Analysis of the Beaufort-Mackenzie Basin, Canada: Burial, Thermal, and Hydrocarbon Histories

TANG, JIE, and IAN LERCHE, University of South Carolina, Columbia, SC

Using a 1-D thermal indicator tomography model, the burial, thermal, and hydrocarbon histories of the Jurassic-Tertiary sedimentary sequences are investigated in three structural zones of the Beaufort-Mackenzie basin. The specific objectives of this study are (1) to reconstruct the burial paths of Jurassic-Tertiary strata, the erosional amounts, and basement subsidence, from which we estimate the basin evolution, (2) to determine the thermal maturation levels of Jurassic-Tertiary source rocks, and (3) to investigate the relationship between the maturity levels of source rocks and present-day oil and gas occurrences.

The reconstructed geohistories of seven wells indicate two stages of tectonics in the study area. The first stage is a rifting event from Jurassic to early Miocene. The second stage is one of post-rifting uplift and erosion as well as thermal subsidence.

Associated with the tectonic activities, inversion of vitrinite reflectance data in the seven wells yielded heating episodes from around 150 to 20 m.y. ago in the Tuktoyaktuk Peninsula province and from around 60 to 10 m.y. ago in the central and western parts of the basin.

Comparison of the thermal maturation patterns with oil and gas occurrences in five of the wells indicates that the oil of Cretaceous reservoirs may come vertically from the Husky Formation, while the oil and gas of the Tertiary reservoirs and the gas of the Cretaceous may undergo extensive horizontal migration.

The combination of thermal history, hydrocarbon generation history, and TOC of source rocks, as well as the relationship between source and reservoir rocks, indicates that exploration for oil and gas should likely concentrate on both the central part and on the Tuktoyaktuk Peninsula of the study area.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)