan complex. These outcrops expose a 300 m thick succession dominated by stacked sequences of amalgamated high-density turbidites and waning-flow high-density turbdites separated by thinner intervals of low-density turbidites. These stacked sequences are interpreted as vertically stacked amalgamated lobe, layered lobe and interlobe deposits.

AAPG Search and Discovery Article #90008©2002 AAPG Pacific Section/SPE Western Region Joint Conference of Geoscientists and Petroleum Engineers, Anchorage, Alaska, May 18–23, 2002.