W. Dallam Masterson1,
Leon I. P. Dzou3,
Albert G. Holba2
(1) ARCO Alaska, Inc, Anchorage, AK
(2) ARCO Exploration and Production Technology, Inc, Plano, TX
(3) BP AMOCO Corp, Houston, TX
Abstract: Petroleum generation, migration, and filling history models for the Prudhoe Bay, Kuparuk, and West Sak fields, North Slope, Alaska
The petroleum generation and migration history of the central Alaskan North Slope coast between the Canning and Colville Rivers was reconstructed with map-based burial history models. Regional structure maps of 6 horizons were combined with source rock oil generation kinetics for Triassic marine carbonate (Shublik Formation), Cretaceous marine shale (HRZ Formation), and Jurassic marine shale (Kingak Formation) to model the filling history of the Prudhoe Bay, Kuparuk, and West Sak fields. Maximum burial of source rocks in the central Alaskan North Slope occurred between Middle Eocene and Late Oligocene time (~ 45 - 23 myBP). Shublik source rock is buried less than 500 feet deeper than the Kingak Shale source interval, but generated hydrocarbons much earlier because Shublik kerogen is sulfur-rich and transforms to hydrocarbons at lower temperatures than the marine shales of the Kingak Formation.
Prudhoe Bay field oil in the Triassic Ivishak sandstone reservoir was generated primarily from Shublik and HRZ source rocks to the south and east. Oils in Jurassic Sag River sandstone reservoirs on the northwestern side of the Prudhoe Bay field are mixtures co-sourced from Shublik carbonate and Kingak Shale. Kuparuk field oils migrated vertically through faults that connect their predominant Shublik source with the Lower Cretaceous Kuparuk River Formation. West Sak field oil is a mixture of moderately biodegraded oil that spilled from the Prudhoe Bay field into Upper Cretaceous West Sak sandstone reservoirs, and a lightly biodegraded secondary gas/condensate charge that leaked up faults from the underlying Kuparuk field.
AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana